* [PATCH 2/4] param: add support for setting parameters with percentages
2025-10-27 6:30 [PATCH 1/4] sound: pwm-beeper: make duty cycle configurable Ahmad Fatoum
@ 2025-10-27 6:30 ` Ahmad Fatoum
2025-10-27 6:30 ` [PATCH 3/4] video: backlight-pwm: switch to gpiod functions Ahmad Fatoum
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Ahmad Fatoum @ 2025-10-27 6:30 UTC (permalink / raw)
To: barebox; +Cc: Ahmad Fatoum
Some parameters have a maximum that's below the maximum value allowed
by the type, which would be convenient to set as percentage, e.g.
volume of a sound card or brightness level of a backlight.
With the new simple_strtofract, we can easily accomplish this, so add
support for that.
Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
include/param.h | 8 ++++++++
lib/parameter.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 54 insertions(+)
diff --git a/include/param.h b/include/param.h
index a15e064ddec2..59aa8a3a385f 100644
--- a/include/param.h
+++ b/include/param.h
@@ -116,6 +116,8 @@ void param_remove(struct param_d *p);
int bobject_param_set_generic(bobject_t bobj, struct param_d *p,
const char *val);
+int param_int_set_scale(struct param_d *p, uint64_t max);
+
#else
static inline const char *bobject_get_param(bobject_t bobj, const char *name)
{
@@ -251,6 +253,12 @@ static inline int bobject_param_set_generic(bobject_t bobj, struct param_d *p,
{
return 0;
}
+
+static inline int param_int_set_scale(struct param_d *p, uint64_t max)
+{
+ return 0;
+}
+
#endif
static inline const char *get_param_value(struct param_d *param)
diff --git a/lib/parameter.c b/lib/parameter.c
index 274e6fcb8376..f36d77d119fa 100644
--- a/lib/parameter.c
+++ b/lib/parameter.c
@@ -354,6 +354,7 @@ struct param_int {
const char *format;
int (*set)(struct param_d *p, void *priv);
int (*get)(struct param_d *p, void *priv);
+ u64 scale_max;
};
static inline struct param_int *to_param_int(struct param_d *p)
@@ -403,6 +404,33 @@ static int param_int_set(struct bobject *bobj, struct param_d *p,
return ret;
}
+static int param_int_set_scaled(struct bobject *bobj, struct param_d *p,
+ const char *val)
+{
+ char buf[sizeof("18446744073709551615")];
+ struct param_int *pi = to_param_int(p);
+ s64 scaled;
+ char *end;
+
+ if (!isempty(val) && val[strlen(val) - 1] == '%') {
+ u64 percent = div_u64(pi->scale_max, 100);
+
+ scaled = simple_strtofract(val, &end, percent);
+ if (val == end || *end != '%' ||
+ scaled < 0 || scaled > percent * 100)
+ return -EINVAL;
+
+ /* saturate at 100% */
+ if (scaled == percent * 100)
+ scaled = pi->scale_max;
+
+ snprintf(buf, sizeof(buf), pi->format, scaled);
+ val = buf;
+ }
+
+ return param_int_set(bobj, p, val);
+}
+
static const char *param_int_get(struct bobject *bobj, struct param_d *p)
{
struct param_int *pi = to_param_int(p);
@@ -432,6 +460,24 @@ static const char *param_int_get(struct bobject *bobj, struct param_d *p)
return p->value;
}
+static void param_int_max_info(struct param_d *p)
+{
+ struct param_int *pi = to_param_int(p);
+ printf(" (maximum: %llu)", pi->scale_max);
+}
+
+int param_int_set_scale(struct param_d *p, uint64_t max)
+{
+ if (IS_ERR(p))
+ return PTR_ERR(p);
+
+ p->info = param_int_max_info;
+ p->set = param_int_set_scaled;
+ to_param_int(p)->scale_max = max;
+
+ return 0;
+}
+
int param_set_readonly(struct param_d *p, void *priv)
{
return -EROFS;
--
2.47.3
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH 3/4] video: backlight-pwm: switch to gpiod functions
2025-10-27 6:30 [PATCH 1/4] sound: pwm-beeper: make duty cycle configurable Ahmad Fatoum
2025-10-27 6:30 ` [PATCH 2/4] param: add support for setting parameters with percentages Ahmad Fatoum
@ 2025-10-27 6:30 ` Ahmad Fatoum
2025-10-27 6:30 ` [PATCH 4/4] backlight: support setting brightness as percentage Ahmad Fatoum
2025-10-28 8:19 ` [PATCH 1/4] sound: pwm-beeper: make duty cycle configurable Sascha Hauer
3 siblings, 0 replies; 5+ messages in thread
From: Ahmad Fatoum @ 2025-10-27 6:30 UTC (permalink / raw)
To: barebox; +Cc: Ahmad Fatoum
Using GPIO descriptors aligns us more with the Linux customs nowadays
and takes care of potential active low handling.
Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
drivers/video/backlight-pwm.c | 27 ++++++++-------------------
1 file changed, 8 insertions(+), 19 deletions(-)
diff --git a/drivers/video/backlight-pwm.c b/drivers/video/backlight-pwm.c
index 87358ca778ec..d3c81114e006 100644
--- a/drivers/video/backlight-pwm.c
+++ b/drivers/video/backlight-pwm.c
@@ -12,8 +12,7 @@
#include <linux/err.h>
#include <of.h>
#include <regulator.h>
-#include <gpio.h>
-#include <of_gpio.h>
+#include <linux/gpio/consumer.h>
#include <linux/math64.h>
struct pwm_backlight {
@@ -22,8 +21,7 @@ struct pwm_backlight {
struct regulator *power;
uint32_t period;
unsigned int *levels;
- int enable_gpio;
- int enable_active_high;
+ struct gpio_desc *enable_gpio;
int enabled;
unsigned int scale;
};
@@ -41,10 +39,7 @@ static int backlight_pwm_enable(struct pwm_backlight *pwm_backlight)
regulator_enable(pwm_backlight->power);
- if (gpio_is_valid(pwm_backlight->enable_gpio)) {
- gpio_direction_output(pwm_backlight->enable_gpio,
- pwm_backlight->enable_active_high);
- }
+ gpiod_direction_output(pwm_backlight->enable_gpio, true);
pwm_backlight->enabled = 1;
@@ -53,13 +48,13 @@ static int backlight_pwm_enable(struct pwm_backlight *pwm_backlight)
static int backlight_pwm_disable(struct pwm_backlight *pwm_backlight)
{
+ int ret;
+
if (!pwm_backlight->enabled)
return 0;
- if (gpio_is_valid(pwm_backlight->enable_gpio)) {
- gpio_direction_output(pwm_backlight->enable_gpio,
- !pwm_backlight->enable_active_high);
-
+ ret = gpiod_direction_output(pwm_backlight->enable_gpio, false);
+ if (!ret) {
regulator_disable(pwm_backlight->power);
/*
@@ -109,7 +104,6 @@ static int pwm_backlight_parse_dt(struct device *dev,
int length;
u32 value;
int ret, i;
- enum of_gpio_flags flags;
if (!node)
return -ENODEV;
@@ -154,12 +148,7 @@ static int pwm_backlight_parse_dt(struct device *dev,
pwm_backlight->backlight.brightness_max = pwm_backlight->scale;
}
- pwm_backlight->enable_gpio = of_get_named_gpio_flags(node, "enable-gpios", 0, &flags);
-
- if (gpio_is_valid(pwm_backlight->enable_gpio)) {
- if (!(flags & OF_GPIO_ACTIVE_LOW))
- pwm_backlight->enable_active_high = 1;
- }
+ pwm_backlight->enable_gpio = gpiod_get_optional(dev, "enable-gpios", 0);
return 0;
}
--
2.47.3
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH 4/4] backlight: support setting brightness as percentage
2025-10-27 6:30 [PATCH 1/4] sound: pwm-beeper: make duty cycle configurable Ahmad Fatoum
2025-10-27 6:30 ` [PATCH 2/4] param: add support for setting parameters with percentages Ahmad Fatoum
2025-10-27 6:30 ` [PATCH 3/4] video: backlight-pwm: switch to gpiod functions Ahmad Fatoum
@ 2025-10-27 6:30 ` Ahmad Fatoum
2025-10-28 8:19 ` [PATCH 1/4] sound: pwm-beeper: make duty cycle configurable Sascha Hauer
3 siblings, 0 replies; 5+ messages in thread
From: Ahmad Fatoum @ 2025-10-27 6:30 UTC (permalink / raw)
To: barebox; +Cc: Ahmad Fatoum
From: Ahmad Fatoum <ahmad@a3f.at>
Unlike the PWN duty cycle, we already have a parameter for the
brightness, so we can't retroactively redefine it to be in terms of
percentages.
By setting the scale, we allow users to enter percentages between 0% and
100% over the same parameter as well.
Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
drivers/video/backlight.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/video/backlight.c b/drivers/video/backlight.c
index 51d245a80fdb..6d8146ee5aa0 100644
--- a/drivers/video/backlight.c
+++ b/drivers/video/backlight.c
@@ -69,6 +69,7 @@ static int backlight_brightness_set(struct param_d *p, void *priv)
int backlight_register(struct backlight_device *bl)
{
+ struct param_d *param;
int ret;
dev_set_name(&bl->dev, "backlight");
@@ -78,8 +79,10 @@ int backlight_register(struct backlight_device *bl)
if (ret)
return ret;
- dev_add_param_uint32(&bl->dev, "brightness", backlight_brightness_set,
- NULL, &bl->brightness, "%u", bl);
+ param = dev_add_param_uint32(&bl->dev, "brightness", backlight_brightness_set,
+ NULL, &bl->brightness, "%u", bl);
+ param_int_set_scale(param, bl->brightness_max);
+
dev_add_param_uint32(&bl->dev, "slew_time_ms", NULL, NULL,
&bl->slew_time_ms, "%u", NULL);
--
2.47.3
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH 1/4] sound: pwm-beeper: make duty cycle configurable
2025-10-27 6:30 [PATCH 1/4] sound: pwm-beeper: make duty cycle configurable Ahmad Fatoum
` (2 preceding siblings ...)
2025-10-27 6:30 ` [PATCH 4/4] backlight: support setting brightness as percentage Ahmad Fatoum
@ 2025-10-28 8:19 ` Sascha Hauer
3 siblings, 0 replies; 5+ messages in thread
From: Sascha Hauer @ 2025-10-28 8:19 UTC (permalink / raw)
To: barebox, Ahmad Fatoum
On Mon, 27 Oct 2025 07:30:36 +0100, Ahmad Fatoum wrote:
> A lower duty cycle may be less jarring to hear, so give users the
> possibility to control it via device parameter attached to the PWM
> beeper device.
>
>
Applied, thanks!
[1/4] sound: pwm-beeper: make duty cycle configurable
https://git.pengutronix.de/cgit/barebox/commit/?id=a1e1f274c4e3 (link may not be stable)
[2/4] param: add support for setting parameters with percentages
https://git.pengutronix.de/cgit/barebox/commit/?id=4c837b2e1417 (link may not be stable)
[3/4] video: backlight-pwm: switch to gpiod functions
https://git.pengutronix.de/cgit/barebox/commit/?id=4c7238df6866 (link may not be stable)
[4/4] backlight: support setting brightness as percentage
https://git.pengutronix.de/cgit/barebox/commit/?id=e6cc85dc1de1 (link may not be stable)
Best regards,
--
Sascha Hauer <s.hauer@pengutronix.de>
^ permalink raw reply [flat|nested] 5+ messages in thread