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Message-ID: <YaDS/+QbTWRl3cOS@paasikivi.fi.intel.com>
Date: Fri, 26 Nov 2021 14:28:47 +0200
From: Sakari Ailus <sakari.ailus@...ux.intel.com>
To: Martin Kepplinger <martin.kepplinger@...i.sm>
Cc: mchehab@...nel.org, broonie@...nel.org, kernel@...i.sm,
linux-kernel@...r.kernel.org, linux-media@...r.kernel.org,
linux-pm@...r.kernel.org, Angus Ainslie <angus@...ea.ca>
Subject: Re: [PATCH v2] media: i2c: dw9714: add optional regulator support
On Fri, Nov 26, 2021 at 12:06:03PM +0100, Martin Kepplinger wrote:
> Am Freitag, dem 26.11.2021 um 12:44 +0200 schrieb Sakari Ailus:
> > Hi Martin,
> >
> > On Fri, Nov 26, 2021 at 10:01:07AM +0100, Martin Kepplinger wrote:
> > > From: Angus Ainslie <angus@...ea.ca>
> > >
> > > Allow the dw9714 to control a regulator and adjust suspend() and
> > > resume()
> > > to support both runtime and system pm.
> > >
> > > Signed-off-by: Angus Ainslie <angus@...ea.ca>
> > > Signed-off-by: Martin Kepplinger <martin.kepplinger@...i.sm>
> > > ---
> > >
> > > revision history
> > > ----------------
> > >
> > > v2: (thank you Mark)
> > > * simplify the regulator_get_optional() error path
> > > * fix regulator usage during probe()
> > >
> > > v1:
> > > https://lore.kernel.org/linux-media/20211125080922.978583-1-martin.kepplinger@puri.sm/
> > >
> > >
> > >
> > > drivers/media/i2c/dw9714.c | 39
> > > ++++++++++++++++++++++++++++++++++++++
> > > 1 file changed, 39 insertions(+)
> > >
> > > diff --git a/drivers/media/i2c/dw9714.c
> > > b/drivers/media/i2c/dw9714.c
> > > index 3863dfeb8293..e8cc19b89861 100644
> > > --- a/drivers/media/i2c/dw9714.c
> > > +++ b/drivers/media/i2c/dw9714.c
> > > @@ -5,6 +5,7 @@
> > > #include <linux/i2c.h>
> > > #include <linux/module.h>
> > > #include <linux/pm_runtime.h>
> > > +#include <linux/regulator/consumer.h>
> > > #include <media/v4l2-ctrls.h>
> > > #include <media/v4l2-device.h>
> > > #include <media/v4l2-event.h>
> > > @@ -36,6 +37,7 @@ struct dw9714_device {
> > > struct v4l2_ctrl_handler ctrls_vcm;
> > > struct v4l2_subdev sd;
> > > u16 current_val;
> > > + struct regulator *vcc;
> > > };
> > >
> > > static inline struct dw9714_device *to_dw9714_vcm(struct v4l2_ctrl
> > > *ctrl)
> > > @@ -145,6 +147,21 @@ static int dw9714_probe(struct i2c_client
> > > *client)
> > > if (dw9714_dev == NULL)
> > > return -ENOMEM;
> > >
> > > + dw9714_dev->vcc = devm_regulator_get_optional(&client->dev,
> > > "vcc");
> >
> > You you used regular devm_regulator_get(), you could remove the error
> > handling below. If there's no regulator, you'll simply get a dummy
> > one.
>
> ok thanks
>
>
> >
> > > + if (IS_ERR(dw9714_dev->vcc)) {
> > > + dev_dbg(&client->dev, "No vcc regulator found:
> > > %ld\n",
> > > + PTR_ERR(dw9714_dev->vcc));
> > > + dw9714_dev->vcc = NULL;
> > > + }
> > > +
> > > + if (dw9714_dev->vcc) {
> >
> > With (dummy) regulators, these checks become unnecessary.
> >
> > > + rval = regulator_enable(dw9714_dev->vcc);
> > > + if (rval < 0) {
> > > + dev_err(&client->dev, "failed to enable
> > > vcc: %d\n", rval);
> > > + return rval;
> > > + }
> > > + }
> > > +
> > > v4l2_i2c_subdev_init(&dw9714_dev->sd, client, &dw9714_ops);
> > > dw9714_dev->sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE |
> > > V4L2_SUBDEV_FL_HAS_EVENTS;
> > > @@ -200,6 +217,9 @@ static int __maybe_unused
> > > dw9714_vcm_suspend(struct device *dev)
> > > struct dw9714_device *dw9714_dev = sd_to_dw9714_vcm(sd);
> > > int ret, val;
> > >
> > > + if (pm_runtime_suspended(&client->dev))
> > > + return 0;
> >
> > This can't take place in a runtime PM suspend callback. You'll need
> > to add
> > system suspend callback for this.
>
> but this function is both the system and runtime suspend callback.
> doesn't splitting up the callbacks just add lines of code
> unnecessarily?
Hmm. After thinking about this a little, I think this could indeed work.
Yeah, please leave it as-is.
>
> >
> > > +
> > > for (val = dw9714_dev->current_val & ~(DW9714_CTRL_STEPS -
> > > 1);
> > > val >= 0; val -= DW9714_CTRL_STEPS) {
> > > ret = dw9714_i2c_write(client,
> > > @@ -208,6 +228,13 @@ static int __maybe_unused
> > > dw9714_vcm_suspend(struct device *dev)
> > > dev_err_once(dev, "%s I2C failure: %d",
> > > __func__, ret);
> > > usleep_range(DW9714_CTRL_DELAY_US,
> > > DW9714_CTRL_DELAY_US + 10);
> > > }
> > > +
> > > + if (dw9714_dev->vcc) {
> > > + ret = regulator_disable(dw9714_dev->vcc);
> > > + if (ret)
> > > + dev_err(dev, "Failed to disable vcc: %d\n",
> > > ret);
> > > + }
> > > +
> > > return 0;
> > > }
> > >
> > > @@ -224,6 +251,18 @@ static int __maybe_unused
> > > dw9714_vcm_resume(struct device *dev)
> > > struct dw9714_device *dw9714_dev = sd_to_dw9714_vcm(sd);
> > > int ret, val;
> > >
> > > + if (pm_runtime_suspended(&client->dev))
> >
> > Same for this one.
> >
> > > + return 0;
> > > +
> > > + if (dw9714_dev->vcc) {
> > > + ret = regulator_enable(dw9714_dev->vcc);
> > > + if (ret) {
> > > + dev_err(dev, "Failed to enable vcc: %d\n",
> > > ret);
> > > + return ret;
> > > + }
> > > + usleep_range(1000, 2000);
> > > + }
> > > +
> > > for (val = dw9714_dev->current_val % DW9714_CTRL_STEPS;
> > > val < dw9714_dev->current_val + DW9714_CTRL_STEPS - 1;
> > > val += DW9714_CTRL_STEPS) {
> >
>
>
--
Sakari Ailus
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