[PATCH v6 1/2] dt-bindings: Add docs for EL15203000

[PATCH v6 1/2] dt-bindings: Add docs for EL15203000

[Oleh Kravchenko]

Add documentation and example for dt-bindings EL15203000.
LED board (aka RED LED board) from Crane Merchandising Systems.

Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua>
---
 .../bindings/leds/leds-el15203000.txt         | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/leds-el15203000.txt

diff --git a/Documentation/devicetree/bindings/leds/leds-el15203000.txt b/Documentation/devicetree/bindings/leds/leds-el15203000.txt
new file mode 100644
index 000000000000..c00e1b55db97
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-el15203000.txt
@@ -0,0 +1,54 @@
+Crane Merchandising System - el15203000 LED driver
+--------------------------------------------------
+
+This LED Board (aka RED LEDs board) is widely used in
+coffee vending machines produced by Crane Merchandising Systems.
+
+Required properties:
+- compatible : "crane,el15203000"
+- reg :
+	see Documentation/devicetree/bindings/spi/spi-bus.txt
+- spi-max-frequency : (optional)
+	see Documentation/devicetree/bindings/spi/spi-bus.txt
+
+Optional LED sub-node properties:
+- function:
+	see Documentation/devicetree/bindings/leds/common.txt
+- color:
+	see Documentation/devicetree/bindings/leds/common.txt
+- label:
+	see Documentation/devicetree/bindings/leds/common.txt (deprecated)
+
+Example
+-------
+
+#include <dt-bindings/leds/common.h>
+
+led-controller@0 {
+	compatible = "crane,el15203000";
+	reg = <0>;
+	spi-max-frequency = <50000>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	/* water pipe */
+	led@50 {
+		reg = <0x50>;
+		function = "pipe";
+		color = <LED_COLOR_ID_RED>;
+	};
+
+	/* screen frame */
+	led@53 {
+		reg = <0x53>;
+		function = "screen";
+		color = <LED_COLOR_ID_RED>;
+	};
+
+	/* vending area */
+	led@56 {
+		reg = <0x56>;
+		function = "vend";
+		color = <LED_COLOR_ID_RED>;
+	};
+};
-- 
2.21.0

[PATCH v6 2/2] leds: add LED driver for EL15203000 board

[Oleh Kravchenko]

This patch adds a LED class driver for the LEDs found on
the Crane Merchandising System EL15203000 LEDs board
(aka RED LEDs board).

Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua>
---
 .../testing/sysfs-class-led-driver-el15203000 |  32 ++
 drivers/leds/Kconfig                          |  13 +
 drivers/leds/Makefile                         |   1 +
 drivers/leds/leds-el15203000.c                | 356 ++++++++++++++++++
 4 files changed, 402 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-el15203000
 create mode 100644 drivers/leds/leds-el15203000.c

diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-el15203000 b/Documentation/ABI/testing/sysfs-class-led-driver-el15203000
new file mode 100644
index 000000000000..5e9cbf49da59
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-driver-el15203000
@@ -0,0 +1,32 @@
+What:		/sys/class/leds/<led>/hw_pattern
+Date:		September 2019
+KernelVersion:	5.5
+Description:
+		Specify a hardware pattern for the EL15203000 LED.
+		The LEDs board supports only predefined patterns by firmware
+		for specific LEDs.
+
+		Breathing mode for Screen frame light tube:
+		"0 4000 1 4000"
+
+		Cascade mode for Pipe LED:
+		"1 800 2 800 4 800 8 800 16 800"
+
+		Inverted cascade mode for Pipe LED:
+		"30 800 29 800 27 800 23 800 15 800"
+
+		Bounce mode for Pipe LED:
+		"1 800 2 800 4 800 8 800 16 800 16 800 8 800 4 800 2 800 1 800"
+
+		Inverted bounce mode for Pipe LED:
+		"30 800 29 800 27 800 23 800 15 800 15 800 23 800 27 800 29 800 30 800"
+
+What:		/sys/class/leds/<led>/repeat
+Date:		September 2019
+KernelVersion:	5.5
+Description:
+		EL15203000 supports only indefinitely patterns,
+		so this file should always store -1.
+
+		For more info, please see:
+		Documentation/ABI/testing/sysfs-class-led-trigger-pattern
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 1988de1d64c0..6e7703fd03d0 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -132,6 +132,19 @@ config LEDS_CR0014114
 	  To compile this driver as a module, choose M here: the module
 	  will be called leds-cr0014114.
 
+config LEDS_EL15203000
+	tristate "LED Support for Crane EL15203000"
+	depends on LEDS_CLASS
+	depends on SPI
+	depends on OF
+	help
+	  This option enables support for EL15203000 LED Board
+	  (aka RED LED board) which is widely used in coffee vending
+	  machines produced by Crane Merchandising Systems.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called leds-el15203000.
+
 config LEDS_LM3530
 	tristate "LCD Backlight driver for LM3530"
 	depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 41fb073a39c1..2da39e896ce8 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -89,6 +89,7 @@ obj-$(CONFIG_LEDS_LM36274)		+= leds-lm36274.o
 # LED SPI Drivers
 obj-$(CONFIG_LEDS_CR0014114)		+= leds-cr0014114.o
 obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
+obj-$(CONFIG_LEDS_EL15203000)		+= leds-el15203000.o
 
 # LED Userspace Drivers
 obj-$(CONFIG_LEDS_USER)			+= uleds.o
diff --git a/drivers/leds/leds-el15203000.c b/drivers/leds/leds-el15203000.c
new file mode 100644
index 000000000000..03d6d5be8094
--- /dev/null
+++ b/drivers/leds/leds-el15203000.c
@@ -0,0 +1,356 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2019 Crane Merchandising Systems. All rights reserved.
+// Copyright (C) 2019 Oleh Kravchenko <oleg@kaa.org.ua>
+
+#include <linux/delay.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+
+/*
+ * EL15203000 SPI protocol description:
+ * +-----+---------+
+ * | LED | COMMAND |
+ * +-----+---------+
+ * |  1  |    1    |
+ * +-----+---------+
+ * (*) LEDs MCU board expects 20 msec delay per byte.
+ *
+ * LEDs:
+ * +----------+--------------+-------------------------------------------+
+ * |    ID    |     NAME     |         DESCRIPTION                       |
+ * +----------+--------------+-------------------------------------------+
+ * | 'P' 0x50 |     Pipe     | Consists from 5 LEDs, controlled by board |
+ * +----------+--------------+-------------------------------------------+
+ * | 'S' 0x53 | Screen frame | Light tube around the screen              |
+ * +----------+--------------+-------------------------------------------+
+ * | 'V' 0x56 | Vending area | Highlights a cup of coffee                |
+ * +----------+--------------+-------------------------------------------+
+ *
+ * COMMAND:
+ * +----------+-----------------+--------------+--------------+
+ * |  VALUES  |       PIPE      | SCREEN FRAME | VENDING AREA |
+ * +----------+-----------------+--------------+--------------+
+ * | '0' 0x30 |                      Off                      |
+ * +----------+-----------------------------------------------+
+ * | '1' 0x31 |                      On                       |
+ * +----------+-----------------+--------------+--------------+
+ * | '2' 0x32 |     Cascade     |   Breathing  |
+ * +----------+-----------------+--------------+
+ * | '3' 0x33 | Inverse cascade |
+ * +----------+-----------------+
+ * | '4' 0x34 |     Bounce      |
+ * +----------+-----------------+
+ * | '5' 0x35 | Inverse bounce  |
+ * +----------+-----------------+
+ */
+
+/* EL15203000 default settings */
+#define EL_FW_DELAY_USEC	20000ul
+#define EL_PATTERN_DELAY_MSEC	800u
+#define EL_PATTERN_LEN		10u
+#define EL_PATTERN_HALF_LEN	(EL_PATTERN_LEN / 2)
+
+enum el15203000_command {
+	/* for all LEDs */
+	EL_OFF			= '0',
+	EL_ON			= '1',
+
+	/* for Screen LED */
+	EL_SCREEN_BREATHING	= '2',
+
+	/* for Pipe LED */
+	EL_PIPE_CASCADE		= '2',
+	EL_PIPE_INV_CASCADE	= '3',
+	EL_PIPE_BOUNCE		= '4',
+	EL_PIPE_INV_BOUNCE	= '5',
+};
+
+struct el15203000_led {
+	struct el15203000	*priv;
+	struct led_classdev	ldev;
+	u32			reg;
+};
+
+struct el15203000 {
+	struct device		*dev;
+	struct mutex		lock;
+	struct spi_device	*spi;
+	unsigned long		delay;
+	size_t			count;
+	struct el15203000_led	leds[];
+};
+
+static int el15203000_cmd(struct el15203000_led *led, u8 brightness)
+{
+	int		ret;
+	u8		cmd[2];
+	size_t		i;
+
+	mutex_lock(&led->priv->lock);
+
+	dev_dbg(led->priv->dev, "Set brightness of 0x%02x(%c) to 0x%02x(%c)",
+		led->reg, led->reg, brightness, brightness);
+
+	/* to avoid SPI mistiming with firmware we should wait some time */
+	if (time_after(led->priv->delay, jiffies)) {
+		dev_dbg(led->priv->dev, "Wait %luus to sync",
+			EL_FW_DELAY_USEC);
+
+		usleep_range(EL_FW_DELAY_USEC,
+			     EL_FW_DELAY_USEC + 1);
+	}
+
+	cmd[0] = led->reg;
+	cmd[1] = brightness;
+
+	for (i = 0; i < ARRAY_SIZE(cmd); i++) {
+		if (i)
+			usleep_range(EL_FW_DELAY_USEC,
+				     EL_FW_DELAY_USEC + 1);
+
+		ret = spi_write(led->priv->spi, &cmd[i], sizeof(cmd[i]));
+		if (ret) {
+			dev_err(led->priv->dev,
+				"spi_write() error %d", ret);
+			break;
+		}
+	}
+
+	led->priv->delay = jiffies + usecs_to_jiffies(EL_FW_DELAY_USEC);
+
+	mutex_unlock(&led->priv->lock);
+
+	return ret;
+}
+
+static int el15203000_set_blocking(struct led_classdev *ldev,
+				   enum led_brightness brightness)
+{
+	struct el15203000_led	*led = container_of(ldev,
+						    struct el15203000_led,
+						    ldev);
+
+	return el15203000_cmd(led, brightness == LED_OFF ? EL_OFF : EL_ON);
+}
+
+static int el15203000_pattern_set_S(struct led_classdev *ldev,
+				    struct led_pattern *pattern,
+				    u32 len, int repeat)
+{
+	struct el15203000_led	*led = container_of(ldev,
+						    struct el15203000_led,
+						    ldev);
+
+	if (repeat > 0 || len != 2 ||
+	    pattern[0].delta_t != 4000 || pattern[0].brightness != 0 ||
+	    pattern[1].delta_t != 4000 || pattern[1].brightness != 1)
+		return -EINVAL;
+
+	dev_dbg(led->priv->dev, "Breathing mode for 0x%02x(%c)",
+		led->reg, led->reg);
+
+	return el15203000_cmd(led, EL_SCREEN_BREATHING);
+}
+
+static bool is_cascade(const struct led_pattern *pattern, u32 len,
+		       bool inv, bool right)
+{
+	int val, t;
+	u32 i;
+
+	if (len != EL_PATTERN_HALF_LEN)
+		return false;
+
+	val = right ? BIT(4) : BIT(0);
+
+	for (i = 0; i < len; i++) {
+		t = inv ? ~val & GENMASK(4, 0) : val;
+
+		if (pattern[i].delta_t != EL_PATTERN_DELAY_MSEC ||
+		    pattern[i].brightness != t)
+			return false;
+
+		val = right ? val >> 1 : val << 1;
+	}
+
+	return true;
+}
+
+static bool is_bounce(const struct led_pattern *pattern, u32 len, bool inv)
+{
+	if (len != EL_PATTERN_LEN)
+		return false;
+
+	return is_cascade(pattern, EL_PATTERN_HALF_LEN, inv, false) &&
+	       is_cascade(pattern +  EL_PATTERN_HALF_LEN,
+			  EL_PATTERN_HALF_LEN, inv, true);
+}
+
+static int el15203000_pattern_set_P(struct led_classdev *ldev,
+				    struct led_pattern *pattern,
+				    u32 len, int repeat)
+{
+	struct el15203000_led	*led = container_of(ldev,
+						    struct el15203000_led,
+						    ldev);
+
+	if (repeat != -1)
+		return -EINVAL;
+
+	if (is_cascade(pattern, len, false, false)) {
+		dev_dbg(led->priv->dev, "Cascade mode for 0x%02x(%c)",
+			led->reg, led->reg);
+
+		return el15203000_cmd(led, EL_PIPE_CASCADE);
+	} else if (is_cascade(pattern, len, true, false)) {
+		dev_dbg(led->priv->dev, "Inverse cascade mode for 0x%02x(%c)",
+			led->reg, led->reg);
+
+		return el15203000_cmd(led, EL_PIPE_INV_CASCADE);
+	} else if (is_bounce(pattern, len, false)) {
+		dev_dbg(led->priv->dev, "Bounce mode for 0x%02x(%c)",
+			led->reg, led->reg);
+
+		return el15203000_cmd(led, EL_PIPE_BOUNCE);
+	} else if (is_bounce(pattern, len, true)) {
+		dev_dbg(led->priv->dev, "Inverse bounce mode for 0x%02x(%c)",
+			led->reg, led->reg);
+
+		return el15203000_cmd(led, EL_PIPE_INV_BOUNCE);
+	}
+
+	return -EINVAL;
+}
+
+static int el15203000_pattern_clear(struct led_classdev *ldev)
+{
+	struct el15203000_led	*led = container_of(ldev,
+						    struct el15203000_led,
+						    ldev);
+
+	return el15203000_cmd(led, EL_OFF);
+}
+
+static int el15203000_probe_dt(struct el15203000 *priv)
+{
+	struct el15203000_led	*led = priv->leds;
+	struct fwnode_handle	*child;
+	int			ret;
+
+	device_for_each_child_node(priv->dev, child) {
+		struct led_init_data	init_data = {};
+
+		ret = fwnode_property_read_u32(child, "reg", &led->reg);
+		if (ret) {
+			dev_err(priv->dev, "LED without ID number");
+			fwnode_handle_put(child);
+
+			return ret;
+		}
+
+		if (led->reg > U8_MAX) {
+			dev_err(priv->dev, "LED value %d is invalid", reg);
+			fwnode_handle_put(child);
+
+			return -EINVAL;
+		}
+
+		fwnode_property_read_string(child, "linux,default-trigger",
+					    &led->ldev.default_trigger);
+
+		led->priv			  = priv;
+		led->ldev.max_brightness	  = LED_ON;
+		led->ldev.brightness_set_blocking = el15203000_set_blocking;
+
+		if (reg == 'S') {
+			led->ldev.pattern_set	= el15203000_pattern_set_S;
+			led->ldev.pattern_clear	= el15203000_pattern_clear;
+		} else if (reg == 'P') {
+			led->ldev.pattern_set	= el15203000_pattern_set_P;
+			led->ldev.pattern_clear	= el15203000_pattern_clear;
+		}
+
+		init_data.fwnode = child;
+		ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,
+						     &init_data);
+		if (ret) {
+			dev_err(priv->dev,
+				"failed to register LED device %s, err %d",
+				led->ldev.name, ret);
+			fwnode_handle_put(child);
+
+			return ret;
+		}
+
+		led++;
+	}
+
+	return ret;
+}
+
+static int el15203000_probe(struct spi_device *spi)
+{
+	struct el15203000	*priv;
+	size_t			count;
+	int			ret;
+
+	count = device_get_child_node_count(&spi->dev);
+	if (!count) {
+		dev_err(&spi->dev, "LEDs are not defined in device tree!");
+		return -ENODEV;
+	}
+
+	priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
+			    GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	mutex_init(&priv->lock);
+	priv->count	= count;
+	priv->dev	= &spi->dev;
+	priv->spi	= spi;
+	priv->delay	= jiffies -
+			  usecs_to_jiffies(EL_FW_DELAY_USEC);
+
+	ret = el15203000_probe_dt(priv);
+	if (ret)
+		return ret;
+
+	spi_set_drvdata(spi, priv);
+
+	return 0;
+}
+
+static int el15203000_remove(struct spi_device *spi)
+{
+	struct el15203000 *priv = spi_get_drvdata(spi);
+
+	mutex_destroy(&priv->lock);
+
+	return 0;
+}
+
+static const struct of_device_id el15203000_dt_ids[] = {
+	{ .compatible = "crane,el15203000", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, el15203000_dt_ids);
+
+static struct spi_driver el15203000_driver = {
+	.probe		= el15203000_probe,
+	.remove		= el15203000_remove,
+	.driver = {
+		.name		= KBUILD_MODNAME,
+		.of_match_table	= el15203000_dt_ids,
+	},
+};
+
+module_spi_driver(el15203000_driver);
+
+MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
+MODULE_DESCRIPTION("el15203000 LED driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("spi:el15203000");
-- 
2.21.0

Re: EL15203000

[Oleh Kravchenko]

Sorry,
I screwed up with Subject :(

06.09.19 16:29, Oleh Kravchenko пише:
> [PATCH v6 1/2] dt-bindings: Add docs for EL15203000
> [PATCH v6 2/2] leds: add LED driver for EL15203000 board
>
> Reworked few minor issues:
> - added 'repeat' entity in test documentation
> - removed variable i
> - few lines of code was moved to make code clear

Re: [PATCH v6 2/2] leds: add LED driver for EL15203000 board

[Jacek Anaszewski]

Hi Oleh,

You seem to have not even compile-tested the patch :-(

In file included from ./include/linux/leds.h:12:0,
                 from drivers/leds/leds-el15203000.c:6:
drivers/leds/leds-el15203000.c: In function 'el15203000_probe_dt':
drivers/leds/leds-el15203000.c:254:50: error: 'reg' undeclared (first
use in this function)
    dev_err(priv->dev, "LED value %d is invalid", reg);
                                                  ^
./include/linux/device.h:1724:32: note: in definition of macro 'dev_err'
  _dev_err(dev, dev_fmt(fmt), ##__VA_ARGS__)
                                ^
drivers/leds/leds-el15203000.c:254:50: note: each undeclared identifier
is reported only once for each function it appears in
    dev_err(priv->dev, "LED value %d is invalid", reg);
                                                  ^
./include/linux/device.h:1724:32: note: in definition of macro 'dev_err'
  _dev_err(dev, dev_fmt(fmt), ##__VA_ARGS__)
                                ^


On 9/6/19 3:29 PM, Oleh Kravchenko wrote:
> This patch adds a LED class driver for the LEDs found on
> the Crane Merchandising System EL15203000 LEDs board
> (aka RED LEDs board).
> 
> Signed-off-by: Oleh Kravchenko <oleg@kaa.org.ua>
> ---
>  .../testing/sysfs-class-led-driver-el15203000 |  32 ++
>  drivers/leds/Kconfig                          |  13 +
>  drivers/leds/Makefile                         |   1 +
>  drivers/leds/leds-el15203000.c                | 356 ++++++++++++++++++
>  4 files changed, 402 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-class-led-driver-el15203000
>  create mode 100644 drivers/leds/leds-el15203000.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-class-led-driver-el15203000 b/Documentation/ABI/testing/sysfs-class-led-driver-el15203000
> new file mode 100644
> index 000000000000..5e9cbf49da59
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-class-led-driver-el15203000
> @@ -0,0 +1,32 @@
> +What:		/sys/class/leds/<led>/hw_pattern
> +Date:		September 2019
> +KernelVersion:	5.5
> +Description:
> +		Specify a hardware pattern for the EL15203000 LED.
> +		The LEDs board supports only predefined patterns by firmware
> +		for specific LEDs.
> +
> +		Breathing mode for Screen frame light tube:
> +		"0 4000 1 4000"
> +
> +		Cascade mode for Pipe LED:
> +		"1 800 2 800 4 800 8 800 16 800"
> +
> +		Inverted cascade mode for Pipe LED:
> +		"30 800 29 800 27 800 23 800 15 800"
> +
> +		Bounce mode for Pipe LED:
> +		"1 800 2 800 4 800 8 800 16 800 16 800 8 800 4 800 2 800 1 800"
> +
> +		Inverted bounce mode for Pipe LED:
> +		"30 800 29 800 27 800 23 800 15 800 15 800 23 800 27 800 29 800 30 800"
> +
> +What:		/sys/class/leds/<led>/repeat
> +Date:		September 2019
> +KernelVersion:	5.5
> +Description:
> +		EL15203000 supports only indefinitely patterns,
> +		so this file should always store -1.
> +
> +		For more info, please see:
> +		Documentation/ABI/testing/sysfs-class-led-trigger-pattern
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index 1988de1d64c0..6e7703fd03d0 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -132,6 +132,19 @@ config LEDS_CR0014114
>  	  To compile this driver as a module, choose M here: the module
>  	  will be called leds-cr0014114.
>  
> +config LEDS_EL15203000
> +	tristate "LED Support for Crane EL15203000"
> +	depends on LEDS_CLASS
> +	depends on SPI
> +	depends on OF
> +	help
> +	  This option enables support for EL15203000 LED Board
> +	  (aka RED LED board) which is widely used in coffee vending
> +	  machines produced by Crane Merchandising Systems.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called leds-el15203000.
> +
>  config LEDS_LM3530
>  	tristate "LCD Backlight driver for LM3530"
>  	depends on LEDS_CLASS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index 41fb073a39c1..2da39e896ce8 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -89,6 +89,7 @@ obj-$(CONFIG_LEDS_LM36274)		+= leds-lm36274.o
>  # LED SPI Drivers
>  obj-$(CONFIG_LEDS_CR0014114)		+= leds-cr0014114.o
>  obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
> +obj-$(CONFIG_LEDS_EL15203000)		+= leds-el15203000.o
>  
>  # LED Userspace Drivers
>  obj-$(CONFIG_LEDS_USER)			+= uleds.o
> diff --git a/drivers/leds/leds-el15203000.c b/drivers/leds/leds-el15203000.c
> new file mode 100644
> index 000000000000..03d6d5be8094
> --- /dev/null
> +++ b/drivers/leds/leds-el15203000.c
> @@ -0,0 +1,356 @@
> +// SPDX-License-Identifier: GPL-2.0
> +// Copyright (c) 2019 Crane Merchandising Systems. All rights reserved.
> +// Copyright (C) 2019 Oleh Kravchenko <oleg@kaa.org.ua>
> +
> +#include <linux/delay.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/spi/spi.h>
> +
> +/*
> + * EL15203000 SPI protocol description:
> + * +-----+---------+
> + * | LED | COMMAND |
> + * +-----+---------+
> + * |  1  |    1    |
> + * +-----+---------+
> + * (*) LEDs MCU board expects 20 msec delay per byte.
> + *
> + * LEDs:
> + * +----------+--------------+-------------------------------------------+
> + * |    ID    |     NAME     |         DESCRIPTION                       |
> + * +----------+--------------+-------------------------------------------+
> + * | 'P' 0x50 |     Pipe     | Consists from 5 LEDs, controlled by board |
> + * +----------+--------------+-------------------------------------------+
> + * | 'S' 0x53 | Screen frame | Light tube around the screen              |
> + * +----------+--------------+-------------------------------------------+
> + * | 'V' 0x56 | Vending area | Highlights a cup of coffee                |
> + * +----------+--------------+-------------------------------------------+
> + *
> + * COMMAND:
> + * +----------+-----------------+--------------+--------------+
> + * |  VALUES  |       PIPE      | SCREEN FRAME | VENDING AREA |
> + * +----------+-----------------+--------------+--------------+
> + * | '0' 0x30 |                      Off                      |
> + * +----------+-----------------------------------------------+
> + * | '1' 0x31 |                      On                       |
> + * +----------+-----------------+--------------+--------------+
> + * | '2' 0x32 |     Cascade     |   Breathing  |
> + * +----------+-----------------+--------------+
> + * | '3' 0x33 | Inverse cascade |
> + * +----------+-----------------+
> + * | '4' 0x34 |     Bounce      |
> + * +----------+-----------------+
> + * | '5' 0x35 | Inverse bounce  |
> + * +----------+-----------------+
> + */
> +
> +/* EL15203000 default settings */
> +#define EL_FW_DELAY_USEC	20000ul
> +#define EL_PATTERN_DELAY_MSEC	800u
> +#define EL_PATTERN_LEN		10u
> +#define EL_PATTERN_HALF_LEN	(EL_PATTERN_LEN / 2)
> +
> +enum el15203000_command {
> +	/* for all LEDs */
> +	EL_OFF			= '0',
> +	EL_ON			= '1',
> +
> +	/* for Screen LED */
> +	EL_SCREEN_BREATHING	= '2',
> +
> +	/* for Pipe LED */
> +	EL_PIPE_CASCADE		= '2',
> +	EL_PIPE_INV_CASCADE	= '3',
> +	EL_PIPE_BOUNCE		= '4',
> +	EL_PIPE_INV_BOUNCE	= '5',
> +};
> +
> +struct el15203000_led {
> +	struct el15203000	*priv;
> +	struct led_classdev	ldev;
> +	u32			reg;
> +};
> +
> +struct el15203000 {
> +	struct device		*dev;
> +	struct mutex		lock;
> +	struct spi_device	*spi;
> +	unsigned long		delay;
> +	size_t			count;
> +	struct el15203000_led	leds[];
> +};
> +
> +static int el15203000_cmd(struct el15203000_led *led, u8 brightness)
> +{
> +	int		ret;
> +	u8		cmd[2];
> +	size_t		i;
> +
> +	mutex_lock(&led->priv->lock);
> +
> +	dev_dbg(led->priv->dev, "Set brightness of 0x%02x(%c) to 0x%02x(%c)",
> +		led->reg, led->reg, brightness, brightness);
> +
> +	/* to avoid SPI mistiming with firmware we should wait some time */
> +	if (time_after(led->priv->delay, jiffies)) {
> +		dev_dbg(led->priv->dev, "Wait %luus to sync",
> +			EL_FW_DELAY_USEC);
> +
> +		usleep_range(EL_FW_DELAY_USEC,
> +			     EL_FW_DELAY_USEC + 1);
> +	}
> +
> +	cmd[0] = led->reg;
> +	cmd[1] = brightness;
> +
> +	for (i = 0; i < ARRAY_SIZE(cmd); i++) {
> +		if (i)
> +			usleep_range(EL_FW_DELAY_USEC,
> +				     EL_FW_DELAY_USEC + 1);
> +
> +		ret = spi_write(led->priv->spi, &cmd[i], sizeof(cmd[i]));
> +		if (ret) {
> +			dev_err(led->priv->dev,
> +				"spi_write() error %d", ret);
> +			break;
> +		}
> +	}
> +
> +	led->priv->delay = jiffies + usecs_to_jiffies(EL_FW_DELAY_USEC);
> +
> +	mutex_unlock(&led->priv->lock);
> +
> +	return ret;
> +}
> +
> +static int el15203000_set_blocking(struct led_classdev *ldev,
> +				   enum led_brightness brightness)
> +{
> +	struct el15203000_led	*led = container_of(ldev,
> +						    struct el15203000_led,
> +						    ldev);
> +
> +	return el15203000_cmd(led, brightness == LED_OFF ? EL_OFF : EL_ON);
> +}
> +
> +static int el15203000_pattern_set_S(struct led_classdev *ldev,
> +				    struct led_pattern *pattern,
> +				    u32 len, int repeat)
> +{
> +	struct el15203000_led	*led = container_of(ldev,
> +						    struct el15203000_led,
> +						    ldev);
> +
> +	if (repeat > 0 || len != 2 ||
> +	    pattern[0].delta_t != 4000 || pattern[0].brightness != 0 ||
> +	    pattern[1].delta_t != 4000 || pattern[1].brightness != 1)
> +		return -EINVAL;
> +
> +	dev_dbg(led->priv->dev, "Breathing mode for 0x%02x(%c)",
> +		led->reg, led->reg);
> +
> +	return el15203000_cmd(led, EL_SCREEN_BREATHING);
> +}
> +
> +static bool is_cascade(const struct led_pattern *pattern, u32 len,
> +		       bool inv, bool right)
> +{
> +	int val, t;
> +	u32 i;
> +
> +	if (len != EL_PATTERN_HALF_LEN)
> +		return false;
> +
> +	val = right ? BIT(4) : BIT(0);
> +
> +	for (i = 0; i < len; i++) {
> +		t = inv ? ~val & GENMASK(4, 0) : val;
> +
> +		if (pattern[i].delta_t != EL_PATTERN_DELAY_MSEC ||
> +		    pattern[i].brightness != t)
> +			return false;
> +
> +		val = right ? val >> 1 : val << 1;
> +	}
> +
> +	return true;
> +}
> +
> +static bool is_bounce(const struct led_pattern *pattern, u32 len, bool inv)
> +{
> +	if (len != EL_PATTERN_LEN)
> +		return false;
> +
> +	return is_cascade(pattern, EL_PATTERN_HALF_LEN, inv, false) &&
> +	       is_cascade(pattern +  EL_PATTERN_HALF_LEN,
> +			  EL_PATTERN_HALF_LEN, inv, true);
> +}
> +
> +static int el15203000_pattern_set_P(struct led_classdev *ldev,
> +				    struct led_pattern *pattern,
> +				    u32 len, int repeat)
> +{
> +	struct el15203000_led	*led = container_of(ldev,
> +						    struct el15203000_led,
> +						    ldev);
> +
> +	if (repeat != -1)
> +		return -EINVAL;
> +
> +	if (is_cascade(pattern, len, false, false)) {
> +		dev_dbg(led->priv->dev, "Cascade mode for 0x%02x(%c)",
> +			led->reg, led->reg);
> +
> +		return el15203000_cmd(led, EL_PIPE_CASCADE);
> +	} else if (is_cascade(pattern, len, true, false)) {
> +		dev_dbg(led->priv->dev, "Inverse cascade mode for 0x%02x(%c)",
> +			led->reg, led->reg);
> +
> +		return el15203000_cmd(led, EL_PIPE_INV_CASCADE);
> +	} else if (is_bounce(pattern, len, false)) {
> +		dev_dbg(led->priv->dev, "Bounce mode for 0x%02x(%c)",
> +			led->reg, led->reg);
> +
> +		return el15203000_cmd(led, EL_PIPE_BOUNCE);
> +	} else if (is_bounce(pattern, len, true)) {
> +		dev_dbg(led->priv->dev, "Inverse bounce mode for 0x%02x(%c)",
> +			led->reg, led->reg);
> +
> +		return el15203000_cmd(led, EL_PIPE_INV_BOUNCE);
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int el15203000_pattern_clear(struct led_classdev *ldev)
> +{
> +	struct el15203000_led	*led = container_of(ldev,
> +						    struct el15203000_led,
> +						    ldev);
> +
> +	return el15203000_cmd(led, EL_OFF);
> +}
> +
> +static int el15203000_probe_dt(struct el15203000 *priv)
> +{
> +	struct el15203000_led	*led = priv->leds;
> +	struct fwnode_handle	*child;
> +	int			ret;
> +
> +	device_for_each_child_node(priv->dev, child) {
> +		struct led_init_data	init_data = {};
> +
> +		ret = fwnode_property_read_u32(child, "reg", &led->reg);
> +		if (ret) {
> +			dev_err(priv->dev, "LED without ID number");
> +			fwnode_handle_put(child);
> +
> +			return ret;
> +		}
> +
> +		if (led->reg > U8_MAX) {
> +			dev_err(priv->dev, "LED value %d is invalid", reg);
> +			fwnode_handle_put(child);
> +
> +			return -EINVAL;
> +		}
> +
> +		fwnode_property_read_string(child, "linux,default-trigger",
> +					    &led->ldev.default_trigger);
> +
> +		led->priv			  = priv;
> +		led->ldev.max_brightness	  = LED_ON;
> +		led->ldev.brightness_set_blocking = el15203000_set_blocking;
> +
> +		if (reg == 'S') {
> +			led->ldev.pattern_set	= el15203000_pattern_set_S;
> +			led->ldev.pattern_clear	= el15203000_pattern_clear;
> +		} else if (reg == 'P') {
> +			led->ldev.pattern_set	= el15203000_pattern_set_P;
> +			led->ldev.pattern_clear	= el15203000_pattern_clear;
> +		}
> +
> +		init_data.fwnode = child;
> +		ret = devm_led_classdev_register_ext(priv->dev, &led->ldev,
> +						     &init_data);
> +		if (ret) {
> +			dev_err(priv->dev,
> +				"failed to register LED device %s, err %d",
> +				led->ldev.name, ret);
> +			fwnode_handle_put(child);
> +
> +			return ret;
> +		}
> +
> +		led++;

I recommend to use what I proposed before.

> +	}
> +
> +	return ret;
> +}
> +
> +static int el15203000_probe(struct spi_device *spi)
> +{
> +	struct el15203000	*priv;
> +	size_t			count;
> +	int			ret;
> +
> +	count = device_get_child_node_count(&spi->dev);
> +	if (!count) {
> +		dev_err(&spi->dev, "LEDs are not defined in device tree!");
> +		return -ENODEV;
> +	}
> +
> +	priv = devm_kzalloc(&spi->dev, struct_size(priv, leds, count),
> +			    GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	mutex_init(&priv->lock);
> +	priv->count	= count;
> +	priv->dev	= &spi->dev;
> +	priv->spi	= spi;
> +	priv->delay	= jiffies -
> +			  usecs_to_jiffies(EL_FW_DELAY_USEC);
> +
> +	ret = el15203000_probe_dt(priv);
> +	if (ret)
> +		return ret;
> +
> +	spi_set_drvdata(spi, priv);
> +
> +	return 0;
> +}
> +
> +static int el15203000_remove(struct spi_device *spi)
> +{
> +	struct el15203000 *priv = spi_get_drvdata(spi);
> +
> +	mutex_destroy(&priv->lock);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id el15203000_dt_ids[] = {
> +	{ .compatible = "crane,el15203000", },
> +	{},
> +};
> +
> +MODULE_DEVICE_TABLE(of, el15203000_dt_ids);
> +
> +static struct spi_driver el15203000_driver = {
> +	.probe		= el15203000_probe,
> +	.remove		= el15203000_remove,
> +	.driver = {
> +		.name		= KBUILD_MODNAME,
> +		.of_match_table	= el15203000_dt_ids,
> +	},
> +};
> +
> +module_spi_driver(el15203000_driver);
> +
> +MODULE_AUTHOR("Oleh Kravchenko <oleg@kaa.org.ua>");
> +MODULE_DESCRIPTION("el15203000 LED driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("spi:el15203000");
> 

-- 
Best regards,
Jacek Anaszewski