[PATCH v2] drm/bridge/sii8620: simplify hardware reset procedure

[Marek Szyprowski]

Hi Andrzej,

On 2018-06-08 08:04, Andrzej Hajda wrote:
> There is no need to flip reset pin twice. Also delays can be changed to
> values present in vendor's code.
>
> Signed-off-by: Andrzej Hajda <a.hajda at samsung.com>

Tested-by: Marek Szyprowski <m.szyprowski at samsung.com>

> ---
> Hi,
>
> This is v2 of forgotten patch, awaiting reviewers, any volunteers.
> Also "drm/bridge/sii8620: fix loops in EDID fetch logic" waits for reviewers.
>
> In this version I have completely removed reset function, and moved its body
> to sii8620_hw_on.
>
> Regards
> Andrzej
> ---
>   drivers/gpu/drm/bridge/sil-sii8620.c | 23 ++++++++++-------------
>   1 file changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
> index 7ab36042a822..d1e780fba4b6 100644
> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
> @@ -971,8 +971,17 @@ static int sii8620_hw_on(struct sii8620 *ctx)
>   	ret = regulator_bulk_enable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
>   	if (ret)
>   		return ret;
> +
>   	usleep_range(10000, 20000);
> -	return clk_prepare_enable(ctx->clk_xtal);
> +	ret = clk_prepare_enable(ctx->clk_xtal);
> +	if (ret)
> +		return ret;
> +
> +	msleep(100);
> +	gpiod_set_value(ctx->gpio_reset, 0);
> +	msleep(100);
> +
> +	return 0;
>   }
>   
>   static int sii8620_hw_off(struct sii8620 *ctx)
> @@ -982,17 +991,6 @@ static int sii8620_hw_off(struct sii8620 *ctx)
>   	return regulator_bulk_disable(ARRAY_SIZE(ctx->supplies), ctx->supplies);
>   }
>   
> -static void sii8620_hw_reset(struct sii8620 *ctx)
> -{
> -	usleep_range(10000, 20000);
> -	gpiod_set_value(ctx->gpio_reset, 0);
> -	usleep_range(5000, 20000);
> -	gpiod_set_value(ctx->gpio_reset, 1);
> -	usleep_range(10000, 20000);
> -	gpiod_set_value(ctx->gpio_reset, 0);
> -	msleep(300);
> -}
> -
>   static void sii8620_cbus_reset(struct sii8620 *ctx)
>   {
>   	sii8620_write(ctx, REG_PWD_SRST, BIT_PWD_SRST_CBUS_RST
> @@ -2112,7 +2110,6 @@ static void sii8620_cable_in(struct sii8620 *ctx)
>   		dev_err(dev, "Error powering on, %d.\n", ret);
>   		return;
>   	}
> -	sii8620_hw_reset(ctx);
>   
>   	sii8620_read_buf(ctx, REG_VND_IDL, ver, ARRAY_SIZE(ver));
>   	ret = sii8620_clear_error(ctx);

Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland