From: Lee Jones <lee.jones@linaro.org>
To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Cc: kernel@stlinux.com, maxime.coquelin@st.com,
thierry.reding@gmail.com, linux-pwm@vger.kernel.org,
ajitpal.singh@st.com, Lee Jones <lee.jones@linaro.org>
Subject: [RESEND 04/11] pwm: sti: Only request clock rate when you need to
Date: Wed, 2 Mar 2016 15:32:02 +0000 [thread overview]
Message-ID: <1456932729-9667-5-git-send-email-lee.jones@linaro.org> (raw)
In-Reply-To: <1456932729-9667-1-git-send-email-lee.jones@linaro.org>
In the original code the clock rate was only obtained during
initialisation; however, the rate may change between then and
its use. This patch ensures the correct rate is acquired just
before use.
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/pwm/pwm-sti.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 4e06c4d..aa217e2 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -51,7 +51,6 @@ struct sti_pwm_compat_data {
struct sti_pwm_chip {
struct device *dev;
- unsigned long clk_rate;
struct clk *pwm_clk;
struct regmap *regmap;
struct sti_pwm_compat_data *cdata;
@@ -86,13 +85,20 @@ static int sti_pwm_get_prescale(struct sti_pwm_chip *pc, unsigned long period,
unsigned int *prescale)
{
struct sti_pwm_compat_data *cdata = pc->cdata;
+ unsigned long clk_rate;
unsigned long val;
unsigned int ps;
+ clk_rate = clk_get_rate(pc->pwm_clk);
+ if (!clk_rate) {
+ dev_err(pc->dev, "failed to get clock rate\n");
+ return -EINVAL;
+ }
+
/*
* prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_count + 1)) - 1
*/
- val = NSEC_PER_SEC / pc->clk_rate;
+ val = NSEC_PER_SEC / clk_rate;
val *= cdata->max_pwm_cnt + 1;
if (period % val) {
@@ -353,12 +359,6 @@ static int sti_pwm_probe(struct platform_device *pdev)
return PTR_ERR(pc->pwm_clk);
}
- pc->clk_rate = clk_get_rate(pc->pwm_clk);
- if (!pc->clk_rate) {
- dev_err(dev, "failed to get clock rate\n");
- return -EINVAL;
- }
-
ret = clk_prepare(pc->pwm_clk);
if (ret) {
dev_err(dev, "failed to prepare clock\n");
--
1.9.1
next prev parent reply other threads:[~2016-03-02 15:34 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 15:31 [RESEND 00/11] pwm: Add support for PWM Capture Lee Jones
2016-03-02 15:31 ` [RESEND 01/11] pwm: Add PWM Capture support Lee Jones
2016-04-12 10:08 ` Thierry Reding
2016-04-13 9:36 ` Lee Jones
2016-04-13 14:50 ` Thierry Reding
2016-03-02 15:32 ` [RESEND 02/11] pwm: sysfs: " Lee Jones
2016-04-12 10:15 ` Thierry Reding
2016-04-13 9:40 ` Lee Jones
2016-03-02 15:32 ` [RESEND 03/11] pwm: sti: Reorganise register names in preparation for new functionality Lee Jones
2016-03-02 15:32 ` Lee Jones [this message]
2016-03-02 15:32 ` [RESEND 05/11] pwm: sti: Supply PWM Capture register addresses and bit locations Lee Jones
2016-03-02 15:32 ` [RESEND 06/11] pwm: sti: Supply PWM Capture clock handling Lee Jones
2016-03-02 15:32 ` [RESEND 07/11] pwm: sti: Initialise PWM Capture channel data Lee Jones
2016-04-12 10:29 ` Thierry Reding
2016-04-15 12:39 ` Lee Jones
2016-04-15 14:22 ` Thierry Reding
2016-04-15 14:31 ` Lee Jones
2016-04-15 13:11 ` Lee Jones
2016-04-15 14:23 ` Thierry Reding
2016-03-02 15:32 ` [RESEND 08/11] pwm: sti: Add support for PWM Capture IRQs Lee Jones
2016-04-12 10:35 ` Thierry Reding
2016-04-13 10:05 ` Lee Jones
2016-04-13 15:16 ` Thierry Reding
2016-03-02 15:32 ` [RESEND 09/11] pwm: sti: Add PWM Capture call-back Lee Jones
2016-04-12 10:53 ` Thierry Reding
2016-04-13 10:25 ` Lee Jones
2016-04-13 15:22 ` Thierry Reding
2016-04-15 8:29 ` Lee Jones
2016-04-15 14:20 ` Thierry Reding
2016-03-02 15:32 ` [RESEND 10/11] pwm: sti: Enable PWM Capture Lee Jones
2016-04-12 10:56 ` Thierry Reding
2016-03-02 15:32 ` [RESEND 11/11] pwm: sti: Take the opportunity to conduct a little house keeping Lee Jones
2016-04-12 7:28 ` [RESEND 00/11] pwm: Add support for PWM Capture Lee Jones
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