Linux-libre 4.5-gnu

1 files changed, 40 insertions, 17 deletions

diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
index 250441040..295b963db 100644
--- a/drivers/pwm/pwm-lpss.c
+++ b/drivers/pwm/pwm-lpss.c
@@ -13,10 +13,12 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/delay.h>
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/pm_runtime.h>
+#include <linux/time.h>
 
 #include "pwm-lpss.h"
 
@@ -24,11 +26,8 @@
 #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 +35,14 @@
 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 +50,7 @@ EXPORT_SYMBOL_GPL(pwm_lpss_byt_info);
 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 +58,7 @@ EXPORT_SYMBOL_GPL(pwm_lpss_bsw_info);
 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);
 
@@ -79,28 +81,37 @@ static inline void pwm_lpss_write(const struct pwm_device *pwm, u32 value)
 	writel(value, lpwm->regs + pwm->hwpwm * PWM_SIZE + PWM);
 }
 
+static void pwm_lpss_update(struct pwm_device *pwm)
+{
+	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
+	/* Give it some time to propagate */
+	usleep_range(10, 50);
+}
+
 static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 			   int duty_ns, int period_ns)
 {
 	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;
@@ -109,13 +120,20 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 	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;
 	pwm_lpss_write(pwm, ctrl);
 
+	/*
+	 * If the PWM is already enabled we need to notify the hardware
+	 * about the change by setting PWM_SW_UPDATE.
+	 */
+	if (pwm_is_enabled(pwm))
+		pwm_lpss_update(pwm);
+
 	pm_runtime_put(chip->dev);
 
 	return 0;
@@ -124,6 +142,12 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	pm_runtime_get_sync(chip->dev);
+
+	/*
+	 * Hardware must first see PWM_SW_UPDATE before the PWM can be
+	 * enabled.
+	 */
+	pwm_lpss_update(pwm);
 	pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
 	return 0;
 }
@@ -135,7 +159,6 @@ static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 }
 
 static const struct pwm_ops pwm_lpss_ops = {
-	.free = pwm_lpss_disable,
 	.config = pwm_lpss_config,
 	.enable = pwm_lpss_enable,
 	.disable = pwm_lpss_disable,
@@ -156,7 +179,7 @@ struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev, struct resource *r,
 	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;