Implement a driver for ISSI IS31FL3743A

app/drivers/CMakeLists.txt

@@ -2,4 +2,5 @@
 # SPDX-License-Identifier: MIT
 
 add_subdirectory(kscan)
+add_subdirectory(led_strip)
 add_subdirectory(sensor)

app/drivers/Kconfig

@@ -2,4 +2,5 @@
 # SPDX-License-Identifier: MIT
 
 rsource "kscan/Kconfig"
+rsource "led_strip/Kconfig"
 rsource "sensor/Kconfig"

app/drivers/led_strip/CMakeLists.txt

@@ -0,0 +1,4 @@
+# Copyright (c) 2020 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+add_subdirectory_ifdef(CONFIG_IS31FL3743A is31fl3743a)

app/drivers/led_strip/Kconfig

@@ -0,0 +1,10 @@
+# Copyright (c) 2020 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+rsource "is31fl3743a/Kconfig"
+
+config LEG_STRIP_INIT_PRIORITY
+	int "LED strip initialization priority"
+	default 90
+	help
+		System initialization priority for LED strip drivers.

app/drivers/led_strip/is31fl3743a/CMakeLists.txt

@@ -0,0 +1,6 @@
+# Copyright (c) 2020 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+zephyr_library()
+
+zephyr_library_sources(is31fl3743a.c)

app/drivers/led_strip/is31fl3743a/Kconfig

@@ -0,0 +1,20 @@
+# Copyright (c) 2020 The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+config IS31FL3743A
+	bool "IS31FL3743A LED Matrix driver"
+	depends on I2C
+	help
+		Enable an IS31FL3743A LED Matrix driver.
+
+			The IS31FL3743A is a general purpose 18xn(n=1-11) LED Matrix
+			programmed via 1MHz I2C compatible interface. Each LED can be
+			dimmed individually with 8-bit PWM data and 8-bit DC scaling data
+			which allows 256 steps of linear PWM dimming and 256 steps of DC
+			current adjustable levels.
+
+config LED_STRIP_INIT_PRIORITY
+	int "LED strip initialization priority"
+	default 90
+	help
+		System initialization priority for LED strip drivers.

app/drivers/led_strip/is31fl3743a/is31fl3743a.c

@@ -0,0 +1,264 @@
+/*
+ * Copyright (c) 2020 The ZMK Contributors
+ *
+ * SPDX-License-Identifier: MIT
+ */
+
+#define DT_DRV_COMPAT issi_is31fl3743a
+
+#include <zephyr.h>
+#include <device.h>
+#include <drivers/gpio.h>
+#include <drivers/i2c.h>
+#include <drivers/led_strip.h>
+#include <logging/log.h>
+#include <sys/math_extras.h>
+#include <sys/util.h>
+
+LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
+
+#define IS31FL3743A_CS_PINS 18
+#define IS31FL3743A_SW_PINS 11
+
+#define IS31FL3743A_PSR (0xfd)
+#define IS31FL3743A_PSWL (0xfe)
+#define IS31FL3743A_PSWL_ENABLE (0xc5)
+#define IS31FL3743A_PSWL_DISABLE (0x00)
+
+#define IS31FL3743A_PAGE_PWM (0x00)
+#define IS31FL3743A_PAGE_SCALING (0x01)
+#define IS31FL3743A_PAGE_FUNCTION (0x02)
+
+struct is31fl3743a_config {
+	char *bus;
+	int reg;
+	char *label;
+	char *sdb_port;
+	gpio_pin_t sdb_pin;
+	gpio_dt_flags_t sdb_flags;
+	uint8_t *px_buffer;
+	size_t px_buffer_size;
+	uint8_t gcc;
+	uint8_t sws;
+	uint8_t sync;
+	uint8_t *cs_map;
+};
+
+struct is31fl3743a_data {
+	const struct device *i2c;
+	const struct device *gpio;
+};
+
+static int is31fl3743a_reg_write(const struct device *dev, uint8_t addr, uint8_t value)
+{
+	const struct is31fl3743a_data *data = dev->data;
+	const struct is31fl3743a_config *config = dev->config;
+
+	if (i2c_reg_write_byte(data->i2c, config->reg, addr, value)) {
+		LOG_ERR("Failed writing value %x to register address %x on device %x.", value, addr, config->reg);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int is31fl3743a_reg_burst_write(const struct device *dev,
+									   uint8_t start_addr,
+									   const uint8_t *buffer,
+									   size_t num_bytes)
+{
+	const struct is31fl3743a_data *data = dev->data;
+	const struct is31fl3743a_config *config = dev->config;
+
+	if (i2c_burst_write(data->i2c, config->reg, start_addr, buffer, num_bytes)) {
+		LOG_ERR("Failed burst write with starting address %x", start_addr);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int is31fl3743a_set_page(const struct device *dev, uint8_t page_addr)
+{
+	if (is31fl3743a_reg_write(dev, IS31FL3743A_PSWL, IS31FL3743A_PSWL_ENABLE)) {
+		return -EIO;
+	}
+
+	if (is31fl3743a_reg_write(dev, IS31FL3743A_PSR, page_addr)) {
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static inline bool num_pixels_ok(const struct is31fl3743a_config *config,
+								 size_t num_pixels)
+{
+	size_t num_bytes;
+
+	const bool overflow = size_mul_overflow(num_pixels, 3, &num_bytes);
+
+	return !overflow && (num_bytes <= config->px_buffer_size);
+}
+
+/*
+ * Updates the RGB LED matrix using cs-order devicetree property
+ * to assign correct R,G,B channels.
+ */
+static int is31fl3743a_strip_update_rgb(const struct device *dev,
+										struct led_rgb *pixels,
+										size_t num_pixels)
+{
+	const struct is31fl3743a_config *config = dev->config;
+
+	uint8_t *px_buffer = config->px_buffer;
+	uint8_t *cs_map = config->cs_map;
+
+	size_t sw_offset = 0;
+	size_t cs = 0;
+
+	if (!num_pixels_ok(config, num_pixels)) {
+		return -ENOMEM;
+	}
+
+	for (size_t i = 0; i < num_pixels; ++i) {
+		px_buffer[sw_offset + cs_map[cs++]] = pixels[i].r;
+		px_buffer[sw_offset + cs_map[cs++]] = pixels[i].g;
+		px_buffer[sw_offset + cs_map[cs++]] = pixels[i].b;
+
+		if (IS31FL3743A_CS_PINS <= cs) {
+			cs = 0;
+			sw_offset += IS31FL3743A_CS_PINS;
+		}
+	}
+
+	if (is31fl3743a_set_page(dev, IS31FL3743A_PAGE_PWM)) {
+		LOG_ERR("Failed to set PWM page on %s", config->label);
+		return -EIO;
+	}
+
+	return is31fl3743a_reg_burst_write(dev, 0x01, px_buffer, config->px_buffer_size);
+}
+
+/**
+ * Updates individual LED channels without an RGB interpretation.
+ */
+static int is31fl3743a_strip_update_channels(const struct device *dev,
+											 uint8_t *channels,
+											 size_t num_channels)
+{
+	const struct is31fl3743a_config *config = dev->config;
+
+	if (config->px_buffer_size < num_channels) {
+		return -ENOMEM;
+	}
+
+	return is31fl3743a_reg_burst_write(dev, 0x01, channels, num_channels);
+}
+
+/*
+ * Initiates a driver instance for IS31FL3743A.
+ *
+ * SDB is pulled high to enable chip operation followed
+ * by a reset to clear out all previous values.
+ *
+ * Function and scaling registers are then pre-configured based on devicetree settings.
+ */
+int static is31fl3743a_init(const struct device *dev)
+{
+	struct is31fl3743a_data *data = dev->data;
+	const struct is31fl3743a_config *config = dev->config;
+
+	data->i2c = device_get_binding(config->bus);
+
+	if (data->i2c == NULL) {
+		LOG_ERR("I2C device %s not found", config->bus);
+		return -ENODEV;
+	}
+
+	data->gpio = device_get_binding(config->sdb_port);
+
+	if (data->gpio == NULL) {
+		LOG_ERR("GPIO device %s not found", config->sdb_port);
+		return -ENODEV;
+	}
+
+	gpio_pin_configure(data->gpio, config->sdb_pin, (GPIO_OUTPUT | config->sdb_flags));
+
+	if (gpio_pin_set(data->gpio, config->sdb_pin, 1)) {
+		LOG_ERR("SDB pin for %s cannot be pulled high", config->label);
+		return -EIO;
+	}
+
+	// Set configuration registers
+	if (is31fl3743a_set_page(dev, IS31FL3743A_PAGE_FUNCTION)) {
+		LOG_ERR("Couldn't switch to function registers on %s", config->label);
+		return -EIO;
+	}
+
+	is31fl3743a_reg_write(dev, 0x2f, 0xae);                                     // Reset
+	is31fl3743a_reg_write(dev, 0x00, (config->sws << 4) | (0x01 << 3) | 0x01 ); // SWS, H logic, Normal operation
+	is31fl3743a_reg_write(dev, 0x01, config->gcc);                              // Set GCC
+	is31fl3743a_reg_write(dev, 0x24, 0x08);                                     // Thermal shutoff at 100*C, put into DT
+	is31fl3743a_reg_write(dev, 0x25, (config->sync << 6));                      // Set SYNC setting
+
+	// Set scaling registers, default to 0xff
+	if (is31fl3743a_set_page(dev, IS31FL3743A_PAGE_SCALING)) {
+		LOG_ERR("Couldn't switch to scaling registers on %s", config->label);
+	}
+
+	uint8_t scaling_buffer[config->px_buffer_size];
+
+	for (size_t i = 0; i < config->px_buffer_size; ++i) {
+		scaling_buffer[i] = 0xff;
+	}
+
+	is31fl3743a_reg_burst_write(dev, 0x01, scaling_buffer, config->px_buffer_size);
+
+	return 0;
+}
+
+static const struct led_strip_driver_api is31fl3743a_api = {
+	.update_rgb = is31fl3743a_strip_update_rgb,
+	.update_channels = is31fl3743a_strip_update_channels,
+};
+
+#define IS31FL3743A_BUFFER_SIZE(idx) \
+	IS31FL3743A_CS_PINS * (IS31FL3743A_SW_PINS - DT_INST_PROP(idx, sw_setting))
+
+#define IS31FL3743A_GCC(idx) \
+	(DT_INST_PROP(idx, riset) * DT_INST_PROP(idx, led_max_current) * 256 * 256) / (343 * 255)
+
+#define IS31FL3743A_DEVICE(idx)													\
+																				\
+	static struct is31fl3743a_data is31fl3743a_##idx##_data;					\
+																				\
+	static uint8_t is31fl3743a_##idx##_px_buffer[IS31FL3743A_BUFFER_SIZE(idx)];	\
+																				\
+	static uint8_t is31fl3743a_##idx##_cs_map[] = DT_INST_PROP(idx, cs_order);	\
+																				\
+	static const struct is31fl3743a_config is31fl3743a_##idx##_config = {		\
+		.bus = DT_INST_BUS_LABEL(idx),											\
+		.reg = DT_INST_REG_ADDR(idx),											\
+		.label = DT_INST_LABEL(idx),											\
+		.sdb_port = DT_INST_GPIO_LABEL(idx, sdb_gpios),							\
+		.sdb_pin = DT_INST_GPIO_PIN(idx, sdb_gpios),							\
+		.sdb_flags = DT_INST_GPIO_FLAGS(idx, sdb_gpios),						\
+		.px_buffer = is31fl3743a_##idx##_px_buffer,								\
+		.px_buffer_size = IS31FL3743A_BUFFER_SIZE(idx),							\
+		.gcc = IS31FL3743A_GCC(idx),											\
+		.sws = DT_INST_PROP(idx, sw_setting),									\
+		.sync = DT_INST_PROP(idx, sync),										\
+		.cs_map = is31fl3743a_##idx##_cs_map,									\
+	};																			\
+																				\
+	DEVICE_AND_API_INIT(is31fl3743a_##idx,										\
+						DT_INST_LABEL(idx),										\
+						&is31fl3743a_init,										\
+						&is31fl3743a_##idx##_data,								\
+						&is31fl3743a_##idx##_config,							\
+						POST_KERNEL,											\
+						CONFIG_LED_STRIP_INIT_PRIORITY,							\
+						&is31fl3743a_api);										\
+
+DT_INST_FOREACH_STATUS_OKAY(IS31FL3743A_DEVICE);

app/drivers/led_strip/is31fl3743a/issi,is31fl3743a.yaml

@@ -0,0 +1,6 @@
+description: |
+  Driver for the IS31FL3743A LED matrix driver
+
+compatible: "issi,issi_is31fl3743a"
+
+include: i2c-device.yaml

app/dts/bindings/led_strip/issi,is31fl3743a.yaml

@@ -0,0 +1,65 @@
+# Copyright (c) 2020, The ZMK Contributors
+# SPDX-License-Identifier: MIT
+
+description: ISSI IS31FL3743A LED Matrix driver
+
+compatible: "issi,is31fl3743a"
+
+include: i2c-device.yaml
+
+properties:
+  sw-setting:
+    type: int
+    required: false
+    enum:
+      - 0x00
+      - 0x01
+      - 0x02
+      - 0x03
+      - 0x04
+      - 0x05
+      - 0x06
+      - 0x07
+      - 0x08
+      - 0x09
+      - 0x0a
+    default: 0x00
+    description: |
+      SW setting used to control the matrix size by turning off SWx pins
+      as described in the datasheet.
+
+  cs-order:
+    type: uint8-array
+    required: false
+    default: [0x02, 0x01, 0x00, 0x05, 0x04, 0x03, 0x08, 0x07, 0x06, 0x0B, 0x0A, 0x09, 0x0E, 0x0D, 0x0C, 0x11, 0x10, 0x0F]
+    description: |
+      Stores the configuration of CS* pins.
+      Each 3 consecutive numbers must be R, G and B pins for a single LED.
+      Matches the reference design from the datasheet by default.
+
+  riset:
+    type: int
+    required: true
+    description: Riset resistor value in kiloohms.
+
+  led-max-current:
+    type: int
+    required: true
+    description: Maximum allowed LED current in mAh. The maximum allowed by the chip is 34.
+
+  sync:
+    type: int
+    enum:
+      - 0x00
+      - 0x10
+      - 0x11
+    required: false
+    default: 0x00
+    description: |
+      Controls the SYNC function. Set to 0x11 to set the device as main or 0x10 for secondary.
+
+  sdb-gpios:
+    type: phandle-array
+    required: true
+    description: |
+      GPIO pin for hardware shutdown functionality.