usb: typec: tps6598x: add reset gpio support

The TPS6598x PD controller provides an active-high hardware reset input
that reinitializes all device settings. If it is not grounded by
design, the driver must be able to de-assert it in order to initialize
the device.

The PD controller is not ready for registration right after the reset
de-assertion and a delay must be introduced in that case. According to
TI, the delay can reach up to 1000 ms [1], which is in line with the
experimental results obtained with a TPS65987D.

Add a GPIO descriptor for the reset signal and basic reset management
for initialization and suspend/resume.

[1] https://e2e.ti.com/support/power-management-group/power-management/
f/power-management-forum/1269856/tps65987d-tps65987d-reset-de-assert-
to-normal-operation/4809389#4809389

Signed-off-by: Javier Carrasco <javier.carrasco@wolfvision.net>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230912-topic-tps6598x_reset-v3-1-0c2873070a77@wolfvision.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
index 196535ad996d080ff50340472e32e00e2445b257..806ef68273ca0e414f00a7570d01a797ae2ff9d3 100644 (file)
--- a/drivers/usb/typec/tipd/core.c
+++ b/drivers/usb/typec/tipd/core.c
@@ -8,6 +8,7 @@
 
 #include <linux/i2c.h>
 #include <linux/acpi.h>
+#include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/power_supply.h>
@@ -64,6 +65,9 @@
 #define TPS_PBMC_RC    0 /* Return code */
 #define TPS_PBMC_DPCS  2 /* device patch complete status */
 
+/* reset de-assertion to ready for operation */
+#define TPS_SETUP_MS                   1000
+
 enum {
        TPS_PORTINFO_SINK,
        TPS_PORTINFO_SINK_ACCESSORY,
@@ -119,6 +123,7 @@ struct tps6598x {
        struct mutex lock; /* device lock */
        u8 i2c_protocol:1;
 
+       struct gpio_desc *reset;
        struct typec_port *port;
        struct typec_partner *partner;
        struct usb_pd_identity partner_identity;
@@ -1191,6 +1196,13 @@ static int tps6598x_probe(struct i2c_client *client)
        mutex_init(&tps->lock);
        tps->dev = &client->dev;
 
+       tps->reset = devm_gpiod_get_optional(tps->dev, "reset", GPIOD_OUT_LOW);
+       if (IS_ERR(tps->reset))
+               return dev_err_probe(tps->dev, PTR_ERR(tps->reset),
+                                    "failed to get reset GPIO\n");
+       if (tps->reset)
+               msleep(TPS_SETUP_MS);
+
        tps->regmap = devm_regmap_init_i2c(client, &tps6598x_regmap_config);
        if (IS_ERR(tps->regmap))
                return PTR_ERR(tps->regmap);
@@ -1348,6 +1360,9 @@ static void tps6598x_remove(struct i2c_client *client)
        /* Reset PD controller to remove any applied patch */
        if (device_is_compatible(tps->dev, "ti,tps25750"))
                tps6598x_exec_cmd_tmo(tps, "GAID", 0, NULL, 0, NULL, 2000, 0);
+
+       if (tps->reset)
+               gpiod_set_value_cansleep(tps->reset, 1);
 }
 
 static int __maybe_unused tps6598x_suspend(struct device *dev)
@@ -1358,6 +1373,8 @@ static int __maybe_unused tps6598x_suspend(struct device *dev)
        if (tps->wakeup) {
                disable_irq(client->irq);
                enable_irq_wake(client->irq);
+       } else if (tps->reset) {
+               gpiod_set_value_cansleep(tps->reset, 1);
        }
 
        if (!client->irq)
@@ -1385,6 +1402,9 @@ static int __maybe_unused tps6598x_resume(struct device *dev)
        if (tps->wakeup) {
                disable_irq_wake(client->irq);
                enable_irq(client->irq);
+       } else if (tps->reset) {
+               gpiod_set_value_cansleep(tps->reset, 0);
+               msleep(TPS_SETUP_MS);
        }
 
        if (!client->irq)