[PATCH] video: Port RAVE SP backlight driver from Linux kernel

[Andrey Smirnov <andrew.smirnov@gmail.com>]

This is a minimal port of a kernel commit 6552d3141064 ("backlight:
Add RAVE SP backlight driver"). All of the changes were kept to a
minimum and limited to impedance matching between Barebox/Linux driver
API.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
---
 drivers/video/Kconfig             |  7 +++
 drivers/video/Makefile            |  2 +
 drivers/video/rave-sp-backlight.c | 72 +++++++++++++++++++++++++++++++
 3 files changed, 81 insertions(+)
 create mode 100644 drivers/video/rave-sp-backlight.c

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 1dcae48f8..79de32cf8 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -124,6 +124,13 @@ config DRIVER_VIDEO_BACKLIGHT_PWM
 	help
 	  Enable this to get support for backlight devices driven by a PWM.
 
+config BACKLIGHT_RAVE_SP
+	tristate "RAVE SP Backlight driver"
+	depends on RAVE_SP_CORE
+	depends on DRIVER_VIDEO_BACKLIGHT
+	help
+	  Support for backlight control on RAVE SP device.
+
 comment "Video encoder chips"
 
 config DRIVER_VIDEO_MTL017
diff --git a/drivers/video/Makefile b/drivers/video/Makefile
index 081e4463d..01fabe880 100644
--- a/drivers/video/Makefile
+++ b/drivers/video/Makefile
@@ -23,3 +23,5 @@ obj-$(CONFIG_DRIVER_VIDEO_SIMPLEFB) += simplefb.o
 obj-$(CONFIG_DRIVER_VIDEO_IMX_IPUV3) += imx-ipu-v3/
 obj-$(CONFIG_DRIVER_VIDEO_EFI_GOP) += efi_gop.o
 obj-$(CONFIG_DRIVER_VIDEO_FB_SSD1307) += ssd1307fb.o
+obj-$(CONFIG_BACKLIGHT_RAVE_SP)	+= rave-sp-backlight.o
+
diff --git a/drivers/video/rave-sp-backlight.c b/drivers/video/rave-sp-backlight.c
new file mode 100644
index 000000000..88ec86e73
--- /dev/null
+++ b/drivers/video/rave-sp-backlight.c
@@ -0,0 +1,72 @@
+/*
+ * LCD Backlight driver for RAVE SP
+ *
+ * Copyright (C) 2018 Zodiac Inflight Innovations
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <init.h>
+#include <video/backlight.h>
+#include <linux/mfd/rave-sp.h>
+
+#define	RAVE_SP_BACKLIGHT_LCD_EN	BIT(7)
+
+static int rave_sp_backlight_set(struct backlight_device *bd, int brightness)
+{
+	struct rave_sp *sp = bd->dev.priv;
+	u8 cmd[] = {
+		[0] = RAVE_SP_CMD_SET_BACKLIGHT,
+		[1] = 0,
+		[2] = brightness ? RAVE_SP_BACKLIGHT_LCD_EN | brightness : 0,
+		[3] = 0,
+		[4] = 0,
+	};
+
+	return rave_sp_exec(sp, cmd, sizeof(cmd), NULL, 0);
+}
+
+static int rave_sp_backlight_probe(struct device_d *dev)
+{
+	struct backlight_device *bd;
+	int ret;
+
+	bd = xzalloc(sizeof(*bd));
+	bd->dev.priv = dev->parent->priv;
+	bd->brightness_default = 50;
+	bd->brightness_max = 100;
+	bd->brightness_set = rave_sp_backlight_set;
+
+	ret = backlight_register(bd);
+	if (ret) {
+		free(bd);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id rave_sp_backlight_of_match[] = {
+	{ .compatible = "zii,rave-sp-backlight" },
+	{}
+};
+
+static struct driver_d rave_sp_backlight_driver = {
+	.name  = "rave-sp-backlight",
+	.probe = rave_sp_backlight_probe,
+	.of_compatible = DRV_OF_COMPAT(rave_sp_backlight_of_match),
+};
+device_platform_driver(rave_sp_backlight_driver);
-- 
2.17.1


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