From 1581b088fc91cbb974ad2b98431a8ecabb4852ee Mon Sep 17 00:00:00 2001 From: Marko Katic Date: Mon, 17 Dec 2012 16:01:14 -0800 Subject: [PATCH] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON Changing backlight intensity on an Akita (Sharp Zaurus C-1000) triggers WARN_ON message: WARNING: at drivers/gpio/gpiolib.c:1672 __gpio_set_value+0x38/0xa4() Modules linked in: Backtrace: corgi_bl_set_intensity+0x0/0x74 corgi_bl_update_status+0x0/0x64 corgi_lcd_probe+0x0/0x258 spi_drv_probe+0x0/0x24 driver_probe_device+0x0/0x208 __driver_attach+0x0/0x94 bus_for_each_dev+0x0/0x90 driver_attach+0x0/0x28 bus_add_driver+0x0/0x22c driver_register+0x0/0x134 spi_register_driver+0x0/0x60 corgi_lcd_driver_init+0x0/0x1c do_one_initcall+0x0/0x174 kernel_init+0x0/0x2a8 Akita machines have backlight controls hooked to a gpio expander chip, max7310 using i2c transfers which can sleep. In this case, pca953x_gpio_set_value() can be called to control gpio, and pca953x_setup_gpio() sets can_sleep flag. Therefore, gpio_set_value_cansleep() should be used in order to avoid WARN_ON on akita machines. Akita is the only exception in this case since other users of corgi_lcd access backlight gpio controls through a different gpio expander which does not set the can_sleep flag. Signed-off-by: Marko Katic Signed-off-by: Jingoo Han Cc: Russell King Cc: Grant Likely Cc: Florian Tobias Schandinat Cc: Richard Purdie Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/backlight/corgi_lcd.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/video/backlight/corgi_lcd.c b/drivers/video/backlight/corgi_lcd.c index e2e1b62bebb1..e323fcbe884e 100644 --- a/drivers/video/backlight/corgi_lcd.c +++ b/drivers/video/backlight/corgi_lcd.c @@ -409,10 +409,10 @@ static int corgi_bl_set_intensity(struct corgi_lcd *lcd, int intensity) cont = !!(intensity & 0x20) ^ lcd->gpio_backlight_cont_inverted; if (gpio_is_valid(lcd->gpio_backlight_cont)) - gpio_set_value(lcd->gpio_backlight_cont, cont); + gpio_set_value_cansleep(lcd->gpio_backlight_cont, cont); if (gpio_is_valid(lcd->gpio_backlight_on)) - gpio_set_value(lcd->gpio_backlight_on, intensity); + gpio_set_value_cansleep(lcd->gpio_backlight_on, intensity); if (lcd->kick_battery) lcd->kick_battery(); -- 2.20.1