Apparently some devices connected via i2c-hid have timing requirements
around when a reset GPIO should be asserted to them. The diagram I
have seen, which I believe is from a Goodix device, looked like this:
+----------------------------------
|
AVDD ----+
+------------------------------
| (a) |
RESET ---------+
+-------------
| (b) |
I2C comm OK ---------+
Where (a) is 10 ms and (b) is 120 ms.
Let's add the ability to support this into the i2c-hid driver.
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
drivers/hid/i2c-hid/i2c-hid-core.c | 18 ++++++++++++++++++
include/linux/platform_data/i2c-hid.h | 5 +++++
2 files changed, 23 insertions(+)
diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
index 786e3e9af1c9..807b344b697b 100644
--- a/drivers/hid/i2c-hid/i2c-hid-core.c
+++ b/drivers/hid/i2c-hid/i2c-hid-core.c
@@ -1005,6 +1005,9 @@ static void i2c_hid_fwnode_probe(struct i2c_client *client,
if (!device_property_read_u32(&client->dev, "post-power-on-delay-ms",
&val))
pdata->post_power_delay_ms = val;
+ if (!device_property_read_u32(&client->dev, "post-gpio-reset-delay-ms",
+ &val))
+ pdata->post_gpio_reset_delay_ms = val;
}
static int i2c_hid_probe(struct i2c_client *client,
@@ -1053,6 +1056,12 @@ static int i2c_hid_probe(struct i2c_client *client,
ihid->pdata.supplies[0].supply = "vdd";
ihid->pdata.supplies[1].supply = "vddl";
+ /* Start out with reset asserted */
+ ihid->pdata.reset_gpio =
+ devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH);
+ if (IS_ERR(ihid->pdata.reset_gpio))
+ return PTR_ERR(ihid->pdata.reset_gpio);
+
ret = devm_regulator_bulk_get(&client->dev,
ARRAY_SIZE(ihid->pdata.supplies),
ihid->pdata.supplies);
@@ -1067,6 +1076,10 @@ static int i2c_hid_probe(struct i2c_client *client,
if (ihid->pdata.post_power_delay_ms)
msleep(ihid->pdata.post_power_delay_ms);
+ gpiod_set_value_cansleep(ihid->pdata.reset_gpio, 0);
+ if (ihid->pdata.post_gpio_reset_delay_ms)
+ msleep(ihid->pdata.post_gpio_reset_delay_ms);
+
i2c_set_clientdata(client, ihid);
ihid->client = client;
@@ -1163,6 +1176,7 @@ static int i2c_hid_remove(struct i2c_client *client)
if (ihid->bufsize)
i2c_hid_free_buffers(ihid);
+ gpiod_set_value_cansleep(ihid->pdata.reset_gpio, 1);
regulator_bulk_disable(ARRAY_SIZE(ihid->pdata.supplies),
ihid->pdata.supplies);
@@ -1228,6 +1242,10 @@ static int i2c_hid_resume(struct device *dev)
if (ihid->pdata.post_power_delay_ms)
msleep(ihid->pdata.post_power_delay_ms);
+
+ gpiod_set_value_cansleep(ihid->pdata.reset_gpio, 0);
+ if (ihid->pdata.post_gpio_reset_delay_ms)
+ msleep(ihid->pdata.post_gpio_reset_delay_ms);
} else if (ihid->irq_wake_enabled) {
wake_status = disable_irq_wake(client->irq);
if (!wake_status)
diff --git a/include/linux/platform_data/i2c-hid.h b/include/linux/platform_data/i2c-hid.h
index c628bb5e1061..b2150223ffa6 100644
--- a/include/linux/platform_data/i2c-hid.h
+++ b/include/linux/platform_data/i2c-hid.h
@@ -12,6 +12,7 @@
#ifndef __LINUX_I2C_HID_H
#define __LINUX_I2C_HID_H
+#include <linux/gpio/consumer.h>
#include <linux/regulator/consumer.h>
#include <linux/types.h>
@@ -20,6 +21,8 @@
* @hid_descriptor_address: i2c register where the HID descriptor is stored.
* @supplies: regulators for powering on the device.
* @post_power_delay_ms: delay after powering on before device is usable.
+ * @post_gpio_reset_delay_ms: delay after reset via GPIO.
+ * @reset_gpio: optional gpio to de-assert after post_power_delay_ms.
*
* Note that it is the responsibility of the platform driver (or the acpi 5.0
* driver, or the flattened device tree) to setup the irq related to the gpio in
@@ -36,6 +39,8 @@ struct i2c_hid_platform_data {
u16 hid_descriptor_address;
struct regulator_bulk_data supplies[2];
int post_power_delay_ms;
+ int post_gpio_reset_delay_ms;
+ struct gpio_desc *reset_gpio;
};
#endif /* __LINUX_I2C_HID_H */
--
2.28.0.1011.ga647a8990f-goog
