Hi Dmitry, On Thu, Dec 01, 2016 at 04:37:37PM -0800, Dmitry Torokhov wrote: > On Thu, Dec 01, 2016 at 04:31:10PM -0800, Brian Norris wrote: > > 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@xxxxxxxxxxxx> > > Signed-off-by: Caesar Wang <wxt@xxxxxxxxxxxxxx> > > Cc: Jiri Kosina <jikos@xxxxxxxxxx> > > Cc: linux-input@xxxxxxxxxxxxxxx > > --- > > v2: > > * support compatible property for wacom, with specific "vdd-supply" name > > * support the 100ms delay needed for this digitizer > > * target regulator support only at specific device > > > > v3: > > * drop Wacom specifics and allow this to be used generically > > * add "init-delay-ms" property support > > > > drivers/hid/i2c-hid/i2c-hid.c | 48 ++++++++++++++++++++++++++++++++++++++++++- > > include/linux/i2c/i2c-hid.h | 6 ++++++ > > 2 files changed, 53 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c > > index b3ec4f2de875..4cb523133d13 100644 > > --- a/drivers/hid/i2c-hid/i2c-hid.c > > +++ b/drivers/hid/i2c-hid/i2c-hid.c > > @@ -37,7 +37,9 @@ > > #include <linux/mutex.h> > > #include <linux/acpi.h> > > #include <linux/of.h> > > +#include <linux/of_device.h> > > #include <linux/gpio/consumer.h> > > +#include <linux/regulator/consumer.h> > > > > #include <linux/i2c/i2c-hid.h> > > > > @@ -937,6 +939,22 @@ static int i2c_hid_of_probe(struct i2c_client *client, > > } > > pdata->hid_descriptor_address = val; > > > > + ret = of_property_read_u32(dev->of_node, "init-delay-ms", &val); > > + if (!ret) > > + pdata->init_delay_ms = ret; > > + > > + pdata->supply = devm_regulator_get_optional(dev, "vdd"); > > Make it devm_regulator_get(), it's cleaner (you'll get a dummy regulator > that you can enable/disbale and not check if it is null or not). > > pdata->supply = devm_regulator_get_optional(dev, "vdd"); > if (IS_ERR(pdata->supply)) { > ret = PTR_ERR(pdata->supply); > if (ret != -EPROBE_DEFER) > dev_err(...); > return ret; > } I had it as devm_regulator_get() in v1, but at that time, I was faking the firmware init delay using a regulator property. Now that I want to delay in this driver after enabling the regulator, I'd like to know the difference between a dummy and a real regulator. There's no need to wait after messing with the dummy regulator. Brian -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html