linux-kernel - Re: [PATCH v1 2/4] soc: imx: imx8m-blk-ctrl: Display Power ON sequence

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Message-ID: <c9cfecf9cf6d75a2fb70fafa5e82baee414c6496.camel@pengutronix.de>
Date:   Mon, 02 May 2022 12:12:22 +0200
From:   Lucas Stach <l.stach@...gutronix.de>
To:     Viraj Shah <viraj.shah@...utronix.de>, shawnguo@...nel.org,
        s.hauer@...gutronix.de
Cc:     Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        Adam Ford <aford173@...il.com>,
        Frieder Schrempf <frieder.schrempf@...tron.de>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/4] soc: imx: imx8m-blk-ctrl: Display Power ON
 sequence

Am Montag, dem 02.05.2022 um 12:02 +0200 schrieb Viraj Shah:
> Enable the dispmix software clock and release the resets
> as shown in the 5.2.9.5 section of reference manual.
> 
> Signed-off-by: Viraj Shah <viraj.shah@...utronix.de>
> ---
>  drivers/soc/imx/imx8m-blk-ctrl.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/imx/imx8m-blk-ctrl.c b/drivers/soc/imx/imx8m-blk-ctrl.c
> index 122f9c884b38..ca63fd30e70a 100644
> --- a/drivers/soc/imx/imx8m-blk-ctrl.c
> +++ b/drivers/soc/imx/imx8m-blk-ctrl.c
> @@ -99,7 +99,10 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
>  		dev_err(bc->dev, "failed to enable clocks\n");
>  		goto bus_put;
>  	}
> -	regmap_set_bits(bc->regmap, BLK_CLK_EN, data->clk_mask);
> +	/* As per section 5.2.9.5 of reference manual imx-8MMini-yhsc.pdf,
> +	 * enable dispmix sft clock to power on the display
> +	 */
> +	regmap_write(bc->regmap, BLK_CLK_EN, 0x1FFF);

Nack. The only clock that needs to be handled here is the ADB clock for
the handshake. All other clocks are enabled by the virtual power
domains provided by this blk-ctrl driver when the peripheral power up.

Regards,
Lucas

>  
>  	/* power up upstream GPC domain */
>  	ret = pm_runtime_get_sync(domain->power_dev);
> @@ -112,7 +115,7 @@ static int imx8m_blk_ctrl_power_on(struct generic_pm_domain *genpd)
>  	udelay(5);
>  
>  	/* release reset */
> -	regmap_set_bits(bc->regmap, BLK_SFT_RSTN, data->rst_mask);
> +	regmap_write(bc->regmap, BLK_SFT_RSTN, 0x7F);
>  	if (data->mipi_phy_rst_mask)
>  		regmap_set_bits(bc->regmap, BLK_MIPI_RESET_DIV, data->mipi_phy_rst_mask);
>