linux-kernel - Re: [PATCH V1 2/2] phy: qcom: Refactor phy_power_on and phy

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Message-ID: <20240124083336.GB4906@thinkpad>
Date: Wed, 24 Jan 2024 14:03:36 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
To: Nitin Rawat <quic_nitirawa@...cinc.com>
Cc: Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Vinod Koul <vkoul@...nel.org>,
	Kishon Vijay Abraham I <kishon@...nel.org>,
	"James E.J. Bottomley" <jejb@...ux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Philipp Zabel <p.zabel@...gutronix.de>,
	linux-arm-msm@...r.kernel.org, linux-phy@...ts.infradead.org,
	linux-kernel@...r.kernel.org, linux-scsi@...r.kernel.org,
	Can Guo <quic_cang@...cinc.com>,
	Naveen Kumar Goud Arepalli <quic_narepall@...cinc.com>
Subject: Re: [PATCH V1 2/2] phy: qcom: Refactor phy_power_on and
 phy_calibrate callbacks

On Fri, Jan 12, 2024 at 09:03:48PM +0530, Nitin Rawat wrote:
> Commit 052553af6a31 ("ufs/phy: qcom: Refactor to use phy_init call")
> puts enabling regulators & clks, calibrating UFS PHY, starting serdes
> and polling PCS ready status into phy_power_on.
> 
> In Current code regulators enable, clks enable, calibrating UFS PHY,
> start_serdes and polling PCS_ready_status are part of phy_power_on.
> 
> UFS PHY registers are retained after power collapse, meaning calibrating
> UFS PHY, start_serdes and polling PCS_ready_status can be done only when
> hba is powered_on, and not needed every time when phy_power_on is called
> during resume. Hence keep the code which enables PHY's regulators & clks
> in phy_power_on and move the rest steps into phy_calibrate function.
> 
> Refactor the code to enable PHY regulators & clks in phy_power_on and
> move rest of the code to phy_calibrate function.
> 

This patch should come before UFS patch since you are introducing the
calibrate() callback here only.

> Co-developed-by: Can Guo <quic_cang@...cinc.com>
> Signed-off-by: Can Guo <quic_cang@...cinc.com>
> Co-developed-by: Naveen Kumar Goud Arepalli <quic_narepall@...cinc.com>
> Signed-off-by: Naveen Kumar Goud Arepalli <quic_narepall@...cinc.com>
> Signed-off-by: Nitin Rawat <quic_nitirawa@...cinc.com>
> ---
>  drivers/phy/qualcomm/phy-qcom-qmp-ufs.c | 183 +++++++++---------------
>  1 file changed, 67 insertions(+), 116 deletions(-)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-ufs.c b/drivers/phy/qualcomm/phy-qcom-qmp-ufs.c
> index 3c2e6255e26f..ae0218738b0b 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp-ufs.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-ufs.c
> @@ -32,14 +32,15 @@
>  /* QPHY_SW_RESET bit */
>  #define SW_RESET				BIT(0)
>  /* QPHY_POWER_DOWN_CONTROL */
> -#define SW_PWRDN				BIT(0)
> +#define SW_PWRUP				BIT(0)
> +#define SW_PWRDN				0

Why 0?

>  /* QPHY_START_CONTROL bits */
>  #define SERDES_START				BIT(0)
>  #define PCS_START				BIT(1)
>  /* QPHY_PCS_READY_STATUS bit */
>  #define PCS_READY				BIT(0)
> 
> -#define PHY_INIT_COMPLETE_TIMEOUT		10000
> +#define PHY_INIT_COMPLETE_TIMEOUT		1000000

Why? This is not mentioned in the commit message. If it is not related to this
refactoring, then it should be a separate patch with justification.

> 
>  struct qmp_phy_init_tbl {
>  	unsigned int offset;
> @@ -1464,8 +1465,25 @@ static void qmp_ufs_init_registers(struct qmp_ufs *qmp, const struct qmp_phy_cfg
>  		qmp_ufs_pcs_init(qmp, &cfg->tbls_hs_g4);
>  }
> 
> -static int qmp_ufs_com_init(struct qmp_ufs *qmp)
> +static int qmp_ufs_power_off(struct phy *phy)
> +{
> +	struct qmp_ufs *qmp = phy_get_drvdata(phy);
> +	const struct qmp_phy_cfg *cfg = qmp->cfg;
> +
> +	/* Put PHY into POWER DOWN state: active low */
> +	qphy_clrbits(qmp->pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL],
> +			SW_PWRDN);
> +
> +	clk_bulk_disable_unprepare(cfg->num_clks, qmp->clks);
> +
> +	regulator_bulk_disable(cfg->num_vregs, qmp->vregs);
> +
> +	return 0;
> +}
> +
> +static int qmp_ufs_power_on(struct phy *phy)
>  {
> +	struct qmp_ufs *qmp = phy_get_drvdata(phy);
>  	const struct qmp_phy_cfg *cfg = qmp->cfg;
>  	void __iomem *pcs = qmp->pcs;
>  	int ret;
> @@ -1480,8 +1498,7 @@ static int qmp_ufs_com_init(struct qmp_ufs *qmp)
>  	if (ret)
>  		goto err_disable_regulators;
> 
> -	qphy_setbits(pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL], SW_PWRDN);
> -
> +	qphy_setbits(pcs, cfg->regs[QPHY_PCS_POWER_DOWN_CONTROL], SW_PWRUP);

Newline please. As mentioned above, why can't you use existing SW_PWRDN macro.

>  	return 0;
> 
>  err_disable_regulators:
> @@ -1490,61 +1507,7 @@ static int qmp_ufs_com_init(struct qmp_ufs *qmp)
>  	return ret;
>  }
> 

[...]

> +static int qmp_ufs_get_phy_reset(struct qmp_ufs *qmp)
> +{
> +	const struct qmp_phy_cfg *cfg = qmp->cfg;
> +	int ret;
> +
> +	if (!cfg->no_pcs_sw_reset)
> +		return 0;
> +
> +	/*
> +	 * Get UFS reset, which is delayed until now to avoid a
> +	 * circular dependency where UFS needs its PHY, but the PHY
> +	 * needs this UFS reset.
> +	 */
> +
> +	qmp->ufs_reset = devm_reset_control_get_exclusive(qmp->dev,
> +							  "ufsphy");

You have moved this to probe from power_on() without any justification. What
about the circular dependency mentioned in the comment.

- Mani

-- 
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