Thread (22 messages) 22 messages, 7 authors, 2018-03-27

Re: [RFC 2/4] sh: ecovec24: conditionally register backlight device

From: jacopo mondi <jacopo@jmondi.org>
Date: 2018-03-16 10:09:55
Also in: linux-sh, lkml

Hello Dmitry

FYI I am brushing the ecovec board these days as well
https://www.spinics.net/lists/linux-sh/msg52536.html

And I have a board to test with but without any display panel, I'm
afraid.

On Thu, Mar 15, 2018 at 03:42:00PM -0700, Dmitry Torokhov wrote:
quoted hunk ↗ jump to hunk
Commit fe79f919f47e ("sh: ecovec24: Use gpio-backlight") removed custom
backlight support and switched over to generic gpio-backlight driver. The
comment when we run with DVI states "no backlight", but setting
gpio_backlight_data.fbdev to NULL actually makes gpio-backlight to react to
events from any framebuffer device, not ignore them.

We want to get rid of platform data in favor of generic device properties
in gpio_backlight driver, so we can not have kernel pointers passed around
to tie the framebuffer device to backlight. Assuming that the intent of the
above referenced commit was to indeed not export backlight when using DVI,
let's switch to conditionally registering backlight device so it is not
present at all in DVI case.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 arch/sh/boards/mach-ecovec24/setup.c | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)
diff --git a/arch/sh/boards/mach-ecovec24/setup.c b/arch/sh/boards/mach-ecovec24/setup.c
index 6f929abe0b50f..67633d2d42390 100644
--- a/arch/sh/boards/mach-ecovec24/setup.c
+++ b/arch/sh/boards/mach-ecovec24/setup.c
@@ -368,7 +368,6 @@ static struct platform_device lcdc_device = {
 };

 static struct gpio_backlight_platform_data gpio_backlight_data = {
-	.fbdev = &lcdc_device.dev,
 	.gpio = GPIO_PTR1,
 	.def_value = 1,
 	.name = "backlight",
@@ -987,7 +986,6 @@ static struct platform_device *ecovec_devices[] __initdata = {
 	&usb1_common_device,
 	&usbhs_device,
 	&lcdc_device,
-	&gpio_backlight_device,
 	&ceu0_device,
 	&ceu1_device,
 	&keysc_device,
@@ -1077,6 +1075,8 @@ static int __init arch_setup(void)
 {
 	struct clk *clk;
 	bool cn12_enabled = false;
+	bool use_backlight = false;
+	int error;

 	/* register board specific self-refresh code */
 	sh_mobile_register_self_refresh(SUSP_SH_STANDBY | SUSP_SH_SF |
@@ -1193,9 +1193,6 @@ static int __init arch_setup(void)
 		lcdc_info.ch[0].lcd_modes		= ecovec_dvi_modes;
 		lcdc_info.ch[0].num_modes		= ARRAY_SIZE(ecovec_dvi_modes);

-		/* No backlight */
-		gpio_backlight_data.fbdev = NULL;
-
 		gpio_set_value(GPIO_PTA2, 1);
 		gpio_set_value(GPIO_PTU1, 1);
 	} else {
@@ -1217,6 +1214,8 @@ static int __init arch_setup(void)
 		/* enable TouchScreen */
 		i2c_register_board_info(0, &ts_i2c_clients, 1);
 		irq_set_irq_type(IRQ0, IRQ_TYPE_LEVEL_LOW);
+
+		use_backlight = true;
 	}

 	/* enable CEU0 */
@@ -1431,8 +1430,19 @@ static int __init arch_setup(void)
 	gpio_set_value(GPIO_PTG4, 1);
 #endif

-	return platform_add_devices(ecovec_devices,
-				    ARRAY_SIZE(ecovec_devices));
+	error = platform_add_devices(ecovec_devices,
+				      ARRAY_SIZE(ecovec_devices));
I would invert this.
Register the backlight first, then all other devices.

+	if (error)
+		return error;
+
+	if (use_backlight) {
+		error = platform_device_add(&gpio_backlight_device);
+		if (error)
+			pr_warn("%s: failed to register backlight: %d\n",
+				error);
Could you use dev_warn here? Also the format is wrong, I assume you
are missing a '__func__' as second function argument.

Also, you may want to return error.

Thanks
   j
+	}
+
+	return 0;
 }
 arch_initcall(arch_setup);

--
2.16.2.804.g6dcf76e118-goog

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