On Wed, Oct 17, 2018 at 09:37:17PM +0200, Jacopo Mondi wrote: > Check that the PLL1 output frequency does not exceed the maximum allowed 1GHz > frequency. > > Signed-off-by: Jacopo Mondi <[email protected]> > --- > drivers/media/i2c/ov5640.c | 23 +++++++++++++++++++---- > 1 file changed, 19 insertions(+), 4 deletions(-) > > diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c > index e098435..1f2e72d 100644 > --- a/drivers/media/i2c/ov5640.c > +++ b/drivers/media/i2c/ov5640.c > @@ -770,7 +770,7 @@ static int ov5640_mod_reg(struct ov5640_dev *sensor, u16 > reg, > * always set to either 1 or 2 in the vendor kernels. > */ > #define OV5640_SYSDIV_MIN 1 > -#define OV5640_SYSDIV_MAX 2 > +#define OV5640_SYSDIV_MAX 16 > > /* > * This is supposed to be ranging from 1 to 16, but the value is always > @@ -806,15 +806,20 @@ static int ov5640_mod_reg(struct ov5640_dev *sensor, > u16 reg, > * This is supposed to be ranging from 1 to 8, but the value is always > * set to 1 in the vendor kernels. > */ > -#define OV5640_PCLK_ROOT_DIV 1 > +#define OV5640_PCLK_ROOT_DIV 1 > +#define OV5640_PLL_SYS_ROOT_DIVIDER_BYPASS 0x00 > > static unsigned long ov5640_compute_sys_clk(struct ov5640_dev *sensor, > u8 pll_prediv, u8 pll_mult, > u8 sysdiv) > { > - unsigned long rate = clk_get_rate(sensor->xclk); > + unsigned long sysclk = sensor->xclk_freq / pll_prediv * pll_mult; > > - return rate / pll_prediv * pll_mult / sysdiv; > + /* PLL1 output cannot exceed 1GHz. */ > + if (sysclk / 1000000 > 1000) > + return 0; > + > + return sysclk / sysdiv; > } > > static unsigned long ov5640_calc_sys_clk(struct ov5640_dev *sensor, > @@ -844,6 +849,16 @@ static unsigned long ov5640_calc_sys_clk(struct > ov5640_dev *sensor, > _rate = ov5640_compute_sys_clk(sensor, > OV5640_PLL_PREDIV, > _pll_mult, _sysdiv); > + > + /* > + * We have reached the maximum allowed PLL1 output, > + * increase sysdiv. > + */ > + if (rate == 0) { > + _pll_mult = OV5640_PLL_MULT_MAX + 1; > + continue; > + } > +
Both your patches look sane to me. However, I guess here you're setting _pll_mult at this value so that you won't reach the for condition on the next iteration? Wouldn't it be cleaner to just use a break statement here? Thanks! Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
signature.asc
Description: PGP signature
