On Sep 05 2016 or thereabouts, Caesar Wang wrote:
> From: Brian Norris <briannor...@chromium.org>
>
> In order to allow supporting the HID based devices that need power on/off
> the regulator. We try to get a power-supply property from the
> device tree.
>
> Signed-off-by: Brian Norris <briannor...@chromium.org>
> Signed-off-by: Caesar Wang <w...@rock-chips.com>
> Cc: Jiri Kosina <ji...@kernel.org>
> Cc: linux-in...@vger.kernel.org
>
> ---
>
> drivers/hid/i2c-hid/i2c-hid.c | 31 ++++++++++++++++++++++++++++++-
> 1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index b3ec4f2..07cc7aa 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -38,6 +38,7 @@
> #include <linux/acpi.h>
> #include <linux/of.h>
> #include <linux/gpio/consumer.h>
> +#include <linux/regulator/consumer.h>
>
> #include <linux/i2c/i2c-hid.h>
>
> @@ -152,6 +153,7 @@ struct i2c_hid {
>
> bool irq_wake_enabled;
> struct mutex reset_lock;
> + struct regulator *supply;
> };
>
> static int __i2c_hid_command(struct i2c_client *client,
> @@ -968,6 +970,21 @@ static int i2c_hid_probe(struct i2c_client *client,
> if (!ihid)
> return -ENOMEM;
>
> + ihid->supply = devm_regulator_get(&client->dev, "power");
> + if (IS_ERR(ihid->supply)) {
I am not familiar with regulators, but what if (like 99% of the
available i2c-hid devices) there is no regulator attached to the device?
Will the pointer be null? Will there be a dummy regulator?
It seems at first sight that you are adding a requirement on the devices
which is not part of the spec, and which will break every existing
systems but yours. Again, I might be wrong, so please provide more
information.
Cheers,
Benjamin
> + ret = PTR_ERR(ihid->supply);
> + dev_err(&client->dev, "Failed to get power regulator: %d\n",
> + ret);
> + return ret;
> + }
> +
> + ret = regulator_enable(ihid->supply);
> + if (ret < 0) {
> + dev_err(&client->dev, "Failed to enable power regulator: %d\n",
> + ret);
> + return ret;
> + }
> +
> if (client->dev.of_node) {
> ret = i2c_hid_of_probe(client, &ihid->pdata);
> if (ret)
> @@ -1100,6 +1117,8 @@ static int i2c_hid_remove(struct i2c_client *client)
> if (ihid->desc)
> gpiod_put(ihid->desc);
>
> + regulator_disable(ihid->supply);
> +
> kfree(ihid);
>
> acpi_dev_remove_driver_gpios(ACPI_COMPANION(&client->dev));
> @@ -1152,6 +1171,11 @@ 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->supply);
> + if (ret < 0)
> + hid_warn(hid, "Failed to disable power supply: %d\n",
> + ret);
> }
>
> return 0;
> @@ -1165,7 +1189,12 @@ 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->supply);
> + if (ret < 0)
> + hid_warn(hid, "Failed to enable power supply: %d\n",
> + ret);
> + } else if (ihid->irq_wake_enabled) {
> wake_status = disable_irq_wake(ihid->irq);
> if (!wake_status)
> ihid->irq_wake_enabled = false;
> --
> 1.9.1
>
