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

From: Mikhail Kshevetskiy mikhail.kshevetskiy@iopsys.eu Date: Fri, 5 Jul 2024 06:26:24 +0400

From: Michael Polyntsov michael.polyntsov@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@iopsys.eu Signed-off-by: Mikhail Kshevetskiy mikhail.kshevetskiy@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@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@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