Re: [PATCH 2/2] phy: qualcomm: usb: Add Super-Speed PHY driver

[Jorge Ramirez]

On 12/20/18 21:29, Stephen Boyd wrote:
> Quoting Jorge Ramirez-Ortiz (2018-12-07 01:55:58)
> > From: Shawn Guo <shawn.guo@xxxxxxxxxx>
> >
> > Driver to control the Synopsys SS PHY 1.0.0 implemeneted in QCS404
> >
> > Based on Sriharsha Allenki's <sallenki@xxxxxxxxxxxxxx> original code.
> >
> > Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@xxxxxxxxxx>
> > Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx>
>
> chain should be swapped?

ok.

Shawn asked me to remove him from the authors list so will remove.

> > Reviewed-by: Vinod Koul <vkoul@xxxxxxxxxx>

will remove the reviewed-by line as well.

> > ---
> > diff --git a/drivers/phy/qualcomm/phy-qcom-usb-ss.c b/drivers/phy/qualcomm/phy-qcom-usb-ss.c
> > new file mode 100644
> > index 0000000..7b6a55e
> > --- /dev/null
> > +++ b/drivers/phy/qualcomm/phy-qcom-usb-ss.c
> > +
> > +struct ssphy_priv {
> > +       void __iomem *base;
> > +       struct device *dev;
> > +       struct reset_control *reset_com;
> > +       struct reset_control *reset_phy;
> > +       struct clk *clk_ref;
> > +       struct clk *clk_phy;
> > +       struct clk *clk_pipe;
>
> Use bulk clk APIs? And just get and enable all the clks?

yes.

> > +       struct regulator *vdda1p8;
> > +       struct regulator *vbus;
> > +       struct regulator *vdd;
> > +       unsigned int vdd_levels[LEVEL_NUM];
> > +};
> > +
> > +static inline void qcom_ssphy_updatel(void __iomem *addr, u32 mask, u32 val)
> > +{
> > +       writel((readl(addr) & ~mask) | val, addr);
> > +}
> > +
> > +static int qcom_ssphy_config_vdd(struct ssphy_priv *priv,
> > +                                enum phy_vdd_level level)
> > +{
> > +       return regulator_set_voltage(priv->vdd,
> > +                                    priv->vdd_levels[level],
> > +                                    priv->vdd_levels[LEVEL_MAX]);
>
> regulator_set_voltage(reg, 0, max) is very suspicious. It's voltage
> corners where the voltages are known?

sorry I dont understand the question

this regulator on the ss phy wold be
vreg_l3_1p05: l3 {
		regulator-min-microvolt = <976000>;
		regulator-max-microvolt = <1160000>;
};
> > +}
> > +
> > +static int qcom_ssphy_ldo_enable(struct ssphy_priv *priv)
> > +{
> > +       int ret;
> > +
> > +       ret = regulator_set_load(priv->vdda1p8, 23000);
>
> Do you need to do this? Why can't the regulator be in high power mode
> all the time and then go low power when it's disabled?

this regulator is shared with the usb hs phy and each (ss/hs) have 
different load requirements. why would it be wrong for the ss phy to 
announce its needs (which will differ from those of the hs phy)?

> > +       if (ret < 0) {
> > +               dev_err(priv->dev, "Failed to set regulator1p8 load\n");
> > +               return ret;
> > +       }
> > +
> > +       ret = regulator_set_voltage(priv->vdda1p8, 1800000, 1800000);
>
> This looks unnecessary. The 1.8V regulator sounds like it better be 1.8V
> so board constraints should enforce that. All that should be here is
> enabling the regulator.

ok

> > +       if (ret) {
> > +               dev_err(priv->dev, "Failed to set regulator1p8 voltage\n");
> > +               goto put_vdda1p8_lpm;
> > +       }
> > +
> > +       ret = regulator_enable(priv->vdda1p8);
> > +       if (ret) {
> > +               dev_err(priv->dev, "Failed to enable regulator1p8\n");
> > +               goto unset_vdda1p8;
> > +       }
> > +
> > +       return ret;
> > +
> > +       /* rollback regulator changes */
> > +
> > +unset_vdda1p8:
> > +       regulator_set_voltage(priv->vdda1p8, 0, 1800000);
> > +
> > +put_vdda1p8_lpm:
> > +       regulator_set_load(priv->vdda1p8, 0);
> > +
> > +       return ret;
> > +}
> > +
> > +static void qcom_ssphy_ldo_disable(struct ssphy_priv *priv)
> > +{
> > +       regulator_disable(priv->vdda1p8);
> > +       regulator_set_voltage(priv->vdda1p8, 0, 1800000);
>
> Urgh why?

since it is being shared with the hs phy I understand this is required 
to vote the transition to the lowest voltage state.
> > +       regulator_set_load(priv->vdda1p8, 0);
> > +}