[PATCH 2/2] HID: i2c-hid: Add the ability to control a reset GPIO
From: Douglas Anderson <dianders@chromium.org>
Date: 2020-10-15 02:09:40
Also in:
lkml
Subsystem:
hid core layer, the rest · Maintainers:
Jiri Kosina, Benjamin Tissoires, Linus Torvalds
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@chromium.org>
---
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