[PATCH v4] phy: phy-imx8mq-usb: add vbus regulator support

[Marek Vasut]

On 7/11/23 00:49, Tim Harvey wrote:
> Add support for enabling and disabling vbus-supply regulator found
> on several imx8mp boards in the usb3_phy0 and usb3_phy1 nodes.
> 
> Signed-off-by: Tim Harvey <tharvey at gateworks.com>
> Reviewed-by: Adam Ford <aford173 at gmail.com>
> Reviewed-by: Marek Vasut <marex at denx.de>
> ---
> v4:
>   - use regulator_set_enable_if_allowed to handle regulator reference counting
>     errors
>   - added Marek's rb tag
> 
> v3:
>   - change pr_err to dev_err
>   - add #if CONFIG_IS_ENABLED around vbus_supply in struct
>   - add fail path to disable clock if regulator enable failed
> 
> v2:
>   - protect ret with __maybe_unused in case CONFIG_CLK and
>     CONFIG_DM_REGULATOR not defined
>   - add error prints on failures
>   - add Adam's rb tag
> ---
>   drivers/phy/phy-imx8mq-usb.c | 39 ++++++++++++++++++++++++++++++++++--
>   1 file changed, 37 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/phy/phy-imx8mq-usb.c b/drivers/phy/phy-imx8mq-usb.c
> index 69f01de55538..6cbcb2338cfe 100644
> --- a/drivers/phy/phy-imx8mq-usb.c
> +++ b/drivers/phy/phy-imx8mq-usb.c
> @@ -14,6 +14,8 @@
>   #include <linux/delay.h>
>   #include <linux/err.h>
>   #include <clk.h>
> +#include <dm/device_compat.h>
> +#include <power/regulator.h>
>   
>   #define PHY_CTRL0			0x0
>   #define PHY_CTRL0_REF_SSP_EN		BIT(2)
> @@ -81,6 +83,9 @@ struct imx8mq_usb_phy {
>   #endif
>   	void __iomem *base;
>   	enum imx8mpq_phy_type type;
> +#if CONFIG_IS_ENABLED(DM_REGULATOR)
> +	struct udevice *vbus_supply;
> +#endif
>   };
>   
>   static const struct udevice_id imx8mq_usb_phy_of_match[] = {
> @@ -172,10 +177,10 @@ static int imx8mq_usb_phy_power_on(struct phy *usb_phy)
>   {
>   	struct udevice *dev = usb_phy->dev;
>   	struct imx8mq_usb_phy *imx_phy = dev_get_priv(dev);
> +	__maybe_unused int ret;
>   	u32 value;
>   
>   #if CONFIG_IS_ENABLED(CLK)
> -	int ret;
>   	ret = clk_enable(&imx_phy->phy_clk);
>   	if (ret) {
>   		printf("Failed to enable usb phy clock\n");
> @@ -183,18 +188,31 @@ static int imx8mq_usb_phy_power_on(struct phy *usb_phy)
>   	}
>   #endif
>   
> +	if (CONFIG_IS_ENABLED(DM_REGULATOR) && imx_phy->vbus_supply) {
> +		ret = regulator_set_enable_if_allowed(imx_phy->vbus_supply, true);
> +		if (ret && ret != -ENOSYS) {
> +			dev_err(dev, "Failed to enable VBUS regulator: %d\n", ret);
> +			goto err;
> +		}
> +	}
> +
>   	/* Disable rx term override */
>   	value = readl(imx_phy->base + PHY_CTRL6);
>   	value &= ~PHY_CTRL6_RXTERM_OVERRIDE_SEL;
>   	writel(value, imx_phy->base + PHY_CTRL6);
>   
>   	return 0;
> +
> +err:
> +	clk_disable(&imx_phy->phy_clk);
> +	return ret;
>   }
>   
>   static int imx8mq_usb_phy_power_off(struct phy *usb_phy)
>   {
>   	struct udevice *dev = usb_phy->dev;
>   	struct imx8mq_usb_phy *imx_phy = dev_get_priv(dev);
> +	__maybe_unused int ret;
>   	u32 value;
>   
>   	/* Override rx term to be 0 */
> @@ -206,6 +224,14 @@ static int imx8mq_usb_phy_power_off(struct phy *usb_phy)
>   	clk_disable(&imx_phy->phy_clk);
>   #endif
>   
> +	if (CONFIG_IS_ENABLED(DM_REGULATOR) && imx_phy->vbus_supply) {
> +		ret = regulator_set_enable_if_allowed(imx_phy->vbus_supply, false);
> +		if (ret && ret != -ENOSYS) {
> +			dev_err(dev, "Failed to disable VBUS regulator: %d\n", ret);
> +			return ret;
> +		}
> +	}
> +
>   	return 0;
>   }
>   
> @@ -224,6 +250,7 @@ struct phy_ops imx8mq_usb_phy_ops = {
>   int imx8mq_usb_phy_probe(struct udevice *dev)
>   {
>   	struct imx8mq_usb_phy *priv = dev_get_priv(dev);
> +	__maybe_unused int ret;
>   
>   	priv->type = dev_get_driver_data(dev);
>   	priv->base = dev_read_addr_ptr(dev);
> @@ -232,7 +259,6 @@ int imx8mq_usb_phy_probe(struct udevice *dev)
>   		return -EINVAL;
>   
>   #if CONFIG_IS_ENABLED(CLK)
> -	int ret;

I _think_ if you were to convert this #if CONFIG...() to if 
(CONFIG...()), you would be able to drop the __maybe_unused . Separate 
conversion patch would be better though.