On 15/09/2023 07:50, Javier Carrasco wrote:
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@xxxxxxxxxxxxxx>
---
drivers/usb/typec/tipd/core.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/typec/tipd/core.c b/drivers/usb/typec/tipd/core.c
index 37b56ce75f39..550f5913e985 100644
--- 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>
@@ -43,6 +44,9 @@
/* TPS_REG_SYSTEM_CONF bits */
#define TPS_SYSCONF_PORTINFO(c) ((c) & 7)
+/* reset de-assertion to ready for operation */
+#define SETUP_MS 1000
+
enum {
TPS_PORTINFO_SINK,
TPS_PORTINFO_SINK_ACCESSORY,
@@ -86,6 +90,7 @@ 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;
@@ -717,6 +722,13 @@ 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(SETUP_MS);
+
This looks a bit odd to me, shouldn't you drive reset to zero ?
if (tps->reset) {
gpiod_set_value_cansleep(tps->reset, 0);
msleep(SETUP_MS);
}
also wouldn't it make sense to functionally decompose that and reuse in
probe() and tps6598x_resume() ?
tps6598x_reset() {
if (tps->reset) {
gpiod_set_value_cansleep(tps->reset, 0);
msleep(SETUP_MS);
}
}
---
bod
