linux-kernel - Re: [PATCH v6 1/3] phy: Update PHY power control sequence

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Date:   Fri, 8 Jun 2018 12:15:55 +0530
From:   Manu Gautam <mgautam@...eaurora.org>
To:     Can Guo <cang@...eaurora.org>, subhashj@...eaurora.org,
        asutoshd@...eaurora.org, vivek.gautam@...eaurora.org,
        kishon@...com, robh+dt@...nel.org, mark.rutland@....com
Cc:     linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v6 1/3] phy: Update PHY power control sequence

Hi,

On 5/29/2018 10:07 AM, Can Guo wrote:
> All PHYs should be powered on before register configuration starts. And
> only PCIe PHYs need an extra power control before deasserts reset state.
>
> Signed-off-by: Can Guo <cang@...eaurora.org>
> ---
>  drivers/phy/qualcomm/phy-qcom-qmp.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c
> index 97ef942..f779b0f 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
> @@ -982,6 +982,8 @@ static int qcom_qmp_phy_com_init(struct qcom_qmp *qmp)
>  	if (cfg->has_phy_com_ctrl)
>  		qphy_setbits(serdes, cfg->regs[QPHY_COM_POWER_DOWN_CONTROL],
>  			     SW_PWRDN);
> +	else
> +		qphy_setbits(pcs, QPHY_POWER_DOWN_CONTROL, cfg->pwrdn_ctrl);

We should power-up PHYs after following dp_com_ctrl programming which
powers-off USB-DP combo PHY when it brings DP_COM block out of reset reset.


>  
>  	if (cfg->has_phy_dp_com_ctrl) {
>  		qphy_setbits(dp_com, QPHY_V3_DP_COM_POWER_DOWN_CTRL,
> @@ -1127,7 +1129,8 @@ static int qcom_qmp_phy_init(struct phy *phy)
>  	 * Pull out PHY from POWER DOWN state.
>  	 * This is active low enable signal to power-down PHY.
>  	 */
> -	qphy_setbits(pcs, QPHY_POWER_DOWN_CONTROL, cfg->pwrdn_ctrl);
> +	if (cfg->type == PHY_TYPE_PCIE)
> +		qphy_setbits(pcs, QPHY_POWER_DOWN_CONTROL, cfg->pwrdn_ctrl);
>  
>  	if (cfg->has_pwrdn_delay)
>  		usleep_range(cfg->pwrdn_delay_min, cfg->pwrdn_delay_max);

-- 
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