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

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Date:   Tue, 12 Jun 2018 17:04:18 +0530
From:   Vivek Gautam <vivek.gautam@...eaurora.org>
To:     Can Guo <cang@...eaurora.org>, subhashj@...eaurora.org,
        asutoshd@...eaurora.org, mgautam@...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 Can,


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);

No definition of 'pcs' in this function. You are doing that in the 
second patch.
But, we should add this definition here.

Also instead of having the change like this:

+	struct qmp_phy *qphy = qmp->phys[0];
  	void __iomem *serdes = qmp->serdes;
+	void __iomem *pcs = qphy->pcs;

Let's pass 'struct qmp_phy' to qcom_qmp_phy_com_init(), and then get
'struct qcom_qmp' and 'void __iomem *pcs' from that.

So,

-static int qcom_qmp_phy_com_init(struct qcom_qmp *qmp)
+static int qcom_qmp_phy_com_init(struct qmp_phy *qphy)
  {
+       struct qcom_qmp *qmp = qphy->qmp;
         const struct qmp_phy_cfg *cfg = qmp->cfg;
         void __iomem *serdes = qmp->serdes;
         void __iomem *dp_com = qmp->dp_com;
+       void __iomem *pcs = qphy->pcs;

and

-       ret = qcom_qmp_phy_com_init(qmp);
+       ret = qcom_qmp_phy_com_init(qphy);

That looks cleaner than extracting from the 0th phys.

BRs
Vivek
>   
>   	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);