[PATCH v5 0/9] extend PWM framework to support PWM modes

[PATCH v5 0/9] extend PWM framework to support PWM modes

[Claudiu Beznea]

Hi,

Please give feedback on these patches which extends the PWM framework in
order to support multiple PWM modes of operations. This series is a rework
of [1] and [2].

The current patch series add the following PWM modes:
- PWM mode normal
- PWM mode complementary
- PWM mode push-pull

Normal mode - for PWM channels with one output; output waveforms looks like
this:
             __    __    __    __
    PWM   __|  |__|  |__|  |__|  |__
            <--T-->

    Where T is the signal period

Since PWMs with more than one output per channel could be used as one
output PWM the normal mode is the default mode for all PWMs (if not
specified otherwise).

Complementary mode - for PWM channels with two outputs; output waveforms
for a PWM channel in complementary mode looks line this:
             __    __    __    __
    PWMH1 __|  |__|  |__|  |__|  |__
          __    __    __    __    __
    PWML1   |__|  |__|  |__|  |__|
            <--T-->

    Where T is the signal period.

Push-pull mode - for PWM channels with two outputs; output waveforms for a
PWM channel in push-pull mode with normal polarity looks like this:
            __          __
    PWMH __|  |________|  |________
                  __          __
    PWML ________|  |________|  |__
           <--T-->

    If polarity is inversed:
         __    ________    ________
    PWMH   |__|        |__|
         ________    ________    __
    PWML         |__|        |__|
           <--T-->

    Where T is the signal period.

The PWM working modes are per PWM channel registered as PWM's capabilities.
The driver registers itself to PWM core a get_caps() function, in
struct pwm_ops, that will be used by PWM core to retrieve PWM capabilities.
If this function is not registered in driver's probe, a default function
will be used to retrieve PWM capabilities. Currently, the default
capabilities includes only PWM normal mode.

PWM state has been updated to keep PWM mode. PWM mode could be configured
via sysfs or via DT. pwm_apply_state() will do the preliminary validation
for PWM mode to be applied.

In sysfs, user could get PWM modes by reading mode file of PWM device:
root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# ls -l
total 0
-r--r--r-- 1 root root 4096 Oct  9 09:07 capture
lrwxrwxrwx 1 root root    0 Oct  9 09:07 device -> ../../pwmchip0
-rw-r--r-- 1 root root 4096 Oct  9 08:42 duty_cycle
-rw-r--r-- 1 root root 4096 Oct  9 08:44 enable
--w------- 1 root root 4096 Oct  9 09:07 export
-rw-r--r-- 1 root root 4096 Oct  9 08:43 mode
-r--r--r-- 1 root root 4096 Oct  9 09:07 npwm
-rw-r--r-- 1 root root 4096 Oct  9 08:42 period
-rw-r--r-- 1 root root 4096 Oct  9 08:44 polarity
drwxr-xr-x 2 root root    0 Oct  9 09:07 power
lrwxrwxrwx 1 root root    0 Oct  9 09:07 subsystem -> ../../../../../../../../class/pwm
-rw-r--r-- 1 root root 4096 Oct  9 08:42 uevent
--w------- 1 root root 4096 Oct  9 09:07 unexport
root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# cat mode
normal complementary [push-pull]

The mode enclosed in bracket is the currently active mode.

The mode could be set, via sysfs, by writing to mode file one of the modes
displayed at read:
root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# echo normal > mode
root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# cat mode
[normal] complementary push-pull 

The PWM push-pull mode could be usefull in applications like half bridge
converters.

This series also add PWM modes support for Atmel/Microchip SoCs.

Thank you,
Claudiu Beznea

[1] https://www.spinics.net/lists/arm-kernel/msg580275.html
[2] https://lkml.org/lkml/2018/1/12/359

Changes in v5:
- solved kbuild errors by removing dummy functions for case where
  CONFIG_PWM is not defined; adopted this approach since the removed
  function are used only only when CONFIG_PWM is defined (in PWM core
  and few drivers from drivers/pwm/ directory)

Changes in v4:
- removed changes related to pwm_config() as per maintainer proposals
- added pwm_mode_get_valid() to retrieve a valid PWM mode fror PWM device
  instead of using BIT(ffs(caps.mode) - 1) and changed drivers to use
  pwm_mode_get_valid() instead of pwm_get_caps() + BIT(ffs(caps.mode) - 1)
  (patches 2, 3, 4 from this series)
- renamed PWM_MODE() macro in PWMC_MODE() to avoid conflicts with
  pwm-sun4i.c driver ('C' stands for capability)
- removed pwm_caps_valid() function
- renamed PWM_DTMODE_COMPLEMENTARY and PWM_DTMODE_PUSH_PULL macros in
  PWM_MODE_COMPLEMENTARY and PWM_MODE_PUSH_PULL

Changes in v3:
- removed changes related to only one of_xlate function for all PWM drivers
- switch to PWM capabilities per PWM channel nor per PWM chip
- squash documentation and bindings patches as requeted by reviewer
- introduced PWM_MODE(name) macro and used a bit enum for pwm modes
- related to DT bindings, used flags cell also for PWM modes
- updated of_xlate specific functions with "state->mode = mode;"
  instructions to avoid pwm_apply_state() failures
- use available modes for PWM channel in pwm_config() by first calling
  pwm_get_caps() to get caps.modes
- use loops through available modes in mode_store()/mode_show() and also in
  of_pwm_xlate_with_flags() instead of "if else" instructions; in this way,
  the addition of a new mode is independent of this code sections
- use DTLI=1, DTHI=0 register settings to obtain push-pull mode waveforms
  for Atmel/Microchip PWM controller.

Changes in v2:
- remove of_xlate and of_pwm_n_cells and use generic functions to pharse DT
  inputs; this is done in patches 1, 2, 3, 4, 5, 6, 7 of this series; this will
  make easy the addition of PWM mode support from DT
- add PWM mode normal
- register PWM modes as capabilities of PWM chips at driver probe and, in case
  driver doesn't provide these capabilities use default ones
- change the way PWM mode is pharsed via DT by using a new input for pwms
  binding property


Claudiu Beznea (9):
  pwm: extend PWM framework with PWM modes
  pwm: clps711x: populate PWM mode in of_xlate function
  pwm: cros-ec: populate PWM mode in of_xlate function
  pwm: pxa: populate PWM mode in of_xlate function
  pwm: add PWM modes
  pwm: atmel: add pwm capabilities
  pwm: add push-pull mode support
  pwm: add documentation for pwm push-pull mode
  pwm: atmel: add push-pull mode support

 Documentation/devicetree/bindings/pwm/pwm.txt |  11 ++-
 Documentation/pwm.txt                         |  42 ++++++++-
 drivers/pwm/core.c                            | 125 +++++++++++++++++++++++++-
 drivers/pwm/pwm-atmel.c                       | 118 +++++++++++++++++-------
 drivers/pwm/pwm-clps711x.c                    |  10 ++-
 drivers/pwm/pwm-cros-ec.c                     |   1 +
 drivers/pwm/pwm-pxa.c                         |   1 +
 drivers/pwm/sysfs.c                           |  61 +++++++++++++
 include/dt-bindings/pwm/pwm.h                 |   2 +
 include/linux/pwm.h                           |  64 +++++++++++++
 10 files changed, 395 insertions(+), 40 deletions(-)

-- 
2.7.4

[PATCH v5 1/9] pwm: extend PWM framework with PWM modes

[Claudiu Beznea]

Add basic PWM modes: normal and complementary. These modes should
differentiate the single output PWM channels from two outputs PWM
channels. These modes could be set as follow:
1. PWM channels with one output per channel:
- normal mode
2. PWM channels with two outputs per channel:
- normal mode
- complementary mode
Since users could use a PWM channel with two output as one output PWM
channel, the PWM normal mode is allowed to be set for PWM channels with
two outputs; in fact PWM normal mode should be supported by all PWMs.

The PWM capabilities were implemented per PWM channel. Every PWM controller
will register a function to get PWM capabilities. If this is not explicitly
set by the driver a default function will be used to retrieve the PWM
capabilities (in this case the PWM capabilities will contain only PWM
normal mode). This function is set in pwmchip_add_with_polarity() as a
member of "struct pwm_chip". To retrieve capabilities the pwm_get_caps()
function could be used.

Every PWM channel have associated a mode in the PWM state. Proper
support was added to get/set PWM mode. The mode could also be set
from DT via flag cells. The valid DT modes are located in
include/dt-bindings/pwm/pwm.h. Only modes supported by PWM channel could be
set. If nothing is specified for a PWM channel, via DT, the first available
mode will be used (normally, this will be PWM normal mode).

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/pwm/core.c  | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 drivers/pwm/sysfs.c |  61 ++++++++++++++++++++++++++
 include/linux/pwm.h |  39 +++++++++++++++++
 3 files changed, 221 insertions(+), 3 deletions(-)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 1581f6ab1b1f..59a9df9120de 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -136,6 +136,7 @@ struct pwm_device *
 of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 {
 	struct pwm_device *pwm;
+	int modebit;
 
 	/* check, whether the driver supports a third cell for flags */
 	if (pc->of_pwm_n_cells < 3)
@@ -154,9 +155,23 @@ of_pwm_xlate_with_flags(struct pwm_chip *pc, const struct of_phandle_args *args)
 
 	pwm->args.period = args->args[1];
 	pwm->args.polarity = PWM_POLARITY_NORMAL;
+	pwm->args.mode = pwm_mode_get_valid(pc, pwm);
 
-	if (args->args_count > 2 && args->args[2] & PWM_POLARITY_INVERTED)
-		pwm->args.polarity = PWM_POLARITY_INVERSED;
+	if (args->args_count > 2) {
+		if (args->args[2] & PWM_POLARITY_INVERTED)
+			pwm->args.polarity = PWM_POLARITY_INVERSED;
+
+		for (modebit = PWMC_MODE_COMPLEMENTARY_BIT;
+		     modebit < PWMC_MODE_CNT; modebit++) {
+			unsigned long mode = BIT(modebit);
+
+			if ((args->args[2] & mode) &&
+			    pwm_mode_valid(pwm, mode)) {
+				pwm->args.mode = mode;
+				break;
+			}
+		}
+	}
 
 	return pwm;
 }
@@ -183,6 +198,7 @@ of_pwm_simple_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
 		return pwm;
 
 	pwm->args.period = args->args[1];
+	pwm->args.mode = pwm_mode_get_valid(pc, pwm);
 
 	return pwm;
 }
@@ -250,6 +266,97 @@ static bool pwm_ops_check(const struct pwm_ops *ops)
 }
 
 /**
+ * pwm_get_caps() - get PWM capabilities of a PWM device
+ * @chip: PWM chip
+ * @pwm: PWM device to get the capabilities for
+ * @caps: returned capabilities
+ *
+ * Returns: 0 on success or a negative error code on failure
+ */
+int pwm_get_caps(struct pwm_chip *chip, struct pwm_device *pwm,
+		 struct pwm_caps *caps)
+{
+	if (!chip || !pwm || !caps)
+		return -EINVAL;
+
+	if (chip->ops && chip->ops->get_caps)
+		pwm->chip->ops->get_caps(chip, pwm, caps);
+	else if (chip->get_default_caps)
+		chip->get_default_caps(caps);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pwm_get_caps);
+
+static void pwmchip_get_default_caps(struct pwm_caps *caps)
+{
+	static const struct pwm_caps default_caps = {
+		.modes = PWMC_MODE(NORMAL),
+	};
+
+	if (!caps)
+		return;
+
+	*caps = default_caps;
+}
+
+/**
+ * pwm_mode_get_valid() - get the first available valid mode for PWM
+ * @chip: PWM chip
+ * @pwm: PWM device to get the valid mode for
+ *
+ * Returns: first valid mode for PWM device
+ */
+unsigned long pwm_mode_get_valid(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+	struct pwm_caps caps;
+
+	if (pwm_get_caps(chip, pwm, &caps))
+		return PWMC_MODE(NORMAL);
+
+	return BIT(ffs(caps.modes) - 1);
+}
+EXPORT_SYMBOL_GPL(pwm_mode_get_valid);
+
+/**
+ * pwm_mode_valid() - check if mode is valid for PWM device
+ * @pwm: PWM device
+ * @mode: PWM mode to check if valid
+ *
+ * Returns: true if mode is valid and false otherwise
+ */
+bool pwm_mode_valid(struct pwm_device *pwm, unsigned long mode)
+{
+	struct pwm_caps caps;
+
+	if (!pwm || !mode)
+		return false;
+
+	if (hweight_long(mode) != 1 || ffs(mode) - 1 >= PWMC_MODE_CNT)
+		return false;
+
+	if (pwm_get_caps(pwm->chip, pwm, &caps))
+		return false;
+
+	return (caps.modes & mode);
+}
+EXPORT_SYMBOL_GPL(pwm_mode_valid);
+
+const char *pwm_mode_desc(struct pwm_device *pwm, unsigned long mode)
+{
+	static const char * const modes[] = {
+		"invalid",
+		"normal",
+		"complementary",
+	};
+
+	if (!pwm_mode_valid(pwm, mode))
+		return modes[0];
+
+	return modes[ffs(mode)];
+}
+
+/**
  * pwmchip_add_with_polarity() - register a new PWM chip
  * @chip: the PWM chip to add
  * @polarity: initial polarity of PWM channels
@@ -275,6 +382,8 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
 
 	mutex_lock(&pwm_lock);
 
+	chip->get_default_caps = pwmchip_get_default_caps;
+
 	ret = alloc_pwms(chip->base, chip->npwm);
 	if (ret < 0)
 		goto out;
@@ -294,6 +403,7 @@ int pwmchip_add_with_polarity(struct pwm_chip *chip,
 		pwm->pwm = chip->base + i;
 		pwm->hwpwm = i;
 		pwm->state.polarity = polarity;
+		pwm->state.mode = pwm_mode_get_valid(chip, pwm);
 
 		if (chip->ops->get_state)
 			chip->ops->get_state(chip, pwm, &pwm->state);
@@ -469,7 +579,8 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
 	int err;
 
 	if (!pwm || !state || !state->period ||
-	    state->duty_cycle > state->period)
+	    state->duty_cycle > state->period ||
+	    !pwm_mode_valid(pwm, state->mode))
 		return -EINVAL;
 
 	if (!memcmp(state, &pwm->state, sizeof(*state)))
@@ -530,6 +641,9 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
 
 			pwm->state.enabled = state->enabled;
 		}
+
+		/* No mode support for non-atomic PWM. */
+		pwm->state.mode = state->mode;
 	}
 
 	return 0;
@@ -579,6 +693,8 @@ int pwm_adjust_config(struct pwm_device *pwm)
 	pwm_get_args(pwm, &pargs);
 	pwm_get_state(pwm, &state);
 
+	state.mode = pargs.mode;
+
 	/*
 	 * If the current period is zero it means that either the PWM driver
 	 * does not support initial state retrieval or the PWM has not yet
@@ -850,6 +966,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
 
 	pwm->args.period = chosen->period;
 	pwm->args.polarity = chosen->polarity;
+	pwm->args.mode = pwm_mode_get_valid(chip, pwm);
 
 	return pwm;
 }
@@ -999,6 +1116,7 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
 		seq_printf(s, " duty: %u ns", state.duty_cycle);
 		seq_printf(s, " polarity: %s",
 			   state.polarity ? "inverse" : "normal");
+		seq_printf(s, " mode: %s", pwm_mode_desc(pwm, state.mode));
 
 		seq_puts(s, "\n");
 	}
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 83f2b0b15712..785eda0b1e67 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -223,11 +223,71 @@ static ssize_t capture_show(struct device *child,
 	return sprintf(buf, "%u %u\n", result.period, result.duty_cycle);
 }
 
+static ssize_t mode_show(struct device *child,
+			 struct device_attribute *attr,
+			 char *buf)
+{
+	struct pwm_device *pwm = child_to_pwm_device(child);
+	struct pwm_state state;
+	unsigned long mode;
+	int modebit, len = 0;
+
+	pwm_get_state(pwm, &state);
+
+	for (modebit = PWMC_MODE_NORMAL_BIT;
+	     modebit < PWMC_MODE_CNT; modebit++) {
+		mode = BIT(modebit);
+		if (pwm_mode_valid(pwm, mode)) {
+			if (state.mode == mode)
+				len += scnprintf(buf + len,
+						 PAGE_SIZE - len, "[%s] ",
+						 pwm_mode_desc(pwm, mode));
+			else
+				len += scnprintf(buf + len,
+						 PAGE_SIZE - len, "%s ",
+						 pwm_mode_desc(pwm, mode));
+		}
+	}
+
+	len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
+	return len;
+}
+
+static ssize_t mode_store(struct device *child,
+			  struct device_attribute *attr,
+			  const char *buf, size_t size)
+{
+	struct pwm_export *export = child_to_pwm_export(child);
+	struct pwm_device *pwm = export->pwm;
+	struct pwm_state state;
+	unsigned long mode;
+	int modebit, ret;
+
+	for (modebit = PWMC_MODE_NORMAL_BIT;
+	     modebit < PWMC_MODE_CNT; modebit++) {
+		mode = BIT(modebit);
+		if (sysfs_streq(buf, pwm_mode_desc(pwm, mode)))
+			break;
+	}
+
+	if (modebit == PWMC_MODE_CNT)
+		return -EINVAL;
+
+	mutex_lock(&export->lock);
+	pwm_get_state(pwm, &state);
+	state.mode = mode;
+	ret = pwm_apply_state(pwm, &state);
+	mutex_unlock(&export->lock);
+
+	return ret ? : size;
+}
+
 static DEVICE_ATTR_RW(period);
 static DEVICE_ATTR_RW(duty_cycle);
 static DEVICE_ATTR_RW(enable);
 static DEVICE_ATTR_RW(polarity);
 static DEVICE_ATTR_RO(capture);
+static DEVICE_ATTR_RW(mode);
 
 static struct attribute *pwm_attrs[] = {
 	&dev_attr_period.attr,
@@ -235,6 +295,7 @@ static struct attribute *pwm_attrs[] = {
 	&dev_attr_enable.attr,
 	&dev_attr_polarity.attr,
 	&dev_attr_capture.attr,
+	&dev_attr_mode.attr,
 	NULL
 };
 ATTRIBUTE_GROUPS(pwm);
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 56518adc31dd..a4ce4ad7edf0 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -26,9 +26,32 @@ enum pwm_polarity {
 };
 
 /**
+ * PWM modes capabilities
+ * @PWMC_MODE_NORMAL_BIT: PWM has one output
+ * @PWMC_MODE_COMPLEMENTARY_BIT: PWM has 2 outputs with opposite polarities
+ * @PWMC_MODE_CNT: PWM modes count
+ */
+enum {
+	PWMC_MODE_NORMAL_BIT,
+	PWMC_MODE_COMPLEMENTARY_BIT,
+	PWMC_MODE_CNT,
+};
+
+#define PWMC_MODE(name)		BIT(PWMC_MODE_##name##_BIT)
+
+/**
+ * struct pwm_caps - PWM capabilities
+ * @modes: PWM modes
+ */
+struct pwm_caps {
+	unsigned long modes;
+};
+
+/**
  * struct pwm_args - board-dependent PWM arguments
  * @period: reference period
  * @polarity: reference polarity
+ * @mode: reference mode
  *
  * This structure describes board-dependent arguments attached to a PWM
  * device. These arguments are usually retrieved from the PWM lookup table or
@@ -41,6 +64,7 @@ enum pwm_polarity {
 struct pwm_args {
 	unsigned int period;
 	enum pwm_polarity polarity;
+	unsigned long mode;
 };
 
 enum {
@@ -53,12 +77,14 @@ enum {
  * @period: PWM period (in nanoseconds)
  * @duty_cycle: PWM duty cycle (in nanoseconds)
  * @polarity: PWM polarity
+ * @mode: PWM mode
  * @enabled: PWM enabled status
  */
 struct pwm_state {
 	unsigned int period;
 	unsigned int duty_cycle;
 	enum pwm_polarity polarity;
+	unsigned long mode;
 	bool enabled;
 };
 
@@ -181,6 +207,7 @@ static inline void pwm_init_state(const struct pwm_device *pwm,
 	state->period = args.period;
 	state->polarity = args.polarity;
 	state->duty_cycle = 0;
+	state->mode = args.mode;
 }
 
 /**
@@ -254,6 +281,7 @@ pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle,
  * @get_state: get the current PWM state. This function is only
  *	       called once per PWM device when the PWM chip is
  *	       registered.
+ * @get_caps: get PWM capabilities.
  * @dbg_show: optional routine to show contents in debugfs
  * @owner: helps prevent removal of modules exporting active PWMs
  */
@@ -272,6 +300,8 @@ struct pwm_ops {
 		     struct pwm_state *state);
 	void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
 			  struct pwm_state *state);
+	void (*get_caps)(struct pwm_chip *chip, struct pwm_device *pwm,
+			 struct pwm_caps *caps);
 #ifdef CONFIG_DEBUG_FS
 	void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s);
 #endif
@@ -287,6 +317,7 @@ struct pwm_ops {
  * @npwm: number of PWMs controlled by this chip
  * @pwms: array of PWM devices allocated by the framework
  * @of_xlate: request a PWM device given a device tree PWM specifier
+ * @get_default_caps: get default PWM capabilities
  * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
  */
 struct pwm_chip {
@@ -300,6 +331,7 @@ struct pwm_chip {
 
 	struct pwm_device * (*of_xlate)(struct pwm_chip *pc,
 					const struct of_phandle_args *args);
+	void (*get_default_caps)(struct pwm_caps *caps);
 	unsigned int of_pwm_n_cells;
 };
 
@@ -438,6 +470,12 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 					 unsigned int index,
 					 const char *label);
 
+int pwm_get_caps(struct pwm_chip *chip, struct pwm_device *pwm,
+		 struct pwm_caps *caps);
+unsigned long pwm_mode_get_valid(struct pwm_chip *chip,
+				 struct pwm_device *pwm);
+bool pwm_mode_valid(struct pwm_device *pwm, unsigned long mode);
+const char *pwm_mode_desc(struct pwm_device *pwm, unsigned long mode);
 struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
 		const struct of_phandle_args *args);
 
@@ -592,6 +630,7 @@ static inline void pwm_apply_args(struct pwm_device *pwm)
 	state.enabled = false;
 	state.polarity = pwm->args.polarity;
 	state.period = pwm->args.period;
+	state.mode = pwm->args.mode;
 
 	pwm_apply_state(pwm, &state);
 }
-- 
2.7.4

[PATCH v5 2/9] pwm: clps711x: populate PWM mode in of_xlate function

[Claudiu Beznea]

Populate PWM mode in of_xlate function to avoid pwm_apply_state() failure.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/pwm/pwm-clps711x.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index 26ec24e457b1..d742e8e375c7 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c
@@ -109,10 +109,18 @@ static const struct pwm_ops clps711x_pwm_ops = {
 static struct pwm_device *clps711x_pwm_xlate(struct pwm_chip *chip,
 					     const struct of_phandle_args *args)
 {
+	struct pwm_device *pwm;
+
 	if (args->args[0] >= chip->npwm)
 		return ERR_PTR(-EINVAL);
 
-	return pwm_request_from_chip(chip, args->args[0], NULL);
+	pwm = pwm_request_from_chip(chip, args->args[0], NULL);
+	if (IS_ERR(pwm))
+		return pwm;
+
+	pwm->args.mode = pwm_mode_get_valid(chip, pwm);
+
+	return pwm;
 }
 
 static int clps711x_pwm_probe(struct platform_device *pdev)
-- 
2.7.4

[PATCH v5 3/9] pwm: cros-ec: populate PWM mode in of_xlate function

[Claudiu Beznea]

Populate PWM mode in of_xlate function to avoid pwm_apply_state() failure.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/pwm/pwm-cros-ec.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pwm/pwm-cros-ec.c b/drivers/pwm/pwm-cros-ec.c
index 9c13694eaa24..78d28d60a468 100644
--- a/drivers/pwm/pwm-cros-ec.c
+++ b/drivers/pwm/pwm-cros-ec.c
@@ -147,6 +147,7 @@ cros_ec_pwm_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
 
 	/* The EC won't let us change the period */
 	pwm->args.period = EC_PWM_MAX_DUTY;
+	pwm->args.mode = pwm_mode_get_valid(pc, pwm);
 
 	return pwm;
 }
-- 
2.7.4

[PATCH v5 4/9] pwm: pxa: populate PWM mode in of_xlate function

[Claudiu Beznea]

Populate PWM mode in of_xlate function to avoid pwm_apply_state() failure.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/pwm/pwm-pxa.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c
index 4143a46684d2..4c88cb47d6ba 100644
--- a/drivers/pwm/pwm-pxa.c
+++ b/drivers/pwm/pwm-pxa.c
@@ -161,6 +161,7 @@ pxa_pwm_of_xlate(struct pwm_chip *pc, const struct of_phandle_args *args)
 		return pwm;
 
 	pwm->args.period = args->args[0];
+	pwm->args.mode = pwm_mode_get_valid(pc, pwm);
 
 	return pwm;
 }
-- 
2.7.4

[PATCH v5 5/9] pwm: add PWM modes

[Claudiu Beznea]

Add PWM normal and complementary modes.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 Documentation/devicetree/bindings/pwm/pwm.txt |  9 +++++++--
 Documentation/pwm.txt                         | 26 +++++++++++++++++++++++---
 include/dt-bindings/pwm/pwm.h                 |  1 +
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt
index 8556263b8502..7c8aaac43f92 100644
--- a/Documentation/devicetree/bindings/pwm/pwm.txt
+++ b/Documentation/devicetree/bindings/pwm/pwm.txt
@@ -46,11 +46,16 @@ period in nanoseconds.
 Optionally, the pwm-specifier can encode a number of flags (defined in
 <dt-bindings/pwm/pwm.h>) in a third cell:
 - PWM_POLARITY_INVERTED: invert the PWM signal polarity
+- PWM_MODE_COMPLEMENTARY: PWM complementary working mode (for PWM channels
+with two outputs); if not specified, the default for PWM channel will be
+used
 
-Example with optional PWM specifier for inverse polarity
+Example with optional PWM specifier for inverse polarity and complementary
+mode:
 
 	bl: backlight {
-		pwms = <&pwm 0 5000000 PWM_POLARITY_INVERTED>;
+		pwms = <&pwm 0 5000000
+			(PWM_MODE_COMPLEMENTARY | PWM_POLARITY_INVERTED)>;
 		pwm-names = "backlight";
 	};
 
diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt
index 8fbf0aa3ba2d..912c43da8b48 100644
--- a/Documentation/pwm.txt
+++ b/Documentation/pwm.txt
@@ -61,9 +61,9 @@ In addition to the PWM state, the PWM API also exposes PWM arguments, which
 are the reference PWM config one should use on this PWM.
 PWM arguments are usually platform-specific and allows the PWM user to only
 care about dutycycle relatively to the full period (like, duty = 50% of the
-period). struct pwm_args contains 2 fields (period and polarity) and should
-be used to set the initial PWM config (usually done in the probe function
-of the PWM user). PWM arguments are retrieved with pwm_get_args().
+period). struct pwm_args contains 3 fields (period, polarity and mode) and
+should be used to set the initial PWM config (usually done in the probe
+function of the PWM user). PWM arguments are retrieved with pwm_get_args().
 
 Using PWMs with the sysfs interface
 -----------------------------------
@@ -110,6 +110,26 @@ channel that was exported. The following properties will then be available:
 	- 0 - disabled
 	- 1 - enabled
 
+  mode
+    Get/set PWM channel working mode.
+
+    Normal mode - for PWM channels with one output; this should be the
+        default working mode for every PWM channel; output waveforms looks
+        like this:
+             __    __    __    __
+    PWM   __|  |__|  |__|  |__|  |__
+            <--T-->
+
+    Complementary mode - for PWM channels with two outputs; output waveforms
+        looks line this:
+             __    __    __    __
+    PWMH1 __|  |__|  |__|  |__|  |__
+          __    __    __    __    __
+    PWML1   |__|  |__|  |__|  |__|
+            <--T-->
+
+    Where T is the signal period.
+
 Implementing a PWM driver
 -------------------------
 
diff --git a/include/dt-bindings/pwm/pwm.h b/include/dt-bindings/pwm/pwm.h
index ab9a077e3c7d..b82279cc1787 100644
--- a/include/dt-bindings/pwm/pwm.h
+++ b/include/dt-bindings/pwm/pwm.h
@@ -11,5 +11,6 @@
 #define _DT_BINDINGS_PWM_PWM_H
 
 #define PWM_POLARITY_INVERTED			(1 << 0)
+#define PWM_MODE_COMPLEMENTARY			(1 << 1)
 
 #endif
-- 
2.7.4

[PATCH v5 6/9] pwm: atmel: add pwm capabilities

[Claudiu Beznea]

Add pwm capabilities for Atmel/Microchip PWM controllers.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/pwm/pwm-atmel.c | 80 ++++++++++++++++++++++++++++++++-----------------
 1 file changed, 52 insertions(+), 28 deletions(-)

diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index 530d7dc5f1b5..87ef54bd492c 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -65,11 +65,16 @@ struct atmel_pwm_registers {
 	u8 duty_upd;
 };
 
+struct atmel_pwm_data {
+	struct atmel_pwm_registers regs;
+	struct pwm_caps caps;
+};
+
 struct atmel_pwm_chip {
 	struct pwm_chip chip;
 	struct clk *clk;
 	void __iomem *base;
-	const struct atmel_pwm_registers *regs;
+	const struct atmel_pwm_data *data;
 
 	unsigned int updated_pwms;
 	/* ISR is cleared when read, ensure only one thread does that */
@@ -150,15 +155,15 @@ static void atmel_pwm_update_cdty(struct pwm_chip *chip, struct pwm_device *pwm,
 	struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
 	u32 val;
 
-	if (atmel_pwm->regs->duty_upd ==
-	    atmel_pwm->regs->period_upd) {
+	if (atmel_pwm->data->regs.duty_upd ==
+	    atmel_pwm->data->regs.period_upd) {
 		val = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm, PWM_CMR);
 		val &= ~PWM_CMR_UPD_CDTY;
 		atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
 	}
 
 	atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm,
-			    atmel_pwm->regs->duty_upd, cdty);
+			    atmel_pwm->data->regs.duty_upd, cdty);
 }
 
 static void atmel_pwm_set_cprd_cdty(struct pwm_chip *chip,
@@ -168,9 +173,9 @@ static void atmel_pwm_set_cprd_cdty(struct pwm_chip *chip,
 	struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
 
 	atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm,
-			    atmel_pwm->regs->duty, cdty);
+			    atmel_pwm->data->regs.duty, cdty);
 	atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm,
-			    atmel_pwm->regs->period, cprd);
+			    atmel_pwm->data->regs.period, cprd);
 }
 
 static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm,
@@ -225,7 +230,7 @@ static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 		    cstate.polarity == state->polarity &&
 		    cstate.period == state->period) {
 			cprd = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
-						  atmel_pwm->regs->period);
+						  atmel_pwm->data->regs.period);
 			atmel_pwm_calculate_cdty(state, cprd, &cdty);
 			atmel_pwm_update_cdty(chip, pwm, cdty);
 			return 0;
@@ -272,32 +277,51 @@ static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	return 0;
 }
 
+static void atmel_pwm_get_caps(struct pwm_chip *chip, struct pwm_device *pwm,
+			       struct pwm_caps *caps)
+{
+	struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
+
+	*caps = atmel_pwm->data->caps;
+}
+
 static const struct pwm_ops atmel_pwm_ops = {
 	.apply = atmel_pwm_apply,
+	.get_caps = atmel_pwm_get_caps,
 	.owner = THIS_MODULE,
 };
 
-static const struct atmel_pwm_registers atmel_pwm_regs_v1 = {
-	.period		= PWMV1_CPRD,
-	.period_upd	= PWMV1_CUPD,
-	.duty		= PWMV1_CDTY,
-	.duty_upd	= PWMV1_CUPD,
+static const struct atmel_pwm_data atmel_pwm_data_v1 = {
+	.regs = {
+		.period		= PWMV1_CPRD,
+		.period_upd	= PWMV1_CUPD,
+		.duty		= PWMV1_CDTY,
+		.duty_upd	= PWMV1_CUPD,
+	},
+	.caps = {
+		.modes = PWMC_MODE(NORMAL),
+	},
 };
 
-static const struct atmel_pwm_registers atmel_pwm_regs_v2 = {
-	.period		= PWMV2_CPRD,
-	.period_upd	= PWMV2_CPRDUPD,
-	.duty		= PWMV2_CDTY,
-	.duty_upd	= PWMV2_CDTYUPD,
+static const struct atmel_pwm_data atmel_pwm_data_v2 = {
+	.regs = {
+		.period		= PWMV2_CPRD,
+		.period_upd	= PWMV2_CPRDUPD,
+		.duty		= PWMV2_CDTY,
+		.duty_upd	= PWMV2_CDTYUPD,
+	},
+	.caps = {
+		.modes = PWMC_MODE(NORMAL) | PWMC_MODE(COMPLEMENTARY),
+	},
 };
 
 static const struct platform_device_id atmel_pwm_devtypes[] = {
 	{
 		.name = "at91sam9rl-pwm",
-		.driver_data = (kernel_ulong_t)&atmel_pwm_regs_v1,
+		.driver_data = (kernel_ulong_t)&atmel_pwm_data_v1,
 	}, {
 		.name = "sama5d3-pwm",
-		.driver_data = (kernel_ulong_t)&atmel_pwm_regs_v2,
+		.driver_data = (kernel_ulong_t)&atmel_pwm_data_v2,
 	}, {
 		/* sentinel */
 	},
@@ -307,20 +331,20 @@ MODULE_DEVICE_TABLE(platform, atmel_pwm_devtypes);
 static const struct of_device_id atmel_pwm_dt_ids[] = {
 	{
 		.compatible = "atmel,at91sam9rl-pwm",
-		.data = &atmel_pwm_regs_v1,
+		.data = &atmel_pwm_data_v1,
 	}, {
 		.compatible = "atmel,sama5d3-pwm",
-		.data = &atmel_pwm_regs_v2,
+		.data = &atmel_pwm_data_v2,
 	}, {
 		.compatible = "atmel,sama5d2-pwm",
-		.data = &atmel_pwm_regs_v2,
+		.data = &atmel_pwm_data_v2,
 	}, {
 		/* sentinel */
 	},
 };
 MODULE_DEVICE_TABLE(of, atmel_pwm_dt_ids);
 
-static inline const struct atmel_pwm_registers *
+static inline const struct atmel_pwm_data *
 atmel_pwm_get_driver_data(struct platform_device *pdev)
 {
 	const struct platform_device_id *id;
@@ -330,18 +354,18 @@ atmel_pwm_get_driver_data(struct platform_device *pdev)
 
 	id = platform_get_device_id(pdev);
 
-	return (struct atmel_pwm_registers *)id->driver_data;
+	return (struct atmel_pwm_data *)id->driver_data;
 }
 
 static int atmel_pwm_probe(struct platform_device *pdev)
 {
-	const struct atmel_pwm_registers *regs;
+	const struct atmel_pwm_data *data;
 	struct atmel_pwm_chip *atmel_pwm;
 	struct resource *res;
 	int ret;
 
-	regs = atmel_pwm_get_driver_data(pdev);
-	if (!regs)
+	data = atmel_pwm_get_driver_data(pdev);
+	if (!data)
 		return -ENODEV;
 
 	atmel_pwm = devm_kzalloc(&pdev->dev, sizeof(*atmel_pwm), GFP_KERNEL);
@@ -373,7 +397,7 @@ static int atmel_pwm_probe(struct platform_device *pdev)
 
 	atmel_pwm->chip.base = -1;
 	atmel_pwm->chip.npwm = 4;
-	atmel_pwm->regs = regs;
+	atmel_pwm->data = data;
 	atmel_pwm->updated_pwms = 0;
 	mutex_init(&atmel_pwm->isr_lock);
 
-- 
2.7.4

[PATCH v5 7/9] pwm: add push-pull mode support

[Claudiu Beznea]

Add push-pull mode support. In push-pull mode the channels' outputs have
same polarities and the edges are complementary delayed for one period.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/pwm/core.c  | 1 +
 include/linux/pwm.h | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 59a9df9120de..5fde2e685ca7 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -348,6 +348,7 @@ const char *pwm_mode_desc(struct pwm_device *pwm, unsigned long mode)
 		"invalid",
 		"normal",
 		"complementary",
+		"push-pull",
 	};
 
 	if (!pwm_mode_valid(pwm, mode))
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index a4ce4ad7edf0..eb170e2ab431 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -29,11 +29,14 @@ enum pwm_polarity {
  * PWM modes capabilities
  * @PWMC_MODE_NORMAL_BIT: PWM has one output
  * @PWMC_MODE_COMPLEMENTARY_BIT: PWM has 2 outputs with opposite polarities
+ * @PWMC_MODE_PUSH_PULL_BIT: PWM has 2 outputs with same polarities and the
+ * edges are complementary delayed for one period
  * @PWMC_MODE_CNT: PWM modes count
  */
 enum {
 	PWMC_MODE_NORMAL_BIT,
 	PWMC_MODE_COMPLEMENTARY_BIT,
+	PWMC_MODE_PUSH_PULL_BIT,
 	PWMC_MODE_CNT,
 };
 
-- 
2.7.4

[PATCH v5 8/9] pwm: add documentation for pwm push-pull mode

[Claudiu Beznea]

Add documentation for PWM push-pull mode.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/pwm/pwm.txt |  2 ++
 Documentation/pwm.txt                         | 16 ++++++++++++++++
 include/dt-bindings/pwm/pwm.h                 |  1 +
 3 files changed, 19 insertions(+)

diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt
index 7c8aaac43f92..6a60c0fca112 100644
--- a/Documentation/devicetree/bindings/pwm/pwm.txt
+++ b/Documentation/devicetree/bindings/pwm/pwm.txt
@@ -49,6 +49,8 @@ Optionally, the pwm-specifier can encode a number of flags (defined in
 - PWM_MODE_COMPLEMENTARY: PWM complementary working mode (for PWM channels
 with two outputs); if not specified, the default for PWM channel will be
 used
+- PWM_MODE_PUSH_PULL: PWM push-pull working modes (for PWM channels with
+two outputs); if not specified the default for PWM channel will be used
 
 Example with optional PWM specifier for inverse polarity and complementary
 mode:
diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt
index 912c43da8b48..675f9351fed1 100644
--- a/Documentation/pwm.txt
+++ b/Documentation/pwm.txt
@@ -128,6 +128,22 @@ channel that was exported. The following properties will then be available:
     PWML1   |__|  |__|  |__|  |__|
             <--T-->
 
+    Push-pull mode - for PWM channels with two outputs; output waveforms
+        for a PWM channel in push-pull mode, with normal polarity looks like
+        this:
+            __          __
+    PWMH __|  |________|  |________
+                  __          __
+    PWML ________|  |________|  |__
+           <--T-->
+
+    If polarity is inversed:
+         __    ________    ________
+    PWMH   |__|        |__|
+         ________    ________    __
+    PWML         |__|        |__|
+           <--T-->
+
     Where T is the signal period.
 
 Implementing a PWM driver
diff --git a/include/dt-bindings/pwm/pwm.h b/include/dt-bindings/pwm/pwm.h
index b82279cc1787..cd4265bce968 100644
--- a/include/dt-bindings/pwm/pwm.h
+++ b/include/dt-bindings/pwm/pwm.h
@@ -12,5 +12,6 @@
 
 #define PWM_POLARITY_INVERTED			(1 << 0)
 #define PWM_MODE_COMPLEMENTARY			(1 << 1)
+#define PWM_MODE_PUSH_PULL			(1 << 2)
 
 #endif
-- 
2.7.4

[PATCH v5 9/9] pwm: atmel: add push-pull mode support

[Claudiu Beznea]

Add support for PWM push-pull mode. This is only supported by SAMA5D2 SoCs.

Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com>
---
 drivers/pwm/pwm-atmel.c | 40 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c
index 87ef54bd492c..aaafc4dd30f2 100644
--- a/drivers/pwm/pwm-atmel.c
+++ b/drivers/pwm/pwm-atmel.c
@@ -33,8 +33,11 @@
 
 #define PWM_CMR			0x0
 /* Bit field in CMR */
-#define PWM_CMR_CPOL		(1 << 9)
-#define PWM_CMR_UPD_CDTY	(1 << 10)
+#define PWM_CMR_CPOL		BIT(9)
+#define PWM_CMR_UPD_CDTY	BIT(10)
+#define PWM_CMR_DTHI		BIT(17)
+#define PWM_CMR_DTLI		BIT(18)
+#define PWM_CMR_PPM		BIT(19)
 #define PWM_CMR_CPRE_MSK	0xF
 
 /* The following registers for PWM v1 */
@@ -219,16 +222,19 @@ static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 {
 	struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip);
 	struct pwm_state cstate;
+	struct pwm_caps caps;
 	unsigned long cprd, cdty;
 	u32 pres, val;
 	int ret;
 
 	pwm_get_state(pwm, &cstate);
+	pwm_get_caps(chip, pwm, &caps);
 
 	if (state->enabled) {
 		if (cstate.enabled &&
 		    cstate.polarity == state->polarity &&
-		    cstate.period == state->period) {
+		    cstate.period == state->period &&
+		    cstate.mode == state->mode) {
 			cprd = atmel_pwm_ch_readl(atmel_pwm, pwm->hwpwm,
 						  atmel_pwm->data->regs.period);
 			atmel_pwm_calculate_cdty(state, cprd, &cdty);
@@ -263,6 +269,18 @@ static int atmel_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 			val &= ~PWM_CMR_CPOL;
 		else
 			val |= PWM_CMR_CPOL;
+
+		/* PWM mode. */
+		if (caps.modes & PWMC_MODE(PUSH_PULL)) {
+			if (state->mode == PWMC_MODE(PUSH_PULL)) {
+				val |= PWM_CMR_PPM | PWM_CMR_DTLI;
+				val &= ~PWM_CMR_DTHI;
+			} else {
+				val &= ~(PWM_CMR_PPM | PWM_CMR_DTLI |
+					 PWM_CMR_DTHI);
+			}
+		}
+
 		atmel_pwm_ch_writel(atmel_pwm, pwm->hwpwm, PWM_CMR, val);
 		atmel_pwm_set_cprd_cdty(chip, pwm, cprd, cdty);
 		mutex_lock(&atmel_pwm->isr_lock);
@@ -315,6 +333,20 @@ static const struct atmel_pwm_data atmel_pwm_data_v2 = {
 	},
 };
 
+static const struct atmel_pwm_data atmel_pwm_data_v3 = {
+	.regs = {
+		.period		= PWMV2_CPRD,
+		.period_upd	= PWMV2_CPRDUPD,
+		.duty		= PWMV2_CDTY,
+		.duty_upd	= PWMV2_CDTYUPD,
+	},
+	.caps = {
+		.modes = PWMC_MODE(NORMAL) |
+			 PWMC_MODE(COMPLEMENTARY) |
+			 PWMC_MODE(PUSH_PULL),
+	},
+};
+
 static const struct platform_device_id atmel_pwm_devtypes[] = {
 	{
 		.name = "at91sam9rl-pwm",
@@ -337,7 +369,7 @@ static const struct of_device_id atmel_pwm_dt_ids[] = {
 		.data = &atmel_pwm_data_v2,
 	}, {
 		.compatible = "atmel,sama5d2-pwm",
-		.data = &atmel_pwm_data_v2,
+		.data = &atmel_pwm_data_v3,
 	}, {
 		/* sentinel */
 	},
-- 
2.7.4

Re: [PATCH v5 0/9] extend PWM framework to support PWM modes

[Claudiu Beznea]

Hi Thierry,

It's been a while since I submitted this version but no feedback so far on
it. I re-done it as you suggested. Do you have any thoughts on this version?

Thank you,
Claudiu beznea

On 22.05.2018 15:07, Claudiu Beznea wrote:
> Hi,
> 
> Please give feedback on these patches which extends the PWM framework in
> order to support multiple PWM modes of operations. This series is a rework
> of [1] and [2].
> 
> The current patch series add the following PWM modes:
> - PWM mode normal
> - PWM mode complementary
> - PWM mode push-pull
> 
> Normal mode - for PWM channels with one output; output waveforms looks like
> this:
>              __    __    __    __
>     PWM   __|  |__|  |__|  |__|  |__
>             <--T-->
> 
>     Where T is the signal period
> 
> Since PWMs with more than one output per channel could be used as one
> output PWM the normal mode is the default mode for all PWMs (if not
> specified otherwise).
> 
> Complementary mode - for PWM channels with two outputs; output waveforms
> for a PWM channel in complementary mode looks line this:
>              __    __    __    __
>     PWMH1 __|  |__|  |__|  |__|  |__
>           __    __    __    __    __
>     PWML1   |__|  |__|  |__|  |__|
>             <--T-->
> 
>     Where T is the signal period.
> 
> Push-pull mode - for PWM channels with two outputs; output waveforms for a
> PWM channel in push-pull mode with normal polarity looks like this:
>             __          __
>     PWMH __|  |________|  |________
>                   __          __
>     PWML ________|  |________|  |__
>            <--T-->
> 
>     If polarity is inversed:
>          __    ________    ________
>     PWMH   |__|        |__|
>          ________    ________    __
>     PWML         |__|        |__|
>            <--T-->
> 
>     Where T is the signal period.
> 
> The PWM working modes are per PWM channel registered as PWM's capabilities.
> The driver registers itself to PWM core a get_caps() function, in
> struct pwm_ops, that will be used by PWM core to retrieve PWM capabilities.
> If this function is not registered in driver's probe, a default function
> will be used to retrieve PWM capabilities. Currently, the default
> capabilities includes only PWM normal mode.
> 
> PWM state has been updated to keep PWM mode. PWM mode could be configured
> via sysfs or via DT. pwm_apply_state() will do the preliminary validation
> for PWM mode to be applied.
> 
> In sysfs, user could get PWM modes by reading mode file of PWM device:
> root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# ls -l
> total 0
> -r--r--r-- 1 root root 4096 Oct  9 09:07 capture
> lrwxrwxrwx 1 root root    0 Oct  9 09:07 device -> ../../pwmchip0
> -rw-r--r-- 1 root root 4096 Oct  9 08:42 duty_cycle
> -rw-r--r-- 1 root root 4096 Oct  9 08:44 enable
> --w------- 1 root root 4096 Oct  9 09:07 export
> -rw-r--r-- 1 root root 4096 Oct  9 08:43 mode
> -r--r--r-- 1 root root 4096 Oct  9 09:07 npwm
> -rw-r--r-- 1 root root 4096 Oct  9 08:42 period
> -rw-r--r-- 1 root root 4096 Oct  9 08:44 polarity
> drwxr-xr-x 2 root root    0 Oct  9 09:07 power
> lrwxrwxrwx 1 root root    0 Oct  9 09:07 subsystem -> ../../../../../../../../class/pwm
> -rw-r--r-- 1 root root 4096 Oct  9 08:42 uevent
> --w------- 1 root root 4096 Oct  9 09:07 unexport
> root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# cat mode
> normal complementary [push-pull]
> 
> The mode enclosed in bracket is the currently active mode.
> 
> The mode could be set, via sysfs, by writing to mode file one of the modes
> displayed at read:
> root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# echo normal > mode
> root@sama5d2-xplained:/sys/class/pwm/pwmchip0/pwm2# cat mode
> [normal] complementary push-pull 
> 
> The PWM push-pull mode could be usefull in applications like half bridge
> converters.
> 
> This series also add PWM modes support for Atmel/Microchip SoCs.
> 
> Thank you,
> Claudiu Beznea
> 
> [1] https://www.spinics.net/lists/arm-kernel/msg580275.html
> [2] https://lkml.org/lkml/2018/1/12/359
> 
> Changes in v5:
> - solved kbuild errors by removing dummy functions for case where
>   CONFIG_PWM is not defined; adopted this approach since the removed
>   function are used only only when CONFIG_PWM is defined (in PWM core
>   and few drivers from drivers/pwm/ directory)
> 
> Changes in v4:
> - removed changes related to pwm_config() as per maintainer proposals
> - added pwm_mode_get_valid() to retrieve a valid PWM mode fror PWM device
>   instead of using BIT(ffs(caps.mode) - 1) and changed drivers to use
>   pwm_mode_get_valid() instead of pwm_get_caps() + BIT(ffs(caps.mode) - 1)
>   (patches 2, 3, 4 from this series)
> - renamed PWM_MODE() macro in PWMC_MODE() to avoid conflicts with
>   pwm-sun4i.c driver ('C' stands for capability)
> - removed pwm_caps_valid() function
> - renamed PWM_DTMODE_COMPLEMENTARY and PWM_DTMODE_PUSH_PULL macros in
>   PWM_MODE_COMPLEMENTARY and PWM_MODE_PUSH_PULL
> 
> Changes in v3:
> - removed changes related to only one of_xlate function for all PWM drivers
> - switch to PWM capabilities per PWM channel nor per PWM chip
> - squash documentation and bindings patches as requeted by reviewer
> - introduced PWM_MODE(name) macro and used a bit enum for pwm modes
> - related to DT bindings, used flags cell also for PWM modes
> - updated of_xlate specific functions with "state->mode = mode;"
>   instructions to avoid pwm_apply_state() failures
> - use available modes for PWM channel in pwm_config() by first calling
>   pwm_get_caps() to get caps.modes
> - use loops through available modes in mode_store()/mode_show() and also in
>   of_pwm_xlate_with_flags() instead of "if else" instructions; in this way,
>   the addition of a new mode is independent of this code sections
> - use DTLI=1, DTHI=0 register settings to obtain push-pull mode waveforms
>   for Atmel/Microchip PWM controller.
> 
> Changes in v2:
> - remove of_xlate and of_pwm_n_cells and use generic functions to pharse DT
>   inputs; this is done in patches 1, 2, 3, 4, 5, 6, 7 of this series; this will
>   make easy the addition of PWM mode support from DT
> - add PWM mode normal
> - register PWM modes as capabilities of PWM chips at driver probe and, in case
>   driver doesn't provide these capabilities use default ones
> - change the way PWM mode is pharsed via DT by using a new input for pwms
>   binding property
> 
> 
> Claudiu Beznea (9):
>   pwm: extend PWM framework with PWM modes
>   pwm: clps711x: populate PWM mode in of_xlate function
>   pwm: cros-ec: populate PWM mode in of_xlate function
>   pwm: pxa: populate PWM mode in of_xlate function
>   pwm: add PWM modes
>   pwm: atmel: add pwm capabilities
>   pwm: add push-pull mode support
>   pwm: add documentation for pwm push-pull mode
>   pwm: atmel: add push-pull mode support
> 
>  Documentation/devicetree/bindings/pwm/pwm.txt |  11 ++-
>  Documentation/pwm.txt                         |  42 ++++++++-
>  drivers/pwm/core.c                            | 125 +++++++++++++++++++++++++-
>  drivers/pwm/pwm-atmel.c                       | 118 +++++++++++++++++-------
>  drivers/pwm/pwm-clps711x.c                    |  10 ++-
>  drivers/pwm/pwm-cros-ec.c                     |   1 +
>  drivers/pwm/pwm-pxa.c                         |   1 +
>  drivers/pwm/sysfs.c                           |  61 +++++++++++++
>  include/dt-bindings/pwm/pwm.h                 |   2 +
>  include/linux/pwm.h                           |  64 +++++++++++++
>  10 files changed, 395 insertions(+), 40 deletions(-)
>