Adding PWM Commands (v4)

Adding PWM Commands (v4)

[Marc Reilly]

Thanks again all for comments so far.

Changes in v4:
- rework set/get into single command
- add more cmd arg checking

Changes in v3:
- fix minor typos
- remove unused 'error' var in pwm_get

Changes in v2:
- remove '-n' option to specify device by number
- fix freeing resources on all return paths
- add pwm_get command

[PATCH v4 1/2] commands: add pwm manipulation command

[Marc Reilly]

This introduces a command to set parameters for a pwm device.

Signed-off-by: Marc Reilly <marc@cpdesign.com.au>
---
 commands/Kconfig  |  12 +++
 commands/Makefile |   1 +
 commands/pwm.c    | 199 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 212 insertions(+)
 create mode 100644 commands/pwm.c

diff --git a/commands/Kconfig b/commands/Kconfig
index 4d3ff631a8..28f9e46a59 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -1929,6 +1929,18 @@ config CMD_I2C
 		  -w		use word (16 bit) wide access
 		  -v		verbose
 
+config CMD_PWM
+	bool
+	depends on PWM
+	prompt "PWM commands: pwm"
+	help
+	  pwm - set or show pwm state
+
+	  Usage: pwm [dDPfwisv]
+
+	  Controls the pwm values such as period and duty cycle, or shows
+	  the current values.
+
 config CMD_LED
 	bool
 	depends on LED
diff --git a/commands/Makefile b/commands/Makefile
index 98625a0373..011ae59427 100644
--- a/commands/Makefile
+++ b/commands/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_CMD_GPIO)		+= gpio.o
 obj-$(CONFIG_CMD_UNCOMPRESS)	+= uncompress.o
 obj-$(CONFIG_CMD_I2C)		+= i2c.o
 obj-$(CONFIG_CMD_SPI)		+= spi.o
+obj-$(CONFIG_CMD_PWM)		+= pwm.o
 obj-$(CONFIG_CMD_MIPI_DBI)	+= mipi_dbi.o
 obj-$(CONFIG_CMD_UBI)		+= ubi.o
 obj-$(CONFIG_CMD_UBIFORMAT)	+= ubiformat.o
diff --git a/commands/pwm.c b/commands/pwm.c
new file mode 100644
index 0000000000..82535d229e
--- /dev/null
+++ b/commands/pwm.c
@@ -0,0 +1,199 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// SPDX-FileCopyrightText: © 2023 Marc Reilly <marc@cpdesign.com.au>
+
+/* pwm - pwm commands */
+
+#include <common.h>
+#include <command.h>
+#include <errno.h>
+#include <malloc.h>
+#include <getopt.h>
+#include <pwm.h>
+
+#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))
+#define HZ_FROM_NANOSECONDS(x) (1000000000UL/(x))
+
+static bool is_equal_state(struct pwm_state *state1, struct pwm_state *state2)
+{
+	return (state1->period_ns == state2->period_ns)
+		&& (state1->duty_ns == state2->duty_ns)
+		&& (state1->polarity == state2->polarity)
+		&& (state1->p_enable == state2->p_enable);
+}
+
+static int do_pwm_cmd(int argc, char *argv[])
+{
+	struct pwm_device *pwm = NULL;
+	struct pwm_state state, orig_state;
+	int error = 0;
+	char *devname = NULL;
+	int duty = -1, period = -1;
+	int freq = -1, width = -1;
+	bool invert_polarity = false, stop = false;
+	bool use_default_width = false;
+	bool verbose = false;
+	int opt;
+
+	while ((opt = getopt(argc, argv, "d:D:P:f:w:F:isv")) > 0) {
+		switch (opt) {
+		case 'd':
+			devname = optarg;
+			break;
+		case 'D':
+			duty = simple_strtol(optarg, NULL, 0);
+			break;
+		case 'P':
+			period = simple_strtol(optarg, NULL, 0);
+			break;
+		case 'F':
+			/* convenience option for changing frequency without
+			 * having to specify duty width */
+			use_default_width = true;
+			/* fallthrough */
+		case 'f':
+			freq = simple_strtol(optarg, NULL, 0);
+			break;
+		case 'w':
+			width = simple_strtol(optarg, NULL, 0);
+			break;
+		case 'i':
+			invert_polarity = true;
+			break;
+		case 's':
+			stop = true;
+			break;
+		case 'v':
+			verbose = true;
+			break;
+		}
+	}
+
+	if (!devname) {
+		printf(" need to specify a device\n");
+		return COMMAND_ERROR_USAGE;
+	}
+	if ((freq == 0) || (period == 0)) {
+		printf(" period or freqency needs to be non-zero\n");
+		return COMMAND_ERROR_USAGE;
+	}
+	if (freq >= 0 && period >= 0) {
+		printf(" specify period or frequency, not both\n");
+		return COMMAND_ERROR_USAGE;
+	}
+	if (duty >= 0 && width >= 0) {
+		printf(" specify duty or width, not both\n");
+		return COMMAND_ERROR_USAGE;
+	}
+	if (width > 100) {
+		printf(" width (%% duty cycle) can't be more than 100%%\n");
+		return COMMAND_ERROR_USAGE;
+	}
+
+	pwm = pwm_request(devname);
+	if (!pwm) {
+		printf(" pwm device %s not found\n", devname);
+		return -ENODEV;
+	}
+
+	pwm_get_state(pwm, &state);
+
+	/* argc will be at least 3 with a valid devname */
+	if (verbose || (argc <= 3)) {
+		printf("pwm params for '%s':\n", devname);
+		printf("  period   : %u (ns)\n", state.period_ns);
+		printf("  duty     : %u (ns)\n", state.duty_ns);
+		printf("  enabled  : %d\n", state.p_enable);
+		printf("  polarity : %s\n", state.polarity == 0 ? "Normal" : "Inverted");
+		printf("  freq     : %lu (Hz)\n", HZ_FROM_NANOSECONDS(state.period_ns));
+
+		pwm_free(pwm);
+		return 0;
+	}
+
+	if ((state.period_ns == 0) && (freq < 0) && (period < 0)) {
+		printf(" need to know some timing info: freq or period\n");
+		pwm_free(pwm);
+		return COMMAND_ERROR_USAGE;
+	}
+
+	orig_state = state;
+
+	if (invert_polarity)
+		state.polarity = invert_polarity;
+
+	/* period */
+	if (freq > 0) {
+		state.p_enable = true;
+		state.period_ns = HZ_TO_NANOSECONDS(freq);
+		if (use_default_width && (width < 0)) {
+			width = 50;
+		}
+	} else if (period > 0) {
+		state.p_enable = true;
+		state.period_ns = period;
+	}
+
+	/* duty */
+	if (width >= 0) {
+		pwm_set_relative_duty_cycle(&state, width, 100);
+	} else if (duty >= 0) {
+		state.duty_ns = duty;
+	}
+
+	if (state.duty_ns > state.period_ns) {
+		printf(" duty_ns must not be greater than period_ns\n");
+	}
+
+	/* only set the state if its changed */
+	if (!is_equal_state(&orig_state, & state))
+		error = pwm_apply_state(pwm, &state);
+
+	if (error < 0)
+		printf(" error while applying state: %d\n", error);
+
+	/* stop handled as an additional step on purpose, allows turning off
+	 * output (eg if duty => 0) and stopping in one command
+	 */
+	if (stop > 0) {
+		state.p_enable = false;
+		error = pwm_apply_state(pwm, &state);
+		if (error < 0)
+			printf(" error while stopping: %d\n", error);
+	}
+
+	pwm_free(pwm);
+
+	return error;
+}
+
+BAREBOX_CMD_HELP_START(pwm)
+BAREBOX_CMD_HELP_TEXT("Sets pwm device parameters, or shows current value.")
+BAREBOX_CMD_HELP_TEXT(" Specify the pwm device by device name.")
+BAREBOX_CMD_HELP_TEXT(" If no other parameters are given, or if args has '-v',")
+BAREBOX_CMD_HELP_TEXT("  then show the current values only.")
+BAREBOX_CMD_HELP_TEXT(" Timings can either be specified via period + duty (on) duration,")
+BAREBOX_CMD_HELP_TEXT("  or via frequency. Duty can be given either as a percentage or time.")
+BAREBOX_CMD_HELP_TEXT(" If a parameter is not specified, the current value will be used")
+BAREBOX_CMD_HELP_TEXT("  where possible.")
+BAREBOX_CMD_HELP_TEXT(" To set an output to inactive state, set the duty to 0.")
+BAREBOX_CMD_HELP_TEXT("  (although note this will not by itself stop the pwm running.)")
+BAREBOX_CMD_HELP_TEXT(" Stopping the pwm device does not necessarily set the output to inactive,")
+BAREBOX_CMD_HELP_TEXT("  but stop is handled last, so can be done in addition to other changes.")
+BAREBOX_CMD_HELP_TEXT("Options:")
+BAREBOX_CMD_HELP_OPT("-d string", "device name (eg 'pwm0')")
+BAREBOX_CMD_HELP_OPT("-D number", "duty cycle (ns)")
+BAREBOX_CMD_HELP_OPT("-P number", "period (ns)")
+BAREBOX_CMD_HELP_OPT("-f number", "frequency (Hz)")
+BAREBOX_CMD_HELP_OPT("-w number", "duty cycle (%) - the on 'width' of each cycle")
+BAREBOX_CMD_HELP_OPT("-i\t", "line inverted polarity")
+BAREBOX_CMD_HELP_OPT("-s\t", "stop (disable) the pwm device")
+BAREBOX_CMD_HELP_OPT("-v\t", "print current values")
+BAREBOX_CMD_HELP_END
+
+BAREBOX_CMD_START(pwm)
+	.cmd		= do_pwm_cmd,
+	BAREBOX_CMD_DESC("pwm")
+	BAREBOX_CMD_OPTS("[-dDPfwisv]")
+	BAREBOX_CMD_GROUP(CMD_GRP_HWMANIP)
+	BAREBOX_CMD_HELP(cmd_pwm_help)
+BAREBOX_CMD_END
-- 
2.35.3

[PATCH v4 2/2] include: pwm: minor function doc fix for pwm_set_relative_duty_cycle()

[Marc Reilly]

Signed-off-by: Marc Reilly <marc@cpdesign.com.au>
---
 include/pwm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/pwm.h b/include/pwm.h
index 643ef4d7ee..02af7d0a5f 100644
--- a/include/pwm.h
+++ b/include/pwm.h
@@ -71,7 +71,7 @@ unsigned int pwm_get_period(struct pwm_device *pwm);
  * @scale: scale in which @duty_cycle is expressed
  *
  * This functions converts a relative into an absolute duty cycle (expressed
- * in nanoseconds), and puts the result in state->duty_cycle.
+ * in nanoseconds), and puts the result in state->duty_ns.
  *
  * For example if you want to configure a 50% duty cycle, call:
  *
-- 
2.35.3

Re: [PATCH v4 1/2] commands: add pwm manipulation command

[Sascha Hauer]

Hi Marc,

I applied this with some small changes.

On Fri, Jun 02, 2023 at 02:53:05PM +1000, Marc Reilly wrote:
> +static int do_pwm_cmd(int argc, char *argv[])
> +{
> +	struct pwm_device *pwm = NULL;
> +	struct pwm_state state, orig_state;
> +	int error = 0;
> +	char *devname = NULL;
> +	int duty = -1, period = -1;
> +	int freq = -1, width = -1;
> +	bool invert_polarity = false, stop = false;
> +	bool use_default_width = false;
> +	bool verbose = false;
> +	int opt;
> +
> +	while ((opt = getopt(argc, argv, "d:D:P:f:w:F:isv")) > 0) {
> +		switch (opt) {
> +		case 'd':
> +			devname = optarg;
> +			break;
> +		case 'D':
> +			duty = simple_strtol(optarg, NULL, 0);
> +			break;
> +		case 'P':
> +			period = simple_strtol(optarg, NULL, 0);
> +			break;
> +		case 'F':
> +			/* convenience option for changing frequency without
> +			 * having to specify duty width */
> +			use_default_width = true;
> +			/* fallthrough */
> +		case 'f':
> +			freq = simple_strtol(optarg, NULL, 0);
> +			break;
> +		case 'w':
> +			width = simple_strtol(optarg, NULL, 0);
> +			break;
> +		case 'i':
> +			invert_polarity = true;
> +			break;
> +		case 's':
> +			stop = true;
> +			break;
> +		case 'v':
> +			verbose = true;
> +			break;

		default:
			return COMMAND_ERROR_USAGE;

> +		}
> +	}
> +
> +	if (!devname) {
> +		printf(" need to specify a device\n");
> +		return COMMAND_ERROR_USAGE;
> +	}
> +	if ((freq == 0) || (period == 0)) {
> +		printf(" period or freqency needs to be non-zero\n");
> +		return COMMAND_ERROR_USAGE;
> +	}
> +	if (freq >= 0 && period >= 0) {
> +		printf(" specify period or frequency, not both\n");
> +		return COMMAND_ERROR_USAGE;
> +	}
> +	if (duty >= 0 && width >= 0) {
> +		printf(" specify duty or width, not both\n");
> +		return COMMAND_ERROR_USAGE;
> +	}
> +	if (width > 100) {
> +		printf(" width (%% duty cycle) can't be more than 100%%\n");
> +		return COMMAND_ERROR_USAGE;
> +	}
> +
> +	pwm = pwm_request(devname);
> +	if (!pwm) {
> +		printf(" pwm device %s not found\n", devname);
> +		return -ENODEV;
> +	}
> +
> +	pwm_get_state(pwm, &state);
> +
> +	/* argc will be at least 3 with a valid devname */
> +	if (verbose || (argc <= 3)) {
> +		printf("pwm params for '%s':\n", devname);
> +		printf("  period   : %u (ns)\n", state.period_ns);
> +		printf("  duty     : %u (ns)\n", state.duty_ns);
> +		printf("  enabled  : %d\n", state.p_enable);
> +		printf("  polarity : %s\n", state.polarity == 0 ? "Normal" : "Inverted");
> +		printf("  freq     : %lu (Hz)\n", HZ_FROM_NANOSECONDS(state.period_ns));

This results in a division by zero crash on a disabled PWM. I changed
this to:

		if (state.period_ns)
			printf("  freq     : %lu (Hz)\n", HZ_FROM_NANOSECONDS(state.period_ns));
		else
			printf("  freq     : -\n");


> +BAREBOX_CMD_HELP_OPT("-d string", "device name (eg 'pwm0')")
> +BAREBOX_CMD_HELP_OPT("-D number", "duty cycle (ns)")
> +BAREBOX_CMD_HELP_OPT("-P number", "period (ns)")
> +BAREBOX_CMD_HELP_OPT("-f number", "frequency (Hz)")
> +BAREBOX_CMD_HELP_OPT("-w number", "duty cycle (%) - the on 'width' of each cycle")

Replaced 'number' with <duty_ns> and similar.

Sascha

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