[PATCH 1/2] led: Implement software led blinking

Mark Kettenis mark.kettenis at xs4all.nl
Fri Jul 5 10:29:51 CEST 2024


> From: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
> Date: Fri,  5 Jul 2024 06:26:24 +0400
> 
> From: Michael Polyntsov <michael.polyntsov at iopsys.eu>
> 
> If hardware (or driver) doesn't support leds blinking, it's
> now possible to use software implementation of blinking instead.
> This relies on cyclic functions.
> 
> v2 changes:
>  * Drop sw_blink_state structure, move its necessary fields to
>    led_uc_plat structure.
>  * Add cyclic_info pointer to led_uc_plat structure. This
>    simplify code a lot.
>  * Remove cyclic function search logic. Not needed anymore.
>  * Fix blinking period. It was twice large.
>  * Other cleanups.
> 
> v3 changes:
>  * Adapt code to recent cyclic function changes
>  * Move software blinking functions to separate file
>  * Other small changes
> 
> Signed-off-by: Michael Polyntsov <michael.polyntsov at iopsys.eu>
> Signed-off-by: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
> ---
>  drivers/led/Kconfig        |  14 +++++
>  drivers/led/Makefile       |   1 +
>  drivers/led/led-uclass.c   |  16 +++++-
>  drivers/led/led_sw_blink.c | 106 +++++++++++++++++++++++++++++++++++++
>  include/led.h              |  17 ++++++
>  5 files changed, 152 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/led/led_sw_blink.c
> 
> diff --git a/drivers/led/Kconfig b/drivers/led/Kconfig
> index 9837960198d..dc9d4c8a757 100644
> --- a/drivers/led/Kconfig
> +++ b/drivers/led/Kconfig
> @@ -73,6 +73,20 @@ config LED_BLINK
>  	  This option enables support for this which adds slightly to the
>  	  code size.
>  
> +config LED_SW_BLINK
> +	bool "Support software LED blinking"
> +	depends on LED_BLINK
> +	select CYCLIC
> +	help
> +	  Turns on led blinking implemented in the software, useful when
> +	  the hardware doesn't support led blinking. Half of the period
> +	  led will be ON and the rest time it will be OFF. Standard
> +	  led commands can be used to configure blinking. Does nothing
> +	  if driver supports blinking.
> +	  WARNING: Blinking may be inaccurate during execution of time
> +	  consuming commands (ex. flash reading). Also it completely
> +	  stops during OS booting.

Doesn't that make this feature pretty much pointless?

>  config SPL_LED
>  	bool "Enable LED support in SPL"
>  	depends on SPL_DM
> diff --git a/drivers/led/Makefile b/drivers/led/Makefile
> index 2bcb8589087..e27aa488482 100644
> --- a/drivers/led/Makefile
> +++ b/drivers/led/Makefile
> @@ -4,6 +4,7 @@
>  # Written by Simon Glass <sjg at chromium.org>
>  
>  obj-y += led-uclass.o
> +obj-$(CONFIG_LED_SW_BLINK) += led_sw_blink.o
>  obj-$(CONFIG_LED_BCM6328) += led_bcm6328.o
>  obj-$(CONFIG_LED_BCM6358) += led_bcm6358.o
>  obj-$(CONFIG_LED_BCM6753) += led_bcm6753.o
> diff --git a/drivers/led/led-uclass.c b/drivers/led/led-uclass.c
> index f37bf6a1550..37dc99cecdc 100644
> --- a/drivers/led/led-uclass.c
> +++ b/drivers/led/led-uclass.c
> @@ -58,6 +58,10 @@ int led_set_state(struct udevice *dev, enum led_state_t state)
>  	if (!ops->set_state)
>  		return -ENOSYS;
>  
> +	if (IS_ENABLED(CONFIG_LED_SW_BLINK) &&
> +	    led_sw_on_state_change(dev, state))
> +		return 0;
> +
>  	return ops->set_state(dev, state);
>  }
>  
> @@ -68,6 +72,10 @@ enum led_state_t led_get_state(struct udevice *dev)
>  	if (!ops->get_state)
>  		return -ENOSYS;
>  
> +	if (IS_ENABLED(CONFIG_LED_SW_BLINK) &&
> +	    led_sw_is_blinking(dev))
> +		return LEDST_BLINK;
> +
>  	return ops->get_state(dev);
>  }
>  
> @@ -76,8 +84,12 @@ int led_set_period(struct udevice *dev, int period_ms)
>  {
>  	struct led_ops *ops = led_get_ops(dev);
>  
> -	if (!ops->set_period)
> -		return -ENOSYS;
> +	if (!ops->set_period) {
> +		if (IS_ENABLED(CONFIG_LED_SW_BLINK))
> +			return led_sw_set_period(dev, period_ms);
> +		else
> +			return -ENOSYS;
> +	}
>  
>  	return ops->set_period(dev, period_ms);
>  }
> diff --git a/drivers/led/led_sw_blink.c b/drivers/led/led_sw_blink.c
> new file mode 100644
> index 00000000000..ab56111a60b
> --- /dev/null
> +++ b/drivers/led/led_sw_blink.c
> @@ -0,0 +1,106 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Software blinking helpers
> + * Copyright (C) 2024 IOPSYS Software Solutions AB
> + * Author: Mikhail Kshevetskiy <mikhail.kshevetskiy at iopsys.eu>
> + */
> +
> +#include <dm.h>
> +#include <led.h>
> +#include <time.h>
> +#include <stdlib.h>
> +
> +static void led_sw_blink(struct cyclic_info *c)
> +{
> +	struct led_uc_plat *uc_plat;
> +	struct udevice *dev;
> +	struct led_ops *ops;
> +
> +	uc_plat = container_of(c, struct led_uc_plat, cyclic);
> +	dev = uc_plat->dev;
> +	ops = led_get_ops(dev);
> +
> +	switch (uc_plat->sw_blink_state) {
> +	case LED_SW_BLINK_ST_OFF:
> +		uc_plat->sw_blink_state = LED_SW_BLINK_ST_ON;
> +		ops->set_state(dev, LEDST_ON);
> +		break;
> +	case LED_SW_BLINK_ST_ON:
> +		uc_plat->sw_blink_state = LED_SW_BLINK_ST_OFF;
> +		ops->set_state(dev, LEDST_OFF);
> +		break;
> +	case LED_SW_BLINK_ST_NOT_READY:
> +		/*
> +		 * led_set_period has been called, but
> +		 * led_set_state(LDST_BLINK) has not yet,
> +		 * so doing nothing
> +		 */
> +		break;
> +	default:
> +		break;
> +	}
> +}
> +
> +int led_sw_set_period(struct udevice *dev, int period_ms)
> +{
> +	struct led_uc_plat *uc_plat = dev_get_uclass_plat(dev);
> +	struct cyclic_info *cyclic = &uc_plat->cyclic;
> +	struct led_ops *ops = led_get_ops(dev);
> +	int half_period_us;
> +	char *name;
> +	int len;
> +
> +	half_period_us = period_ms * 1000 / 2;
> +
> +	name = (char *)cyclic->name;
> +	if (name == NULL) {
> +		len = snprintf(NULL, 0, "led_sw_blink_%s", uc_plat->label);
> +		if (len <= 0)
> +			return -ENOMEM;
> +
> +		name = malloc(len + 1);
> +		if (!name)
> +			return -ENOMEM;
> +
> +		snprintf(name, len + 1, "led_sw_blink_%s", uc_plat->label);
> +	}
> +
> +	if (uc_plat->sw_blink_state == LED_SW_BLINK_ST_DISABLED) {
> +		uc_plat->dev = dev;
> +		cyclic_register(cyclic, led_sw_blink, half_period_us, name);
> +	} else {
> +		cyclic->delay_us = half_period_us;
> +		cyclic->start_time_us = timer_get_us();
> +	}
> +
> +	uc_plat->sw_blink_state = LED_SW_BLINK_ST_NOT_READY;
> +	ops->set_state(dev, LEDST_OFF);
> +
> +	return 0;
> +}
> +
> +bool led_sw_is_blinking(struct udevice *dev)
> +{
> +	struct led_uc_plat *uc_plat = dev_get_uclass_plat(dev);
> +
> +	return (uc_plat->sw_blink_state > LED_SW_BLINK_ST_NOT_READY);
> +}
> +
> +bool led_sw_on_state_change(struct udevice *dev, enum led_state_t state)
> +{
> +	struct led_uc_plat *uc_plat = dev_get_uclass_plat(dev);
> +
> +	if (uc_plat->sw_blink_state != LED_SW_BLINK_ST_DISABLED) {
> +		if (state == LEDST_BLINK) {
> +			/* start blinking on next led_sw_blink() call */
> +			uc_plat->sw_blink_state = LED_SW_BLINK_ST_OFF;
> +			return true;
> +		}
> +
> +		/* stop blinking */
> +		cyclic_unregister(&uc_plat->cyclic);
> +		uc_plat->sw_blink_state = LED_SW_BLINK_ST_DISABLED;
> +	}
> +
> +	return false;
> +}
> diff --git a/include/led.h b/include/led.h
> index a6353166289..26955269d3e 100644
> --- a/include/led.h
> +++ b/include/led.h
> @@ -20,6 +20,13 @@ enum led_state_t {
>  	LEDST_COUNT,
>  };
>  
> +enum led_sw_blink_state_t {
> +	LED_SW_BLINK_ST_DISABLED,
> +	LED_SW_BLINK_ST_NOT_READY,
> +	LED_SW_BLINK_ST_OFF,
> +	LED_SW_BLINK_ST_ON,
> +};
> +
>  /**
>   * struct led_uc_plat - Platform data the uclass stores about each device
>   *
> @@ -29,6 +36,11 @@ enum led_state_t {
>  struct led_uc_plat {
>  	const char *label;
>  	enum led_state_t default_state;
> +#ifdef CONFIG_LED_SW_BLINK
> +	struct udevice *dev;
> +	struct cyclic_info cyclic;
> +	enum led_sw_blink_state_t sw_blink_state;
> +#endif
>  };
>  
>  /**
> @@ -118,4 +130,9 @@ int led_set_period(struct udevice *dev, int period_ms);
>   */
>  int led_bind_generic(struct udevice *parent, const char *driver_name);
>  
> +/* Internal functions for software blinking. Do not use them in your code */
> +int led_sw_set_period(struct udevice *dev, int period_ms);
> +bool led_sw_is_blinking(struct udevice *dev);
> +bool led_sw_on_state_change(struct udevice *dev, enum led_state_t state);
> +
>  #endif
> -- 
> 2.39.2
> 
> 


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