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

Elson Roy Serrao
2024-07-30T22:24:48Z

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);
+ 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);
+
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