pwm: lpss: Update PWM setting for Broxton
For Broxton PWM controller, base unit is defined as 8-bit integer
and 14-bit fraction, so need to update base unit setting to output
wave with right frequency.
Signed-off-by: Qipeng Zha <qipeng.zha@intel.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index 3f61c50..ebf8450 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -17,6 +17,7 @@
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pm_runtime.h>
+#include <linux/time.h>
#include "pwm-lpss.h"
@@ -24,11 +25,8 @@
#define PWM_ENABLE BIT(31)
#define PWM_SW_UPDATE BIT(30)
#define PWM_BASE_UNIT_SHIFT 8
-#define PWM_BASE_UNIT_MASK 0x00ffff00
#define PWM_ON_TIME_DIV_MASK 0x000000ff
#define PWM_DIVISION_CORRECTION 0x2
-#define PWM_LIMIT (0x8000 + PWM_DIVISION_CORRECTION)
-#define NSECS_PER_SEC 1000000000UL
/* Size of each PWM register space if multiple */
#define PWM_SIZE 0x400
@@ -36,13 +34,14 @@
struct pwm_lpss_chip {
struct pwm_chip chip;
void __iomem *regs;
- unsigned long clk_rate;
+ const struct pwm_lpss_boardinfo *info;
};
/* BayTrail */
const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
.clk_rate = 25000000,
.npwm = 1,
+ .base_unit_bits = 16,
};
EXPORT_SYMBOL_GPL(pwm_lpss_byt_info);
@@ -50,6 +49,7 @@
const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
.clk_rate = 19200000,
.npwm = 1,
+ .base_unit_bits = 16,
};
EXPORT_SYMBOL_GPL(pwm_lpss_bsw_info);
@@ -57,6 +57,7 @@
const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
.clk_rate = 19200000,
.npwm = 4,
+ .base_unit_bits = 22,
};
EXPORT_SYMBOL_GPL(pwm_lpss_bxt_info);
@@ -84,23 +85,25 @@
{
struct pwm_lpss_chip *lpwm = to_lpwm(chip);
u8 on_time_div;
- unsigned long c;
- unsigned long long base_unit, freq = NSECS_PER_SEC;
+ unsigned long c, base_unit_range;
+ unsigned long long base_unit, freq = NSEC_PER_SEC;
u32 ctrl;
do_div(freq, period_ns);
- /* The equation is: base_unit = ((freq / c) * 65536) + correction */
- base_unit = freq * 65536;
+ /*
+ * The equation is:
+ * base_unit = ((freq / c) * base_unit_range) + correction
+ */
+ base_unit_range = BIT(lpwm->info->base_unit_bits);
+ base_unit = freq * base_unit_range;
- c = lpwm->clk_rate;
+ c = lpwm->info->clk_rate;
if (!c)
return -EINVAL;
do_div(base_unit, c);
base_unit += PWM_DIVISION_CORRECTION;
- if (base_unit > PWM_LIMIT)
- return -EINVAL;
if (duty_ns <= 0)
duty_ns = 1;
@@ -109,8 +112,10 @@
pm_runtime_get_sync(chip->dev);
ctrl = pwm_lpss_read(pwm);
- ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK);
- ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT;
+ ctrl &= ~PWM_ON_TIME_DIV_MASK;
+ ctrl &= ~((base_unit_range - 1) << PWM_BASE_UNIT_SHIFT);
+ base_unit &= (base_unit_range - 1);
+ ctrl |= (u32) base_unit << PWM_BASE_UNIT_SHIFT;
ctrl |= on_time_div;
/* request PWM to update on next cycle */
ctrl |= PWM_SW_UPDATE;
@@ -155,7 +160,7 @@
if (IS_ERR(lpwm->regs))
return ERR_CAST(lpwm->regs);
- lpwm->clk_rate = info->clk_rate;
+ lpwm->info = info;
lpwm->chip.dev = dev;
lpwm->chip.ops = &pwm_lpss_ops;
lpwm->chip.base = -1;