HID: i2c-hid: elan: Add ili9882t timing

The ili9882t is a TDDI IC (Touch with Display Driver). The
datasheet specifies there should be 60ms between touch SDA
sleep and panel RESX. Doug's series[1] allows panels and
touchscreens to power on/off together, so we can add the 65 ms
delay in i2c_hid_core_suspend before panel_unprepare.

Because ili9882t touchscrgeen is a panel follower, and
needs to use vccio-supply instead of vcc33-supply, so set
it NULL to ili9882t_chip_data, then not use vcc33 regulator.

[1]: https://lore.kernel.org/all/20230727171750.633410-1-dianders@chromium.org

Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Cong Yang <yangcong5@huaqin.corp-partner.google.com>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20230802071947.1683318-3-yangcong5@huaqin.corp-partner.google.com
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

diff --git a/drivers/hid/i2c-hid/i2c-hid-of-elan.c b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
index 029045d..31abab5 100644 (file)
--- a/drivers/hid/i2c-hid/i2c-hid-of-elan.c
+++ b/drivers/hid/i2c-hid/i2c-hid-of-elan.c
@@ -18,9 +18,11 @@
 #include "i2c-hid.h"
 
 struct elan_i2c_hid_chip_data {
-       unsigned int post_gpio_reset_delay_ms;
+       unsigned int post_gpio_reset_on_delay_ms;
+       unsigned int post_gpio_reset_off_delay_ms;
        unsigned int post_power_delay_ms;
        u16 hid_descriptor_address;
+       const char *main_supply_name;
 };
 
 struct i2c_hid_of_elan {
@@ -38,9 +40,11 @@ static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
                container_of(ops, struct i2c_hid_of_elan, ops);
        int ret;
 
-       ret = regulator_enable(ihid_elan->vcc33);
-       if (ret)
-               return ret;
+       if (ihid_elan->vcc33) {
+               ret = regulator_enable(ihid_elan->vcc33);
+               if (ret)
+                       return ret;
+       }
 
        ret = regulator_enable(ihid_elan->vccio);
        if (ret) {
@@ -52,8 +56,8 @@ static int elan_i2c_hid_power_up(struct i2chid_ops *ops)
                msleep(ihid_elan->chip_data->post_power_delay_ms);
 
        gpiod_set_value_cansleep(ihid_elan->reset_gpio, 0);
-       if (ihid_elan->chip_data->post_gpio_reset_delay_ms)
-               msleep(ihid_elan->chip_data->post_gpio_reset_delay_ms);
+       if (ihid_elan->chip_data->post_gpio_reset_on_delay_ms)
+               msleep(ihid_elan->chip_data->post_gpio_reset_on_delay_ms);
 
        return 0;
 }
@@ -64,8 +68,12 @@ static void elan_i2c_hid_power_down(struct i2chid_ops *ops)
                container_of(ops, struct i2c_hid_of_elan, ops);
 
        gpiod_set_value_cansleep(ihid_elan->reset_gpio, 1);
+       if (ihid_elan->chip_data->post_gpio_reset_off_delay_ms)
+               msleep(ihid_elan->chip_data->post_gpio_reset_off_delay_ms);
+
        regulator_disable(ihid_elan->vccio);
-       regulator_disable(ihid_elan->vcc33);
+       if (ihid_elan->vcc33)
+               regulator_disable(ihid_elan->vcc33);
 }
 
 static int i2c_hid_of_elan_probe(struct i2c_client *client)
@@ -89,24 +97,42 @@ static int i2c_hid_of_elan_probe(struct i2c_client *client)
        if (IS_ERR(ihid_elan->vccio))
                return PTR_ERR(ihid_elan->vccio);
 
-       ihid_elan->vcc33 = devm_regulator_get(&client->dev, "vcc33");
-       if (IS_ERR(ihid_elan->vcc33))
-               return PTR_ERR(ihid_elan->vcc33);
-
        ihid_elan->chip_data = device_get_match_data(&client->dev);
 
+       if (ihid_elan->chip_data->main_supply_name) {
+               ihid_elan->vcc33 = devm_regulator_get(&client->dev,
+                                                     ihid_elan->chip_data->main_supply_name);
+               if (IS_ERR(ihid_elan->vcc33))
+                       return PTR_ERR(ihid_elan->vcc33);
+       }
+
        return i2c_hid_core_probe(client, &ihid_elan->ops,
                                  ihid_elan->chip_data->hid_descriptor_address, 0);
 }
 
 static const struct elan_i2c_hid_chip_data elan_ekth6915_chip_data = {
        .post_power_delay_ms = 1,
-       .post_gpio_reset_delay_ms = 300,
+       .post_gpio_reset_on_delay_ms = 300,
+       .hid_descriptor_address = 0x0001,
+       .main_supply_name = "vcc33",
+};
+
+static const struct elan_i2c_hid_chip_data ilitek_ili9882t_chip_data = {
+       .post_power_delay_ms = 1,
+       .post_gpio_reset_on_delay_ms = 200,
+       .post_gpio_reset_off_delay_ms = 65,
        .hid_descriptor_address = 0x0001,
+       /*
+        * this touchscreen is tightly integrated with the panel and assumes
+        * that the relevant power rails (other than the IO rail) have already
+        * been turned on by the panel driver because we're a panel follower.
+        */
+       .main_supply_name = NULL,
 };
 
 static const struct of_device_id elan_i2c_hid_of_match[] = {
        { .compatible = "elan,ekth6915", .data = &elan_ekth6915_chip_data },
+       { .compatible = "ilitek,ili9882t", .data = &ilitek_ili9882t_chip_data },
        { }
 };
 MODULE_DEVICE_TABLE(of, elan_i2c_hid_of_match);