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Date: Wed, 26 Feb 2020 15:33:12 +0100
From: Nicolas Belin <nbelin@...libre.com>
To: linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
jacek.anaszewski@...il.com, pavel@....cz, dmurphy@...com,
devicetree@...r.kernel.org
Cc: baylibre-upstreaming@...ups.io, Nicolas Belin <nbelin@...libre.com>
Subject: [PATCH RFC v2 3/3] drivers: leds: add support for apa102c leds
Initilial commit in order to support the apa102c RGB leds. This
is based on the Multicolor Framework.
Reviewed-by: Corentin Labbe <clabbe@...libre.com>
Signed-off-by: Nicolas Belin <nbelin@...libre.com>
---
drivers/leds/Kconfig | 7 ++
drivers/leds/Makefile | 1 +
drivers/leds/leds-apa102c.c | 291 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 299 insertions(+)
create mode 100644 drivers/leds/leds-apa102c.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 5dc6535a88ef..71e29727c6ec 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -79,6 +79,13 @@ config LEDS_AN30259A
To compile this driver as a module, choose M here: the module
will be called leds-an30259a.
+config LEDS_APA102C
+ tristate "LED Support for Shiji APA102C"
+ depends on SPI
+ depends on LEDS_CLASS_MULTI_COLOR
+ help
+ This option enables support for APA102C LEDs.
+
config LEDS_APU
tristate "Front panel LED support for PC Engines APU/APU2/APU3 boards"
depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index b5305b7d43fb..8334cb6dc7e8 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -90,6 +90,7 @@ obj-$(CONFIG_LEDS_LM36274) += leds-lm36274.o
obj-$(CONFIG_LEDS_TPS6105X) += leds-tps6105x.o
# LED SPI Drivers
+obj-$(CONFIG_LEDS_APA102C) += leds-apa102c.o
obj-$(CONFIG_LEDS_CR0014114) += leds-cr0014114.o
obj-$(CONFIG_LEDS_DAC124S085) += leds-dac124s085.o
obj-$(CONFIG_LEDS_EL15203000) += leds-el15203000.o
diff --git a/drivers/leds/leds-apa102c.c b/drivers/leds/leds-apa102c.c
new file mode 100644
index 000000000000..b46db0db7501
--- /dev/null
+++ b/drivers/leds/leds-apa102c.c
@@ -0,0 +1,291 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+#include <linux/led-class-multicolor.h>
+
+/*
+ * Copyright (C) 2020 BayLibre, SAS
+ * Author: Nicolas Belin <nbelin@...libre.com>
+ */
+
+/*
+ * APA102C SPI protocol description:
+ * +------+----------------------------------------+------+
+ * |START | DATA FIELD: | END |
+ * |FRAME | N LED FRAMES |FRAME |
+ * +------+------+------+------+------+-----+------+------+
+ * | 0*32 | LED1 | LED2 | LED3 | LED4 | --- | LEDN | 1*32 |
+ * +------+------+------+------+------+-----+------+------+
+ *
+ * +-----------------------------------+
+ * |START FRAME 32bits |
+ * +--------+--------+--------+--------+
+ * |00000000|00000000|00000000|00000000|
+ * +--------+--------+--------+--------+
+ *
+ * +------------------------------------+
+ * |LED FRAME 32bits |
+ * +---+-----+--------+--------+--------+
+ * |111|LUMA | BLUE | GREEN | RED |
+ * +---+-----+--------+--------+--------+
+ * |3b |5bits| 8bits | 8bits | 8bits |
+ * +---+-----+--------+--------+--------+
+ * |MSB LSB|MSB LSB|MSB LSB|MSB LSB|
+ * +---+-----+--------+--------+--------+
+ *
+ * +-----------------------------------+
+ * |END FRAME 32bits |
+ * +--------+--------+--------+--------+
+ * |11111111|11111111|11111111|11111111|
+ * +--------+--------+--------+--------+
+ */
+
+/* apa102c default settings */
+#define MAX_BRIGHTNESS GENMASK(4, 0)
+#define CH_NUM 4
+#define START_BYTE 0
+#define END_BYTE GENMASK(7, 0)
+#define LED_FRAME_HEADER GENMASK(7, 5)
+
+#define IS_RGB (1<<LED_COLOR_ID_RED \
+ | 1<<LED_COLOR_ID_GREEN \
+ | 1<<LED_COLOR_ID_BLUE)
+
+#define APA_DEV_NAME "apa102c"
+
+struct apa102c_led {
+ struct apa102c *priv;
+ struct led_classdev ldev;
+ struct led_classdev_mc mc_cdev;
+};
+
+struct apa102c {
+ size_t led_count;
+ struct device *dev;
+ struct mutex lock;
+ struct spi_device *spi;
+ u8 *buf;
+ struct apa102c_led leds[];
+};
+
+static void apa102c_set_rgb_bytes(u8 *bgr_buf, struct list_head *color_list)
+{
+ struct led_mc_color_entry *color_data;
+
+ /* Looking for the RGB values and putting them in the buffer in
+ * BGR order
+ */
+ list_for_each_entry(color_data, color_list, list) {
+ switch (color_data->led_color_id) {
+ case LED_COLOR_ID_RED:
+ bgr_buf[2] = color_data->intensity;
+ break;
+ case LED_COLOR_ID_GREEN:
+ bgr_buf[1] = color_data->intensity;
+ break;
+ case LED_COLOR_ID_BLUE:
+ bgr_buf[0] = color_data->intensity;
+ break;
+ }
+ }
+}
+
+static int apa102c_sync(struct apa102c *priv)
+{
+ int ret;
+ size_t i;
+ struct apa102c_led *leds = priv->leds;
+ u8 *buf = priv->buf;
+
+ /* creating the data that will be sent to all the leds at once */
+ for (i = 0; i < 4; i++)
+ *buf++ = START_BYTE;
+
+ /* looping on each multicolor led getting the luma and the RGB values */
+ for (i = 0; i < priv->led_count; i++) {
+ *buf++ = LED_FRAME_HEADER | leds[i].ldev.brightness;
+ apa102c_set_rgb_bytes(buf, &leds[i].mc_cdev.color_list);
+ buf += 3;
+ }
+
+ for (i = 0; i < 4; i++)
+ *buf++ = END_BYTE;
+
+ ret = spi_write(priv->spi, priv->buf, priv->led_count*4 + 8);
+
+ return ret;
+}
+
+static int apa102c_brightness_set(struct led_classdev *ldev,
+ enum led_brightness brightness)
+{
+ int ret;
+ struct apa102c_led *led = container_of(ldev,
+ struct apa102c_led,
+ ldev);
+
+ mutex_lock(&led->priv->lock);
+ /* updating the brightness then synching all the leds */
+ ldev->brightness = brightness;
+ ret = apa102c_sync(led->priv);
+ mutex_unlock(&led->priv->lock);
+
+ return ret;
+}
+
+static int apa102c_probe_dt(struct apa102c *priv)
+{
+ int ret = 0;
+ int num_colors;
+ u32 color_id, i;
+ struct apa102c_led *led;
+ struct fwnode_handle *child, *grandchild;
+ struct led_init_data init_data;
+
+ device_for_each_child_node(priv->dev, child) {
+
+ ret = fwnode_property_read_u32(child, "reg", &i);
+ if (ret) {
+ dev_err(priv->dev, "coudld not read reg %d\n", ret);
+ goto child_out;
+ }
+
+ if (i >= priv->led_count) {
+ ret = -EINVAL;
+ dev_err(priv->dev, "reg value too big\n");
+ goto child_out;
+ }
+
+ led = &priv->leds[i];
+ /* checking if this led config is already used */
+ if (led->mc_cdev.led_cdev) {
+ ret = -EINVAL;
+ dev_err(priv->dev, "using the same reg value twice\n");
+ goto child_out;
+ }
+
+ led->priv = priv;
+ led->ldev.max_brightness = MAX_BRIGHTNESS;
+ fwnode_property_read_string(child, "linux,default-trigger",
+ &led->ldev.default_trigger);
+
+ init_data.fwnode = child;
+ init_data.devicename = APA_DEV_NAME;
+ init_data.default_label = ":";
+
+ num_colors = 0;
+ fwnode_for_each_child_node(child, grandchild) {
+ ret = fwnode_property_read_u32(grandchild, "color",
+ &color_id);
+ if (ret) {
+ dev_err(priv->dev, "Cannot read color\n");
+ goto child_out;
+ }
+
+ set_bit(color_id, &led->mc_cdev.available_colors);
+ num_colors++;
+ }
+
+ if (num_colors != 3) {
+ ret = -EINVAL;
+ dev_err(priv->dev, "There should be 3 colors\n");
+ goto child_out;
+ }
+
+ if (led->mc_cdev.available_colors != IS_RGB) {
+ ret = -EINVAL;
+ dev_err(priv->dev, "The led is expected to be RGB\n");
+ goto child_out;
+ }
+
+ led->mc_cdev.num_leds = num_colors;
+ led->mc_cdev.led_cdev = &led->ldev;
+ led->ldev.brightness_set_blocking = apa102c_brightness_set;
+ ret = devm_led_classdev_multicolor_register_ext(priv->dev,
+ &led->mc_cdev,
+ &init_data);
+ if (ret) {
+ dev_err(priv->dev, "led register err: %d\n", ret);
+ fwnode_handle_put(child);
+ goto child_out;
+ }
+ }
+
+child_out:
+ return ret;
+}
+
+static int apa102c_probe(struct spi_device *spi)
+{
+ struct apa102c *priv;
+ size_t led_count;
+ int ret;
+
+ led_count = device_get_child_node_count(&spi->dev);
+ if (!led_count) {
+ dev_err(&spi->dev, "No LEDs defined in device tree!");
+ return -ENODEV;
+ }
+
+ priv = devm_kzalloc(&spi->dev,
+ struct_size(priv, leds, led_count),
+ GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->buf = devm_kzalloc(&spi->dev, (led_count + 2) * 4, GFP_KERNEL);
+ if (!priv->buf)
+ return -ENOMEM;
+
+ mutex_init(&priv->lock);
+ priv->led_count = led_count;
+ priv->dev = &spi->dev;
+ priv->spi = spi;
+
+ ret = apa102c_probe_dt(priv);
+ if (ret)
+ return ret;
+
+ /* Set the LEDs with default values at start */
+ apa102c_sync(priv);
+ if (ret)
+ return ret;
+
+ spi_set_drvdata(spi, priv);
+
+ return 0;
+}
+
+static int apa102c_remove(struct spi_device *spi)
+{
+ struct apa102c *priv = spi_get_drvdata(spi);
+
+ mutex_destroy(&priv->lock);
+
+ return 0;
+}
+
+static const struct of_device_id apa102c_dt_ids[] = {
+ { .compatible = "shiji,apa102c", },
+ {},
+};
+
+MODULE_DEVICE_TABLE(of, apa102c_dt_ids);
+
+static struct spi_driver apa102c_driver = {
+ .probe = apa102c_probe,
+ .remove = apa102c_remove,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = apa102c_dt_ids,
+ },
+};
+
+module_spi_driver(apa102c_driver);
+
+MODULE_AUTHOR("Nicolas Belin <nbelin@...libre.com>");
+MODULE_DESCRIPTION("apa102c LED driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("spi:apa102c");
--
2.7.4
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