Hi Prabhakar,
On Thu, Mar 12, 2020 at 09:52:38PM +0000, Prabhakar Mahadev Lad wrote:
> On 12 March 2020 21:42, Geert Uytterhoeven wrote:
> > On Thu, Mar 12, 2020 at 10:13 PM Lad Prabhakar wrote:
> > > This patch switches to assigned-clock-rates for specifying the clock rate.
> > > The clk-conf.c internally handles setting the clock rate when
> > > assigned-clock-rates is passed.
> > >
> > > The driver now sets the clock frequency only if the deprecated
> > > property clock-frequency is defined instead assigned-clock-rates, this
> > > is to avoid breakage with existing DT binaries.
> > >
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> >
> > Thanks for your patch!
> >
> > > --- a/drivers/media/i2c/ov5645.c
> > > +++ b/drivers/media/i2c/ov5645.c
> > > @@ -1055,6 +1055,7 @@ static int ov5645_probe(struct i2c_client *client)
> > > struct device_node *endpoint;
> > > struct ov5645 *ov5645;
> > > u8 chip_id_high, chip_id_low;
> > > + bool set_clk = false;
> > > unsigned int i;
> > > u32 xclk_freq;
> > > int ret;
> > > @@ -1094,10 +1095,17 @@ static int ov5645_probe(struct i2c_client
> > *client)
> > > return PTR_ERR(ov5645->xclk);
> > > }
> > >
> > > - ret = of_property_read_u32(dev->of_node, "clock-frequency",
> > &xclk_freq);
> > > + ret = of_property_read_u32(dev->of_node, "assigned-clock-rates",
> > > + &xclk_freq);
> > > if (ret) {
> >
> > I think you can just leave out the above check...
> >
> > > - dev_err(dev, "could not get xclk frequency\n");
> > > - return ret;
> > > + /* check if deprecated property clock-frequency is defined */
> > > + ret = of_property_read_u32(dev->of_node, "clock-frequency",
> > > + &xclk_freq);
> > > + if (ret) {
> >
> > ... and ignore the absence of the deprecated property.
> >
> > > + dev_err(dev, "could not get xclk frequency\n");
> > > + return ret;
> > > + }
> > > + set_clk = true;
> >
> > I.e. just
> >
> > /* check if deprecated property clock-frequency is defined */
> > xclk_freq = 0;
> > of_property_read_u32(dev->of_node, "clock-frequency", &xclk_freq);
> > if (xclk_freq) {
> > ret = clk_set_rate(ov5645->xclk, xclk_freq);
> > if (ret) {
> > dev_err(dev, "could not set xclk frequency\n");
> > return ret;
> > }
> > } else {
> > xclk_freq = clk_get_rate(ov5645->xclk, xclk_freq);
> > }
> >
> I did think about it initially, but realized the clk_get_rate may vary platform to platform
> for example in G2E clk_get_rate() returns a frequency of 24242424 with
> assigned-clock-rates set to 24000000 and probe would fail due to a check for
> external clock must be 24MHz, with 1% tolerance.
Then you need to handle the tolerance in this driver :-)
> > > }
> > >
> > > /* external clock must be 24MHz, allow 1% tolerance */ @@
> > > -1107,10 +1115,12 @@ static int ov5645_probe(struct i2c_client *client)
> > > return -EINVAL;
> > > }
> > >
> > > - ret = clk_set_rate(ov5645->xclk, xclk_freq);
> > > - if (ret) {
> > > - dev_err(dev, "could not set xclk frequency\n");
> > > - return ret;
> > > + if (set_clk) {
> > > + ret = clk_set_rate(ov5645->xclk, xclk_freq);
> > > + if (ret) {
> > > + dev_err(dev, "could not set xclk frequency\n");
> > > + return ret;
> > > + }
> > >
> > > }
> > >
> > > for (i = 0; i < OV5645_NUM_SUPPLIES; i++)
--
Regards,
Laurent Pinchart
