On Tue, Jan 25, 2011 at 10:18, Hiremath, Vaibhav <hvaibhav@xxxxxx> wrote:
>
>> -----Original Message-----
>> From: Semwal, Sumit
>> Sent: Tuesday, January 25, 2011 8:05 AM
>> To: Hiremath, Vaibhav
>> Cc: linux-omap@xxxxxxxxxxxxxxx; tony@xxxxxxxxxxx; tomi.valkeinen@xxxxxxxxx
>> Subject: Re: [PATCH-V2] OMAP3EVM: Made backlight GPIO default state to off
>>
>> Vaibhav,
>>
>> On Tue, Jan 25, 2011 at 12:52 AM, Vaibhav Hiremath <hvaibhav@xxxxxx>
>> wrote:
>> > If you choose default output to DVI, the LCD backlight used to
>> > stay on, since panel->disable function never gets called.
>> >
>> > So, during init put backlight GPIO to off state and the driver
>> > code will decide which output to enable.
>> >
>> > Signed-off-by: Vaibhav Hiremath <hvaibhav@xxxxxx>
>> > ---
>> > Changes from V1 -
>> > - Added check for return value
>> >
>> > arch/arm/mach-omap2/board-omap3evm.c | 15 +++++++++++++--
>> > 1 files changed, 13 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/arch/arm/mach-omap2/board-omap3evm.c b/arch/arm/mach-
>> omap2/board-omap3evm.c
>> > index 7119380..a888a7d 100644
>> > --- a/arch/arm/mach-omap2/board-omap3evm.c
>> > +++ b/arch/arm/mach-omap2/board-omap3evm.c
>> > @@ -411,6 +411,8 @@ static struct platform_device leds_gpio = {
>> > static int omap3evm_twl_gpio_setup(struct device *dev,
>> > unsigned gpio, unsigned ngpio)
>> > {
>> > + int r;
>> > +
>> > /* gpio + 0 is "mmc0_cd" (input/IRQ) */
>> > omap_mux_init_gpio(63, OMAP_PIN_INPUT);
>> > mmc[0].gpio_cd = gpio + 0;
>> > @@ -426,8 +428,17 @@ static int omap3evm_twl_gpio_setup(struct device
>> *dev,
>> > */
>> >
>> > /* TWL4030_GPIO_MAX + 0 == ledA, LCD Backlight control */
>> > - gpio_request(gpio + TWL4030_GPIO_MAX, "EN_LCD_BKL");
>> > - gpio_direction_output(gpio + TWL4030_GPIO_MAX, 0);
>> > + r = gpio_request(gpio + TWL4030_GPIO_MAX, "EN_LCD_BKL");
>> > + if (r)
>> > + printk(KERN_ERR "failed to get lcd_bkl gpio\n");
>> So even if the gpio_request fails, this code prints an error and
>> continues?
> [Hiremath, Vaibhav] yes, that's correct and intended.
As pointed out by Sumit, you should not continue modifying the
direction of a gpio whose request failed (may be some other module
is using this gpio)? Please mention why this is intentionally done so.
>
> Thanks,
> Vaibhav
>> > +
>> > + if (get_omap3_evm_rev() >= OMAP3EVM_BOARD_GEN_2)
>> > + r = gpio_direction_output(gpio + TWL4030_GPIO_MAX, 1);
>> > + else
>> > + r = gpio_direction_output(gpio + TWL4030_GPIO_MAX, 0);
>> > +
>> > + if (r)
>> > + printk(KERN_ERR "failed to set direction of lcd_bkl
>> gpio\n");
>> >
>> > /* gpio + 7 == DVI Enable */
>> > gpio_request(gpio + 7, "EN_DVI");
>> > --
>> > 1.6.2.4
>> >
>> > --
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