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Subject[PATCH 4/4] usb: typec: ucsi: stm32g0: add support for power management
Date
Type-C connector can be used as a wakeup source (typically to detect
changes on the port, attach or detach...).
Add suspend / resume routines to enable wake irqs, and signal a wakeup
event in case the IRQ has fired while in suspend.
The i2c core is doing the necessary initialization when the "wakeup-source"
flag is provided.
Note: the interrupt handler shouldn't be called before the i2c bus resumes.
So, the interrupts are disabled during suspend period, and re-enabled
upon resume, to avoid i2c transfer while suspended, from the irq handler.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
---
drivers/usb/typec/ucsi/ucsi_stm32g0.c | 52 +++++++++++++++++++++++++++
1 file changed, 52 insertions(+)

diff --git a/drivers/usb/typec/ucsi/ucsi_stm32g0.c b/drivers/usb/typec/ucsi/ucsi_stm32g0.c
index 91222f4e07aee..1c7f4b92eba7c 100644
--- a/drivers/usb/typec/ucsi/ucsi_stm32g0.c
+++ b/drivers/usb/typec/ucsi/ucsi_stm32g0.c
@@ -66,6 +66,8 @@ struct ucsi_stm32g0 {
unsigned long flags;
const char *fw_name;
struct ucsi *ucsi;
+ bool suspended;
+ bool wakeup_event;
};

/*
@@ -416,6 +418,9 @@ static irqreturn_t ucsi_stm32g0_irq_handler(int irq, void *data)
u32 cci;
int ret;

+ if (g0->suspended)
+ g0->wakeup_event = true;
+
ret = ucsi_stm32g0_read(g0->ucsi, UCSI_CCI, &cci, sizeof(cci));
if (ret)
return IRQ_NONE;
@@ -696,6 +701,52 @@ static int ucsi_stm32g0_remove(struct i2c_client *client)
return 0;
}

+static int ucsi_stm32g0_suspend(struct device *dev)
+{
+ struct ucsi_stm32g0 *g0 = dev_get_drvdata(dev);
+ struct i2c_client *client = g0->client;
+
+ if (g0->in_bootloader)
+ return 0;
+
+ /* Keep the interrupt disabled until the i2c bus has been resumed */
+ disable_irq(client->irq);
+
+ g0->suspended = true;
+ g0->wakeup_event = false;
+
+ if (device_may_wakeup(dev) || device_wakeup_path(dev))
+ enable_irq_wake(client->irq);
+
+ return 0;
+}
+
+static int ucsi_stm32g0_resume(struct device *dev)
+{
+ struct ucsi_stm32g0 *g0 = dev_get_drvdata(dev);
+ struct i2c_client *client = g0->client;
+
+ if (g0->in_bootloader)
+ return 0;
+
+ if (device_may_wakeup(dev) || device_wakeup_path(dev))
+ disable_irq_wake(client->irq);
+
+ enable_irq(client->irq);
+
+ /* Enforce any pending handler gets called to signal a wakeup_event */
+ synchronize_irq(client->irq);
+
+ if (g0->wakeup_event)
+ pm_wakeup_event(g0->dev, 0);
+
+ g0->suspended = false;
+
+ return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(ucsi_stm32g0_pm_ops, ucsi_stm32g0_suspend, ucsi_stm32g0_resume);
+
static const struct of_device_id __maybe_unused ucsi_stm32g0_typec_of_match[] = {
{ .compatible = "st,stm32g0-typec" },
{},
@@ -712,6 +763,7 @@ static struct i2c_driver ucsi_stm32g0_i2c_driver = {
.driver = {
.name = "ucsi-stm32g0-i2c",
.of_match_table = of_match_ptr(ucsi_stm32g0_typec_of_match),
+ .pm = pm_sleep_ptr(&ucsi_stm32g0_pm_ops),
},
.probe = ucsi_stm32g0_probe,
.remove = ucsi_stm32g0_remove,
--
2.25.1
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