linux-kernel - Re: [PATCH v2 1/2] phy: qcom: pcie: Determine has_nocsr

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Message-ID: <6c38b6e028858662aa5d45f4a14b993860b73cc0.camel@pengutronix.de>
Date: Tue, 11 Feb 2025 10:53:26 +0100
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Wenbin Yao <quic_wenbyao@...cinc.com>, vkoul@...nel.org,
 kishon@...nel.org,  dmitry.baryshkov@...aro.org, abel.vesa@...aro.org,
 quic_qianyu@...cinc.com,  neil.armstrong@...aro.org,
 manivannan.sadhasivam@...aro.org,  quic_devipriy@...cinc.com,
 konrad.dybcio@....qualcomm.com,  linux-arm-msm@...r.kernel.org,
 linux-phy@...ts.infradead.org,  linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/2] phy: qcom: pcie: Determine has_nocsr_reset
 dynamically

On Di, 2025-02-11 at 17:42 +0800, Wenbin Yao wrote:
> From: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
> 
> Decide the in-driver logic based on whether the nocsr reset is present
> and defer checking the appropriateness of that to dt-bindings to save
> on boilerplate.
> 
> Reset controller APIs are fine consuming a nullptr, so no additional
> checks are necessary there.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@....qualcomm.com>
> Signed-off-by: Wenbin Yao <quic_wenbyao@...cinc.com>
> Reviewed-by: Abel Vesa <abel.vesa@...aro.org>
> Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> ---
>  drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 18 +++++++-----------
>  1 file changed, 7 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> index 873f2f9844c6..ac42e4b01065 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> @@ -2793,8 +2793,6 @@ struct qmp_phy_cfg {
>  
>  	bool skip_start_delay;
>  
> -	bool has_nocsr_reset;
> -
>  	/* QMP PHY pipe clock interface rate */
>  	unsigned long pipe_clock_rate;
>  
> @@ -3685,7 +3683,6 @@ static const struct qmp_phy_cfg sm8550_qmp_gen4x2_pciephy_cfg = {
>  
>  	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
>  	.phy_status		= PHYSTATUS_4_20,
> -	.has_nocsr_reset	= true,
>  
>  	/* 20MHz PHY AUX Clock */
>  	.aux_clock_rate		= 20000000,
> @@ -3718,7 +3715,6 @@ static const struct qmp_phy_cfg sm8650_qmp_gen4x2_pciephy_cfg = {
>  
>  	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
>  	.phy_status		= PHYSTATUS_4_20,
> -	.has_nocsr_reset	= true,
>  
>  	/* 20MHz PHY AUX Clock */
>  	.aux_clock_rate		= 20000000,
> @@ -3836,7 +3832,6 @@ static const struct qmp_phy_cfg x1e80100_qmp_gen4x2_pciephy_cfg = {
>  
>  	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
>  	.phy_status		= PHYSTATUS_4_20,
> -	.has_nocsr_reset	= true,
>  };
>  
>  static const struct qmp_phy_cfg x1e80100_qmp_gen4x4_pciephy_cfg = {
> @@ -3870,7 +3865,6 @@ static const struct qmp_phy_cfg x1e80100_qmp_gen4x4_pciephy_cfg = {
>  
>  	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
>  	.phy_status		= PHYSTATUS_4_20,
> -	.has_nocsr_reset	= true,
>  };
>  
>  static const struct qmp_phy_cfg x1e80100_qmp_gen4x8_pciephy_cfg = {
> @@ -3902,7 +3896,6 @@ static const struct qmp_phy_cfg x1e80100_qmp_gen4x8_pciephy_cfg = {
>  
>  	.pwrdn_ctrl		= SW_PWRDN | REFCLK_DRV_DSBL,
>  	.phy_status		= PHYSTATUS_4_20,
> -	.has_nocsr_reset	= true,
>  };
>  
>  static void qmp_pcie_init_port_b(struct qmp_pcie *qmp, const struct qmp_phy_cfg_tbls *tbls)
> @@ -4203,11 +4196,14 @@ static int qmp_pcie_reset_init(struct qmp_pcie *qmp)
>  	if (ret)
>  		return dev_err_probe(dev, ret, "failed to get resets\n");
>  
> -	if (cfg->has_nocsr_reset) {
> -		qmp->nocsr_reset = devm_reset_control_get_exclusive(dev, "phy_nocsr");
> -		if (IS_ERR(qmp->nocsr_reset))
> +	qmp->nocsr_reset = devm_reset_control_get_exclusive(dev, "phy_nocsr");
> +	if (IS_ERR(qmp->nocsr_reset)) {
> +		if (PTR_ERR(qmp->nocsr_reset) == -ENOENT ||
> +		    PTR_ERR(qmp->nocsr_reset) == -EINVAL)

Why is -EINVAL ignored here?

Without this you could just use
devm_reset_control_get_optional_exclusive(), which already turns -
ENOENT into NULL. That seems to me the correct thing to do, as from
driver point-of-view, this reset control is optional.

> +			qmp->nocsr_reset = NULL;
> +		else
>  			return dev_err_probe(dev, PTR_ERR(qmp->nocsr_reset),
> -						"failed to get no-csr reset\n");
> +					     "failed to get no-csr reset\n");
>  	}
>  
>  	return 0;

regards
Philipp