[PATCH AUTOSEL for 4.14 64/67] clk: axi-clkgen: Correctly handle nocount bit in recalc_rate()

Sasha Levin
2018-03-08T04:59:55Z

From: Lars-Peter Clausen <lars@metafoo.de>

[ Upstream commit 063578dc5f407f67d149133818efabe457daafda ]

If the nocount bit is set the divider is bypassed and the settings for the
divider count should be ignored and a divider value of 1 should be assumed.
Handle this correctly in the driver recalc_rate() callback.

While the driver sets up the part so that the read back dividers values
yield the correct result the power-on reset settings of the part might not
reflect this and hence calling e.g. clk_get_rate() without prior calls to
clk_set_rate() will yield the wrong result.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/clk/clk-axi-clkgen.c | 29 ++++++++++++++++++++++++-----
1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/clk/clk-axi-clkgen.c b/drivers/clk/clk-axi-clkgen.c
index 5e918e7afaba..95a6e9834392 100644
--- a/drivers/clk/clk-axi-clkgen.c
+++ b/drivers/clk/clk-axi-clkgen.c
@@ -40,6 +40,10 @@
#define MMCM_REG_FILTER1 0x4e
#define MMCM_REG_FILTER2 0x4f

+#define MMCM_CLKOUT_NOCOUNT BIT(6)
+
+#define MMCM_CLK_DIV_NOCOUNT BIT(12)
+
struct axi_clkgen {
void __iomem *base;
struct clk_hw clk_hw;
@@ -315,12 +319,27 @@ static unsigned long axi_clkgen_recalc_rate(struct clk_hw *clk_hw,
unsigned int reg;
unsigned long long tmp;

- axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLKOUT0_1, &reg);
- dout = (reg & 0x3f) + ((reg >> 6) & 0x3f);
+ axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLKOUT0_2, &reg);
+ if (reg & MMCM_CLKOUT_NOCOUNT) {
+ dout = 1;
+ } else {
+ axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLKOUT0_1, &reg);
+ dout = (reg & 0x3f) + ((reg >> 6) & 0x3f);
+ }
+
axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLK_DIV, &reg);
- d = (reg & 0x3f) + ((reg >> 6) & 0x3f);
- axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLK_FB1, &reg);
- m = (reg & 0x3f) + ((reg >> 6) & 0x3f);
+ if (reg & MMCM_CLK_DIV_NOCOUNT)
+ d = 1;
+ else
+ d = (reg & 0x3f) + ((reg >> 6) & 0x3f);
+
+ axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLK_FB2, &reg);
+ if (reg & MMCM_CLKOUT_NOCOUNT) {
+ m = 1;
+ } else {
+ axi_clkgen_mmcm_read(axi_clkgen, MMCM_REG_CLK_FB1, &reg);
+ m = (reg & 0x3f) + ((reg >> 6) & 0x3f);
+ }

if (d == 0 || dout == 0)
return 0;
--
2.14.1