From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> The clock divider calculation right now clamps the divider to the highest possible fractional divider. So typically (BIT(div_int_bits) - 1) + 4095 / 4096. As the fractional clock divider is alterating between (Fosc / div_int) and (Fosc / (div_int + 1)) the divider will overflow for the (div_int + 1) case. As with the "underflow" case we have seen for (div < 2), we can assume that the same applies on the upper limit as well. So this patch will instead clamp to the divider to the max of (BIT(div_int_bits) - 1) Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> --- drivers/clk/bcm/clk-bcm2835.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c index 10e97b7..3d6490f 100644 --- a/drivers/clk/bcm/clk-bcm2835.c +++ b/drivers/clk/bcm/clk-bcm2835.c @@ -1182,9 +1182,9 @@ static u32 bcm2835_clock_choose_div(struct clk_hw *hw, /* divider must be >= 2 */ div = max_t(u32, div, (2 << CM_DIV_FRAC_BITS)); - /* clamp to max divider allowed */ + /* clamp to max divider allowed - max is integer divider */ div = min_t(u32, div, GENMASK(data->int_bits + CM_DIV_FRAC_BITS - 1, - CM_DIV_FRAC_BITS - data->frac_bits)); + CM_DIV_FRAC_BITS)); return div; } -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
