HID: i2c-hid: support regulator power on/off

On some boards, we need to enable a regulator before using the HID, and
it's also nice to save power in suspend by disabling it. Support an
optional "vdd-supply" and a companion initialization delay.

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: linux-input@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

2 files changed, 46 insertions, 2 deletions

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index ea3c3546cef7..a3f6daf0886b 100644
--- a/drivers/hid/i2c-hid/i2c-hid.c
+++ b/drivers/hid/i2c-hid/i2c-hid.c
@@ -994,6 +994,11 @@ static int i2c_hid_of_probe(struct i2c_client *client,
         }
         pdata->hid_descriptor_address = val;
 
+        ret = of_property_read_u32(dev->of_node, "post-power-on-delay-ms",
+                                   &val);
+        if (!ret)
+                pdata->post_power_delay_ms = val;
+
         return 0;
 }
 
@@ -1053,6 +1058,24 @@ static int i2c_hid_probe(struct i2c_client *client,
                 ihid->pdata = *platform_data;
         }
 
+        ihid->pdata.supply = devm_regulator_get(&client->dev, "vdd");
+        if (IS_ERR(ihid->pdata.supply)) {
+                ret = PTR_ERR(ihid->pdata.supply);
+                if (ret != -EPROBE_DEFER)
+                        dev_err(&client->dev, "Failed to get regulator: %d\n",
+                                ret);
+                return ret;
+        }
+
+        ret = regulator_enable(ihid->pdata.supply);
+        if (ret < 0) {
+                dev_err(&client->dev, "Failed to enable regulator: %d\n",
+                        ret);
+                goto err;
+        }
+        if (ihid->pdata.post_power_delay_ms)
+                msleep(ihid->pdata.post_power_delay_ms);
+
         i2c_set_clientdata(client, ihid);
 
         ihid->client = client;
@@ -1068,7 +1091,7 @@ static int i2c_hid_probe(struct i2c_client *client,
          * real computation later. */
         ret = i2c_hid_alloc_buffers(ihid, HID_MIN_BUFFER_SIZE);
         if (ret < 0)
-                goto err;
+                goto err_regulator;
 
         pm_runtime_get_noresume(&client->dev);
         pm_runtime_set_active(&client->dev);
@@ -1125,6 +1148,9 @@ err_pm:
         pm_runtime_put_noidle(&client->dev);
         pm_runtime_disable(&client->dev);
 
+err_regulator:
+        regulator_disable(ihid->pdata.supply);
+
 err:
         i2c_hid_free_buffers(ihid);
         kfree(ihid);
@@ -1149,6 +1175,8 @@ static int i2c_hid_remove(struct i2c_client *client)
         if (ihid->bufsize)
                 i2c_hid_free_buffers(ihid);
 
+        regulator_disable(ihid->pdata.supply);
+
         kfree(ihid);
 
         return 0;
@@ -1199,6 +1227,10 @@ static int i2c_hid_suspend(struct device *dev)
                 else
                         hid_warn(hid, "Failed to enable irq wake: %d\n",
                                 wake_status);
+        } else {
+                ret = regulator_disable(ihid->pdata.supply);
+                if (ret < 0)
+                        hid_warn(hid, "Failed to disable supply: %d\n", ret);
         }
 
         return 0;
@@ -1212,7 +1244,13 @@ static int i2c_hid_resume(struct device *dev)
         struct hid_device *hid = ihid->hid;
         int wake_status;
 
-        if (device_may_wakeup(&client->dev) && ihid->irq_wake_enabled) {
+        if (!device_may_wakeup(&client->dev)) {
+                ret = regulator_enable(ihid->pdata.supply);
+                if (ret < 0)
+                        hid_warn(hid, "Failed to enable supply: %d\n", ret);
+                if (ihid->pdata.post_power_delay_ms)
+                        msleep(ihid->pdata.post_power_delay_ms);
+        } else if (ihid->irq_wake_enabled) {
                 wake_status = disable_irq_wake(client->irq);
                 if (!wake_status)
                         ihid->irq_wake_enabled = false;
diff --git a/include/linux/i2c/i2c-hid.h b/include/linux/i2c/i2c-hid.h
index 7aa901d92058..1fb088239d12 100644
--- a/include/linux/i2c/i2c-hid.h
+++ b/include/linux/i2c/i2c-hid.h
@@ -14,9 +14,13 @@
 
 #include <linux/types.h>
 
+struct regulator;
+
 /**
  * struct i2chid_platform_data - used by hid over i2c implementation.
  * @hid_descriptor_address: i2c register where the HID descriptor is stored.
+ * @supply: regulator for powering on the device.
+ * @post_power_delay_ms: delay after powering on before device is usable.
  *
  * 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
@@ -31,6 +35,8 @@
  */
 struct i2c_hid_platform_data {
         u16 hid_descriptor_address;
+        struct regulator *supply;
+        int post_power_delay_ms;
 };
 
 #endif /* __LINUX_I2C_HID_H */