Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1331150 > unrolled thread

[PATCH 00/11] pwm: Add support for PWM Capture

Back to article view | Back to linux.kernel

Contents

  [PATCH 00/11] pwm: Add support for PWM Capture Lee Jones <lee.jones@linaro.org> - 2016-02-10 14:10 +0100
    [PATCH 04/11] pwm: sti: Only request clock rate when you need to Lee Jones <lee.jones@linaro.org> - 2016-02-10 14:10 +0100
    [PATCH 07/11] pwm: sti: Initialise PWM Capture channel data Lee Jones <lee.jones@linaro.org> - 2016-02-10 14:10 +0100

#1331150 — [PATCH 00/11] pwm: Add support for PWM Capture

The first part of this set extends the current PWM API to allow external
code to request a PWM Capture.  Subsequent patches then make use of the
new API by providing a userspace offering via /sysfs.  The final part of
the set supplies PWM Capture functionality into the already existing STi
PWM driver.

This patch-set has been tested end to end via /sysfs.

Lee Jones (11):
  pwm: Add PWM Capture support
  pwm: sysfs: Add PWM Capture support
  pwm: sti: Reorganise register names in preparation for new
    functionality
  pwm: sti: Only request clock rate when you need to
  pwm: sti: Supply PWM Capture register addresses and bit locations
  pwm: sti: Supply PWM Capture clock handling
  pwm: sti: Initialise PWM Capture channel data
  pwm: sti: Add support for PWM Capture IRQs
  pwm: sti: Add PWM Capture call-back
  pwm: sti: Enable PWM Capture
  pwm: sti: Take the opportunity to conduct a little house keeping

 drivers/pwm/core.c    |  26 ++++
 drivers/pwm/pwm-sti.c | 383 ++++++++++++++++++++++++++++++++++++++++++--------
 drivers/pwm/sysfs.c   |  28 ++++
 include/linux/pwm.h   |  13 ++
 4 files changed, 391 insertions(+), 59 deletions(-)

-- 
1.9.1

[toc] | [next] | [standalone]

#1331151 — [PATCH 04/11] pwm: sti: Only request clock rate when you need to

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

[toc] | [prev] | [next] | [standalone]

#1331152 — [PATCH 07/11] pwm: sti: Initialise PWM Capture channel data

Each PWM Capture channel is allocated a structure to hold its own
state.  During a capture the channel may be partaking in one of 3
phases.  Initial (rising) phase change, a subsequent (falling)
phase change indicating end of the duty-cycle phase and finally
a final (rising) phase change indicating the end of the period.
The timer value snapshot each event is held in a variable of the
same name, and the phase number (0, 1, 2) is contained in the
index variable.  Other channel specific information, such as GPIO
pin, the IRQ wait queue and locking is also contained in the
structure.  This patch initialises this structure for each of
the available channels.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/pwm/pwm-sti.c | 49 ++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 42 insertions(+), 7 deletions(-)

diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 9e6b1c8..fca692a 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -11,15 +11,19 @@
  */
 
 #include <linux/clk.h>
+#include <linux/gpio.h>
 #include <linux/math64.h>
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_gpio.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
 #include <linux/regmap.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/time.h>
+#include <linux/wait.h>
 
 #define PWM_OUT_VAL(x)	(0x00 + (4 * (x))) /* Channel's Duty Cycle register */
 #define PWM_CPT_VAL(x)	(0x10 + (4 * (x))) /* Capture value */
@@ -64,9 +68,18 @@ enum sti_cpt_edge {
 	CPT_EDGE_BOTH,
 };
 
+struct sti_cpt_data {
+	u32 snapshot[3];
+	int index;
+	int gpio;
+	struct mutex lock;
+	wait_queue_head_t wait;
+};
+
 struct sti_pwm_compat_data {
 	const struct reg_field *reg_fields;
-	unsigned int num_chan;
+	unsigned int pwm_num_chan;
+	unsigned int cpt_num_chan;
 	unsigned int max_pwm_cnt;
 	unsigned int max_prescale;
 };
@@ -77,6 +90,7 @@ struct sti_pwm_chip {
 	struct clk *cpt_clk;
 	struct regmap *regmap;
 	struct sti_pwm_compat_data *cdata;
+	struct sti_cpt_data *cpt_data[STI_MAX_CPT_CHANS];
 	struct regmap_field *prescale_low;
 	struct regmap_field *prescale_high;
 	struct regmap_field *pwm_out_en;
@@ -307,10 +321,15 @@ static int sti_pwm_probe_dt(struct sti_pwm_chip *pc)
 	struct device_node *np = dev->of_node;
 	struct sti_pwm_compat_data *cdata = pc->cdata;
 	u32 num_chan;
+	int ret;
 
-	of_property_read_u32(np, "st,pwm-num-chan", &num_chan);
-	if (num_chan)
-		cdata->num_chan = num_chan;
+	ret = of_property_read_u32(np, "st,pwm-num-chan", &num_chan);
+	if (!ret)
+		cdata->pwm_num_chan = num_chan;
+
+	ret = of_property_read_u32(np, "st,capture-num-chan", &num_chan);
+	if (!ret)
+		cdata->cpt_num_chan = num_chan;
 
 	reg_fields = cdata->reg_fields;
 
@@ -347,9 +366,11 @@ static const struct regmap_config sti_pwm_regmap_config = {
 static int sti_pwm_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
 	struct sti_pwm_compat_data *cdata;
 	struct sti_pwm_chip *pc;
 	struct resource *res;
+	unsigned int chan;
 	int ret;
 
 	pc = devm_kzalloc(dev, sizeof(*pc), GFP_KERNEL);
@@ -378,7 +399,8 @@ static int sti_pwm_probe(struct platform_device *pdev)
 	cdata->reg_fields   = &sti_pwm_regfields[0];
 	cdata->max_prescale = 0xff;
 	cdata->max_pwm_cnt  = 255;
-	cdata->num_chan     = 1;
+	cdata->pwm_num_chan     = 1;
+	cdata->cpt_num_chan	= 0;
 
 	pc->cdata = cdata;
 	pc->dev = dev;
@@ -389,6 +411,19 @@ static int sti_pwm_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	for (chan = 0; chan < cdata->cpt_num_chan; chan++) {
+		struct sti_cpt_data *data;
+
+		data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+		if (!data)
+			return -ENOMEM;
+
+		init_waitqueue_head(&data->wait);
+		mutex_init(&data->lock);
+		data->gpio = of_get_named_gpio(np, "capture-gpios", chan);
+		pc->cpt_data[chan] = data;
+	}
+
 	pc->pwm_clk = of_clk_get_by_name(dev->of_node, "pwm");
 	if (IS_ERR(pc->pwm_clk)) {
 		dev_err(dev, "failed to get PWM clock\n");
@@ -416,7 +451,7 @@ static int sti_pwm_probe(struct platform_device *pdev)
 	pc->chip.dev = dev;
 	pc->chip.ops = &sti_pwm_ops;
 	pc->chip.base = -1;
-	pc->chip.npwm = pc->cdata->num_chan;
+	pc->chip.npwm = pc->cdata->pwm_num_chan;
 	pc->chip.can_sleep = true;
 
 	ret = pwmchip_add(&pc->chip);
@@ -436,7 +471,7 @@ static int sti_pwm_remove(struct platform_device *pdev)
 	struct sti_pwm_chip *pc = platform_get_drvdata(pdev);
 	unsigned int i;
 
-	for (i = 0; i < pc->cdata->num_chan; i++)
+	for (i = 0; i < pc->cdata->pwm_num_chan; i++)
 		pwm_disable(&pc->chip.pwms[i]);
 
 	clk_unprepare(pc->pwm_clk);
-- 
1.9.1

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web