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Date: Mon, 14 Jul 2014 15:33:32 +0100
From: Lee Jones <lee.jones@...aro.org>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: lee.jones@...aro.org, kernel@...inux.com, thierry.reding@...il.com,
linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
ajitpal.singh@...com
Subject: [PATCH v2 11/11] pwm: sti: Remove PWM period table
From: Ajit Pal Singh <ajitpal.singh@...com>
Removes the PWM period table. Instead the prescaler is computed
from the period value passed in the config() function.
Signed-off-by: Ajit Pal Singh <ajitpal.singh@...com>
Signed-off-by: Lee Jones <lee.jones@...aro.org>
---
drivers/pwm/pwm-sti.c | 64 +++++++++++++--------------------------------------
1 file changed, 16 insertions(+), 48 deletions(-)
diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 1aa901d..ceeeef6 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -10,7 +10,6 @@
* (at your option) any later version.
*/
-#include <linux/bsearch.h>
#include <linux/clk.h>
#include <linux/math64.h>
#include <linux/mfd/syscon.h>
@@ -56,7 +55,6 @@ struct sti_pwm_chip {
struct regmap_field *prescale_high;
struct regmap_field *pwm_en;
struct regmap_field *pwm_int_en;
- unsigned long *pwm_periods;
struct pwm_chip chip;
struct pwm_device *cur;
unsigned int en_count;
@@ -77,29 +75,31 @@ static inline struct sti_pwm_chip *to_sti_pwmchip(struct pwm_chip *chip)
}
/*
- * Calculate the period values supported by the PWM for the
- * current clock rate.
+ * Calculate the prescaler value corresponding to the period.
*/
-static void sti_pwm_calc_periods(struct sti_pwm_chip *pc)
+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;
- struct device *dev = pc->dev;
unsigned long val;
- int i;
+ unsigned int ps;
/*
- * period_ns = (10^9 * (prescaler + 1) * (MAX_PWM_COUNT + 1)) / CLK_RATE
+ * prescale = ((period_ns * clk_rate) / (10^9 * (max_pwm_count + 1)) - 1
*/
val = NSEC_PER_SEC / pc->clk_rate;
val *= cdata->max_pwm_cnt + 1;
- dev_dbg(dev, "possible periods for clkrate[HZ]:%lu\n", pc->clk_rate);
-
- for (i = 0; i <= cdata->max_prescale; i++) {
- pc->pwm_periods[i] = val * (i + 1);
- dev_dbg(dev, "prescale:%d, period[ns]:%lu\n",
- i, pc->pwm_periods[i]);
+ if (period % val) {
+ return -EINVAL;
+ } else {
+ ps = period / val - 1;
+ if (ps > cdata->max_prescale)
+ return -EINVAL;
}
+ *prescale = ps;
+
+ return 0;
}
/* Calculate the number of PWM devices configured with a period. */
@@ -120,17 +120,6 @@ unsigned int sti_pwm_count_configured(struct pwm_chip *chip)
return ncfg;
}
-static int sti_pwm_cmp_periods(const void *key, const void *elt)
-{
- unsigned long i = *(unsigned long *)key;
- unsigned long j = *(unsigned long *)elt;
-
- if (i < j)
- return -1;
- else
- return i == j ? 0 : 1;
-}
-
/*
* For STiH4xx PWM IP, the PWM period is fixed to 256 local clock cycles.
* The only way to change the period (apart from changing the PWM input clock)
@@ -148,7 +137,6 @@ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_device *cur = pc->cur;
struct device *dev = pc->dev;
unsigned int prescale = 0, pwmvalx;
- unsigned long *found;
int ret;
unsigned int ncfg;
bool period_same = false;
@@ -178,21 +166,9 @@ static int sti_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
return ret;
if (!period_same) {
- /*
- * Search for matching period value.
- * The corresponding index is our prescale value.
- */
- found = bsearch(&period_ns, &pc->pwm_periods[0],
- cdata->max_prescale + 1,
- sizeof(unsigned long),
- sti_pwm_cmp_periods);
- if (!found) {
- dev_err(dev,
- "failed to find matching period\n");
- ret = -EINVAL;
+ ret = sti_pwm_get_prescale(pc, period_ns, &prescale);
+ if (ret)
goto clk_dis;
- }
- prescale = found - &pc->pwm_periods[0];
ret =
regmap_field_write(pc->prescale_low,
@@ -373,12 +349,6 @@ static int sti_pwm_probe(struct platform_device *pdev)
if (ret)
return ret;
- pc->pwm_periods = devm_kzalloc(dev,
- sizeof(unsigned long) * (pc->cdata->max_prescale + 1),
- GFP_KERNEL);
- if (!pc->pwm_periods)
- return -ENOMEM;
-
pc->clk = of_clk_get_by_name(np, "pwm");
if (IS_ERR(pc->clk)) {
dev_err(dev, "failed to get PWM clock\n");
@@ -397,8 +367,6 @@ static int sti_pwm_probe(struct platform_device *pdev)
return ret;
}
- sti_pwm_calc_periods(pc);
-
pc->chip.dev = dev;
pc->chip.ops = &sti_pwm_ops;
pc->chip.base = -1;
--
1.8.3.2
--
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