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,
patrice.chotard@st.com, thierry.reding@gmail.com,
robh+dt@kernel.org, linux-pwm@vger.kernel.org,
devicetree@vger.kernel.org, Lee Jones <lee.jones@linaro.org>
Subject: [PATCH v3 12/20] pwm: sti: Only request clock rate when you need to
Date: Wed, 8 Jun 2016 10:21:27 +0100 [thread overview]
Message-ID: <20160608092135.21184-13-lee.jones@linaro.org> (raw)
In-Reply-To: <20160608092135.21184-1-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 5fbee61..c4a34af 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");
--
2.8.3
next prev parent reply other threads:[~2016-06-08 9:27 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-08 9:21 [PATCH v3 00/20] pwm: Add support for PWM Capture Lee Jones
2016-06-08 9:21 ` [PATCH v3 01/20] ARM: dts: STi: Rename properites in line with PWM naming conventions Lee Jones
2016-06-08 9:21 ` [PATCH v3 02/20] ARM: dts: STiH407: Supply PWM Capture IRQ Lee Jones
2016-06-08 9:21 ` [PATCH v3 03/20] ARM: dts: STiH407: Declare PWM Capture data lines via Pinctrl Lee Jones
2016-06-08 9:21 ` [PATCH v3 04/20] ARM: dts: STiH416: Supply PWM Capture IRQs Lee Jones
2016-06-08 9:21 ` [PATCH v3 05/20] ARM: dts: STiH416: Declare PWM Capture data lines via Pinctrl Lee Jones
2016-06-08 9:21 ` [PATCH v3 06/20] ARM: dts: STiH416: Define PWM Capture clock Lee Jones
2016-06-08 9:21 ` [PATCH v3 07/20] ARM: dts: STiH416: Define the number of PWM Capture channels Lee Jones
2016-06-08 9:21 ` [PATCH v3 08/20] pwm: Add PWM Capture support Lee Jones
2016-06-10 13:53 ` Thierry Reding
2016-06-10 14:38 ` Lee Jones
2016-06-10 16:39 ` Thierry Reding
2016-06-20 11:14 ` Lee Jones
2016-06-08 9:21 ` [PATCH v3 09/20] pwm: sti: Rename channel => device Lee Jones
2016-06-08 9:21 ` [PATCH v3 10/20] pwm: sysfs: Add PWM Capture support Lee Jones
2016-06-10 14:04 ` Thierry Reding
2016-06-10 14:36 ` Lee Jones
2016-06-08 9:21 ` [PATCH v3 11/20] pwm: sti: Reorganise register names in preparation for new functionality Lee Jones
2016-06-08 9:21 ` Lee Jones [this message]
2016-06-08 9:21 ` [PATCH v3 13/20] pwm: sti: Supply PWM Capture register addresses and bit locations Lee Jones
2016-06-08 9:21 ` [PATCH v3 14/20] pwm: sti: Supply PWM Capture clock handling Lee Jones
2016-06-08 9:21 ` [PATCH v3 15/20] pwm: sti: Initialise PWM Capture device data Lee Jones
2016-06-08 9:21 ` [PATCH v3 16/20] pwm: sti: Add support for PWM Capture IRQs Lee Jones
2016-06-08 9:21 ` [PATCH v3 17/20] pwm: sti: Add PWM Capture call-back Lee Jones
2016-06-08 9:21 ` [PATCH v3 18/20] pwm: sti: It's now valid for number of PWM channels to be zero Lee Jones
2016-06-08 9:21 ` [PATCH v3 19/20] pwm: sti: Take the opportunity to conduct a little house keeping Lee Jones
2016-06-08 9:21 ` [PATCH v3 20/20] dt-bindings: pwm: sti: Update DT bindings with recent changes Lee Jones
2016-06-08 20:51 ` Rob Herring
2016-06-09 11:41 ` Lee Jones
2016-06-10 13:18 ` Thierry Reding
2016-06-10 14:06 ` Lee Jones
2016-06-10 14:53 ` Thierry Reding
2016-06-10 15:19 ` Lee Jones
2016-07-13 9:02 ` Lee Jones
2016-06-10 13:10 ` Thierry Reding
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