[RESEND PATCH v3 0/7] backlight: gpio: simplify the driver

[RESEND PATCH v3 0/7] backlight: gpio: simplify the driver

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

While working on my other series related to gpio-backlight[1] I noticed
that we could simplify the driver if we made the only user of platform
data use GPIO lookups and device properties. This series tries to do
that.

The first patch adds all necessary data structures to ecovec24. Patch
2/7 unifies much of the code for both pdata and non-pdata cases. Patches
3-4/7 remove unused platform data fields. Last three patches contain
additional improvements for the GPIO backlight driver while we're already
modifying it.

I don't have access to this HW but hopefully this works. Only compile
tested.

[1] https://lkml.org/lkml/2019/6/25/900

v1 -> v2:
- rebased on top of v5.3-rc1 and adjusted to the recent changes from Andy
- added additional two patches with minor improvements

v2 -> v3:
- in patch 7/7: used initializers to set values for pdata and dev local vars

Bartosz Golaszewski (7):
  sh: ecovec24: add additional properties to the backlight device
  backlight: gpio: simplify the platform data handling
  sh: ecovec24: don't set unused fields in platform data
  backlight: gpio: remove unused fields from platform data
  backlight: gpio: remove dev from struct gpio_backlight
  backlight: gpio: remove def_value from struct gpio_backlight
  backlight: gpio: use a helper variable for &pdev->dev

 arch/sh/boards/mach-ecovec24/setup.c         | 33 ++++++--
 drivers/video/backlight/gpio_backlight.c     | 82 +++++---------------
 include/linux/platform_data/gpio_backlight.h |  3 -
 3 files changed, 44 insertions(+), 74 deletions(-)

-- 
2.21.0

[RESEND PATCH v3 1/7] sh: ecovec24: add additional properties to the backlight device

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Add a GPIO lookup entry and a device property for GPIO backlight to the
board file. Tie them to the platform device which is now registered using
platform_device_register_full() because of the properties. These changes
are inactive now but will be used once the gpio backlight driver is
modified.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 arch/sh/boards/mach-ecovec24/setup.c | 30 +++++++++++++++++++++++-----
 1 file changed, 25 insertions(+), 5 deletions(-)

diff --git a/arch/sh/boards/mach-ecovec24/setup.c b/arch/sh/boards/mach-ecovec24/setup.c
index f402aa741bf3..6926bb3865b9 100644
--- a/arch/sh/boards/mach-ecovec24/setup.c
+++ b/arch/sh/boards/mach-ecovec24/setup.c
@@ -371,6 +371,19 @@ static struct platform_device lcdc_device = {
 	},
 };
 
+static struct gpiod_lookup_table gpio_backlight_lookup = {
+	.dev_id		= "gpio-backlight.0",
+	.table = {
+		GPIO_LOOKUP("sh7724_pfc", GPIO_PTR1, NULL, GPIO_ACTIVE_HIGH),
+		{ }
+	},
+};
+
+static struct property_entry gpio_backlight_props[] = {
+	PROPERTY_ENTRY_BOOL("default-on"),
+	{ }
+};
+
 static struct gpio_backlight_platform_data gpio_backlight_data = {
 	.fbdev = &lcdc_device.dev,
 	.gpio = GPIO_PTR1,
@@ -378,13 +391,15 @@ static struct gpio_backlight_platform_data gpio_backlight_data = {
 	.name = "backlight",
 };
 
-static struct platform_device gpio_backlight_device = {
+static const struct platform_device_info gpio_backlight_device_info = {
 	.name = "gpio-backlight",
-	.dev = {
-		.platform_data = &gpio_backlight_data,
-	},
+	.data = &gpio_backlight_data,
+	.size_data = sizeof(gpio_backlight_data),
+	.properties = gpio_backlight_props,
 };
 
+static struct platform_device *gpio_backlight_device;
+
 /* CEU0 */
 static struct ceu_platform_data ceu0_pdata = {
 	.num_subdevs			= 2,
@@ -1006,7 +1021,6 @@ static struct platform_device *ecovec_devices[] __initdata = {
 	&usb1_common_device,
 	&usbhs_device,
 	&lcdc_device,
-	&gpio_backlight_device,
 	&keysc_device,
 	&cn12_power,
 #if defined(CONFIG_MMC_SDHI) || defined(CONFIG_MMC_SDHI_MODULE)
@@ -1464,6 +1478,12 @@ static int __init arch_setup(void)
 #endif
 #endif
 
+	gpiod_add_lookup_table(&gpio_backlight_lookup);
+	gpio_backlight_device = platform_device_register_full(
+					&gpio_backlight_device_info);
+	if (IS_ERR(gpio_backlight_device))
+		return PTR_ERR(gpio_backlight_device);
+
 	return platform_add_devices(ecovec_devices,
 				    ARRAY_SIZE(ecovec_devices));
 }
-- 
2.21.0

[RESEND PATCH v3 2/7] backlight: gpio: simplify the platform data handling

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Now that the last user of platform data (sh ecovec24) defines a proper
GPIO lookup and sets the 'default-on' device property, we can drop the
platform_data-specific GPIO handling and unify a big chunk of code.

The only field used from the platform data is now the fbdev pointer.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/video/backlight/gpio_backlight.c | 64 +++++-------------------
 1 file changed, 13 insertions(+), 51 deletions(-)

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index e84f3087e29f..01262186fa1e 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -55,30 +55,6 @@ static const struct backlight_ops gpio_backlight_ops = {
 	.check_fb	= gpio_backlight_check_fb,
 };
 
-static int gpio_backlight_probe_dt(struct platform_device *pdev,
-				   struct gpio_backlight *gbl)
-{
-	struct device *dev = &pdev->dev;
-	enum gpiod_flags flags;
-	int ret;
-
-	gbl->def_value = device_property_read_bool(dev, "default-on");
-	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
-
-	gbl->gpiod = devm_gpiod_get(dev, NULL, flags);
-	if (IS_ERR(gbl->gpiod)) {
-		ret = PTR_ERR(gbl->gpiod);
-
-		if (ret != -EPROBE_DEFER) {
-			dev_err(dev,
-				"Error: The gpios parameter is missing or invalid.\n");
-		}
-		return ret;
-	}
-
-	return 0;
-}
-
 static int gpio_backlight_probe(struct platform_device *pdev)
 {
 	struct gpio_backlight_platform_data *pdata =
@@ -86,6 +62,7 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	struct backlight_properties props;
 	struct backlight_device *bl;
 	struct gpio_backlight *gbl;
+	enum gpiod_flags flags;
 	int ret;
 
 	gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
@@ -94,35 +71,20 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 
 	gbl->dev = &pdev->dev;
 
-	if (pdev->dev.fwnode) {
-		ret = gpio_backlight_probe_dt(pdev, gbl);
-		if (ret)
-			return ret;
-	} else if (pdata) {
-		/*
-		 * Legacy platform data GPIO retrieveal. Do not expand
-		 * the use of this code path, currently only used by one
-		 * SH board.
-		 */
-		unsigned long flags = GPIOF_DIR_OUT;
-
+	if (pdata)
 		gbl->fbdev = pdata->fbdev;
-		gbl->def_value = pdata->def_value;
-		flags |= gbl->def_value ? GPIOF_INIT_HIGH : GPIOF_INIT_LOW;
-
-		ret = devm_gpio_request_one(gbl->dev, pdata->gpio, flags,
-					    pdata ? pdata->name : "backlight");
-		if (ret < 0) {
-			dev_err(&pdev->dev, "unable to request GPIO\n");
-			return ret;
+
+	gbl->def_value = device_property_read_bool(&pdev->dev, "default-on");
+	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
+
+	gbl->gpiod = devm_gpiod_get(&pdev->dev, NULL, flags);
+	if (IS_ERR(gbl->gpiod)) {
+		ret = PTR_ERR(gbl->gpiod);
+		if (ret != -EPROBE_DEFER) {
+			dev_err(&pdev->dev,
+				"Error: The gpios parameter is missing or invalid.\n");
 		}
-		gbl->gpiod = gpio_to_desc(pdata->gpio);
-		if (!gbl->gpiod)
-			return -EINVAL;
-	} else {
-		dev_err(&pdev->dev,
-			"failed to find platform data or device tree node.\n");
-		return -ENODEV;
+		return ret;
 	}
 
 	memset(&props, 0, sizeof(props));
-- 
2.21.0

[RESEND PATCH v3 3/7] sh: ecovec24: don't set unused fields in platform data

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Platform data fields other than fbdev are no longer used by the
backlight driver. Remove them.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
---
 arch/sh/boards/mach-ecovec24/setup.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/arch/sh/boards/mach-ecovec24/setup.c b/arch/sh/boards/mach-ecovec24/setup.c
index 6926bb3865b9..64a5a1662b6d 100644
--- a/arch/sh/boards/mach-ecovec24/setup.c
+++ b/arch/sh/boards/mach-ecovec24/setup.c
@@ -386,9 +386,6 @@ static struct property_entry gpio_backlight_props[] = {
 
 static struct gpio_backlight_platform_data gpio_backlight_data = {
 	.fbdev = &lcdc_device.dev,
-	.gpio = GPIO_PTR1,
-	.def_value = 1,
-	.name = "backlight",
 };
 
 static const struct platform_device_info gpio_backlight_device_info = {
-- 
2.21.0

[RESEND PATCH v3 4/7] backlight: gpio: remove unused fields from platform data

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Remove the platform data fields that nobody uses.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
---
 include/linux/platform_data/gpio_backlight.h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/include/linux/platform_data/gpio_backlight.h b/include/linux/platform_data/gpio_backlight.h
index 34179d600360..1a8b5b1946fe 100644
--- a/include/linux/platform_data/gpio_backlight.h
+++ b/include/linux/platform_data/gpio_backlight.h
@@ -9,9 +9,6 @@ struct device;
 
 struct gpio_backlight_platform_data {
 	struct device *fbdev;
-	int gpio;
-	int def_value;
-	const char *name;
 };
 
 #endif
-- 
2.21.0

[RESEND PATCH v3 5/7] backlight: gpio: remove dev from struct gpio_backlight

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

This field is unused. Remove it.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
---
 drivers/video/backlight/gpio_backlight.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index 01262186fa1e..70882556f047 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -19,9 +19,7 @@
 #include <linux/slab.h>
 
 struct gpio_backlight {
-	struct device *dev;
 	struct device *fbdev;
-
 	struct gpio_desc *gpiod;
 	int def_value;
 };
@@ -69,8 +67,6 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	if (gbl == NULL)
 		return -ENOMEM;
 
-	gbl->dev = &pdev->dev;
-
 	if (pdata)
 		gbl->fbdev = pdata->fbdev;
 
-- 
2.21.0

[RESEND PATCH v3 6/7] backlight: gpio: remove def_value from struct gpio_backlight

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

This field is unused outside of probe(). There's no need to store it.
We can make it into a local variable.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
---
 drivers/video/backlight/gpio_backlight.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index 70882556f047..cd6a75bca9cc 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -21,7 +21,6 @@
 struct gpio_backlight {
 	struct device *fbdev;
 	struct gpio_desc *gpiod;
-	int def_value;
 };
 
 static int gpio_backlight_update_status(struct backlight_device *bl)
@@ -61,7 +60,7 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	struct backlight_device *bl;
 	struct gpio_backlight *gbl;
 	enum gpiod_flags flags;
-	int ret;
+	int ret, def_value;
 
 	gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
 	if (gbl == NULL)
@@ -70,8 +69,8 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	if (pdata)
 		gbl->fbdev = pdata->fbdev;
 
-	gbl->def_value = device_property_read_bool(&pdev->dev, "default-on");
-	flags = gbl->def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
+	def_value = device_property_read_bool(&pdev->dev, "default-on");
+	flags = def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
 
 	gbl->gpiod = devm_gpiod_get(&pdev->dev, NULL, flags);
 	if (IS_ERR(gbl->gpiod)) {
@@ -94,7 +93,7 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 		return PTR_ERR(bl);
 	}
 
-	bl->props.brightness = gbl->def_value;
+	bl->props.brightness = def_value;
 	backlight_update_status(bl);
 
 	platform_set_drvdata(pdev, bl);
-- 
2.21.0

[RESEND PATCH v3 7/7] backlight: gpio: use a helper variable for &pdev->dev

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Instead of dereferencing pdev each time, use a helper variable for
the associated device pointer.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/video/backlight/gpio_backlight.c | 19 +++++++++----------
 1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/drivers/video/backlight/gpio_backlight.c b/drivers/video/backlight/gpio_backlight.c
index cd6a75bca9cc..7dc4f90d926b 100644
--- a/drivers/video/backlight/gpio_backlight.c
+++ b/drivers/video/backlight/gpio_backlight.c
@@ -54,29 +54,29 @@ static const struct backlight_ops gpio_backlight_ops = {
 
 static int gpio_backlight_probe(struct platform_device *pdev)
 {
-	struct gpio_backlight_platform_data *pdata =
-		dev_get_platdata(&pdev->dev);
+	struct device *dev = &pdev->dev;
+	struct gpio_backlight_platform_data *pdata = dev_get_platdata(dev);
 	struct backlight_properties props;
 	struct backlight_device *bl;
 	struct gpio_backlight *gbl;
 	enum gpiod_flags flags;
 	int ret, def_value;
 
-	gbl = devm_kzalloc(&pdev->dev, sizeof(*gbl), GFP_KERNEL);
+	gbl = devm_kzalloc(dev, sizeof(*gbl), GFP_KERNEL);
 	if (gbl == NULL)
 		return -ENOMEM;
 
 	if (pdata)
 		gbl->fbdev = pdata->fbdev;
 
-	def_value = device_property_read_bool(&pdev->dev, "default-on");
+	def_value = device_property_read_bool(dev, "default-on");
 	flags = def_value ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
 
-	gbl->gpiod = devm_gpiod_get(&pdev->dev, NULL, flags);
+	gbl->gpiod = devm_gpiod_get(dev, NULL, flags);
 	if (IS_ERR(gbl->gpiod)) {
 		ret = PTR_ERR(gbl->gpiod);
 		if (ret != -EPROBE_DEFER) {
-			dev_err(&pdev->dev,
+			dev_err(dev,
 				"Error: The gpios parameter is missing or invalid.\n");
 		}
 		return ret;
@@ -85,11 +85,10 @@ static int gpio_backlight_probe(struct platform_device *pdev)
 	memset(&props, 0, sizeof(props));
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = 1;
-	bl = devm_backlight_device_register(&pdev->dev, dev_name(&pdev->dev),
-					&pdev->dev, gbl, &gpio_backlight_ops,
-					&props);
+	bl = devm_backlight_device_register(dev, dev_name(dev), dev, gbl,
+					    &gpio_backlight_ops, &props);
 	if (IS_ERR(bl)) {
-		dev_err(&pdev->dev, "failed to register backlight\n");
+		dev_err(dev, "failed to register backlight\n");
 		return PTR_ERR(bl);
 	}
 
-- 
2.21.0