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Date:   Wed, 11 Aug 2021 23:09:50 +0530
From:   Pratyush Yadav <p.yadav@ti.com>
To:     Vinod Koul <vkoul@kernel.org>
CC:     Nikhil Devshatwar <nikhil.nd@ti.com>,
        Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>,
        Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
        Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Kishon Vijay Abraham I <kishon@ti.com>,
        Peter Chen <peter.chen@nxp.com>,
        <linux-kernel@vger.kernel.org>, <linux-phy@lists.infradead.org>
Subject: Re: [PATCH v3 2/7] phy: cdns-dphy: Prepare for Rx support
Message-ID: <20210811173948.cezk6zu366c3huhw@ti.com>
References: <20210624184108.21312-1-p.yadav@ti.com>
 <20210624184108.21312-3-p.yadav@ti.com>
 <YQ0MZqI36bz1Jp87@matsya>
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On 06/08/21 03:48PM, Vinod Koul wrote:
> On 25-06-21, 00:11, Pratyush Yadav wrote:
> > The Rx programming sequence differs from the Tx programming sequence.
> > Currently only Tx mode is supported. Move all the Tx related parts into
> > a set of Tx-specific hooks that are then called by the main PHY
> > framework hooks. This way when Rx support is added all that is needed to
> > be done is to plug in the Rx hooks.
> > 
> > The clocks "psm" and "pll_ref" are not used by the Rx path so make them
> > optional in the probe and then check if they exist in the power_on()
> > hook.
> > 
> > Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> > ---
> > 
> > (no changes since v1)
> > 
> >  drivers/phy/cadence/cdns-dphy.c | 140 ++++++++++++++++++++++++--------
> >  1 file changed, 104 insertions(+), 36 deletions(-)
> > 
> > diff --git a/drivers/phy/cadence/cdns-dphy.c b/drivers/phy/cadence/cdns-dphy.c
> > index ba042e39cfaf..8656f2102a91 100644
> > --- a/drivers/phy/cadence/cdns-dphy.c
> > +++ b/drivers/phy/cadence/cdns-dphy.c
> > @@ -75,6 +75,11 @@ struct cdns_dphy;
> >  struct cdns_dphy_ops {
> >  	int (*probe)(struct cdns_dphy *dphy);
> >  	void (*remove)(struct cdns_dphy *dphy);
> > +	int (*power_on)(struct cdns_dphy *dphy);
> > +	int (*power_off)(struct cdns_dphy *dphy);
> > +	int (*validate)(struct cdns_dphy *dphy, enum phy_mode mode, int submode,
> > +			union phy_configure_opts *opts);
> > +	int (*configure)(struct cdns_dphy *dphy, union phy_configure_opts *opts);
> >  	void (*set_psm_div)(struct cdns_dphy *dphy, u8 div);
> >  	void (*set_clk_lane_cfg)(struct cdns_dphy *dphy,
> >  				 enum cdns_dphy_clk_lane_cfg cfg);
> > @@ -86,12 +91,18 @@ struct cdns_dphy_ops {
> >  struct cdns_dphy {
> >  	struct cdns_dphy_cfg cfg;
> >  	void __iomem *regs;
> > +	struct device *dev;
> >  	struct clk *psm_clk;
> >  	struct clk *pll_ref_clk;
> >  	const struct cdns_dphy_ops *ops;
> >  	struct phy *phy;
> >  };
> >  
> > +struct cdns_dphy_driver_data {
> > +	const struct cdns_dphy_ops *tx;
> > +	const struct cdns_dphy_ops *rx;
> > +};
> > +
> >  static int cdns_dsi_get_dphy_pll_cfg(struct cdns_dphy *dphy,
> >  				     struct cdns_dphy_cfg *cfg,
> >  				     struct phy_configure_opts_mipi_dphy *opts,
> > @@ -199,20 +210,9 @@ static void cdns_dphy_ref_set_psm_div(struct cdns_dphy *dphy, u8 div)
> >  	       dphy->regs + DPHY_PSM_CFG);
> >  }
> >  
> > -/*
> > - * This is the reference implementation of DPHY hooks. Specific integration of
> > - * this IP may have to re-implement some of them depending on how they decided
> > - * to wire things in the SoC.
> > - */
> > -static const struct cdns_dphy_ops ref_dphy_ops = {
> > -	.get_wakeup_time_ns = cdns_dphy_ref_get_wakeup_time_ns,
> > -	.set_pll_cfg = cdns_dphy_ref_set_pll_cfg,
> > -	.set_psm_div = cdns_dphy_ref_set_psm_div,
> > -};
> > -
> > -static int cdns_dphy_config_from_opts(struct phy *phy,
> > -				      struct phy_configure_opts_mipi_dphy *opts,
> > -				      struct cdns_dphy_cfg *cfg)
> > +static int cdns_dphy_tx_config_from_opts(struct phy *phy,
> > +					 struct phy_configure_opts_mipi_dphy *opts,
> > +					 struct cdns_dphy_cfg *cfg)
> >  {
> >  	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> >  	unsigned int dsi_hfp_ext = 0;
> > @@ -232,24 +232,13 @@ static int cdns_dphy_config_from_opts(struct phy *phy,
> >  	return 0;
> >  }
> >  
> > -static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode, int submode,
> > -			      union phy_configure_opts *opts)
> > +static int cdns_dphy_tx_configure(struct cdns_dphy *dphy,
> > +				  union phy_configure_opts *opts)
> >  {
> >  	struct cdns_dphy_cfg cfg = { 0 };
> > -
> > -	if (mode != PHY_MODE_MIPI_DPHY)
> > -		return -EINVAL;
> > -
> > -	return cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> > -}
> > -
> > -static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
> > -{
> > -	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > -	struct cdns_dphy_cfg cfg = { 0 };
> >  	int ret;
> >  
> > -	ret = cdns_dphy_config_from_opts(phy, &opts->mipi_dphy, &cfg);
> > +	ret = cdns_dphy_tx_config_from_opts(dphy->phy, &opts->mipi_dphy, &cfg);
> >  	if (ret)
> >  		return ret;
> >  
> > @@ -279,9 +268,21 @@ static int cdns_dphy_configure(struct phy *phy, union phy_configure_opts *opts)
> >  	return 0;
> >  }
> >  
> > -static int cdns_dphy_power_on(struct phy *phy)
> > +static int cdns_dphy_tx_validate(struct cdns_dphy *dphy, enum phy_mode mode,
> > +				 int submode, union phy_configure_opts *opts)
> >  {
> > -	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > +	struct cdns_dphy_cfg cfg = { 0 };
> > +
> > +	if (submode != PHY_MIPI_DPHY_SUBMODE_TX)
> > +		return -EINVAL;
> > +
> > +	return cdns_dphy_tx_config_from_opts(dphy->phy, &opts->mipi_dphy, &cfg);
> > +}
> > +
> > +static int cdns_dphy_tx_power_on(struct cdns_dphy *dphy)
> > +{
> > +	if (!dphy->psm_clk || !dphy->pll_ref_clk)
> > +		return -EINVAL;
> >  
> >  	clk_prepare_enable(dphy->psm_clk);
> >  	clk_prepare_enable(dphy->pll_ref_clk);
> > @@ -293,16 +294,77 @@ static int cdns_dphy_power_on(struct phy *phy)
> >  	return 0;
> >  }
> >  
> > -static int cdns_dphy_power_off(struct phy *phy)
> > +static int cdns_dphy_tx_power_off(struct cdns_dphy *dphy)
> >  {
> > -	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > -
> >  	clk_disable_unprepare(dphy->pll_ref_clk);
> >  	clk_disable_unprepare(dphy->psm_clk);
> >  
> >  	return 0;
> >  }
> >  
> > +static const struct cdns_dphy_ops tx_ref_dphy_ops = {
> > +	.power_on = cdns_dphy_tx_power_on,
> > +	.power_off = cdns_dphy_tx_power_off,
> > +	.validate = cdns_dphy_tx_validate,
> > +	.configure = cdns_dphy_tx_configure,
> > +	.get_wakeup_time_ns = cdns_dphy_ref_get_wakeup_time_ns,
> > +	.set_pll_cfg = cdns_dphy_ref_set_pll_cfg,
> > +	.set_psm_div = cdns_dphy_ref_set_psm_div,
> > +};
> > +
> > +/*
> > + * This is the reference implementation of DPHY hooks. Specific integration of
> > + * this IP may have to re-implement some of them depending on how they decided
> > + * to wire things in the SoC.
> > + */
> > +static const struct cdns_dphy_driver_data ref_dphy_ops = {
> > +	.tx = &tx_ref_dphy_ops,
> > +};
> > +
> > +static int cdns_dphy_validate(struct phy *phy, enum phy_mode mode, int submode,
> > +			      union phy_configure_opts *opts)
> > +{
> > +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > +
> > +	if (mode != PHY_MODE_MIPI_DPHY)
> > +		return -EINVAL;
> > +
> > +	if (dphy->ops->validate)
> > +		return dphy->ops->validate(dphy, mode, submode, opts);
> > +
> > +	return 0;
> > +}
> > +
> > +static int cdns_dphy_power_on(struct phy *phy)
> > +{
> > +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > +
> > +	if (dphy->ops->power_on)
> > +		return dphy->ops->power_on(dphy);
> > +
> > +	return 0;
> > +}
> > +
> > +static int cdns_dphy_power_off(struct phy *phy)
> > +{
> > +	struct cdns_dphy *dphy = phy_get_drvdata(phy);
> > +
> > +	if (dphy->ops->power_off)
> > +		return dphy->ops->power_off(dphy);
> > +
> > +	return 0;
> > +}
> 
> why do you need a dphy specific power_on/off only to call internal
> ops..? If there is no additional logic lets drop this and continue the
> phy ops for this

I don't clearly understand what you are trying to say. The internal ops 
(dphy->ops) are DPHY-specific. So for example, you might have different 
power on/off sequences for Rx and Tx mode DPHYs. You would then 
implement different power_on() and power_off() hooks for those and store 
them in dphy->ops. How else would you handle this?

> 
> -- 
> ~Vinod

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.