Hi Hans,
On Fri, Mar 10, 2017 at 09:55:53AM +0100, Hans Verkuil wrote:
> On 09/03/17 21:38, Sakari Ailus wrote:
> > Hi Hans,
> >
> > On Mon, Mar 06, 2017 at 03:56:05PM +0100, Hans Verkuil wrote:
> >> From: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> >>
> >> Get the clock for this sensor.
> >>
> >> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
> >> ---
> >> drivers/media/i2c/ov7670.c | 12 ++++++++++++
> >> 1 file changed, 12 insertions(+)
> >>
> >> diff --git a/drivers/media/i2c/ov7670.c b/drivers/media/i2c/ov7670.c
> >> index 50e4466a2b37..da0843617a49 100644
> >> --- a/drivers/media/i2c/ov7670.c
> >> +++ b/drivers/media/i2c/ov7670.c
> >> @@ -10,6 +10,7 @@
> >> * This file may be distributed under the terms of the GNU General
> >> * Public License, version 2.
> >> */
> >> +#include <linux/clk.h>
> >> #include <linux/init.h>
> >> #include <linux/module.h>
> >> #include <linux/slab.h>
> >> @@ -227,6 +228,7 @@ struct ov7670_info {
> >> struct v4l2_ctrl *hue;
> >> };
> >> struct ov7670_format_struct *fmt; /* Current format */
> >> + struct clk *clk;
> >> int min_width; /* Filter out smaller sizes */
> >> int min_height; /* Filter out smaller sizes */
> >> int clock_speed; /* External clock speed (MHz) */
> >> @@ -1587,6 +1589,15 @@ static int ov7670_probe(struct i2c_client *client,
> >> info->pclk_hb_disable = true;
> >> }
> >>
> >> + info->clk = devm_clk_get(&client->dev, "xclk");
> >> + if (IS_ERR(info->clk))
> >> + return -EPROBE_DEFER;
> >> + clk_prepare_enable(info->clk);
> >> +
> >> + info->clock_speed = clk_get_rate(info->clk) / 1000000;
> >> + if (info->clock_speed < 10 || info->clock_speed > 48)
> >> + return -EINVAL;
> >
> > clk_disable_unprepare() before return?
>
> It is my understanding that devm_clk_get will call that for you.
>
> Correct me if I am wrong.
devm_clk_get() obtained clock is released using devm_clk_release() which is
just calling clk_put(). Which caller prepared or enabled the clock is not
tracked. It's the responsibility of the caller.
--
Regards,
Sakari Ailus
e-mail: sakari.ailus@xxxxxx XMPP: sailus@xxxxxxxxxxxxxx
