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Date: Mon, 19 May 2014 14:50:52 +0100
From: Lee Jones <lee.jones@linaro.org>
To: Tony Lindgren <tony@atomide.com>
Cc: linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org,
        linux-omap@vger.kernel.org, Bryan Wu <cooloney@gmail.com>,
        Jingoo Han <jg1.han@samsung.com>,
        Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
        Tomi Valkeinen <tomi.valkeinen@ti.com>
Subject: Re: [PATCH] backlight: gpio-backlight: Fix warning when the GPIO is
 on a I2C chip
Message-ID: <20140519135052.GK4978@lee--X1>
References: <20140509012454.GL2198@atomide.com>
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> If the GPIO for the backlight is on an I2C chip, we currently
> get nasty warnings like this during the boot:
> 
> WARNING: CPU: 0 PID: 6 at drivers/gpio/gpiolib.c:2364 gpiod_set_raw_value+0x40/0x4c()
> Modules linked in:
> CPU: 0 PID: 6 Comm: kworker/u2:0 Not tainted 3.15.0-rc4-12393-gcde9f4e #400
> Workqueue: deferwq deferred_probe_work_func
> [<c0014cbc>] (unwind_backtrace) from [<c001191c>] (show_stack+0x10/0x14)
> [<c001191c>] (show_stack) from [<c0566ae0>] (dump_stack+0x80/0x9c)
> [<c0566ae0>] (dump_stack) from [<c003f61c>] (warn_slowpath_common+0x68/0x8c)
> [<c003f61c>] (warn_slowpath_common) from [<c003f65c>] (warn_slowpath_null+0x1c/0x24)
> [<c003f65c>] (warn_slowpath_null) from [<c02f7e10>] (gpiod_set_raw_value+0x40/0x4c)
> [<c02f7e10>] (gpiod_set_raw_value) from [<c0308fbc>] (gpio_backlight_update_status+0x4c/0x74)
> [<c0308fbc>] (gpio_backlight_update_status) from [<c030914c>] (gpio_backlight_probe+0x168/0x254)
> [<c030914c>] (gpio_backlight_probe) from [<c0378fa8>] (platform_drv_probe+0x18/0x48)
> [<c0378fa8>] (platform_drv_probe) from [<c0377c40>] (driver_probe_device+0x10c/0x238)
> [<c0377c40>] (driver_probe_device) from [<c0376330>] (bus_for_each_drv+0x44/0x8c)
> [<c0376330>] (bus_for_each_drv) from [<c0377afc>] (device_attach+0x74/0x8c)
> [<c0377afc>] (device_attach) from [<c03771c4>] (bus_probe_device+0x88/0xb0)
> [<c03771c4>] (bus_probe_device) from [<c03775c8>] (deferred_probe_work_func+0x64/0x94)
> [<c03775c8>] (deferred_probe_work_func) from [<c00572e8>] (process_one_work+0x1b4/0x4bc)
> [<c00572e8>] (process_one_work) from [<c00579d0>] (worker_thread+0x11c/0x398)
> [<c00579d0>] (worker_thread) from [<c005dfd8>] (kthread+0xc8/0xe4)
> [<c005dfd8>] (kthread) from [<c000e768>] (ret_from_fork+0x14/0x2c)
> 
> Fix this by using gpio_set_value_cansleep() as suggested in
> drivers/gpio/gpiolib.c:2364. This is what the other backlight drivers
> are also doing.
> 
> Signed-off-by: Tony Lindgren <tony@atomide.com>

Applied, thanks.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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