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Subject[PATCH v2] clk: tegra: divider: Check UART's divider enable-bit state on rate's recalculation
Date
UART clock is divided using divisor values from DLM/DLL registers when
enable-bit is unset in clk register and clk's divider configuration isn't
taken onto account in this case. This doesn't cause any problems, but
let's add a check for the divider's enable-bit state, for consistency.

Acked-by: Peter De Schrijver <pdeschrijver@nvidia.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---

Changelog:

v2: In the comment to v1 Peter De Schrijver pointed out that UART's DLM/DLL
registers configuration is used when enable bit is unset, thus the
commit's title and message are changed accordingly.

drivers/clk/tegra/clk-divider.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/tegra/clk-divider.c b/drivers/clk/tegra/clk-divider.c
index e76731fb7d69..f33c19045386 100644
--- a/drivers/clk/tegra/clk-divider.c
+++ b/drivers/clk/tegra/clk-divider.c
@@ -40,8 +40,13 @@ static unsigned long clk_frac_div_recalc_rate(struct clk_hw *hw,
int div, mul;
u64 rate = parent_rate;

- reg = readl_relaxed(divider->reg) >> divider->shift;
- div = reg & div_mask(divider);
+ reg = readl_relaxed(divider->reg);
+
+ if ((divider->flags & TEGRA_DIVIDER_UART) &&
+ !(reg & PERIPH_CLK_UART_DIV_ENB))
+ return rate;
+
+ div = (reg >> divider->shift) & div_mask(divider);

mul = get_mul(divider);
div += mul;
--
2.23.0
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