| Message ID | 1417170507-11172-4-git-send-email-josh.wu@atmel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Josh, (CC'ing the devicetree@vger.kernel.org mailing list) Thank you for the patch. On Friday 28 November 2014 18:28:26 Josh Wu wrote: > The master clock can be optional. It's a common clock framework clock. > It can make sensor output a pixel clock to the camera interface. > > If you just use a external oscillator clock as the master clock, then, > just don't need set 'mck' in dt node. > > Signed-off-by: Josh Wu <josh.wu@atmel.com> > --- > drivers/media/i2c/soc_camera/ov2640.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/drivers/media/i2c/soc_camera/ov2640.c > b/drivers/media/i2c/soc_camera/ov2640.c index 6506126..06c2aa9 100644 > --- a/drivers/media/i2c/soc_camera/ov2640.c > +++ b/drivers/media/i2c/soc_camera/ov2640.c > @@ -13,6 +13,7 @@ > * published by the Free Software Foundation. > */ > > +#include <linux/clk.h> > #include <linux/init.h> > #include <linux/module.h> > #include <linux/i2c.h> > @@ -31,6 +32,8 @@ > > #define VAL_SET(x, mask, rshift, lshift) \ > ((((x) >> rshift) & mask) << lshift) > +#define DEFAULT_MASTER_CLK_FREQ 25000000 > + > /* > * DSP registers > * register offset for BANK_SEL == BANK_SEL_DSP > @@ -284,6 +287,7 @@ struct ov2640_priv { > struct v4l2_ctrl_handler hdl; > u32 cfmt_code; > struct v4l2_clk *clk; > + struct clk *master_clk; > const struct ov2640_win_size *win; > > struct soc_camera_subdev_desc ssdd_dt; > @@ -746,6 +750,7 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int > on) struct soc_camera_subdev_desc *ssdd = soc_camera_i2c_to_desc(client); > struct ov2640_priv *priv = to_ov2640(client); > struct v4l2_clk *clk; > + int ret = 0; > > if (!priv->clk) { > clk = v4l2_clk_get(&client->dev, "mclk"); > @@ -755,6 +760,16 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int > on) priv->clk = clk; > } > > + if (!IS_ERR(priv->master_clk)) { The clock should be mandatory, you can thus drop this check. > + if (on) > + ret = clk_prepare_enable(priv->master_clk); > + else > + clk_disable_unprepare(priv->master_clk); > + > + if (ret) > + return ret; You can move the error check inside the first branch of the if and remove the ret = 0 initialization above. > + } > + > return soc_camera_set_power(&client->dev, ssdd, priv->clk, on); If this call fails you should disable or enable the clock to undo the enable/disable above. > } > > @@ -1153,6 +1168,16 @@ static int ov2640_probe(struct i2c_client *client, > } > } > > + priv->master_clk = devm_clk_get(&client->dev, "mck"); > + if (!IS_ERR(priv->master_clk)) { > + /* Set ISI_MCK's frequency, it should be faster than pixel > + * clock. > + */ > + ret = clk_set_rate(priv->master_clk, DEFAULT_MASTER_CLK_FREQ); The clock frequency should be system-dependent. For the DT case an easy implementation would be to use the assigned-clock-rates to set the desired clock frequency is case of a variable clock, as adding a sensor-specific property to specify the desired clock frequency only to read that property in the driver and call clk_set_rate() seems a bit pointless to me. > + if (ret < 0) > + return ret; > + } > + > v4l2_i2c_subdev_init(&priv->subdev, client, &ov2640_subdev_ops); > v4l2_ctrl_handler_init(&priv->hdl, 2); > v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,
Hi, Laurent On 12/2/2014 6:26 AM, Laurent Pinchart wrote: > Hi Josh, > > (CC'ing the devicetree@vger.kernel.org mailing list) > > Thank you for the patch. > > On Friday 28 November 2014 18:28:26 Josh Wu wrote: >> The master clock can be optional. It's a common clock framework clock. >> It can make sensor output a pixel clock to the camera interface. >> >> If you just use a external oscillator clock as the master clock, then, >> just don't need set 'mck' in dt node. >> >> Signed-off-by: Josh Wu <josh.wu@atmel.com> >> --- >> drivers/media/i2c/soc_camera/ov2640.c | 25 +++++++++++++++++++++++++ >> 1 file changed, 25 insertions(+) >> >> diff --git a/drivers/media/i2c/soc_camera/ov2640.c >> b/drivers/media/i2c/soc_camera/ov2640.c index 6506126..06c2aa9 100644 >> --- a/drivers/media/i2c/soc_camera/ov2640.c >> +++ b/drivers/media/i2c/soc_camera/ov2640.c >> @@ -13,6 +13,7 @@ >> * published by the Free Software Foundation. >> */ >> >> +#include <linux/clk.h> >> #include <linux/init.h> >> #include <linux/module.h> >> #include <linux/i2c.h> >> @@ -31,6 +32,8 @@ >> >> #define VAL_SET(x, mask, rshift, lshift) \ >> ((((x) >> rshift) & mask) << lshift) >> +#define DEFAULT_MASTER_CLK_FREQ 25000000 >> + >> /* >> * DSP registers >> * register offset for BANK_SEL == BANK_SEL_DSP >> @@ -284,6 +287,7 @@ struct ov2640_priv { >> struct v4l2_ctrl_handler hdl; >> u32 cfmt_code; >> struct v4l2_clk *clk; >> + struct clk *master_clk; >> const struct ov2640_win_size *win; >> >> struct soc_camera_subdev_desc ssdd_dt; >> @@ -746,6 +750,7 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int >> on) struct soc_camera_subdev_desc *ssdd = soc_camera_i2c_to_desc(client); >> struct ov2640_priv *priv = to_ov2640(client); >> struct v4l2_clk *clk; >> + int ret = 0; >> >> if (!priv->clk) { >> clk = v4l2_clk_get(&client->dev, "mclk"); >> @@ -755,6 +760,16 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int >> on) priv->clk = clk; >> } >> >> + if (!IS_ERR(priv->master_clk)) { > The clock should be mandatory, you can thus drop this check. OK. sure. > >> + if (on) >> + ret = clk_prepare_enable(priv->master_clk); >> + else >> + clk_disable_unprepare(priv->master_clk); >> + >> + if (ret) >> + return ret; > You can move the error check inside the first branch of the if and remove the > ret = 0 initialization above. > >> + } >> + >> return soc_camera_set_power(&client->dev, ssdd, priv->clk, on); > If this call fails you should disable or enable the clock to undo the > enable/disable above. ah, I totally forget this. will fix in next version. Thanks. > >> } >> >> @@ -1153,6 +1168,16 @@ static int ov2640_probe(struct i2c_client *client, >> } >> } >> >> + priv->master_clk = devm_clk_get(&client->dev, "mck"); >> + if (!IS_ERR(priv->master_clk)) { >> + /* Set ISI_MCK's frequency, it should be faster than pixel >> + * clock. >> + */ >> + ret = clk_set_rate(priv->master_clk, DEFAULT_MASTER_CLK_FREQ); > The clock frequency should be system-dependent. For the DT case an easy > implementation would be to use the assigned-clock-rates to set the desired > clock frequency is case of a variable clock, as adding a sensor-specific > property to specify the desired clock frequency only to read that property in > the driver and call clk_set_rate() seems a bit pointless to me. I tried assigned-clock-rates and it works fine. The only issue is the it cannot used by multiple nodes. But I think I can put a comments in the dt node for this. Thanks. Best Regards, Josh Wu > >> + if (ret < 0) >> + return ret; >> + } >> + >> v4l2_i2c_subdev_init(&priv->subdev, client, &ov2640_subdev_ops); >> v4l2_ctrl_handler_init(&priv->hdl, 2); >> v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,
diff --git a/drivers/media/i2c/soc_camera/ov2640.c b/drivers/media/i2c/soc_camera/ov2640.c index 6506126..06c2aa9 100644 --- a/drivers/media/i2c/soc_camera/ov2640.c +++ b/drivers/media/i2c/soc_camera/ov2640.c @@ -13,6 +13,7 @@ * published by the Free Software Foundation. */ +#include <linux/clk.h> #include <linux/init.h> #include <linux/module.h> #include <linux/i2c.h> @@ -31,6 +32,8 @@ #define VAL_SET(x, mask, rshift, lshift) \ ((((x) >> rshift) & mask) << lshift) +#define DEFAULT_MASTER_CLK_FREQ 25000000 + /* * DSP registers * register offset for BANK_SEL == BANK_SEL_DSP @@ -284,6 +287,7 @@ struct ov2640_priv { struct v4l2_ctrl_handler hdl; u32 cfmt_code; struct v4l2_clk *clk; + struct clk *master_clk; const struct ov2640_win_size *win; struct soc_camera_subdev_desc ssdd_dt; @@ -746,6 +750,7 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int on) struct soc_camera_subdev_desc *ssdd = soc_camera_i2c_to_desc(client); struct ov2640_priv *priv = to_ov2640(client); struct v4l2_clk *clk; + int ret = 0; if (!priv->clk) { clk = v4l2_clk_get(&client->dev, "mclk"); @@ -755,6 +760,16 @@ static int ov2640_s_power(struct v4l2_subdev *sd, int on) priv->clk = clk; } + if (!IS_ERR(priv->master_clk)) { + if (on) + ret = clk_prepare_enable(priv->master_clk); + else + clk_disable_unprepare(priv->master_clk); + + if (ret) + return ret; + } + return soc_camera_set_power(&client->dev, ssdd, priv->clk, on); } @@ -1153,6 +1168,16 @@ static int ov2640_probe(struct i2c_client *client, } } + priv->master_clk = devm_clk_get(&client->dev, "mck"); + if (!IS_ERR(priv->master_clk)) { + /* Set ISI_MCK's frequency, it should be faster than pixel + * clock. + */ + ret = clk_set_rate(priv->master_clk, DEFAULT_MASTER_CLK_FREQ); + if (ret < 0) + return ret; + } + v4l2_i2c_subdev_init(&priv->subdev, client, &ov2640_subdev_ops); v4l2_ctrl_handler_init(&priv->hdl, 2); v4l2_ctrl_new_std(&priv->hdl, &ov2640_ctrl_ops,
The master clock can be optional. It's a common clock framework clock. It can make sensor output a pixel clock to the camera interface. If you just use a external oscillator clock as the master clock, then, just don't need set 'mck' in dt node. Signed-off-by: Josh Wu <josh.wu@atmel.com> --- drivers/media/i2c/soc_camera/ov2640.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)