Re: [PATCH 1/2] backlight: Add RAVE SP backlight driver

From: Daniel Thompson
Date: Thu Mar 08 2018 - 11:58:31 EST


On 07/03/18 02:40, Andrey Smirnov wrote:
This driver provides access to RAVE SP backlight control
functionality.

Cc: Lee Jones <lee.jones@xxxxxxxxxx>
Cc: Daniel Thompson <daniel.thompson@xxxxxxxxxx>
Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: Chris Healy <cphealy@xxxxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: Aleksander Morgado <aleksander@xxxxxxxxxxxxx>
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
drivers/video/backlight/Kconfig | 6 +++
drivers/video/backlight/Makefile | 1 +
drivers/video/backlight/rave-sp-backlight.c | 82 +++++++++++++++++++++++++++++
include/linux/mfd/rave-sp.h | 1 +
4 files changed, 90 insertions(+)
create mode 100644 drivers/video/backlight/rave-sp-backlight.c

diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig
index 4e1d2ad50ba1..5d2d0d7e8100 100644
--- a/drivers/video/backlight/Kconfig
+++ b/drivers/video/backlight/Kconfig
@@ -467,6 +467,12 @@ config BACKLIGHT_ARCXCNN
If you have an ARCxCnnnn family backlight say Y to enable
the backlight driver.
+config BACKLIGHT_RAVE_SP
+ tristate "RAVE SP Backlight driver"
+ depends on RAVE_SP_CORE
+ help
+ Support for backlight control on RAVE SP device.
+
endif # BACKLIGHT_CLASS_DEVICE
endif # BACKLIGHT_LCD_SUPPORT
diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile
index 5e28f01c8391..19da71d518bf 100644
--- a/drivers/video/backlight/Makefile
+++ b/drivers/video/backlight/Makefile
@@ -57,3 +57,4 @@ obj-$(CONFIG_BACKLIGHT_TOSA) += tosa_bl.o
obj-$(CONFIG_BACKLIGHT_TPS65217) += tps65217_bl.o
obj-$(CONFIG_BACKLIGHT_WM831X) += wm831x_bl.o
obj-$(CONFIG_BACKLIGHT_ARCXCNN) += arcxcnn_bl.o
+obj-$(CONFIG_BACKLIGHT_RAVE_SP) += rave-sp-backlight.o
diff --git a/drivers/video/backlight/rave-sp-backlight.c b/drivers/video/backlight/rave-sp-backlight.c
new file mode 100644
index 000000000000..62836ba561db
--- /dev/null
+++ b/drivers/video/backlight/rave-sp-backlight.c
@@ -0,0 +1,82 @@
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * LCD Backlight driver for RAVE SP
+ *
+ * Copyright (C) 2018 Zodiac Inflight Innovations
+ *
+ */
+
+#include <linux/backlight.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mfd/rave-sp.h>
+#include <linux/platform_device.h>
+
+#define RAVE_SP_BACKLIGHT_LCD_EN BIT(7)
+
+static int rave_sp_backlight_update_status(struct backlight_device *bd)
+{
+ const struct backlight_properties *p = &bd->props;
+ const u8 intensity =
+ (p->power == FB_BLANK_UNBLANK) ? p->brightness : 0;
+ struct rave_sp *sp = dev_get_drvdata(&bd->dev);
+ u8 cmd[] = {
+ [0] = RAVE_SP_CMD_SET_BACKLIGHT,
+ [1] = 0,
+ [2] = intensity ? RAVE_SP_BACKLIGHT_LCD_EN | intensity : 0,
+ [3] = 0,
+ [4] = 0,
+ };
+
+ return rave_sp_exec(sp, cmd, sizeof(cmd), NULL, 0);
+}
+
+static const struct backlight_ops rave_sp_backlight_ops = {
+ .options = BL_CORE_SUSPENDRESUME,
+ .update_status = rave_sp_backlight_update_status,
+};
+
+static struct backlight_properties rave_sp_backlight_props = {
+ .type = BACKLIGHT_FIRMWARE,

I would have thought BACKLIGHT_PLATFORM would be more suitable here. BACKLIGHT_FIRMWARE is used for things like the ACPI backlight driver.

Why did you select this one?


Daniel.


+ .max_brightness = 100,
+ .brightness = 50,
+};
+
+static int rave_sp_backlight_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct backlight_device *bd;
+
+ bd = devm_backlight_device_register(dev, pdev->name, dev->parent,
+ dev_get_drvdata(dev->parent),
+ &rave_sp_backlight_ops,
+ &rave_sp_backlight_props);
+ if (IS_ERR(bd))
+ return PTR_ERR(bd);
+
+ backlight_update_status(bd);
+
+ return 0;
+}
+
+static const struct of_device_id rave_sp_backlight_of_match[] = {
+ { .compatible = "zii,rave-sp-backlight" },
+ {}
+};
+
+static struct platform_driver rave_sp_backlight_driver = {
+ .probe = rave_sp_backlight_probe,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = rave_sp_backlight_of_match,
+ },
+};
+module_platform_driver(rave_sp_backlight_driver);
+
+MODULE_DEVICE_TABLE(of, rave_sp_backlight_of_match);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@xxxxxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@xxxxxxxxxxxxxxxxxx>");
+MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@xxxxxxxxx>");
+MODULE_DESCRIPTION("RAVE SP Backlight driver");
diff --git a/include/linux/mfd/rave-sp.h b/include/linux/mfd/rave-sp.h
index 796fb9794c9e..fe0ce7bc59cf 100644
--- a/include/linux/mfd/rave-sp.h
+++ b/include/linux/mfd/rave-sp.h
@@ -21,6 +21,7 @@ enum rave_sp_command {
RAVE_SP_CMD_STATUS = 0xA0,
RAVE_SP_CMD_SW_WDT = 0xA1,
RAVE_SP_CMD_PET_WDT = 0xA2,
+ RAVE_SP_CMD_SET_BACKLIGHT = 0xA6,
RAVE_SP_CMD_RESET = 0xA7,
RAVE_SP_CMD_RESET_REASON = 0xA8,