[PATCH 1/3] i2c: Add slices for I2C adapters

[PATCH 1/3] i2c: Add slices for I2C adapters

[Sascha Hauer]

Add a slice for I2C adapters so that devices using I2C in the background
can check if a I2C bus is busy.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/i2c/i2c.c | 5 +++++
 include/i2c/i2c.h | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/drivers/i2c/i2c.c b/drivers/i2c/i2c.c
index 300365bd1f..4d4a9a3948 100644
--- a/drivers/i2c/i2c.c
+++ b/drivers/i2c/i2c.c
@@ -23,6 +23,7 @@
 #include <init.h>
 #include <of.h>
 #include <gpio.h>
+#include <slice.h>
 
 #include <i2c/i2c.h>
 
@@ -62,6 +63,8 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 	uint64_t start;
 	int ret, try;
 
+	slice_acquire(&adap->slice);
+
 	/*
 	 * REVISIT the fault reporting model here is weak:
 	 *
@@ -96,6 +99,8 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
 			break;
 	}
 
+	slice_release(&adap->slice);
+
 	return ret;
 }
 EXPORT_SYMBOL(i2c_transfer);
diff --git a/include/i2c/i2c.h b/include/i2c/i2c.h
index b1ab72850c..4fc278f800 100644
--- a/include/i2c/i2c.h
+++ b/include/i2c/i2c.h
@@ -18,6 +18,7 @@
 
 #include <driver.h>
 #include <init.h>
+#include <slice.h>
 #include <linux/types.h>
 
 struct i2c_adapter;
@@ -121,6 +122,7 @@ int i2c_generic_scl_recovery(struct i2c_adapter *adap);
  */
 struct i2c_adapter {
 	struct device		dev;	/* ptr to device */
+	struct slice		slice;
 	int			nr;	/* bus number */
 	int (*master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
 	struct list_head	list;
@@ -318,6 +320,11 @@ static inline int i2c_adapter_id(struct i2c_adapter *adap)
 	return adap->nr;
 }
 
+static inline struct slice *i2c_client_slice(struct i2c_client *client)
+{
+	return &client->adapter->slice;
+}
+
 extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
 extern int i2c_master_send(struct i2c_client *client, const char *buf, int count);
 extern int i2c_master_recv(struct i2c_client *client, char *buf, int count);
-- 
2.39.2

[PATCH 2/3] spi: Add slices for SPI controllers

[Sascha Hauer]

Add a slice for SPI controllers so that devices using SPI in the background
can check if a SPI bus is busy.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/spi/spi.c | 10 +++++++++-
 include/spi/spi.h |  8 ++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 584d4ab777..1b8e5f4512 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -12,6 +12,7 @@
 #include <spi/spi.h>
 #include <xfuncs.h>
 #include <malloc.h>
+#include <slice.h>
 #include <errno.h>
 #include <init.h>
 #include <of.h>
@@ -352,12 +353,19 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 int spi_sync(struct spi_device *spi, struct spi_message *message)
 {
 	int status;
+	int ret;
 
 	status = __spi_validate(spi, message);
 	if (status != 0)
 		return status;
 
-	return spi->controller->transfer(spi, message);
+	slice_acquire(&spi->controller->slice);
+
+	ret = spi->controller->transfer(spi, message);
+
+	slice_release(&spi->controller->slice);
+
+	return ret;
 }
 
 /**
diff --git a/include/spi/spi.h b/include/spi/spi.h
index f806c7a30b..45d6f5931c 100644
--- a/include/spi/spi.h
+++ b/include/spi/spi.h
@@ -3,6 +3,7 @@
 #define __INCLUDE_SPI_H
 
 #include <driver.h>
+#include <slice.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
@@ -161,6 +162,8 @@ struct spi_message;
 struct spi_controller {
 	struct device *dev;
 
+	struct slice		slice;
+
 	/* other than negative (== assign one dynamically), bus_num is fully
 	 * board-specific.  usually that simplifies to being SOC-specific.
 	 * example:  one SOC has three SPI controllers, numbered 0..2,
@@ -601,6 +604,11 @@ static inline int spi_driver_register(struct driver *drv)
 	return register_driver(drv);
 }
 
+static inline struct slice *spi_device_slice(struct spi_device *spi)
+{
+	return &spi->controller->slice;
+}
+
 #ifdef CONFIG_SPI
 #define coredevice_spi_driver(drv)	\
 	register_driver_macro(coredevice,spi,drv)
-- 
2.39.2

[PATCH 3/3] net: ksz9477: Add mdio bus slice dependency to i2c/spi device

[Sascha Hauer]

On mdio busses the attached phys check for link status in a poller.
Add a slice dependency from the mdio bus to the I2C/SPI controller
so that we do not end up doing bus accesses while we are in a
I2C/SPI access on the same bus already.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/net/ksz9477.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ksz9477.c b/drivers/net/ksz9477.c
index 9665e0f723..1abea9d040 100644
--- a/drivers/net/ksz9477.c
+++ b/drivers/net/ksz9477.c
@@ -464,6 +464,13 @@ static int microchip_switch_probe(struct device *dev)
 	if (ret)
 		return ret;
 
+	if (priv->i2c)
+		slice_depends_on(mdiobus_slice(ds->slave_mii_bus),
+				 i2c_client_slice(priv->i2c));
+	else
+		slice_depends_on(mdiobus_slice(ds->slave_mii_bus),
+				 spi_device_slice(priv->spi));
+
 	return regmap_multi_register_cdev(priv->regmap[0], priv->regmap[1],
 					  priv->regmap[2], NULL);
 }
-- 
2.39.2

Re: [PATCH 3/3] net: ksz9477: Add mdio bus slice dependency to i2c/spi device

[Ahmad Fatoum]

On 08.09.23 15:04, Sascha Hauer wrote:
> On mdio busses the attached phys check for link status in a poller.
> Add a slice dependency from the mdio bus to the I2C/SPI controller
> so that we do not end up doing bus accesses while we are in a
> I2C/SPI access on the same bus already.
> 
> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>  drivers/net/ksz9477.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/net/ksz9477.c b/drivers/net/ksz9477.c
> index 9665e0f723..1abea9d040 100644
> --- a/drivers/net/ksz9477.c
> +++ b/drivers/net/ksz9477.c
> @@ -464,6 +464,13 @@ static int microchip_switch_probe(struct device *dev)
>  	if (ret)
>  		return ret;
>  
> +	if (priv->i2c)
> +		slice_depends_on(mdiobus_slice(ds->slave_mii_bus),
> +				 i2c_client_slice(priv->i2c));
> +	else
> +		slice_depends_on(mdiobus_slice(ds->slave_mii_bus),
> +				 spi_device_slice(priv->spi));

Is there no way to do this in the core?

> +
>  	return regmap_multi_register_cdev(priv->regmap[0], priv->regmap[1],
>  					  priv->regmap[2], NULL);
>  }

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