Re: [PATCH v3] phy: qcom-mipi-csi2: Add support for single power-domain SoCs

[bod@kernel.org]

On 2026-11-02 13:39 -0800, Anusha Arun Nandi wrote:
> sa8775p, qcs8300 and sc7280 each list exactly one power-domain ("top")
> on the CSI2 PHY node. For a device with a single power-domain phandle,
> the generic platform-bus code (platform_probe() ->
> dev_pm_domain_attach()) auto-attaches it via genpd_dev_pm_attach()
> before the driver's own probe() runs. phy_qcom_mipi_csi2_probe() then
> unconditionally calls devm_pm_domain_attach_list(), which fails with
> -EEXIST because dev->pm_domain is already set, and the driver treats
> that as fatal:
> 
>   1. qcom-mipi-csi2-phy ace6000.phy: error -EEXIST: Failed to attach
>   power-domain list
>   2. qcom-mipi-csi2-phy ace6000.phy: probe with driver qcom-mipi-csi2-phy
>   failed with error -17
> 
> x1e80100 is unaffected: it lists three power-domains, so the generic
> code does not auto-attach any of them (auto-attach only applies to
> single-power-domain devices); the driver's explicit attach is the
> only one that runs.
> 
> For the single power-domain case, call dev_pm_domain_attach() instead
> of devm_pm_domain_attach_list(): it returns early when dev->pm_domain
> is already set, so csi2phy->pd_list is left NULL rather than built up
> by hand. The three call sites that walk pd_list for genpd
> performance-state scaling now guard against a NULL pd_list, which is
> harmless since scaling is unused (scaled = false) on every SoC that has
> a single "top" domain.
> 
> devm_pm_domain_attach_list() returns the number of attached
> power-domains on success, so a bare "ret < 0" check in probe() is not
> enough to catch the case where it succeeds without actually attaching
> any domains. phy_qcom_mipi_csi2_attach_pm_domains() now also checks for
> that case directly and reports -ENODEV, keeping probe()'s own check
> unchanged.
> 
> Reviewed-by: Jigarkumar Zala <jigarkumar.zala@oss.qualcomm.com>
> Signed-off-by: Anusha Arun Nandi <anusha.nandi@oss.qualcomm.com>
> ---
>  .../phy/qualcomm/phy-qcom-mipi-csi2-core.c    | 25 +++++++++++--------
>  1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-mipi-csi2-core.c b/drivers/phy/qualcomm/phy-qcom-mipi-csi2-core.c
> index c0a4fa20eaf0..269232499fca 100644
> --- a/drivers/phy/qualcomm/phy-qcom-mipi-csi2-core.c
> +++ b/drivers/phy/qualcomm/phy-qcom-mipi-csi2-core.c
> @@ -43,7 +43,7 @@ phy_qcom_mipi_csi2_set_clock_rates(struct mipi_csi2phy_device *csi2phy,
>  	}
>  
>  	pstate = 0;
> -	for (i = 0; i < csi2phy->pd_list->num_pds; i++) {
> +	for (i = 0; csi2phy->pd_list && i < csi2phy->pd_list->num_pds; i++) {
>  		unsigned int perf;
>  
>  		if (!csi2phy->soc_cfg->genpds[i].scaled)
> @@ -174,7 +174,7 @@ static int phy_qcom_mipi_csi2_power_on(struct phy *phy)
>  unset_rate:
>  	dev_pm_opp_set_rate(csi2phy->dev, 0);
>  
> -	for (i = 0; i < csi2phy->pd_list->num_pds; i++) {
> +	for (i = 0; csi2phy->pd_list && i < csi2phy->pd_list->num_pds; i++) {
>  		if (!csi2phy->soc_cfg->genpds[i].scaled)
>  			continue;
>  
> @@ -204,7 +204,7 @@ static int phy_qcom_mipi_csi2_power_off(struct phy *phy)
>  
>  	dev_pm_opp_set_rate(csi2phy->dev, 0);
>  
> -	for (i = 0; i < csi2phy->pd_list->num_pds; i++) {
> +	for (i = 0; csi2phy->pd_list && i < csi2phy->pd_list->num_pds; i++) {
>  		if (!csi2phy->soc_cfg->genpds[i].scaled)
>  			continue;
>  
> @@ -231,7 +231,11 @@ static int phy_qcom_mipi_csi2_attach_pm_domains(struct mipi_csi2phy_device *csi2
>  {
>  	struct dev_pm_domain_attach_data pd_data = { 0 };
>  	const char **pd_names;
> -	int i;
> +	int i, ret;
> +
> +	/* Single power-domain devices are already attached by the bus core. */
> +	if (csi2phy->soc_cfg->num_genpds == 1)
> +		return dev_pm_domain_attach(csi2phy->dev, 0);
>  
>  	pd_names = devm_kzalloc(csi2phy->dev,
>  				sizeof(char *) * csi2phy->soc_cfg->num_genpds,
> @@ -245,8 +249,12 @@ static int phy_qcom_mipi_csi2_attach_pm_domains(struct mipi_csi2phy_device *csi2
>  	pd_data.pd_names = pd_names;
>  	pd_data.num_pd_names = csi2phy->soc_cfg->num_genpds;
>  
> -	return devm_pm_domain_attach_list(csi2phy->dev, &pd_data,
> -					  &csi2phy->pd_list);
> +	ret = devm_pm_domain_attach_list(csi2phy->dev, &pd_data,
> +					 &csi2phy->pd_list);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
>  }
>  
>  static int phy_qcom_mipi_csi2_parse_routing(struct mipi_csi2phy_device *csi2phy)
> @@ -369,11 +377,8 @@ static int phy_qcom_mipi_csi2_probe(struct platform_device *pdev)
>  		return ret;
>  
>  	ret = phy_qcom_mipi_csi2_attach_pm_domains(csi2phy);
> -	if (ret < 0 || csi2phy->pd_list == NULL) {
> -		if (ret == 0)
> -			ret = -ENODEV;
> +	if (ret < 0)

I thought you said you were going to fix this ?

Once done you may add


Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>

But not until ;)