From mboxrd@z Thu Jan 1 00:00:00 1970 From: jg1.han@samsung.com (Jingoo Han) Date: Wed, 05 Dec 2012 09:29:59 +0900 Subject: [PATCH v3] backlight: corgi_lcd: Use gpio_set_value_cansleep() to avoid WARN_ON In-Reply-To: References: <000b01cdd1e0$293f0d90$7bbd28b0$%han@samsung.com> Message-ID: <000001cdd27f$a88f1000$f9ad3000$%han@samsung.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wednesday, December 05, 2012 8:28 AM, Marko Katic wrote > On Tue, Dec 4, 2012 at 6:28 AM, Jingoo Han wrote: > > From: Marko Katic > > > > 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: > > [] (dump_backtrace+0x0/0x110) from [] (dump_stack+0x18/0x1c) > > r6:c0158fc8 r5:00000009 r4:00000000 r3:c03d4f70 > > [] (dump_stack+0x0/0x1c) from [] (warn_slowpath_common+0x54/0x6c) > > [] (warn_slowpath_common+0x0/0x6c) from [] (warn_slowpath_null+0x24/0x2c) > > r8:c38d5c00 r7:c03f82c0 r6:00000000 r5:000000d0 r4:c384e4fc > > r3:00000009 > > [] (warn_slowpath_null+0x0/0x2c) from [] (__gpio_set_value+0x38/0xa4) > > [] (__gpio_set_value+0x0/0xa4) from [] (corgi_bl_set_intensity+0x44/0x74) > > r7:c3933418 r6:c3933400 r5:c392cdf0 r4:0000002f > > [] (corgi_bl_set_intensity+0x0/0x74) from [] (corgi_bl_update_status+0x5c/0x64) > > r5:c03d31f0 r4:c3933400 > > [] (corgi_bl_update_status+0x0/0x64) from [] (corgi_lcd_probe+0x1a8/0x258) > > r4:c392cdf0 r3:c0169bc0 > > [] (corgi_lcd_probe+0x0/0x258) from [] (spi_drv_probe+0x20/0x24) > > r8:00000052 r7:c0192d9c r6:c03da6e8 r5:c38d5c34 r4:c38d5c00 > > [] (spi_drv_probe+0x0/0x24) from [] (driver_probe_device+0xb0/0x208) > > [] (driver_probe_device+0x0/0x208) from [] (__driver_attach+0x70/0x94) > > r6:c03da6e8 r5:c38d5c34 r4:c38d5c00 r3:00000000 > > [] (__driver_attach+0x0/0x94) from [] (bus_for_each_dev+0x54/0x90) > > r6:c03da6e8 r5:c3827e80 r4:00000000 r3:00000000 > > [] (bus_for_each_dev+0x0/0x90) from [] (driver_attach+0x20/0x28) > > r7:00000000 r6:c03e29ec r5:c3932980 r4:c03da6e8 > > [] (driver_attach+0x0/0x28) from [] (bus_add_driver+0xd4/0x22c) > > [] (bus_add_driver+0x0/0x22c) from [] (driver_register+0xa4/0x134) > > r8:00000052 r7:c03ea900 r6:c03c32ac r5:c03bdfc8 r4:c03da6e8 > > [] (driver_register+0x0/0x134) from [] (spi_register_driver+0x4c/0x60) > > [] (spi_register_driver+0x0/0x60) from [] (corgi_lcd_driver_init+0x14/0x1c) > > [] (corgi_lcd_driver_init+0x0/0x1c) from [] (do_one_initcall+0x9c/0x174) > > [] (do_one_initcall+0x0/0x174) from [] (kernel_init+0xf4/0x2a8) > > [] (kernel_init+0x0/0x2a8) from [] (ret_from_fork+0x14/0x24) > > ---[ end trace a863a63f242ee38c ]--- > > > > Akita machines have backlight controls hooked to a gpio expander chip, > > max7310. 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 such as > > max7310 which does not set the can_sleep flag. > > I think you forgot to delete "such as max7310". Akita has > the max7310, all the other models have a different expander. Yes, you're right. I added an unnecessary word, 'such as max7310'. It should be deleted. I will send v4 patch, soon. Best regards, Jingoo Han > > > > > [jg1.han at samsung.com: used gpio_cansleep()] > > Signed-off-by: Marko Katic > > Signed-off-by: Jingoo Han > > --- > > drivers/video/backlight/corgi_lcd.c | 17 +++++++++++++---- > > 1 files changed, 13 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/video/backlight/corgi_lcd.c b/drivers/video/backlight/corgi_lcd.c > > index e2e1b62..e5168f4 100644 > > --- a/drivers/video/backlight/corgi_lcd.c > > +++ b/drivers/video/backlight/corgi_lcd.c > > @@ -408,11 +408,20 @@ static int corgi_bl_set_intensity(struct corgi_lcd *lcd, int intensity) > > /* Bit 5 via GPIO_BACKLIGHT_CONT */ > > cont = !!(intensity & 0x20) ^ lcd->gpio_backlight_cont_inverted; > > > > - if (gpio_is_valid(lcd->gpio_backlight_cont)) > > - gpio_set_value(lcd->gpio_backlight_cont, cont); > > + if (gpio_is_valid(lcd->gpio_backlight_cont)) { > > + if (gpio_cansleep(lcd->gpio_backlight_cont)) > > + gpio_set_value_cansleep(lcd->gpio_backlight_cont, cont); > > + else > > + gpio_set_value(lcd->gpio_backlight_cont, cont); > > + } > > > > - if (gpio_is_valid(lcd->gpio_backlight_on)) > > - gpio_set_value(lcd->gpio_backlight_on, intensity); > > + if (gpio_is_valid(lcd->gpio_backlight_on)) { > > + if (gpio_cansleep(lcd->gpio_backlight_on)) > > + gpio_set_value_cansleep(lcd->gpio_backlight_on, > > + intensity); > > + else > > + gpio_set_value(lcd->gpio_backlight_on, intensity); > > + } > > > > if (lcd->kick_battery) > > lcd->kick_battery(); > > -- > > 1.7.2.5 > > > >