[PATCH V3 1/6] clk: bcm2835: the minimum clock divider is 2
kernel at martin.sperl.org
kernel at martin.sperl.org
Thu Jan 14 05:45:36 PST 2016
From: Martin Sperl <kernel at martin.sperl.org>
Testing with different clock divider values has shown
that (at least for the PCM clock) the clock divider
has to be at least 2, otherwise the clock will not
output a signal.
So the clamping has changed from 1 to 2 and comments
about the kind of clamping applied have been added.
Signed-off-by: Martin Sperl <kernel at martin.sperl.org>
---
drivers/clk/bcm/clk-bcm2835.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/bcm/clk-bcm2835.c b/drivers/clk/bcm/clk-bcm2835.c
index 015e687..10e97b7 100644
--- a/drivers/clk/bcm/clk-bcm2835.c
+++ b/drivers/clk/bcm/clk-bcm2835.c
@@ -1178,7 +1178,11 @@ static u32 bcm2835_clock_choose_div(struct clk_hw *hw,
div &= ~unused_frac_mask;
/* Clamp to the limits. */
- div = max(div, unused_frac_mask + 1);
+
+ /* divider must be >= 2 */
+ div = max_t(u32, div, (2 << CM_DIV_FRAC_BITS));
+
+ /* clamp to max divider allowed */
div = min_t(u32, div, GENMASK(data->int_bits + CM_DIV_FRAC_BITS - 1,
CM_DIV_FRAC_BITS - data->frac_bits));
--
1.7.10.4
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