diff mbox

[RESEND,07/11] pwm: sti: Initialise PWM Capture channel data

Message ID 1456932729-9667-8-git-send-email-lee.jones@linaro.org
State New
Headers show

Commit Message

Lee Jones March 2, 2016, 3:32 p.m. UTC 
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(-)

-- 
1.9.1

Comments

Lee Jones April 15, 2016, 12:39 p.m. UTC | #1 
On Tue, 12 Apr 2016, Thierry Reding wrote:

> On Wed, Mar 02, 2016 at 03:32:05PM +0000, Lee Jones wrote:

> [...]

> > +struct sti_cpt_data {

> > +	u32 snapshot[3];

> > +	int index;

> > +	int gpio;

> 

> On a side-note, this should probably use struct gpio_desc * instead of

> an integer along with the gpiod_*() APIs for the GPIO handling.


Why would you need to do that?

of_get_named_gpio() does all that for you.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
Lee Jones April 15, 2016, 1:11 p.m. UTC | #2 
On Tue, 12 Apr 2016, Thierry Reding wrote:
> On Wed, Mar 02, 2016 at 03:32:05PM +0000, Lee Jones wrote:

> [...]

> > +struct sti_cpt_data {

> > +	u32 snapshot[3];

> > +	int index;

> > +	int gpio;


[...]

> > +

> > +		init_waitqueue_head(&data->wait);

> > +		mutex_init(&data->lock);

> > +		data->gpio = of_get_named_gpio(np, "capture-gpios", chan);

> > +		pc->cpt_data[chan] = data;

> 

> Converting to per-PWM data should be as simple as turning this last line

> into:

> 

> 	pwm_set_chip_data(pc->chip.pwms[chan], data);

> 

> Also I don't see any cleanup for this data in the driver. The memory for

> the per-PWM data should be freed by devm_*() infrastructure, but how

> will the GPIO be released?


There is no reason to release a GPIO.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
Lee Jones April 15, 2016, 2:31 p.m. UTC | #3 
On Fri, 15 Apr 2016, Thierry Reding wrote:

> On Fri, Apr 15, 2016 at 01:39:41PM +0100, Lee Jones wrote:

> > On Tue, 12 Apr 2016, Thierry Reding wrote:

> > 

> > > On Wed, Mar 02, 2016 at 03:32:05PM +0000, Lee Jones wrote:

> > > [...]

> > > > +struct sti_cpt_data {

> > > > +	u32 snapshot[3];

> > > > +	int index;

> > > > +	int gpio;

> > > 

> > > On a side-note, this should probably use struct gpio_desc * instead of

> > > an integer along with the gpiod_*() APIs for the GPIO handling.

> > 

> > Why would you need to do that?

> > 

> > of_get_named_gpio() does all that for you.

> 

> Use the of_get_named_gpio*d*() function instead. My understanding is

> that referring to GPIOs by integer is deprecated and should not be used

> in new code.


I've since conducted some research and have now converted over to
gpiod.  Thanks for the pointer.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
diff mbox

Patch

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);