[PATCH 1/7] gpio: allow for arch-specific ARCH_NR_GPIOS > 256

[PATCH 1/7] gpio: allow for arch-specific ARCH_NR_GPIOS > 256

[Ahmad Fatoum]

Some architectures have non-contiguous GPIO ranges where some GPIOs can
have identifiers exceeding the hardcoded ARCH_NR_GPIOs of 256.

One such example is the STM32MP, whose gpioz controller has identifiers
that go up to ('Z' - 'A' + 1) * 0x10 - 1 = 415.
Instead of increasing the array size for all architectures or doing
some sort of packing, allow architecture to define their own overriding
CONFIG_ARCH_NR_GPIO like the kernel does.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 include/gpio.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/gpio.h b/include/gpio.h
index e822fd53475d..1926edeca757 100644
--- a/include/gpio.h
+++ b/include/gpio.h
@@ -45,7 +45,11 @@ static inline int gpio_direction_active(unsigned gpio, int value)
 }
 #endif
 
+#if defined(CONFIG_ARCH_NR_GPIO) && CONFIG_ARCH_NR_GPIO > 0
+#define ARCH_NR_GPIOS CONFIG_ARCH_NR_GPIO
+#else
 #define ARCH_NR_GPIOS 256
+#endif
 
 static inline int gpio_is_valid(int gpio)
 {
-- 
2.20.1


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[PATCH 2/7] ARM: stm32mp: set CONFIG_ARCH_NR_GPIO = (26 * 16)

[Ahmad Fatoum]

The STM32MP1 GPIO bindings uses the range [400; 415] for the gpioz
controller, which exceeds the barebox-wide ARCH_NR_GPIOS of 256.
Therefore have the stm32mp define a subarch-specific max of 416.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/arm/mach-stm32mp/Kconfig | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/mach-stm32mp/Kconfig b/arch/arm/mach-stm32mp/Kconfig
index be16294f5ad7..3bb8eb0096cb 100644
--- a/arch/arm/mach-stm32mp/Kconfig
+++ b/arch/arm/mach-stm32mp/Kconfig
@@ -1,5 +1,9 @@
 if ARCH_STM32MP
 
+config ARCH_NR_GPIO
+	int
+	default 416
+
 config ARCH_STM32MP1157
 	bool
 
-- 
2.20.1


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[PATCH 3/7] ARM: dts: stm32mp157c: correct gpioz id

[Ahmad Fatoum]

The pinctrl-stm32 driver uses the alias id to infer the index of the
first GPIO supported by a controller. Because gpioz' identifiers
start at ('Z' - 'A') * 0x10, change the id to 25.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/arm/dts/stm32mp157c.dtsi | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/dts/stm32mp157c.dtsi b/arch/arm/dts/stm32mp157c.dtsi
index b97622c8d4cb..8d9c84a04785 100644
--- a/arch/arm/dts/stm32mp157c.dtsi
+++ b/arch/arm/dts/stm32mp157c.dtsi
@@ -17,6 +17,6 @@
 		gpio8 = &gpioi;
 		gpio9 = &gpioj;
 		gpio10 = &gpiok;
-		gpio11 = &gpioz;
+		gpio25 = &gpioz;
 	};
 };
-- 
2.20.1


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[PATCH 4/7] reset: add reset controller driver for STM32 RCC

[Ahmad Fatoum]

On the STM32MP, reset of the I2C, SPI and USB IPs occurs over the RCC.
This driver adds support for the controller, so it may be reused by
other drivers.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/reset/Kconfig       |   5 ++
 drivers/reset/Makefile      |   1 +
 drivers/reset/reset-stm32.c | 109 ++++++++++++++++++++++++++++++++++++
 3 files changed, 115 insertions(+)
 create mode 100644 drivers/reset/reset-stm32.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index caf1dc9acb44..048f2081f82a 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -21,4 +21,9 @@ config RESET_IMX7
 	help
 	  This enables the reset controller driver for i.MX7 SoCs.
 
+config RESET_STM32
+	bool "STM32 Reset Driver"
+	help
+	  This enables the reset controller driver for STM32MP and STM32 MCUs.
+
 endif
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 0b55caa20445..8460c4b154f5 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -1,3 +1,4 @@
 obj-$(CONFIG_RESET_CONTROLLER) += core.o
 obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_RESET_IMX7) += reset-imx7.o
+obj-$(CONFIG_RESET_STM32) += reset-stm32.o
diff --git a/drivers/reset/reset-stm32.c b/drivers/reset/reset-stm32.c
new file mode 100644
index 000000000000..ff66fe310e1a
--- /dev/null
+++ b/drivers/reset/reset-stm32.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
+ * Copyright (C) 2019, Ahmad Fatoum, Pengutronix
+ * Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
+ */
+
+#include <common.h>
+#include <init.h>
+#include <linux/err.h>
+#include <linux/reset-controller.h>
+#include <asm/io.h>
+
+#define RCC_CL 0x4
+
+struct stm32_reset {
+	void __iomem *base;
+	struct reset_controller_dev rcdev;
+	void (*reset)(void __iomem *reg, unsigned offset, bool assert);
+};
+
+static struct stm32_reset *to_stm32_reset(struct reset_controller_dev *rcdev)
+{
+	return container_of(rcdev, struct stm32_reset, rcdev);
+}
+
+static void stm32mp_reset(void __iomem *reg, unsigned offset, bool assert)
+{
+	if (assert)
+		offset += RCC_CL;
+
+	writel(BIT(offset), reg);
+}
+
+static void stm32mcu_reset(void __iomem *reg, unsigned offset, bool assert)
+{
+	if (assert)
+		setbits_le32(reg, BIT(offset));
+	else
+		clrbits_le32(reg, BIT(offset));
+}
+
+static void stm32_reset(struct stm32_reset *priv, unsigned long id, bool assert)
+{
+	int bank = (id / BITS_PER_LONG) * 4;
+	int offset = id % BITS_PER_LONG;
+
+	priv->reset(priv->base + bank, offset, assert);
+}
+
+static int stm32_reset_assert(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	stm32_reset(to_stm32_reset(rcdev), id, true);
+	return 0;
+}
+
+static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	stm32_reset(to_stm32_reset(rcdev), id, false);
+	return 0;
+}
+
+static const struct reset_control_ops stm32_reset_ops = {
+	.assert		= stm32_reset_assert,
+	.deassert	= stm32_reset_deassert,
+};
+
+static int stm32_reset_probe(struct device_d *dev)
+{
+	struct stm32_reset *priv;
+	struct resource *iores;
+	int ret;
+
+	priv = xzalloc(sizeof(*priv));
+	ret = dev_get_drvdata(dev, (const void **)&priv->reset);
+	if (ret)
+		return ret;
+
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores))
+		return PTR_ERR(iores);
+
+	priv->base = IOMEM(iores->start);
+	priv->rcdev.nr_resets = (iores->end - iores->start) * BITS_PER_BYTE;
+	priv->rcdev.ops = &stm32_reset_ops;
+	priv->rcdev.of_node = dev->device_node;
+
+	return reset_controller_register(&priv->rcdev);
+}
+
+static const struct of_device_id stm32_rcc_reset_dt_ids[] = {
+	{ .compatible = "st,stm32mp1-rcc", .data = stm32mp_reset },
+	{ .compatible = "st,stm32-rcc", .data = stm32mcu_reset },
+	{ /* sentinel */ },
+};
+
+static struct driver_d stm32_rcc_reset_driver = {
+	.name = "stm32_rcc_reset",
+	.probe = stm32_reset_probe,
+	.of_compatible = DRV_OF_COMPAT(stm32_rcc_reset_dt_ids),
+};
+
+static int stm32_rcc_reset_init(void)
+{
+	return platform_driver_register(&stm32_rcc_reset_driver);
+}
+postcore_initcall(stm32_rcc_reset_init);
-- 
2.20.1


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[PATCH] fixup! reset: add reset controller driver for STM32 RCC

[Ahmad Fatoum]

This fixes some unfortunate last-moment refactoring.
With this change, the reset works correctly now.
---
 drivers/reset/reset-stm32.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/reset/reset-stm32.c b/drivers/reset/reset-stm32.c
index ff66fe310e1a..5689dfd4888a 100644
--- a/drivers/reset/reset-stm32.c
+++ b/drivers/reset/reset-stm32.c
@@ -26,8 +26,8 @@ static struct stm32_reset *to_stm32_reset(struct reset_controller_dev *rcdev)
 
 static void stm32mp_reset(void __iomem *reg, unsigned offset, bool assert)
 {
-	if (assert)
-		offset += RCC_CL;
+	if (!assert)
+		reg += RCC_CL;
 
 	writel(BIT(offset), reg);
 }
-- 
2.20.1


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[PATCH 5/7] i2c: add stm32f7 I2C adapter driver

[Ahmad Fatoum]

This patch adds initial support for the STM32F7 I2C controller.
It was tested to work with the STM32MP157C.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/i2c/busses/Kconfig     |   5 +
 drivers/i2c/busses/Makefile    |   1 +
 drivers/i2c/busses/i2c-stm32.c | 856 +++++++++++++++++++++++++++++++++
 3 files changed, 862 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-stm32.c

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 6d874357b79f..0b762201136f 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -55,4 +55,9 @@ config I2C_VERSATILE
 	  Say yes if you want to support the I2C serial bus on ARMs Versatile
 	  range of platforms.
 
+config I2C_STM32
+	bool "STM32 I2C master driver"
+	select RESET_CONTROLLER
+	depends on HAVE_CLK
+
 endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 61d7c86e7692..7e450ead2738 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_I2C_OMAP)		+= i2c-omap.o
 obj-$(CONFIG_I2C_TEGRA)		+= i2c-tegra.o
 obj-$(CONFIG_I2C_VERSATILE)	+= i2c-versatile.o
 obj-$(CONFIG_I2C_DESIGNWARE)	+= i2c-designware.o
+obj-$(CONFIG_I2C_STM32)		+= i2c-stm32.o
diff --git a/drivers/i2c/busses/i2c-stm32.c b/drivers/i2c/busses/i2c-stm32.c
new file mode 100644
index 000000000000..0ca48df02e92
--- /dev/null
+++ b/drivers/i2c/busses/i2c-stm32.c
@@ -0,0 +1,856 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2017 STMicroelectronics
+ * Copyright 2019 Ahmad Fatoum, Pengutronix
+ */
+
+#include <common.h>
+#include <i2c/i2c.h>
+#include <init.h>
+#include <linux/clk.h>
+#include <linux/iopoll.h>
+#include <linux/reset.h>
+
+/* STM32 I2C registers */
+struct __packed stm32_i2c_regs {
+	u32 cr1;	/* I2C control register 1 */
+	u32 cr2;	/* I2C control register 2 */
+	u32 oar1;	/* I2C own address 1 register */
+	u32 oar2;	/* I2C own address 2 register */
+	u32 timingr;	/* I2C timing register */
+	u32 timeoutr;	/* I2C timeout register */
+	u32 isr;	/* I2C interrupt and status register */
+	u32 icr;	/* I2C interrupt clear register */
+	u32 pecr;	/* I2C packet error checking register */
+	u32 rxdr;	/* I2C receive data register */
+	u32 txdr;	/* I2C transmit data register */
+};
+
+#define STM32_I2C_CR1				0x00
+#define STM32_I2C_CR2				0x04
+#define STM32_I2C_TIMINGR			0x10
+#define STM32_I2C_ISR				0x18
+#define STM32_I2C_ICR				0x1C
+#define STM32_I2C_RXDR				0x24
+#define STM32_I2C_TXDR				0x28
+
+/* STM32 I2C control 1 */
+#define STM32_I2C_CR1_ANFOFF			BIT(12)
+#define STM32_I2C_CR1_ERRIE			BIT(7)
+#define STM32_I2C_CR1_TCIE			BIT(6)
+#define STM32_I2C_CR1_STOPIE			BIT(5)
+#define STM32_I2C_CR1_NACKIE			BIT(4)
+#define STM32_I2C_CR1_ADDRIE			BIT(3)
+#define STM32_I2C_CR1_RXIE			BIT(2)
+#define STM32_I2C_CR1_TXIE			BIT(1)
+#define STM32_I2C_CR1_PE			BIT(0)
+
+/* STM32 I2C control 2 */
+#define STM32_I2C_CR2_AUTOEND			BIT(25)
+#define STM32_I2C_CR2_RELOAD			BIT(24)
+#define STM32_I2C_CR2_NBYTES_MASK		GENMASK(23, 16)
+#define STM32_I2C_CR2_NBYTES(n)			((n & 0xff) << 16)
+#define STM32_I2C_CR2_NACK			BIT(15)
+#define STM32_I2C_CR2_STOP			BIT(14)
+#define STM32_I2C_CR2_START			BIT(13)
+#define STM32_I2C_CR2_HEAD10R			BIT(12)
+#define STM32_I2C_CR2_ADD10			BIT(11)
+#define STM32_I2C_CR2_RD_WRN			BIT(10)
+#define STM32_I2C_CR2_SADD10_MASK		GENMASK(9, 0)
+#define STM32_I2C_CR2_SADD10(n)			(n & STM32_I2C_CR2_SADD10_MASK)
+#define STM32_I2C_CR2_SADD7_MASK		GENMASK(7, 1)
+#define STM32_I2C_CR2_SADD7(n)			((n & 0x7f) << 1)
+#define STM32_I2C_CR2_RESET_MASK		(STM32_I2C_CR2_HEAD10R \
+						| STM32_I2C_CR2_NBYTES_MASK \
+						| STM32_I2C_CR2_SADD7_MASK \
+						| STM32_I2C_CR2_RELOAD \
+						| STM32_I2C_CR2_RD_WRN)
+
+/* STM32 I2C Interrupt Status */
+#define STM32_I2C_ISR_BUSY			BIT(15)
+#define STM32_I2C_ISR_ARLO			BIT(9)
+#define STM32_I2C_ISR_BERR			BIT(8)
+#define STM32_I2C_ISR_TCR			BIT(7)
+#define STM32_I2C_ISR_TC			BIT(6)
+#define STM32_I2C_ISR_STOPF			BIT(5)
+#define STM32_I2C_ISR_NACKF			BIT(4)
+#define STM32_I2C_ISR_ADDR			BIT(3)
+#define STM32_I2C_ISR_RXNE			BIT(2)
+#define STM32_I2C_ISR_TXIS			BIT(1)
+#define STM32_I2C_ISR_TXE			BIT(0)
+#define STM32_I2C_ISR_ERRORS			(STM32_I2C_ISR_BERR \
+						| STM32_I2C_ISR_ARLO)
+
+/* STM32 I2C Interrupt Clear */
+#define STM32_I2C_ICR_ARLOCF			BIT(9)
+#define STM32_I2C_ICR_BERRCF			BIT(8)
+#define STM32_I2C_ICR_STOPCF			BIT(5)
+#define STM32_I2C_ICR_NACKCF			BIT(4)
+
+/* STM32 I2C Timing */
+#define STM32_I2C_TIMINGR_PRESC(n)		((n & 0xf) << 28)
+#define STM32_I2C_TIMINGR_SCLDEL(n)		((n & 0xf) << 20)
+#define STM32_I2C_TIMINGR_SDADEL(n)		((n & 0xf) << 16)
+#define STM32_I2C_TIMINGR_SCLH(n)		((n & 0xff) << 8)
+#define STM32_I2C_TIMINGR_SCLL(n)		(n & 0xff)
+
+#define STM32_I2C_MAX_LEN			0xff
+
+#define STM32_I2C_DNF_DEFAULT			0
+#define STM32_I2C_DNF_MAX			16
+
+#define STM32_I2C_ANALOG_FILTER_ENABLE	1
+#define STM32_I2C_ANALOG_FILTER_DELAY_MIN	50	/* ns */
+#define STM32_I2C_ANALOG_FILTER_DELAY_MAX	260	/* ns */
+
+#define STM32_I2C_RISE_TIME_DEFAULT		25	/* ns */
+#define STM32_I2C_FALL_TIME_DEFAULT		10	/* ns */
+
+#define STM32_PRESC_MAX				BIT(4)
+#define STM32_SCLDEL_MAX			BIT(4)
+#define STM32_SDADEL_MAX			BIT(4)
+#define STM32_SCLH_MAX				BIT(8)
+#define STM32_SCLL_MAX				BIT(8)
+
+#define STANDARD_RATE				100000
+#define FAST_RATE				400000
+#define FAST_PLUS_RATE				1000000
+
+enum stm32_i2c_speed {
+	STM32_I2C_SPEED_STANDARD, /* 100 kHz */
+	STM32_I2C_SPEED_FAST, /* 400 kHz */
+	STM32_I2C_SPEED_FAST_PLUS, /* 1 MHz */
+	STM32_I2C_SPEED_END,
+};
+
+/**
+ * struct stm32_i2c_spec - private i2c specification timing
+ * @rate: I2C bus speed (Hz)
+ * @rate_min: 80% of I2C bus speed (Hz)
+ * @rate_max: 120% of I2C bus speed (Hz)
+ * @fall_max: Max fall time of both SDA and SCL signals (ns)
+ * @rise_max: Max rise time of both SDA and SCL signals (ns)
+ * @hddat_min: Min data hold time (ns)
+ * @vddat_max: Max data valid time (ns)
+ * @sudat_min: Min data setup time (ns)
+ * @l_min: Min low period of the SCL clock (ns)
+ * @h_min: Min high period of the SCL clock (ns)
+ */
+
+struct stm32_i2c_spec {
+	u32 rate;
+	u32 rate_min;
+	u32 rate_max;
+	u32 fall_max;
+	u32 rise_max;
+	u32 hddat_min;
+	u32 vddat_max;
+	u32 sudat_min;
+	u32 l_min;
+	u32 h_min;
+};
+
+/**
+ * struct stm32_i2c_setup - private I2C timing setup parameters
+ * @speed: I2C speed mode (standard, Fast Plus)
+ * @speed_freq: I2C speed frequency  (Hz)
+ * @clock_src: I2C clock source frequency (Hz)
+ * @rise_time: Rise time (ns)
+ * @fall_time: Fall time (ns)
+ * @dnf: Digital filter coefficient (0-16)
+ * @analog_filter: Analog filter delay (On/Off)
+ */
+struct stm32_i2c_setup {
+	enum stm32_i2c_speed speed;
+	u32 speed_freq;
+	u32 clock_src;
+	u32 rise_time;
+	u32 fall_time;
+	u8 dnf;
+	bool analog_filter;
+};
+
+/**
+ * struct stm32_i2c_timings - private I2C output parameters
+ * @prec: Prescaler value
+ * @scldel: Data setup time
+ * @sdadel: Data hold time
+ * @sclh: SCL high period (master mode)
+ * @sclh: SCL low period (master mode)
+ */
+struct stm32_i2c_timings {
+	struct list_head node;
+	u8 presc;
+	u8 scldel;
+	u8 sdadel;
+	u8 sclh;
+	u8 scll;
+};
+
+static const struct stm32_i2c_spec i2c_specs[] = {
+	[STM32_I2C_SPEED_STANDARD] = {
+		.rate = STANDARD_RATE,
+		.rate_min = 8000,
+		.rate_max = 120000,
+		.fall_max = 300,
+		.rise_max = 1000,
+		.hddat_min = 0,
+		.vddat_max = 3450,
+		.sudat_min = 250,
+		.l_min = 4700,
+		.h_min = 4000,
+	},
+	[STM32_I2C_SPEED_FAST] = {
+		.rate = FAST_RATE,
+		.rate_min = 320000,
+		.rate_max = 480000,
+		.fall_max = 300,
+		.rise_max = 300,
+		.hddat_min = 0,
+		.vddat_max = 900,
+		.sudat_min = 100,
+		.l_min = 1300,
+		.h_min = 600,
+	},
+	[STM32_I2C_SPEED_FAST_PLUS] = {
+		.rate = FAST_PLUS_RATE,
+		.rate_min = 800000,
+		.rate_max = 1200000,
+		.fall_max = 100,
+		.rise_max = 120,
+		.hddat_min = 0,
+		.vddat_max = 450,
+		.sudat_min = 50,
+		.l_min = 500,
+		.h_min = 260,
+	},
+};
+
+struct stm32_i2c {
+	struct stm32_i2c_regs __iomem *regs;
+	struct clk *clk;
+	struct i2c_adapter adapter;
+	struct stm32_i2c_setup setup;
+};
+#define to_stm32_i2c(a)	container_of(a, struct stm32_i2c, adapter)
+
+static inline int stm32_i2c_check_device_busy(struct stm32_i2c *priv)
+{
+	u32 status = readl(&priv->regs->isr);
+	return status & STM32_I2C_ISR_BUSY;
+}
+
+static void stm32_i2c_message_start(struct stm32_i2c *i2c_priv,
+				    struct i2c_msg *msg, bool stop)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 cr2 = readl(&regs->cr2);
+
+	/* Set transfer direction */
+	cr2 &= ~STM32_I2C_CR2_RD_WRN;
+	if (msg->flags & I2C_M_RD)
+		cr2 |= STM32_I2C_CR2_RD_WRN;
+
+	/* Set slave address */
+	cr2 &= ~(STM32_I2C_CR2_HEAD10R | STM32_I2C_CR2_ADD10);
+	if (msg->flags & I2C_M_TEN) {
+		cr2 &= ~STM32_I2C_CR2_SADD10_MASK;
+		cr2 |= STM32_I2C_CR2_SADD10(msg->addr);
+		cr2 |= STM32_I2C_CR2_ADD10;
+	} else {
+		cr2 &= ~STM32_I2C_CR2_SADD7_MASK;
+		cr2 |= STM32_I2C_CR2_SADD7(msg->addr);
+	}
+
+	/* Set nb bytes to transfer and reload or autoend bits */
+	cr2 &= ~(STM32_I2C_CR2_NBYTES_MASK | STM32_I2C_CR2_RELOAD |
+		 STM32_I2C_CR2_AUTOEND);
+	if (msg->len > STM32_I2C_MAX_LEN) {
+		cr2 |= STM32_I2C_CR2_NBYTES(STM32_I2C_MAX_LEN);
+		cr2 |= STM32_I2C_CR2_RELOAD;
+	} else {
+		cr2 |= STM32_I2C_CR2_NBYTES(msg->len);
+	}
+
+	/* Write configurations register */
+	writel(cr2, &regs->cr2);
+
+	/* START/ReSTART generation */
+	setbits_le32(&regs->cr2, STM32_I2C_CR2_START);
+}
+
+/*
+ * RELOAD mode must be selected if total number of data bytes to be
+ * sent is greater than MAX_LEN
+ */
+
+static void stm32_i2c_handle_reload(struct stm32_i2c *i2c_priv,
+				    struct i2c_msg *msg, bool stop)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 cr2 = readl(&regs->cr2);
+
+	cr2 &= ~STM32_I2C_CR2_NBYTES_MASK;
+
+	if (msg->len > STM32_I2C_MAX_LEN) {
+		cr2 |= STM32_I2C_CR2_NBYTES(STM32_I2C_MAX_LEN);
+	} else {
+		cr2 &= ~STM32_I2C_CR2_RELOAD;
+		cr2 |= STM32_I2C_CR2_NBYTES(msg->len);
+	}
+
+	writel(cr2, &regs->cr2);
+}
+
+static int stm32_i2c_wait_flags(struct stm32_i2c *i2c_priv,
+				u32 flags, u32 *status)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+
+	return readl_poll_timeout(&regs->isr, *status,
+				  *status & flags, USEC_PER_SEC);
+}
+
+static int stm32_i2c_check_end_of_message(struct stm32_i2c *i2c_priv)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 mask = STM32_I2C_ISR_ERRORS | STM32_I2C_ISR_NACKF |
+		   STM32_I2C_ISR_STOPF;
+	u32 status;
+	int ret;
+
+	ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+	if (ret)
+		return ret;
+
+	if (status & STM32_I2C_ISR_BERR) {
+		debug("%s: Bus error\n", __func__);
+
+		/* Clear BERR flag */
+		setbits_le32(&regs->icr, STM32_I2C_ICR_BERRCF);
+
+		return -EIO;
+	}
+
+	if (status & STM32_I2C_ISR_ARLO) {
+		debug("%s: Arbitration lost\n", __func__);
+
+		/* Clear ARLO flag */
+		setbits_le32(&regs->icr, STM32_I2C_ICR_ARLOCF);
+
+		return -EAGAIN;
+	}
+
+	if (status & STM32_I2C_ISR_NACKF) {
+		debug("%s: Receive NACK\n", __func__);
+
+		/* Clear NACK flag */
+		setbits_le32(&regs->icr, STM32_I2C_ICR_NACKCF);
+
+		/* Wait until STOPF flag is set */
+		mask = STM32_I2C_ISR_STOPF;
+		ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+		if (ret)
+			return ret;
+
+		ret = -EIO;
+	}
+
+	if (status & STM32_I2C_ISR_STOPF) {
+		/* Clear STOP flag */
+		setbits_le32(&regs->icr, STM32_I2C_ICR_STOPCF);
+
+		/* Clear control register 2 */
+		setbits_le32(&regs->cr2, STM32_I2C_CR2_RESET_MASK);
+	}
+
+	return ret;
+}
+
+static int stm32_i2c_message_xfer(struct stm32_i2c *i2c_priv,
+				  struct i2c_msg *msg, bool stop)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 status;
+	u32 mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE :
+		   STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF;
+	int bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ?
+			  STM32_I2C_MAX_LEN : msg->len;
+	int ret = 0;
+
+	/* Add errors */
+	mask |= STM32_I2C_ISR_ERRORS;
+
+	stm32_i2c_message_start(i2c_priv, msg, stop);
+
+	while (msg->len) {
+		/*
+		 * Wait until TXIS/NACKF/BERR/ARLO flags or
+		 * RXNE/BERR/ARLO flags are set
+		 */
+		ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+		if (ret)
+			break;
+
+		if (status & (STM32_I2C_ISR_NACKF | STM32_I2C_ISR_ERRORS))
+			break;
+
+		if (status & STM32_I2C_ISR_RXNE) {
+			*msg->buf++ = readb(&regs->rxdr);
+			msg->len--;
+			bytes_to_rw--;
+		}
+
+		if (status & STM32_I2C_ISR_TXIS) {
+			writeb(*msg->buf++, &regs->txdr);
+			msg->len--;
+			bytes_to_rw--;
+		}
+
+		if (!bytes_to_rw && msg->len) {
+			/* Wait until TCR flag is set */
+			mask = STM32_I2C_ISR_TCR;
+			ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+			if (ret)
+				break;
+
+			bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ?
+				      STM32_I2C_MAX_LEN : msg->len;
+			mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE :
+			       STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF;
+
+			stm32_i2c_handle_reload(i2c_priv, msg, stop);
+		} else if (!bytes_to_rw) {
+			/* Wait until TC flag is set */
+			mask = STM32_I2C_ISR_TC;
+			ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+			if (ret)
+				break;
+
+			if (!stop)
+				/* Message sent, new message has to be sent */
+				return 0;
+		}
+	}
+
+	/* End of transfer, send stop condition */
+	mask = STM32_I2C_CR2_STOP;
+	setbits_le32(&regs->cr2, mask);
+
+	return stm32_i2c_check_end_of_message(i2c_priv);
+}
+
+static int stm32_i2c_xfer(struct i2c_adapter *adapter,
+			  struct i2c_msg *msg, int nmsgs)
+{
+	struct stm32_i2c *i2c_priv = to_stm32_i2c(adapter);
+	int ret;
+	int i;
+
+	ret = stm32_i2c_check_device_busy(i2c_priv);
+	if (ret)
+		return -EBUSY;
+
+	for (i = 0; i < nmsgs; i++) {
+		ret = stm32_i2c_message_xfer(i2c_priv, &msg[i], i == nmsgs - 1);
+		if (ret)
+			return ret;
+	}
+
+	return nmsgs;
+}
+
+
+static int stm32_i2c_compute_solutions(struct stm32_i2c_setup *setup,
+				       struct list_head *solutions)
+{
+	struct stm32_i2c_timings *v;
+	u32 p_prev = STM32_PRESC_MAX;
+	u32 i2cclk = DIV_ROUND_CLOSEST(NSEC_PER_SEC, setup->clock_src);
+	u32 af_delay_min, af_delay_max;
+	u16 p, l, a;
+	int sdadel_min, sdadel_max, scldel_min;
+	int ret = 0;
+
+	af_delay_min = setup->analog_filter ?
+		       STM32_I2C_ANALOG_FILTER_DELAY_MIN : 0;
+	af_delay_max = setup->analog_filter ?
+		       STM32_I2C_ANALOG_FILTER_DELAY_MAX : 0;
+
+	sdadel_min = i2c_specs[setup->speed].hddat_min + setup->fall_time -
+		     af_delay_min - (setup->dnf + 3) * i2cclk;
+
+	sdadel_max = i2c_specs[setup->speed].vddat_max - setup->rise_time -
+		     af_delay_max - (setup->dnf + 4) * i2cclk;
+
+	scldel_min = setup->rise_time + i2c_specs[setup->speed].sudat_min;
+
+	if (sdadel_min < 0)
+		sdadel_min = 0;
+	if (sdadel_max < 0)
+		sdadel_max = 0;
+
+	debug("%s: SDADEL(min/max): %i/%i, SCLDEL(Min): %i\n", __func__,
+	      sdadel_min, sdadel_max, scldel_min);
+
+	/* Compute possible values for PRESC, SCLDEL and SDADEL */
+	for (p = 0; p < STM32_PRESC_MAX; p++) {
+		for (l = 0; l < STM32_SCLDEL_MAX; l++) {
+			u32 scldel = (l + 1) * (p + 1) * i2cclk;
+
+			if (scldel < scldel_min)
+				continue;
+
+			for (a = 0; a < STM32_SDADEL_MAX; a++) {
+				u32 sdadel = (a * (p + 1) + 1) * i2cclk;
+
+				if (((sdadel >= sdadel_min) &&
+				     (sdadel <= sdadel_max)) &&
+				    (p != p_prev)) {
+					v = calloc(1, sizeof(*v));
+					if (!v)
+						return -ENOMEM;
+
+					v->presc = p;
+					v->scldel = l;
+					v->sdadel = a;
+					p_prev = p;
+
+					list_add_tail(&v->node, solutions);
+					break;
+				}
+			}
+
+			if (p_prev == p)
+				break;
+		}
+	}
+
+	if (list_empty(solutions)) {
+		pr_err("%s: no Prescaler solution\n", __func__);
+		ret = -EPERM;
+	}
+
+	return ret;
+}
+
+static int stm32_i2c_choose_solution(struct stm32_i2c_setup *setup,
+				     struct list_head *solutions,
+				     struct stm32_i2c_timings *s)
+{
+	struct stm32_i2c_timings *v;
+	u32 i2cbus = DIV_ROUND_CLOSEST(NSEC_PER_SEC, setup->speed_freq);
+	u32 clk_error_prev = i2cbus;
+	u32 i2cclk = DIV_ROUND_CLOSEST(NSEC_PER_SEC, setup->clock_src);
+	u32 clk_min, clk_max;
+	u32 af_delay_min;
+	u32 dnf_delay;
+	u32 tsync;
+	u16 l, h;
+	bool sol_found = false;
+	int ret = 0;
+
+	af_delay_min = setup->analog_filter ?
+		       STM32_I2C_ANALOG_FILTER_DELAY_MIN : 0;
+	dnf_delay = setup->dnf * i2cclk;
+
+	tsync = af_delay_min + dnf_delay + (2 * i2cclk);
+	clk_max = NSEC_PER_SEC / i2c_specs[setup->speed].rate_min;
+	clk_min = NSEC_PER_SEC / i2c_specs[setup->speed].rate_max;
+
+	/*
+	 * Among Prescaler possibilities discovered above figures out SCL Low
+	 * and High Period. Provided:
+	 * - SCL Low Period has to be higher than Low Period of the SCL Clock
+	 *   defined by I2C Specification. I2C Clock has to be lower than
+	 *   (SCL Low Period - Analog/Digital filters) / 4.
+	 * - SCL High Period has to be lower than High Period of the SCL Clock
+	 *   defined by I2C Specification
+	 * - I2C Clock has to be lower than SCL High Period
+	 */
+	list_for_each_entry(v, solutions, node) {
+		u32 prescaler = (v->presc + 1) * i2cclk;
+
+		for (l = 0; l < STM32_SCLL_MAX; l++) {
+			u32 tscl_l = (l + 1) * prescaler + tsync;
+
+			if ((tscl_l < i2c_specs[setup->speed].l_min) ||
+			    (i2cclk >=
+			     ((tscl_l - af_delay_min - dnf_delay) / 4))) {
+				continue;
+			}
+
+			for (h = 0; h < STM32_SCLH_MAX; h++) {
+				u32 tscl_h = (h + 1) * prescaler + tsync;
+				u32 tscl = tscl_l + tscl_h +
+					   setup->rise_time + setup->fall_time;
+
+				if ((tscl >= clk_min) && (tscl <= clk_max) &&
+				    (tscl_h >= i2c_specs[setup->speed].h_min) &&
+				    (i2cclk < tscl_h)) {
+					int clk_error = tscl - i2cbus;
+
+					if (clk_error < 0)
+						clk_error = -clk_error;
+
+					if (clk_error < clk_error_prev) {
+						clk_error_prev = clk_error;
+						v->scll = l;
+						v->sclh = h;
+						sol_found = true;
+						memcpy(s, v, sizeof(*s));
+					}
+				}
+			}
+		}
+	}
+
+	if (!sol_found) {
+		pr_err("%s: no solution at all\n", __func__);
+		ret = -EPERM;
+	}
+
+	return ret;
+}
+
+static int stm32_i2c_compute_timing(struct stm32_i2c *i2c_priv,
+				    struct stm32_i2c_setup *setup,
+				    struct stm32_i2c_timings *output)
+{
+	struct stm32_i2c_timings *v, *_v;
+	struct list_head solutions;
+	int ret;
+
+	if (setup->speed >= STM32_I2C_SPEED_END) {
+		pr_err("%s: speed out of bound {%d/%d}\n", __func__,
+		       setup->speed, STM32_I2C_SPEED_END - 1);
+		return -EINVAL;
+	}
+
+	if ((setup->rise_time > i2c_specs[setup->speed].rise_max) ||
+	    (setup->fall_time > i2c_specs[setup->speed].fall_max)) {
+		pr_err("%s :timings out of bound Rise{%d>%d}/Fall{%d>%d}\n",
+		       __func__,
+		       setup->rise_time, i2c_specs[setup->speed].rise_max,
+		       setup->fall_time, i2c_specs[setup->speed].fall_max);
+		return -EINVAL;
+	}
+
+	if (setup->dnf > STM32_I2C_DNF_MAX) {
+		pr_err("%s: DNF out of bound %d/%d\n", __func__,
+		       setup->dnf, STM32_I2C_DNF_MAX);
+		return -EINVAL;
+	}
+
+	if (setup->speed_freq > i2c_specs[setup->speed].rate) {
+		pr_err("%s: Freq {%d/%d}\n", __func__,
+		       setup->speed_freq, i2c_specs[setup->speed].rate);
+		return -EINVAL;
+	}
+
+	INIT_LIST_HEAD(&solutions);
+	ret = stm32_i2c_compute_solutions(setup, &solutions);
+	if (ret)
+		goto exit;
+
+	ret = stm32_i2c_choose_solution(setup, &solutions, output);
+	if (ret)
+		goto exit;
+
+	debug("%s: Presc: %i, scldel: %i, sdadel: %i, scll: %i, sclh: %i\n",
+	      __func__, output->presc,
+	      output->scldel, output->sdadel,
+	      output->scll, output->sclh);
+
+exit:
+	/* Release list and memory */
+	list_for_each_entry_safe(v, _v, &solutions, node) {
+		list_del(&v->node);
+		free(v);
+	}
+
+	return ret;
+}
+
+static int stm32_i2c_setup_timing(struct stm32_i2c *i2c_priv,
+				  enum stm32_i2c_speed speed,
+				  struct stm32_i2c_timings *timing)
+{
+	struct stm32_i2c_setup *setup = &i2c_priv->setup;
+	int ret = 0;
+
+	setup->speed = speed;
+	setup->speed_freq = i2c_specs[setup->speed].rate;
+	setup->clock_src = clk_get_rate(i2c_priv->clk);
+
+	if (!setup->clock_src) {
+		pr_err("%s: clock rate is 0\n", __func__);
+		return -EINVAL;
+	}
+
+	do {
+		ret = stm32_i2c_compute_timing(i2c_priv, setup, timing);
+		if (ret) {
+			debug("%s: failed to compute I2C timings.\n",
+			      __func__);
+			if (speed > STM32_I2C_SPEED_STANDARD) {
+				speed--;
+				setup->speed = speed;
+				setup->speed_freq = i2c_specs[setup->speed].rate;
+				debug("%s: downgrade I2C Speed Freq to (%i)\n",
+				      __func__, i2c_specs[setup->speed].rate);
+			} else {
+				break;
+			}
+		}
+	} while (ret);
+
+	if (ret) {
+		pr_err("%s: impossible to compute I2C timings.\n", __func__);
+		return ret;
+	}
+
+	debug("%s: I2C Speed(%i), Freq(%i), Clk Source(%i)\n", __func__,
+	      setup->speed, setup->speed_freq, setup->clock_src);
+	debug("%s: I2C Rise(%i) and Fall(%i) Time\n", __func__,
+	      setup->rise_time, setup->fall_time);
+	debug("%s: I2C Analog Filter(%s), DNF(%i)\n", __func__,
+	      setup->analog_filter ? "On" : "Off", setup->dnf);
+
+	return 0;
+}
+
+static int stm32_i2c_hw_config(struct stm32_i2c *i2c_priv,
+			       enum stm32_i2c_speed speed)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	struct stm32_i2c_timings t;
+	int ret;
+	u32 timing = 0;
+
+	ret = stm32_i2c_setup_timing(i2c_priv, speed, &t);
+	if (ret)
+		return ret;
+
+	/* Disable I2C */
+	clrbits_le32(&regs->cr1, STM32_I2C_CR1_PE);
+
+	/* Timing settings */
+	timing |= STM32_I2C_TIMINGR_PRESC(t.presc);
+	timing |= STM32_I2C_TIMINGR_SCLDEL(t.scldel);
+	timing |= STM32_I2C_TIMINGR_SDADEL(t.sdadel);
+	timing |= STM32_I2C_TIMINGR_SCLH(t.sclh);
+	timing |= STM32_I2C_TIMINGR_SCLL(t.scll);
+	writel(timing, &regs->timingr);
+
+	/* Enable I2C */
+	if (i2c_priv->setup.analog_filter)
+		clrbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF);
+	else
+		setbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF);
+	setbits_le32(&regs->cr1, STM32_I2C_CR1_PE);
+
+	return 0;
+}
+
+static int stm32_i2c_set_bus_speed(struct stm32_i2c *i2c_priv, unsigned speed)
+{
+	enum stm32_i2c_speed stm32_speed;
+	switch (speed) {
+	case STANDARD_RATE:
+		stm32_speed = STM32_I2C_SPEED_STANDARD;
+		break;
+	case FAST_RATE:
+		stm32_speed = STM32_I2C_SPEED_FAST;
+		break;
+	case FAST_PLUS_RATE:
+		stm32_speed = STM32_I2C_SPEED_FAST_PLUS;
+		break;
+	default:
+		pr_warn("%s: Speed %d not supported\n", __func__, speed);
+		return -EINVAL;
+	}
+
+	return stm32_i2c_hw_config(i2c_priv, stm32_speed);
+}
+
+static int __init stm32_i2c_probe(struct device_d *dev)
+{
+	struct device_node *np = dev->device_node;
+	struct resource *iores;
+	struct stm32_i2c *stm32_i2c;
+	struct i2c_platform_data *pdata;
+	struct reset_control *rst;
+	const struct stm32_i2c_setup *setup;
+	int bitrate;
+	int ret;
+
+	pdata = dev->platform_data;
+
+	stm32_i2c = xzalloc(sizeof(*stm32_i2c));
+
+	stm32_i2c->clk = clk_get(dev, NULL);
+	if (IS_ERR(stm32_i2c->clk))
+		return PTR_ERR(stm32_i2c->clk);
+	clk_enable(stm32_i2c->clk);
+
+	rst = reset_control_get(dev, NULL);
+	if (IS_ERR(rst))
+		return PTR_ERR(rst);
+
+	reset_control_assert(rst);
+	udelay(2);
+	reset_control_deassert(rst);
+
+	ret = dev_get_drvdata(dev, (const void **)&setup);
+	if (ret)
+		return ret;
+
+	stm32_i2c->setup = *setup;
+
+	of_property_read_u32(np, "i2c-scl-rising-time-ns",
+				   &stm32_i2c->setup.rise_time);
+	of_property_read_u32(np, "i2c-scl-falling-time-ns",
+				   &stm32_i2c->setup.fall_time);
+
+	/* Setup stm32_i2c driver structure */
+	stm32_i2c->adapter.master_xfer = stm32_i2c_xfer;
+	stm32_i2c->adapter.nr = dev->id;
+	stm32_i2c->adapter.dev.parent = dev;
+	stm32_i2c->adapter.dev.device_node = dev->device_node;
+	iores = dev_request_mem_resource(dev, 0);
+	if (IS_ERR(iores))
+		return PTR_ERR(iores);
+
+	stm32_i2c->regs = IOMEM(iores->start);
+
+	bitrate = STANDARD_RATE;
+	of_property_read_u32(dev->device_node, "clock-frequency", &bitrate);
+	if (pdata && pdata->bitrate)
+		bitrate = pdata->bitrate;
+
+	ret = stm32_i2c_set_bus_speed(stm32_i2c, bitrate);
+	if (ret)
+		return ret;
+
+	return i2c_add_numbered_adapter(&stm32_i2c->adapter);
+}
+
+static const struct stm32_i2c_setup stm32f7_setup = {
+	.rise_time = STM32_I2C_RISE_TIME_DEFAULT,
+	.fall_time = STM32_I2C_FALL_TIME_DEFAULT,
+	.dnf = STM32_I2C_DNF_DEFAULT,
+	.analog_filter = STM32_I2C_ANALOG_FILTER_ENABLE,
+};
+
+static __maybe_unused struct of_device_id stm32_i2c_dt_ids[] = {
+	{ .compatible = "st,stm32f7-i2c", .data = &stm32f7_setup, },
+	{ /* sentinel */ }
+};
+
+static struct driver_d stm32_i2c_driver = {
+	.probe	= stm32_i2c_probe,
+	.name	= "stm32f7-i2c",
+	.of_compatible = DRV_OF_COMPAT(stm32_i2c_dt_ids),
+};
+coredevice_platform_driver(stm32_i2c_driver);
-- 
2.20.1


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Re: [PATCH 5/7] i2c: add stm32f7 I2C adapter driver

[Sascha Hauer]

On Wed, Jul 10, 2019 at 10:11:10PM +0200, Ahmad Fatoum wrote:
> +
> +static int stm32_i2c_check_end_of_message(struct stm32_i2c *i2c_priv)
> +{
> +	struct stm32_i2c_regs *regs = i2c_priv->regs;
> +	u32 mask = STM32_I2C_ISR_ERRORS | STM32_I2C_ISR_NACKF |
> +		   STM32_I2C_ISR_STOPF;
> +	u32 status;
> +	int ret;
> +
> +	ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
> +	if (ret)
> +		return ret;
> +
> +	if (status & STM32_I2C_ISR_BERR) {
> +		debug("%s: Bus error\n", __func__);

Please replace with dev_dbg and friends.

> +
> +static int stm32_i2c_message_xfer(struct stm32_i2c *i2c_priv,
> +				  struct i2c_msg *msg, bool stop)
> +{
> +	struct stm32_i2c_regs *regs = i2c_priv->regs;
> +	u32 status;
> +	u32 mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE :
> +		   STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF;
> +	int bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ?
> +			  STM32_I2C_MAX_LEN : msg->len;
> +	int ret = 0;
> +
> +	/* Add errors */
> +	mask |= STM32_I2C_ISR_ERRORS;
> +
> +	stm32_i2c_message_start(i2c_priv, msg, stop);
> +
> +	while (msg->len) {
> +		/*
> +		 * Wait until TXIS/NACKF/BERR/ARLO flags or
> +		 * RXNE/BERR/ARLO flags are set
> +		 */
> +		ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
> +		if (ret)
> +			break;
> +
> +		if (status & (STM32_I2C_ISR_NACKF | STM32_I2C_ISR_ERRORS))
> +			break;
> +
> +		if (status & STM32_I2C_ISR_RXNE) {
> +			*msg->buf++ = readb(&regs->rxdr);
> +			msg->len--;

The driver shouldn't modify the message. Please create local variables
for the length counter and buf pointer.

> +
> +static int __init stm32_i2c_probe(struct device_d *dev)
> +{
> +	struct device_node *np = dev->device_node;
> +	struct resource *iores;
> +	struct stm32_i2c *stm32_i2c;
> +	struct i2c_platform_data *pdata;
> +	struct reset_control *rst;
> +	const struct stm32_i2c_setup *setup;
> +	int bitrate;
> +	int ret;
> +
> +	pdata = dev->platform_data;
> +
> +	stm32_i2c = xzalloc(sizeof(*stm32_i2c));
> +
> +	stm32_i2c->clk = clk_get(dev, NULL);
> +	if (IS_ERR(stm32_i2c->clk))
> +		return PTR_ERR(stm32_i2c->clk);
> +	clk_enable(stm32_i2c->clk);
> +
> +	rst = reset_control_get(dev, NULL);
> +	if (IS_ERR(rst))
> +		return PTR_ERR(rst);
> +
> +	reset_control_assert(rst);
> +	udelay(2);
> +	reset_control_deassert(rst);
> +
> +	ret = dev_get_drvdata(dev, (const void **)&setup);
> +	if (ret)
> +		return ret;
> +
> +	stm32_i2c->setup = *setup;
> +
> +	of_property_read_u32(np, "i2c-scl-rising-time-ns",
> +				   &stm32_i2c->setup.rise_time);
> +	of_property_read_u32(np, "i2c-scl-falling-time-ns",
> +				   &stm32_i2c->setup.fall_time);

The Kernel has a helper function for reading these generic properties.
Can we have a similar function?

Sascha

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[PATCH 6/7] mfd: add support for STPMIC1

[Ahmad Fatoum]

The PMIC is addressable over I2C and, besides power management,
integrates a watchdog, a user power on key handling and 64 bit of
non-volatile memory.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/mfd/Kconfig   |  6 +++
 drivers/mfd/Makefile  |  1 +
 drivers/mfd/stpmic1.c | 99 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+)
 create mode 100644 drivers/mfd/stpmic1.c

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index d04431fbc86d..7d924cfca1eb 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -61,4 +61,10 @@ config RAVE_SP_CORE
 	  Select this to get support for the Supervisory Processor
 	  device found on several devices in RAVE line of hardware.
 
+config MFD_STPMIC1
+	depends on I2C
+	bool "STPMIC1 MFD driver"
+	help
+	  Select this to support communication with the STPMIC1.
+
 endmenu
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 8b23a1023eb3..16a74abd77f3 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -11,3 +11,4 @@ obj-$(CONFIG_MFD_TWLCORE)	+= twl-core.o
 obj-$(CONFIG_MFD_TWL4030)	+= twl4030.o
 obj-$(CONFIG_MFD_TWL6030)	+= twl6030.o
 obj-$(CONFIG_RAVE_SP_CORE)	+= rave-sp.o
+obj-$(CONFIG_MFD_STPMIC1)	+= stpmic1.o
diff --git a/drivers/mfd/stpmic1.c b/drivers/mfd/stpmic1.c
new file mode 100644
index 000000000000..88c7921990fc
--- /dev/null
+++ b/drivers/mfd/stpmic1.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2019 Ahmad Fatoum, Pengutronix
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <errno.h>
+#include <i2c/i2c.h>
+#include <init.h>
+#include <malloc.h>
+#include <of.h>
+#include <regmap.h>
+#include <xfuncs.h>
+
+#define VERSION_SR		0x6
+
+struct stpmic1 {
+	struct device_d		*dev;
+	struct i2c_client	*client;
+};
+
+static int stpmic1_i2c_reg_read(void *ctx, unsigned int reg, unsigned int *val)
+{
+	struct stpmic1 *stpmic1 = ctx;
+	u8 buf[1];
+	int ret;
+
+	ret = i2c_read_reg(stpmic1->client, reg, buf, 1);
+	*val = buf[0];
+
+	return ret == 1 ? 0 : ret;
+}
+
+static int stpmic1_i2c_reg_write(void *ctx, unsigned int reg, unsigned int val)
+{
+	struct stpmic1 *stpmic1 = ctx;
+	u8 buf[] = {
+		val & 0xff,
+	};
+	int ret;
+
+	ret = i2c_write_reg(stpmic1->client, reg, buf, 1);
+
+	return ret == 1 ? 0 : ret;
+}
+
+static struct regmap_bus regmap_stpmic1_i2c_bus = {
+	.reg_write = stpmic1_i2c_reg_write,
+	.reg_read = stpmic1_i2c_reg_read,
+};
+
+static const struct regmap_config stpmic1_regmap_i2c_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+	.max_register = 0xB3,
+};
+
+static int __init stpmic1_probe(struct device_d *dev)
+{
+	struct stpmic1 *stpmic1;
+	struct regmap *regmap;
+	u32 reg;
+	int ret;
+
+	stpmic1 = xzalloc(sizeof(*stpmic1));
+	stpmic1->dev = dev;
+
+	stpmic1->client = to_i2c_client(dev);
+	regmap = regmap_init(dev, &regmap_stpmic1_i2c_bus,
+			     stpmic1, &stpmic1_regmap_i2c_config);
+	dev->priv = regmap;
+
+	ret = regmap_register_cdev(regmap, NULL);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(regmap, VERSION_SR, &reg);
+	if (ret) {
+		dev_err(dev, "Unable to read PMIC version\n");
+		return ret;
+	}
+	dev_info(dev, "PMIC Chip Version: 0x%x\n", reg);
+
+	return of_platform_populate(dev->device_node, NULL, dev);
+}
+
+static __maybe_unused struct of_device_id stpmic1_dt_ids[] = {
+	{ .compatible = "st,stpmic1" },
+	{ /* sentinel */ }
+};
+
+static struct driver_d stpmic1_i2c_driver = {
+	.name		= "stpmic1-i2c",
+	.probe		= stpmic1_probe,
+	.of_compatible	= DRV_OF_COMPAT(stpmic1_dt_ids),
+};
+
+device_i2c_driver(stpmic1_i2c_driver);
-- 
2.20.1


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[PATCH 7/7] watchdog: add support for STPMIC1 integrated watchdog

[Ahmad Fatoum]

The driver adds support for the PMIC's watchdog, reset, poweroff
and reset reason query capabilities.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/watchdog/Kconfig       |   7 ++
 drivers/watchdog/Makefile      |   1 +
 drivers/watchdog/stpmic1_wdt.c | 224 +++++++++++++++++++++++++++++++++
 3 files changed, 232 insertions(+)
 create mode 100644 drivers/watchdog/stpmic1_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 486ef784eb79..fbaab896d460 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -89,4 +89,11 @@ config STM32_IWDG_WATCHDOG
 	help
 	  Enable to support configuration of the STM32's on-SoC IWDG watchdog.
 	  Once started by the user, the IWDG can't be disabled.
+
+config STPMIC1_WATCHDOG
+	bool "STPMIC1 Watchdog"
+	depends on MFD_STPMIC1
+	help
+	  Enable to support configuration of the stpmic1's built-in watchdog.
+
 endif
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index e731c632c9aa..1fbd780885cb 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_WATCHDOG_ORION) += orion_wdt.o
 obj-$(CONFIG_ARCH_BCM283X) += bcm2835_wdt.o
 obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
 obj-$(CONFIG_STM32_IWDG_WATCHDOG) += stm32_iwdg.o
+obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o
diff --git a/drivers/watchdog/stpmic1_wdt.c b/drivers/watchdog/stpmic1_wdt.c
new file mode 100644
index 000000000000..9b37a5ae3b92
--- /dev/null
+++ b/drivers/watchdog/stpmic1_wdt.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
+/*
+ * Copyright (C) 2018, STMicroelectronics - All Rights Reserved
+ */
+
+#include <common.h>
+#include <init.h>
+#include <watchdog.h>
+#include <asm/io.h>
+#include <of_device.h>
+#include <linux/iopoll.h>
+#include <poweroff.h>
+#include <mfd/syscon.h>
+#include <restart.h>
+#include <reset_source.h>
+
+#define RESTART_SR		0x05
+#define MAIN_CR			0x10
+#define WCHDG_CR		0x1B
+#define WCHDG_TIMER_CR		0x1C
+
+/* Restart Status Register (RESTART_SR) */
+#define R_RST			BIT(0)
+#define R_SWOFF			BIT(1)
+#define R_WDG			BIT(2)
+#define R_PKEYLKP		BIT(3)
+#define R_VINOK_FA		BIT(4)
+
+/* Main PMIC Control Register (MAIN_CR) */
+#define SWOFF                   BIT(0)
+#define RREQ_EN                 BIT(1)
+
+/* Watchdog Control Register (WCHDG_CR) */
+#define WDT_START		BIT(0)
+#define WDT_PING		BIT(1)
+#define WDT_START_MASK		BIT(0)
+#define WDT_PING_MASK		BIT(1)
+#define WDT_STOP		0
+
+#define PMIC_WDT_MIN_TIMEOUT 1
+#define PMIC_WDT_MAX_TIMEOUT 256
+#define PMIC_WDT_DEFAULT_TIMEOUT 30
+
+
+struct stpmic1_reset_reason {
+	uint32_t mask;
+	enum reset_src_type type;
+	int instance;
+};
+
+struct stpmic1_wdt {
+	struct watchdog wdd;
+	struct restart_handler restart;
+	struct poweroff_handler poweroff;
+	struct regmap *regmap;
+	unsigned int timeout;
+};
+
+static inline struct stpmic1_wdt *to_stpmic1_wdt(struct watchdog *wdd)
+{
+	return container_of(wdd, struct stpmic1_wdt, wdd);
+}
+
+static int stpmic1_wdt_ping(struct regmap *regmap)
+{
+	return regmap_update_bits(regmap, WCHDG_CR, WDT_PING_MASK, WDT_PING);
+}
+
+static int stpmic1_wdt_start(struct regmap *regmap, unsigned int timeout)
+{
+	int ret = regmap_write(regmap, WCHDG_TIMER_CR, timeout - 1);
+	if (ret)
+		return ret;
+
+	return regmap_update_bits(regmap, WCHDG_CR, WDT_START_MASK, WDT_START);
+}
+
+static int stpmic1_wdt_stop(struct regmap *regmap)
+{
+	return regmap_update_bits(regmap, WCHDG_CR, WDT_START_MASK, WDT_STOP);
+}
+
+static int stpmic1_wdt_set_timeout(struct watchdog *wdd, unsigned int timeout)
+{
+	struct stpmic1_wdt *wdt = to_stpmic1_wdt(wdd);
+	int ret;
+
+	if (!timeout)
+		return stpmic1_wdt_stop(wdt->regmap);
+
+	if (timeout < PMIC_WDT_MIN_TIMEOUT || timeout > wdd->timeout_max)
+		return -EINVAL;
+
+	if (wdt->timeout == timeout)
+		return stpmic1_wdt_ping(wdt->regmap);
+
+	ret = stpmic1_wdt_start(wdt->regmap, timeout);
+	if (ret)
+		return ret;
+
+	wdt->timeout = timeout;
+	return 0;
+}
+
+static void __noreturn stpmic1_restart_handler(struct restart_handler *rst)
+{
+	struct stpmic1_wdt *wdt = container_of(rst, struct stpmic1_wdt, restart);
+
+	regmap_write_bits(wdt->regmap, MAIN_CR,
+			  SWOFF | RREQ_EN, SWOFF | RREQ_EN);
+
+	mdelay(1000);
+	hang();
+}
+
+static void __noreturn stpmic1_poweroff(struct poweroff_handler *handler)
+{
+	struct stpmic1_wdt *wdt = container_of(handler, struct stpmic1_wdt, poweroff);
+
+	shutdown_barebox();
+
+	regmap_write_bits(wdt->regmap, MAIN_CR,
+			  SWOFF | RREQ_EN, SWOFF);
+
+	mdelay(1000);
+	hang();
+}
+
+static const struct stpmic1_reset_reason stpmic1_reset_reasons[] = {
+	{ R_VINOK_FA,	RESET_BROWNOUT, 0 },
+	{ R_PKEYLKP,	RESET_EXT, 0 },
+	{ R_WDG,	RESET_WDG, 2 },
+	{ R_SWOFF,	RESET_RST, 0 },
+	{ R_RST,	RESET_EXT, 0 },
+	{ /* sentinel */ }
+};
+
+static int stpmic1_set_reset_reason(struct regmap *map)
+{
+	enum reset_src_type type = RESET_POR;
+	u32 reg;
+	int ret;
+	int i, instance = 0;
+
+	ret = regmap_read(map, RESTART_SR, &reg);
+	if (ret)
+		return ret;
+
+	for (i = 0; stpmic1_reset_reasons[i].mask; i++) {
+		if (reg & stpmic1_reset_reasons[i].mask) {
+			type     = stpmic1_reset_reasons[i].type;
+			instance = stpmic1_reset_reasons[i].instance;
+			break;
+		}
+	}
+
+	reset_source_set_priority(type, 400);
+	reset_source_set_instance(type, instance);
+
+	pr_info("STPMIC1 reset reason %s (RESTART_SR: 0x%08x)\n",
+		reset_source_name(), reg);
+
+	return 0;
+}
+
+static int stpmic1_wdt_probe(struct device_d *dev)
+{
+	struct stpmic1_wdt *wdt;
+	struct watchdog *wdd;
+	int ret;
+
+	wdt = xzalloc(sizeof(*wdt));
+	wdt->regmap = dev->parent->priv;
+
+	wdd = &wdt->wdd;
+	wdd->hwdev = dev;
+	wdd->set_timeout = stpmic1_wdt_set_timeout;
+	wdd->timeout_max = PMIC_WDT_MAX_TIMEOUT;
+	wdd->timeout_cur = PMIC_WDT_DEFAULT_TIMEOUT;
+
+	/* have the watchdog reset, not power-off the system */
+	regmap_write_bits(wdt->regmap, MAIN_CR, RREQ_EN, RREQ_EN);
+
+	ret = watchdog_register(wdd);
+	if (ret) {
+		dev_err(dev, "Failed to register watchdog device\n");
+		return ret;
+	}
+
+	wdt->restart.name = "stpmic1-reset";
+	wdt->restart.restart = stpmic1_restart_handler;
+	wdt->restart.priority = 300;
+
+	ret = restart_handler_register(&wdt->restart);
+	if (ret)
+		dev_warn(dev, "Cannot register restart handler\n");
+
+	wdt->poweroff.name = "stpmic1-poweroff";
+	wdt->poweroff.poweroff = stpmic1_poweroff;
+	wdt->poweroff.priority = 200;
+
+	ret = poweroff_handler_register(&wdt->poweroff);
+	if (ret)
+		dev_warn(dev, "Cannot register poweroff handler\n");
+
+	stpmic1_set_reset_reason(wdt->regmap);
+	if (ret)
+		dev_warn(dev, "Cannot query reset reason\n");
+
+	dev_info(dev, "probed\n");
+	return 0;
+}
+
+static __maybe_unused const struct of_device_id stpmic1_wdt_of_match[] = {
+	{ .compatible = "st,stpmic1-wdt" },
+	{ /* sentinel */ }
+};
+
+static struct driver_d stpmic1_wdt_driver = {
+	.name  = "stpmic1-wdt",
+	.probe = stpmic1_wdt_probe,
+	.of_compatible = DRV_OF_COMPAT(stpmic1_wdt_of_match),
+};
+device_platform_driver(stpmic1_wdt_driver);
-- 
2.20.1


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Re: [PATCH 1/7] gpio: allow for arch-specific ARCH_NR_GPIOS > 256

[Sascha Hauer]

On Wed, Jul 10, 2019 at 10:11:06PM +0200, Ahmad Fatoum wrote:
> Some architectures have non-contiguous GPIO ranges where some GPIOs can
> have identifiers exceeding the hardcoded ARCH_NR_GPIOs of 256.
> 
> One such example is the STM32MP, whose gpioz controller has identifiers
> that go up to ('Z' - 'A' + 1) * 0x10 - 1 = 415.
> Instead of increasing the array size for all architectures or doing
> some sort of packing, allow architecture to define their own overriding
> CONFIG_ARCH_NR_GPIO like the kernel does.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  include/gpio.h | 4 ++++
>  1 file changed, 4 insertions(+)

Applied 1-4, thanks

Sascha


-- 
Pengutronix e.K.                           |                             |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0    |
Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |

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