[PATCH v4 2/2] leds: add LED driver for EL15203000 board

Oleh Kravchenko
2019-08-08T20:35:04Z

This patch adds a LED class driver for the RGB 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 | 22 +
drivers/leds/Kconfig | 13 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-el15203000.c | 478 ++++++++++++++++++
4 files changed, 514 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..91a483e493d9
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-class-led-driver-el15203000
@@ -0,0 +1,22 @@
+What: /sys/class/leds/<led>/hw_pattern
+Date: August 2019
+KernelVersion: 5.3
+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 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 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"
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 760f73a49c9f..0cbdb9ba5213 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -129,6 +129,19 @@ 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 1e9702ebffee..1f193ffc2feb 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -85,6 +85,7 @@ obj-$(CONFIG_LEDS_LM3601X) += leds-lm3601x.o
# LED SPI Drivers
obj-$(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..c62da5ec6630
--- /dev/null
+++ b/drivers/leds/leds-el15203000.c
@@ -0,0 +1,478 @@
+// 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/limits.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+#include <uapi/linux/uleds.h>
+
+/*
+ * EL15203000 SPI protocol description:
+ * +-----+------------+
+ * | LED | BRIGHTNESS |
+ * +-----+------------+
+ * | 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 |
+ * +----------+--------------+-------------------------------------------+
+ *
+ * BRIGHTNESS:
+ * +----------+-----------------+--------------+--------------+
+ * | 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 20000
+
+enum el15203000_brightness {
+ /* 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;
+ char name[LED_MAX_NAME_SIZE];
+ u8 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;
+ unsigned long jdelay, udelay, now;
+
+ mutex_lock(&led->priv->lock);
+
+ dev_dbg(led->priv->dev, "Set brightness of %s to %d",
+ led->name, brightness);
+
+ /* to avoid SPI mistiming with firmware we should wait some time */
+ now = jiffies;
+ if (time_after(led->priv->delay, now)) {
+ jdelay = led->priv->delay - now;
+ udelay = jiffies_to_usecs(jdelay);
+
+ dev_dbg(led->priv->dev, "Wait %luus (%lu jiffies) to sync",
+ udelay, jdelay);
+
+ usleep_range(udelay, udelay + 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 led_pattern_cmp(const struct led_pattern *p1, u32 p1_len,
+ const struct led_pattern *p2, u32 p2_len)
+{
+ u32 i;
+
+ if (p1_len != p2_len)
+ return -1;
+
+ for (i = 0; i < p1_len; i ++)
+ if (p1[i].delta_t != p2[i].delta_t ||
+ p1[i].brightness != p2[i].brightness)
+ return -1;
+
+ return 0;
+}
+
+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);
+ struct led_pattern scr_pattern[] = {{
+ .delta_t = 4000,
+ .brightness = 0,
+ }, {
+ .delta_t = 4000,
+ .brightness = 1,
+ }};
+
+ if (repeat > 0)
+ return -EINVAL;
+
+ if (led_pattern_cmp(scr_pattern, ARRAY_SIZE(scr_pattern), pattern, len))
+ return -EINVAL;
+
+ dev_dbg(led->priv->dev, "Breathing mode for '%s'", led->name);
+
+ return el15203000_cmd(led, EL_SCREEN_BREATHING);
+}
+
+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);
+
+ struct led_pattern cascade[] = {{
+ .delta_t = 800,
+ .brightness = 1,
+ }, {
+ .delta_t = 800,
+ .brightness = 2,
+ }, {
+ .delta_t = 800,
+ .brightness = 4,
+ }, {
+ .delta_t = 800,
+ .brightness = 8,
+ }, {
+ .delta_t = 800,
+ .brightness = 16,
+ }, {
+ .delta_t = 800,
+ .brightness = 1,
+ }, {
+ .delta_t = 800,
+ .brightness = 2,
+ }, {
+ .delta_t = 800,
+ .brightness = 4,
+ }, {
+ .delta_t = 800,
+ .brightness = 8,
+ }, {
+ .delta_t = 800,
+ .brightness = 16,
+ }};
+
+ struct led_pattern inv_cascade[] = {{
+ .delta_t = 800,
+ .brightness = 30,
+ }, {
+ .delta_t = 800,
+ .brightness = 29,
+ }, {
+ .delta_t = 800,
+ .brightness = 27,
+ }, {
+ .delta_t = 800,
+ .brightness = 23,
+ }, {
+ .delta_t = 800,
+ .brightness = 15,
+ }, {
+ .delta_t = 800,
+ .brightness = 30,
+ }, {
+ .delta_t = 800,
+ .brightness = 29,
+ }, {
+ .delta_t = 800,
+ .brightness = 27,
+ }, {
+ .delta_t = 800,
+ .brightness = 23,
+ }, {
+ .delta_t = 800,
+ .brightness = 15,
+ }};
+
+ struct led_pattern bounce[] = {{
+ .delta_t = 800,
+ .brightness = 1,
+ }, {
+ .delta_t = 800,
+ .brightness = 2,
+ }, {
+ .delta_t = 800,
+ .brightness = 4,
+ }, {
+ .delta_t = 800,
+ .brightness = 8,
+ }, {
+ .delta_t = 800,
+ .brightness = 16,
+ }, {
+ .delta_t = 800,
+ .brightness = 16,
+ }, {
+ .delta_t = 800,
+ .brightness = 8,
+ }, {
+ .delta_t = 800,
+ .brightness = 4,
+ }, {
+ .delta_t = 800,
+ .brightness = 2,
+ }, {
+ .delta_t = 800,
+ .brightness = 1,
+ }};
+
+ struct led_pattern inv_bounce[] = {{
+ .delta_t = 800,
+ .brightness = 30,
+ }, {
+ .delta_t = 800,
+ .brightness = 29,
+ }, {
+ .delta_t = 800,
+ .brightness = 27,
+ }, {
+ .delta_t = 800,
+ .brightness = 23,
+ }, {
+ .delta_t = 800,
+ .brightness = 15,
+ }, {
+ .delta_t = 800,
+ .brightness = 15,
+ }, {
+ .delta_t = 800,
+ .brightness = 23,
+ }, {
+ .delta_t = 800,
+ .brightness = 27,
+ }, {
+ .delta_t = 800,
+ .brightness = 29,
+ }, {
+ .delta_t = 800,
+ .brightness = 30,
+ }};
+
+ if (repeat > 0)
+ return -EINVAL;
+
+ if (!led_pattern_cmp(cascade, ARRAY_SIZE(cascade), pattern, len)) {
+ dev_dbg(led->priv->dev, "Cascade mode for '%s'", led->name);
+ return el15203000_cmd(led, EL_PIPE_CASCADE);
+ } else if (!led_pattern_cmp(inv_cascade, ARRAY_SIZE(inv_cascade), pattern, len)) {
+ dev_dbg(led->priv->dev, "Inverse cascade mode for '%s'", led->name);
+ return el15203000_cmd(led, EL_PIPE_INV_CASCADE);
+ } else if (!led_pattern_cmp(bounce, ARRAY_SIZE(bounce), pattern, len)) {
+ dev_dbg(led->priv->dev, "Bounce mode for '%s'", led->name);
+ return el15203000_cmd(led, EL_PIPE_BOUNCE);
+ } else if (!led_pattern_cmp(inv_bounce, ARRAY_SIZE(inv_bounce), pattern, len)) {
+ dev_dbg(led->priv->dev, "Inverse bounce mode for '%s'", led->name);
+ return el15203000_cmd(led, EL_PIPE_INV_BOUNCE);
+ }
+
+ return -EINVAL;
+}
+
+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)
+{
+ size_t i = 0;
+ struct el15203000_led *led;
+ struct fwnode_handle *child;
+ int ret;
+ const char *str;
+ u32 reg;
+
+ device_for_each_child_node(priv->dev, child) {
+ led = &priv->leds[i];
+
+ ret = fwnode_property_read_u32(child, "reg", &reg);
+ if (ret) {
+ dev_err(priv->dev, "LED without ID number");
+ fwnode_handle_put(child);
+
+ return ret;
+ }
+
+ if (reg > U8_MAX) {
+ dev_err(priv->dev, "LED value %d is invalid", reg);
+ fwnode_handle_put(child);
+
+ return -EINVAL;
+ }
+
+ led->reg = reg;
+
+ ret = fwnode_property_read_string(child, "label", &str);
+ if (ret)
+ str = ":";
+ snprintf(led->name, sizeof(led->name), "el15203000:%s", str);
+
+ fwnode_property_read_string(child, "linux,default-trigger",
+ &led->ldev.default_trigger);
+
+ led->ldev.max_brightness = LED_ON;
+ led->priv = priv;
+ led->ldev.name = led->name;
+ 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;
+ }
+
+ ret = devm_led_classdev_register(priv->dev, &led->ldev);
+ if (ret) {
+ dev_err(priv->dev,
+ "failed to register LED device %s, err %d",
+ led->name, ret);
+ fwnode_handle_put(child);
+ return ret;
+ }
+
+ i++;
+ }
+
+ 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);
+ dev_dbg(priv->dev, "%zd LEDs registered", priv->count);
+
+ 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