Re: [PATCH 7/8] usb: misc: eud: Handle usb role switch notifications

Dmitry Baryshkov
2024-07-31T13:06:44Z

On Tue, Jul 30, 2024 at 03:24:38PM GMT, Elson Roy Serrao wrote:
> Since EUD is physically present between the USB connector and
> the USB controller, it should relay the usb role notifications
> from the connector. Hence register a role switch handler to
> process and relay these roles to the USB controller. This results
> in a common framework to send both connector related events
> and eud attach/detach events to the USB controller.
>
> Signed-off-by: Elson Roy Serrao <quic_eserrao@quicinc.com>
> ---
> drivers/usb/misc/qcom_eud.c | 91 ++++++++++++++++++++++++++++---------
> 1 file changed, 69 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/usb/misc/qcom_eud.c b/drivers/usb/misc/qcom_eud.c
> index 3de7d465912c..9a49c934e8cf 100644
> --- a/drivers/usb/misc/qcom_eud.c
> +++ b/drivers/usb/misc/qcom_eud.c
> @@ -10,6 +10,7 @@
> #include <linux/iopoll.h>
> #include <linux/kernel.h>
> #include <linux/module.h>
> +#include <linux/mutex.h>
> #include <linux/of.h>
> #include <linux/phy/phy.h>
> #include <linux/platform_device.h>
> @@ -35,12 +36,16 @@ struct eud_chip {
> struct device *dev;
> struct usb_role_switch *role_sw;
> struct phy *usb2_phy;
> +
> + /* mode lock */
> + struct mutex mutex;
> void __iomem *base;
> void __iomem *mode_mgr;
> unsigned int int_status;
> int irq;
> bool enabled;
> bool usb_attached;
> + enum usb_role current_role;
> };
>
> static int eud_phy_enable(struct eud_chip *chip)
> @@ -64,6 +69,38 @@ static void eud_phy_disable(struct eud_chip *chip)
> phy_exit(chip->usb2_phy);
> }
>
> +static int eud_usb_role_set(struct eud_chip *chip, enum usb_role role)
> +{
> + struct usb_role_switch *sw;
> + int ret = 0;
> +
> + mutex_lock(&chip->mutex);
> +
> + /* Avoid duplicate role handling */
> + if (role == chip->current_role)
> + goto err;
> +
> + sw = usb_role_switch_get(chip->dev);

Why isn't chip->role_sw good enough? Why do you need to get it each
time?

> + if (IS_ERR_OR_NULL(sw)) {
> + dev_err(chip->dev, "failed to get usb switch\n");
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + ret = usb_role_switch_set_role(sw, role);
> + usb_role_switch_put(sw);
> +
> + if (ret) {
> + dev_err(chip->dev, "failed to set role\n");
> + goto err;
> + }
> + chip->current_role = role;
> +err:
> + mutex_unlock(&chip->mutex);
> +
> + return ret;
> +}
> +
> static int enable_eud(struct eud_chip *priv)
> {
> int ret;
> @@ -77,7 +114,7 @@ static int enable_eud(struct eud_chip *priv)
> priv->base + EUD_REG_INT1_EN_MASK);
> writel(1, priv->mode_mgr + EUD_REG_EUD_EN2);
>
> - return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE);
> + return ret;
> }
>
> static void disable_eud(struct eud_chip *priv)
> @@ -106,15 +143,20 @@ static ssize_t enable_store(struct device *dev,
> if (kstrtobool(buf, &enable))
> return -EINVAL;
>
> + /* EUD enable is applicable only in DEVICE mode */
> + if (enable && chip->current_role != USB_ROLE_DEVICE)
> + return -EINVAL;
> +
> if (enable) {
> ret = enable_eud(chip);
> - if (!ret)
> - chip->enabled = enable;
> - else
> - disable_eud(chip);
> + if (ret) {
> + dev_err(chip->dev, "failed to enable eud\n");
> + return count;
> + }
> } else {
> disable_eud(chip);
> }
> + chip->enabled = enable;
>
> return count;
> }
> @@ -185,11 +227,9 @@ static irqreturn_t handle_eud_irq_thread(int irq, void *data)
> int ret;
>
> if (chip->usb_attached)
> - ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_DEVICE);
> + ret = eud_usb_role_set(chip, USB_ROLE_DEVICE);
> else
> - ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_HOST);
> - if (ret)
> - dev_err(chip->dev, "failed to set role switch\n");
> + ret = eud_usb_role_set(chip, USB_ROLE_HOST);
>
> /* set and clear vbus_int_clr[0] to clear interrupt */
> writel(BIT(0), chip->base + EUD_REG_VBUS_INT_CLR);
> @@ -198,16 +238,18 @@ static irqreturn_t handle_eud_irq_thread(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> -static void eud_role_switch_release(void *data)
> +static int eud_usb_role_switch_set(struct usb_role_switch *sw,
> + enum usb_role role)
> {
> - struct eud_chip *chip = data;
> + struct eud_chip *chip = usb_role_switch_get_drvdata(sw);
>
> - usb_role_switch_put(chip->role_sw);
> + return eud_usb_role_set(chip, role);
> }
>
> static int eud_probe(struct platform_device *pdev)
> {
> struct eud_chip *chip;
> + struct usb_role_switch_desc eud_role_switch = {NULL};
> int ret;
>
> chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
> @@ -221,16 +263,6 @@ static int eud_probe(struct platform_device *pdev)
> return dev_err_probe(chip->dev, PTR_ERR(chip->usb2_phy),
> "no usb2 phy configured\n");
>
> - chip->role_sw = usb_role_switch_get(&pdev->dev);
> - if (IS_ERR(chip->role_sw))
> - return dev_err_probe(chip->dev, PTR_ERR(chip->role_sw),
> - "failed to get role switch\n");
> -
> - ret = devm_add_action_or_reset(chip->dev, eud_role_switch_release, chip);
> - if (ret)
> - return dev_err_probe(chip->dev, ret,
> - "failed to add role switch release action\n");
> -
> chip->base = devm_platform_ioremap_resource(pdev, 0);
> if (IS_ERR(chip->base))
> return PTR_ERR(chip->base);
> @@ -248,6 +280,18 @@ static int eud_probe(struct platform_device *pdev)
> if (ret)
> return dev_err_probe(chip->dev, ret, "failed to allocate irq\n");
>
> + eud_role_switch.fwnode = dev_fwnode(chip->dev);
> + eud_role_switch.set = eud_usb_role_switch_set;
> + eud_role_switch.get = NULL;
> + eud_role_switch.driver_data = chip;
> + chip->role_sw = usb_role_switch_register(chip->dev, &eud_role_switch);
> +
> + if (IS_ERR(chip->role_sw))
> + return dev_err_probe(chip->dev, PTR_ERR(chip->role_sw),
> + "failed to register role switch\n");
> +
> + mutex_init(&chip->mutex);

please move mutex_init earlier.

> +
> enable_irq_wake(chip->irq);
>
> platform_set_drvdata(pdev, chip);
> @@ -262,6 +306,9 @@ static void eud_remove(struct platform_device *pdev)
> if (chip->enabled)
> disable_eud(chip);
>
> + if (chip->role_sw)
> + usb_role_switch_unregister(chip->role_sw);
> +
> device_init_wakeup(&pdev->dev, false);
> disable_irq_wake(chip->irq);
> }
> --
> 2.17.1
>

--
With best wishes
Dmitry