[U-Boot] [PATCH 09/10] exynos: Enable the LCD backlight for snow

Simon Glass
2014-03-30T00:06:44Z

Hi Ajay,

On 29 March 2014 16:35, Ajay kumar <ajaynumb@gmail.com> wrote:

> Hi Simon,
>
> Find my comments below:
>
> On Wed, Mar 26, 2014 at 11:26 PM, Simon Glass <sjg@chromium.org> wrote:
>
>> The backlight uses FETs on the TPS65090. Enable this so that the display
>> is visible.
>>
>> Signed-off-by: Simon Glass <sjg@chromium.org>
>> ---
>>
>> board/samsung/smdk5250/exynos5-dt.c | 90
>> +++++++++++++++++++++++++++++++++++++
>> 1 file changed, 90 insertions(+)
>>
>> diff --git a/board/samsung/smdk5250/exynos5-dt.c
>> b/board/samsung/smdk5250/exynos5-dt.c
>> index c83b034..a0ae641 100644
>> --- a/board/samsung/smdk5250/exynos5-dt.c
>> +++ b/board/samsung/smdk5250/exynos5-dt.c
>> @@ -20,6 +20,7 @@
>> #include <asm/arch/sromc.h>
>> #include <power/pmic.h>
>> #include <power/max77686_pmic.h>
>> +#include <power/tps65090_pmic.h>
>> #include <tmu.h>
>>
>> DECLARE_GLOBAL_DATA_PTR;
>> @@ -60,6 +61,52 @@ int checkboard(void)
>> #endif
>>
>> #ifdef CONFIG_LCD
>>
> We should make sure this code runs only for snow, and not for SMDK.
> Only Snow contains the bridge chip.
>

I'll add it to the device tree.

> +static int board_dp_bridge_setup(void)
>> +{
>> + struct exynos5_gpio_part1 *gpio1 =
>> + (struct exynos5_gpio_part1
>> *)samsung_get_base_gpio_part1();
>> + const int MAX_TRIES = 10;
>> + int num_tries;
>> +
>> + debug("%s\n", __func__);
>> +
>> + /* Setup the GPIOs */
>> +
>> + /* PD is ACTIVE_LOW, and initially de-asserted */
>> + s5p_gpio_set_pull(&gpio1->y2, 5, GPIO_PULL_NONE);
>> + s5p_gpio_direction_output(&gpio1->y2, 5, 1);
>> +
>> + /* Reset is ACTIVE_LOW */
>> + s5p_gpio_set_pull(&gpio1->x1, 5, GPIO_PULL_NONE);
>> + s5p_gpio_direction_output(&gpio1->x1, 5, 0);
>> +
>> + udelay(10);
>> + s5p_gpio_set_value(&gpio1->x1, 5, 1);
>> +
>> + s5p_gpio_direction_input(&gpio1->x0, 7);
>> +
>> + /*
>> + * We need to wait for 90ms after bringing up the bridge since
>> there
>> + * is a phantom "high" on the HPD chip during its bootup. The
>> phantom
>> + * high comes within 7ms of de-asserting PD and persists for at
>> least
>> + * 15ms. The real high comes roughly 50ms after PD is
>> de-asserted. The
>> + * phantom high makes it hard for us to know when the NXP chip is
>> up.
>> + */
>> + mdelay(90);
>> +
>> + for (num_tries = 0; num_tries < MAX_TRIES; num_tries++) {
>> + /* Check HPD. If it's high, we're all good. */
>> + if (s5p_gpio_get_value(&gpio1->x0, 7))
>> + return 0;
>> +
>> + debug("%s: eDP bridge failed to come up; try %d of %d\n",
>> + __func__, num_tries, MAX_TRIES);
>> + }
>> +
>> + /* Immediately go into bridge reset if the hp line is not high */
>> + return -ENODEV;
>> +}
>> +
>> void exynos_cfg_lcd_gpio(void)
>> {
>> struct exynos5_gpio_part1 *gpio1 =
>> @@ -81,4 +128,47 @@ void exynos_set_dp_phy(unsigned int onoff)
>> {
>> set_dp_phy_ctrl(onoff);
>> }
>> +
>> +void exynos_backlight_on(unsigned int onoff)
>> +{
>> + debug("%s(%u)\n", __func__, onoff);
>> +
>> + if (onoff) {
>> +#ifdef CONFIG_POWER_TPS65090
>> + struct exynos5_gpio_part1 *gpio1 =
>> + (struct exynos5_gpio_part1 *)
>> + samsung_get_base_gpio_part1();
>> + int ret;
>> +
>> + ret = tps65090_fet_enable(1); /* Enable FET1, backlight */
>> + if (ret)
>> + return;
>> +
>> + /* T5 in the LCD timing spec (defined as > 10ms) */
>> + mdelay(10);
>>
> Can you check for backlight without using the above delay?
>

I think we need to keep these delays due to the LCD timing spec. It often
does work, but we need it to always work.

> +
>> + /* board_dp_backlight_pwm */
>> + s5p_gpio_direction_output(&gpio1->b2, 0, 1);
>>
> +
>> + /* T6 in the LCD timing spec (defined as > 10ms) */
>> + mdelay(10);
>>
> Can you check for backlight without using the above delay?
>
>> +
>> + /* board_dp_backlight_en */
>> + s5p_gpio_direction_output(&gpio1->x3, 0, 1);
>> +#endif
>> + }
>> +}
>> +
>> +void exynos_lcd_power_on(void)
>> +{
>> + debug("%s\n", __func__);
>> +
>> +#ifdef CONFIG_POWER_TPS65090
>> + /* board_dp_lcd_vdd */
>> + tps65090_fet_enable(6); /* Enable FET6, lcd panel */
>> +#endif
>> +
>> + board_dp_bridge_setup();
>>
> returning int. check for return value and print in case of failure.
>

Will do.

Regads,
Simon