linux-kernel - Re: [PATCH v1 7/8] phy: qcom-qmp: Move UFS phy to phy

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Date:   Fri, 18 Jan 2019 14:39:01 -0800
From:   Stephen Boyd <swboyd@...omium.org>
To:     Andy Gross <andy.gross@...aro.org>,
        Evan Green <evgreen@...omium.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Rob Herring <robh+dt@...nel.org>
Cc:     Can Guo <cang@...eaurora.org>,
        Douglas Anderson <dianders@...omium.org>,
        Asutosh Das <asutoshd@...eaurora.org>,
        Vivek Gautam <vivek.gautam@...eaurora.org>,
        Evan Green <evgreen@...omium.org>,
        linux-kernel@...r.kernel.org, Manu Gautam <mgautam@...eaurora.org>
Subject: Re: [PATCH v1 7/8] phy: qcom-qmp: Move UFS phy to phy_poweron/off

Quoting Evan Green (2019-01-11 15:01:28)
> For UFS, move the actual firing up of the PHY to phy_poweron and
> phy_poweroff callbacks, rather than init/exit. UFS calls
> phy_poweroff during suspend, so now all clocks and regulators for
> the phy can be powered down during suspend.
> 
> Signed-off-by: Evan Green <evgreen@...omium.org>
> 
> ---
> 
>  drivers/phy/qualcomm/phy-qcom-qmp.c | 82 ++++++++---------------------
>  1 file changed, 23 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp.c b/drivers/phy/qualcomm/phy-qcom-qmp.c
> index eb1cac8f0fd4e..7766c6384d0a8 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp.c
> @@ -1224,7 +1223,6 @@ static int qcom_qmp_phy_init(struct phy *phy)
>         int ret;
>  
>         dev_vdbg(qmp->dev, "Initializing QMP phy\n");
> -
>         if (cfg->has_ufsphy_reset) {
>                 /*
>                  * Get UFS reset, which is delayed until now to avoid a

Nitpick: Drop this hunk.

> @@ -1360,7 +1353,6 @@ static int qcom_qmp_phy_exit(struct phy *phy)
>  
>         /* Put PHY into POWER DOWN state: active low */
>         qphy_clrbits(qphy->pcs, QPHY_POWER_DOWN_CONTROL, cfg->pwrdn_ctrl);
> -
>         if (cfg->has_lane_rst)
>                 reset_control_assert(qphy->lane_rst);
>  

And this hunk.

> @@ -1371,44 +1363,6 @@ static int qcom_qmp_phy_exit(struct phy *phy)
>         return 0;
>  }
>  
> -static int qcom_qmp_phy_poweron(struct phy *phy)
> -{
> -       struct qmp_phy *qphy = phy_get_drvdata(phy);
> -       struct qcom_qmp *qmp = qphy->qmp;
> -       const struct qmp_phy_cfg *cfg = qmp->cfg;
> -       void __iomem *pcs = qphy->pcs;
> -       void __iomem *status;
> -       unsigned int mask, val;
> -       int ret = 0;
> -
> -       if (cfg->type != PHY_TYPE_UFS)
> -               return 0;
> -
> -       /*
> -        * For UFS PHY that has not software reset control, serdes start
> -        * should only happen when UFS driver explicitly calls phy_power_on
> -        * after it deasserts software reset.
> -        */
> -       if (cfg->no_pcs_sw_reset && !qmp->phy_initialized &&
> -           (qmp->init_count != 0)) {
> -               /* start SerDes and Phy-Coding-Sublayer */
> -               qphy_setbits(pcs, cfg->regs[QPHY_START_CTRL], cfg->start_ctrl);
> -
> -               status = pcs + cfg->regs[QPHY_PCS_READY_STATUS];
> -               mask = cfg->mask_pcs_ready;
> -
> -               ret = readl_poll_timeout(status, val, !(val & mask), 1,
> -                                        PHY_INIT_COMPLETE_TIMEOUT);

So we never need to poll this bit anymore?

> -               if (ret) {
> -                       dev_err(qmp->dev, "phy initialization timed-out\n");
> -                       return ret;
> -               }
> -               qmp->phy_initialized = true;
> -       }
> -
> -       return ret;
> -}
> -
>  static int qcom_qmp_phy_set_mode(struct phy *phy,
>                                  enum phy_mode mode, int submode)
>  {
> @@ -1658,9 +1612,15 @@ static int phy_pipe_clk_register(struct qcom_qmp *qmp, struct device_node *np)
>  }
>  
>  static const struct phy_ops qcom_qmp_phy_gen_ops = {
> -       .init           = qcom_qmp_phy_init,
> -       .exit           = qcom_qmp_phy_exit,
> -       .power_on       = qcom_qmp_phy_poweron,
> +       .init           = qcom_qmp_phy_enable,
> +       .exit           = qcom_qmp_phy_disable,
> +       .set_mode       = qcom_qmp_phy_set_mode,
> +       .owner          = THIS_MODULE,
> +};
> +
> +static const struct phy_ops qcom_qmp_ufs_ops = {
> +       .power_on       = qcom_qmp_phy_enable,
> +       .power_off      = qcom_qmp_phy_disable,
>         .set_mode       = qcom_qmp_phy_set_mode,
>         .owner          = THIS_MODULE,
>  };

So the UFS and the non-UFS phys will use the same single function, but
the callers of the phys will see that phy_power_on() powers on the phy
for UFS but does nothing for non-UFS devices? Do the users of this
common phy call the API differently between drivers? Kishon, is there
guidance on how phys are supposed to be used by drivers?