[PATCH] drm/bridge: tc358767: do a software reset if reset pin isn't connected

[Andrzej Hajda]

On 27.06.2019 10:59, Lucas Stach wrote:
> To get the chip into the expected state, even when the hardware reset pin
> isn't connected, do a software reset in this case. It isn't as thorough as
> the hardware reset, as the I2C communication block can not be reset for
> obvious reasons, but it's getting the chip into a defined state.
>
> Signed-off-by: Lucas Stach <l.stach at pengutronix.de>

Queued to drm-misc-next.


Regards

Andrzej


> ---
>  drivers/gpu/drm/bridge/tc358767.c | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
> index 13ade28a36a8..1d5ba451e268 100644
> --- a/drivers/gpu/drm/bridge/tc358767.c
> +++ b/drivers/gpu/drm/bridge/tc358767.c
> @@ -70,6 +70,13 @@
>  #define DP0_VIDSRC_DSI_RX		(1 << 0)
>  #define DP0_VIDSRC_DPI_RX		(2 << 0)
>  #define DP0_VIDSRC_COLOR_BAR		(3 << 0)
> +#define SYSRSTENB		0x050c
> +#define ENBI2C				(1 << 0)
> +#define ENBLCD0				(1 << 2)
> +#define ENBBM				(1 << 3)
> +#define ENBDSIRX			(1 << 4)
> +#define ENBREG				(1 << 5)
> +#define ENBHDCP				(1 << 8)
>  #define GPIOM			0x0540
>  #define GPIOC			0x0544
>  #define GPIOO			0x0548
> @@ -1497,6 +1504,22 @@ static int tc_probe(struct i2c_client *client, const struct i2c_device_id *id)
>  
>  	tc->assr = (tc->rev == 0x6601); /* Enable ASSR for eDP panels */
>  
> +	if (!tc->reset_gpio) {
> +		/*
> +		 * If the reset pin isn't present, do a software reset. It isn't
> +		 * as thorough as the hardware reset, as we can't reset the I2C
> +		 * communication block for obvious reasons, but it's getting the
> +		 * chip into a defined state.
> +		 */
> +		regmap_update_bits(tc->regmap, SYSRSTENB,
> +				ENBLCD0 | ENBBM | ENBDSIRX | ENBREG | ENBHDCP,
> +				0);
> +		regmap_update_bits(tc->regmap, SYSRSTENB,
> +				ENBLCD0 | ENBBM | ENBDSIRX | ENBREG | ENBHDCP,
> +				ENBLCD0 | ENBBM | ENBDSIRX | ENBREG | ENBHDCP);
> +		usleep_range(5000, 10000);
> +	}
> +
>  	if (tc->hpd_pin >= 0) {
>  		u32 lcnt_reg = tc->hpd_pin == 0 ? INT_GP0_LCNT : INT_GP1_LCNT;
>  		u32 h_lc = INT_GPIO_H(tc->hpd_pin) | INT_GPIO_LC(tc->hpd_pin);