[RFC 08/13] smiapp-pll: Take existing divisor into account in minimum divisor check

From: Pavel Machek
Date: Tue Feb 14 2017 - 08:40:34 EST


From: Sakari Ailus <sakari.ailus@xxxxxx>

Required added multiplier (and divisor) calculation did not take into
account the existing divisor when checking the values against the
minimum divisor. Do just that.

Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxx>
Signed-off-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@xxxxxxxxx>
Signed-off-by: Pavel Machek <pavel@xxxxxx>
---
drivers/media/i2c/smiapp-pll.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/media/i2c/smiapp-pll.c b/drivers/media/i2c/smiapp-pll.c
index 771db56..166bbaf 100644
--- a/drivers/media/i2c/smiapp-pll.c
+++ b/drivers/media/i2c/smiapp-pll.c
@@ -16,6 +16,8 @@
* General Public License for more details.
*/

+#define DEBUG
+
#include <linux/device.h>
#include <linux/gcd.h>
#include <linux/lcm.h>
@@ -227,7 +229,8 @@ static int __smiapp_pll_calculate(

more_mul_factor = lcm(div, pll->pre_pll_clk_div) / div;
dev_dbg(dev, "more_mul_factor: %u\n", more_mul_factor);
- more_mul_factor = lcm(more_mul_factor, op_limits->min_sys_clk_div);
+ more_mul_factor = lcm(more_mul_factor,
+ DIV_ROUND_UP(op_limits->min_sys_clk_div, div));
dev_dbg(dev, "more_mul_factor: min_op_sys_clk_div: %d\n",
more_mul_factor);
i = roundup(more_mul_min, more_mul_factor);
@@ -456,6 +459,10 @@ int smiapp_pll_calculate(struct device *dev,
i = gcd(pll->pll_op_clk_freq_hz, pll->ext_clk_freq_hz);
mul = div_u64(pll->pll_op_clk_freq_hz, i);
div = pll->ext_clk_freq_hz / i;
+ if (!mul) {
+ dev_err(dev, "forcing mul to 1\n");
+ mul = 1;
+ }
dev_dbg(dev, "mul %u / div %u\n", mul, div);

min_pre_pll_clk_div =
--
2.1.4


--
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