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authorLaxman Dewangan <ldewangan@nvidia.com>2017-04-13 17:10:27 +0300
committerThierry Reding <thierry.reding@gmail.com>2017-04-13 18:35:40 +0300
commit46fa8bc08744c373d405a87430e0b3e13ae94b4c (patch)
tree3936ba632d247f98ce59baa31fef009c7faa28d9 /drivers/pwm
parentc40c461e1944b9cfb520e04184ec1e5c80fb210b (diff)
downloadlinux-46fa8bc08744c373d405a87430e0b3e13ae94b4c.tar.xz
pwm: tegra: Read PWM clock source rate in driver init
It is required to know the PWM clock source frequency to calculate the PWM period. In driver, the clock source frequency of the PWM does not get change and, hence, get the clock source frequency in driver init. Get this values later for period calculation from pwm_config(). This will help in avoiding the clock call for getting clock rate in the pwm_config() each time. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
-rw-r--r--drivers/pwm/pwm-tegra.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/pwm/pwm-tegra.c b/drivers/pwm/pwm-tegra.c
index c040f87ee144..8c6ed556db28 100644
--- a/drivers/pwm/pwm-tegra.c
+++ b/drivers/pwm/pwm-tegra.c
@@ -50,6 +50,8 @@ struct tegra_pwm_chip {
struct clk *clk;
struct reset_control*rst;
+ unsigned long clk_rate;
+
void __iomem *regs;
const struct tegra_pwm_soc *soc;
@@ -94,7 +96,7 @@ static int tegra_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
* Compute the prescaler value for which (1 << PWM_DUTY_WIDTH)
* cycles at the PWM clock rate will take period_ns nanoseconds.
*/
- rate = clk_get_rate(pc->clk) >> PWM_DUTY_WIDTH;
+ rate = pc->clk_rate >> PWM_DUTY_WIDTH;
/* Consider precision in PWM_SCALE_WIDTH rate calculation */
hz = DIV_ROUND_CLOSEST_ULL(100ULL * NSEC_PER_SEC, period_ns);
@@ -199,6 +201,9 @@ static int tegra_pwm_probe(struct platform_device *pdev)
if (IS_ERR(pwm->clk))
return PTR_ERR(pwm->clk);
+ /* Read PWM clock rate from source */
+ pwm->clk_rate = clk_get_rate(pwm->clk);
+
pwm->rst = devm_reset_control_get(&pdev->dev, "pwm");
if (IS_ERR(pwm->rst)) {
ret = PTR_ERR(pwm->rst);