Re: [PATCH 2/2] HID: i2c-hid: support regulator power on/off

On Dec 02 2016 or thereabouts, Dmitry Torokhov wrote:

On Fri, Dec 02, 2016 at 02:19:00PM -0800, Brian Norris wrote:

quoted

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 <redacted>
Signed-off-by: Caesar Wang <redacted>
Cc: Jiri Kosina <redacted>
Cc: linux-input-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
---
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

v4:
 * use devm_regulator_get() (with a 'dummy' regulator for most cases)
   instead of _optional() version, to make code less conditional (Dmitry)
 * fix but where 'init_delay_ms' wasn't getting assigned properly
 * disable regulator in probe() failure path
---
 drivers/hid/i2c-hid/i2c-hid.c | 44 +++++++++++++++++++++++++++++++++++++++++--
 include/linux/i2c/i2c-hid.h   |  6 ++++++
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
index b3ec4f2de875..5c6e037613d7 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>
 

@@ -937,6 +938,10 @@ 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 = val;
+
 	return 0;
 }
 

@@ -983,6 +988,15 @@ static int i2c_hid_probe(struct i2c_client *client,
 		ihid->pdata = *platform_data;
 	}
 
+	ihid->pdata.supply = devm_regulator_get(&client->dev, "vdd");

Oh, haveni't noticed that the rest of the driver does not use devm.
Well, I'll leave it up to hid-i2c folks to decide if they are OK with
mixing up the managed and non-managed resources, it seems safe to me in
this case.

Yeah, it looks good to me as well. However, I think that will be the
trigger to request a devm conversion of the i2c-hid driver. Something
I'll add to my list of things to consider for v4.11 then :)

Acked-by: Benjamin Tissoires <redacted>

Cheers,
Benjamin

Reviewed-by: Dmitry Torokhov <redacted>

Thanks.

-- 
Dmitry

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