On Mon, Feb 8, 2016 at 4:49 PM, Youngmin Nam <ym0914@xxxxxxxxx> wrote: > Previously, samsung_gpio_drection_in/output function were not covered with > one spinlock. > > For example, samsung_gpio_direction_output function consists of two functions. > 1. samsung_gpio_set > 2. samsung_gpio_set_direction > > When 2 CPUs try to control the same gpio pin heavily, > (situation like i2c control with gpio emulation) > This situation can cause below problem. > > CPU 0 | CPU1 > | > samsung_gpio_direction_output | > samsung_gpio_set(pin A as 1) | samsung_gpio_direction_output > | samsung_gpio_set(pin A as 0) > samsung_gpio_set_direction | > | samsung_gpio_set_direction > > The initial value of pin A will be set as 0 while we wanted to set pin A as 1. > > This patch modifies samsung_gpio_direction_in/output function > to be done in one spinlock to fix race condition. > > Additionally, the new samsung_gpio_set_value was added to implement > gpio set callback(samsung_gpio_set) with spinlock using this function. > > Signed-off-by: Youngmin Nam <ym0914@xxxxxxxxx> > Acked-by: Tomasz Figa <tomasz.figa@xxxxxxxxx> This v4 applied. I renamed the commit "fix SMP race condition" which is what it's all about AFAICT. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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