drivers: led: Add LED driver support for TI LP3943

Add support for Texas Instruments LP3943 - 16 channel LED driver.
Supported blinking period: 0 to 1600ms
Supported brightness value: 0 to 100%

This driver supports the following APIs:

1. led_blink
2. led_set_brightness
3. led_on
4. led_off

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

boards/arm/96b_neonkey/96b_neonkey.dts

@@ -72,6 +72,12 @@
 
 &i2c3 {
 	clock-frequency = <I2C_BITRATE_FAST>;
+
+	lp3943@60 {
+		compatible = "ti,lp3943";
+		reg = <0x60>;
+		label = "LP3943";
+	};
 };
 
 &spi1 {

boards/arm/96b_neonkey/Kconfig.board

@@ -7,3 +7,4 @@
 config BOARD_96B_NEONKEY
 	bool "96Boards Neonkey"
 	depends on SOC_STM32F411XE
+	select HAS_DTS_I2C_DEVICE

boards/arm/96b_neonkey/dts.fixup

@@ -0,0 +1,9 @@
+/* This file is a temporary workaround for mapping of the generated information
+ * to the current driver definitions.  This will be removed when the drivers
+ * are modified to handle the generated information, or the mapping of
+ * generated data matches the driver definitions.
+ */
+
+#define CONFIG_LP3943_DEV_NAME			ST_STM32_I2C_V1_40005C00_TI_LP3943_60_LABEL
+#define CONFIG_LP3943_I2C_ADDRESS		ST_STM32_I2C_V1_40005C00_TI_LP3943_60_BASE_ADDRESS
+#define CONFIG_LP3943_I2C_MASTER_DEV_NAME	ST_STM32_I2C_V1_40005C00_TI_LP3943_60_BUS_NAME

drivers/led/CMakeLists.txt

@@ -1 +1 @@
-# Nothing here (yet)
+zephyr_sources_ifdef(CONFIG_LP3943 lp3943.c)

drivers/led/Kconfig

@@ -10,7 +10,7 @@ menuconfig LED
 	bool "LED drivers"
 	default n
 	help
-		Include LED drivers in the system configuration.
+	  Include LED drivers in the system configuration.
 
 if LED
 
@@ -20,14 +20,20 @@ config SYS_LOG_LED_LEVEL
 	default 0
 	range 0 4
 	help
-		Sets the log level for LED drivers. You must have
+	  Sets the log level for LED drivers. You must have
-		system logging enabled.
+	  system logging enabled.
-		Levels are:
+
-		0 OFF, do not write
+	  Levels are:
-		1 ERROR, only write SYS_LOG_ERR
+
-		2 WARNING, write SYS_LOG_WRN in addition to previous level
+	  - 0 OFF, do not write
-		3 INFO, write SYS_LOG_INF in addition to previous levels
+
-		4 DEBUG, write SYS_LOG_DBG in addition to previous levels
+	  - 1 ERROR, only write SYS_LOG_ERR
+
+	  - 2 WARNING, write SYS_LOG_WRN in addition to previous level
+
+	  - 3 INFO, write SYS_LOG_INF in addition to previous levels
+
+	  - 4 DEBUG, write SYS_LOG_DBG in addition to previous levels
 
 config LED_INIT_PRIORITY
 	int "LED initialization priority"
@@ -35,4 +41,6 @@ config LED_INIT_PRIORITY
 	help
 	  System initialization priority for LED drivers.
 
+source "drivers/led/Kconfig.lp3943"
+
 endif # LED

drivers/led/Kconfig.lp3943

@@ -0,0 +1,48 @@
+#
+# Copyright (c) 2018 Linaro Limited
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+menuconfig LP3943
+	bool "LP3943 LED driver"
+	depends on I2C
+	default n
+	help
+	  Enable LED driver for LP3943.
+
+	  LP3943 LED driver has 16 channels each with multi-programmable
+	  states at a specified rate. Each channel can drive upto 25 mA
+	  per LED.
+
+if !HAS_DTS_I2C_DEVICE
+
+config LP3943_DEV_NAME
+	string "LP3943 device name"
+	default "LP3943"
+	help
+	  Device name for LP3943 LED driver.
+
+config LP3943_I2C_ADDRESS
+	hex "LP3943 I2C slave address"
+	range 0x60 0x67
+	default 0x60
+	help
+	  Specify the I2C slave address for the LP3943 LED driver.
+	  0x60: ADR0 = 0, ADR1 = 0, ADR2 = 0
+	  0x61: ADR0 = 0, ADR1 = 0, ADR2 = 1
+	  0x62: ADR0 = 0, ADR1 = 1, ADR2 = 0
+	  0x63: ADR0 = 0, ADR1 = 1, ADR2 = 1
+	  0x64: ADR0 = 1, ADR1 = 0, ADR2 = 0
+	  0x65: ADR0 = 1, ADR1 = 0, ADR2 = 1
+	  0x66: ADR0 = 1, ADR1 = 1, ADR2 = 0
+	  0x67: ADR0 = 1, ADR1 = 1, ADR2 = 1
+
+config LP3943_I2C_MASTER_DEV_NAME
+	string "I2C master where LP3943 is connected"
+	default "I2C_0"
+	help
+	  Specify the device name of the I2C master device to which
+	  LP3943 is connected.
+
+endif

drivers/led/lp3943.c

@@ -0,0 +1,263 @@
+/*
+ * Copyright (c) 2018 Linaro Ltd.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief LP3943 LED driver
+ *
+ * Limitations:
+ * - Blink period and brightness value are controlled by two sets of PSCx/PWMx
+ *   registers. This driver partitions the available LEDs into two groups as
+ *   0 to 7 and 8 to 15 and assigns PSC0/PWM0 to LEDs from 0 to 7 and PSC1/PWM1
+ *   to LEDs from 8 to 15. So, it is not possible to set unique blink period
+ *   and brightness value for LEDs in a group, changing either of these
+ *   values for a LED will affect other LEDs also.
+ */
+
+#include <i2c.h>
+#include <led.h>
+#include <misc/util.h>
+#include <zephyr.h>
+
+#define SYS_LOG_LEVEL CONFIG_SYS_LOG_LED_LEVEL
+#include <logging/sys_log.h>
+
+#include "led_context.h"
+
+/* LP3943 Registers */
+#define LP3943_INPUT_1 0x00
+#define LP3943_INPUT_2 0x01
+#define LP3943_PSC0 0x02
+#define LP3943_PWM0 0x03
+#define LP3943_PSC1 0x04
+#define LP3943_PWM1 0x05
+#define LP3943_LS0 0x06
+#define LP3943_LS1 0x07
+#define LP3943_LS2 0x08
+#define LP3943_LS3 0x09
+
+#define LP3943_MASK 0x03
+
+enum lp3943_modes {
+	LP3943_OFF,
+	LP3943_ON,
+	LP3943_DIM0,
+	LP3943_DIM1,
+};
+
+struct lp3943_data {
+	struct device *i2c;
+	struct led_data dev_data;
+};
+
+static int lp3943_get_led_reg(u32_t *led, u8_t *reg)
+{
+	switch (*led) {
+	case 0 ... 3:
+		*reg = LP3943_LS0;
+		break;
+	case 4 ... 7:
+		*reg = LP3943_LS1;
+		*led -= 4;
+		break;
+	case 8 ... 11:
+		*reg = LP3943_LS2;
+		*led -= 8;
+		break;
+	case 12 ... 15:
+		*reg = LP3943_LS3;
+		*led -= 12;
+		break;
+	default:
+		SYS_LOG_ERR("Invalid LED specified");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int lp3943_set_dim_states(struct lp3943_data *data, u32_t led, u8_t mode)
+{
+	int ret;
+	u8_t reg;
+
+	ret = lp3943_get_led_reg(&led, &reg);
+	if (ret) {
+		return ret;
+	}
+
+	/* Set DIMx states for the LEDs */
+	if (i2c_reg_update_byte(data->i2c, CONFIG_LP3943_I2C_ADDRESS, reg,
+				LP3943_MASK << (led << 1),
+				mode << (led << 1))) {
+		SYS_LOG_ERR("LED reg update failed");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int lp3943_led_blink(struct device *dev, u32_t led,
+			    u32_t delay_on, u32_t delay_off)
+{
+	struct lp3943_data *data = dev->driver_data;
+	struct led_data *dev_data = &data->dev_data;
+	int ret;
+	u16_t period;
+	u8_t reg, val, mode;
+
+	period = delay_on + delay_off;
+
+	if (period < dev_data->min_period || period > dev_data->max_period) {
+		return -EINVAL;
+	}
+
+	/* Use DIM0 for LEDs 0 to 7 and DIM1 for LEDs 8 to 15 */
+	if (led < 8) {
+		mode = LP3943_DIM0;
+	} else {
+		mode = LP3943_DIM1;
+	}
+
+	if (mode == LP3943_DIM0) {
+		reg = LP3943_PSC0;
+	} else {
+		reg = LP3943_PSC1;
+	}
+
+	val = (period * 255) / dev_data->max_period;
+	if (i2c_reg_write_byte(data->i2c, CONFIG_LP3943_I2C_ADDRESS,
+			       reg, val)) {
+		SYS_LOG_ERR("LED write failed");
+		return -EIO;
+	}
+
+	ret = lp3943_set_dim_states(data, led, mode);
+	if (ret) {
+		return ret;
+	}
+
+	return 0;
+}
+
+static int lp3943_led_set_brightness(struct device *dev, u32_t led,
+				     u8_t value)
+{
+	struct lp3943_data *data = dev->driver_data;
+	struct led_data *dev_data = &data->dev_data;
+	int ret;
+	u8_t reg, val, mode;
+
+	if (value < dev_data->min_brightness ||
+			value > dev_data->max_brightness) {
+		return -EINVAL;
+	}
+
+	/* Use DIM0 for LEDs 0 to 7 and DIM1 for LEDs 8 to 15 */
+	if (led < 8) {
+		mode = LP3943_DIM0;
+	} else {
+		mode = LP3943_DIM1;
+	}
+
+	if (mode == LP3943_DIM0) {
+		reg = LP3943_PWM0;
+	} else {
+		reg = LP3943_PWM1;
+	}
+
+	val = (value * 255) / dev_data->max_brightness;
+	if (i2c_reg_write_byte(data->i2c, CONFIG_LP3943_I2C_ADDRESS,
+			       reg, val)) {
+		SYS_LOG_ERR("LED write failed");
+		return -EIO;
+	}
+
+	ret = lp3943_set_dim_states(data, led, mode);
+	if (ret) {
+		return ret;
+	}
+
+	return 0;
+}
+
+static inline int lp3943_led_on(struct device *dev, u32_t led)
+{
+	struct lp3943_data *data = dev->driver_data;
+	int ret;
+	u8_t reg, mode;
+
+	ret = lp3943_get_led_reg(&led, &reg);
+	if (ret) {
+		return ret;
+	}
+
+	/* Set LED state to ON */
+	mode = LP3943_ON;
+	if (i2c_reg_update_byte(data->i2c, CONFIG_LP3943_I2C_ADDRESS, reg,
+				LP3943_MASK << (led << 1),
+				mode << (led << 1))) {
+		SYS_LOG_ERR("LED reg update failed");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static inline int lp3943_led_off(struct device *dev, u32_t led)
+{
+	struct lp3943_data *data = dev->driver_data;
+	int ret;
+	u8_t reg;
+
+	ret = lp3943_get_led_reg(&led, &reg);
+	if (ret) {
+		return ret;
+	}
+
+	/* Set LED state to OFF */
+	if (i2c_reg_update_byte(data->i2c, CONFIG_LP3943_I2C_ADDRESS, reg,
+				LP3943_MASK << (led << 1), 0)) {
+		SYS_LOG_ERR("LED reg update failed");
+		return -EIO;
+	}
+
+	return 0;
+}
+
+static int lp3943_led_init(struct device *dev)
+{
+	struct lp3943_data *data = dev->driver_data;
+	struct led_data *dev_data = &data->dev_data;
+
+	data->i2c = device_get_binding(CONFIG_LP3943_I2C_MASTER_DEV_NAME);
+	if (data->i2c == NULL) {
+		SYS_LOG_DBG("Failed to get I2C device");
+		return -EINVAL;
+	}
+
+	/* Hardware specific limits */
+	dev_data->min_period = 0;
+	dev_data->max_period = 1600;
+	dev_data->min_brightness = 0;
+	dev_data->max_brightness = 100;
+
+	return 0;
+}
+
+static struct lp3943_data lp3943_led_data;
+
+static const struct led_driver_api lp3943_led_api = {
+	.blink = lp3943_led_blink,
+	.set_brightness = lp3943_led_set_brightness,
+	.on = lp3943_led_on,
+	.off = lp3943_led_off,
+};
+
+DEVICE_AND_API_INIT(lp3943_led, CONFIG_LP3943_DEV_NAME,
+		    &lp3943_led_init, &lp3943_led_data,
+		    NULL, POST_KERNEL, CONFIG_LED_INIT_PRIORITY,
+		    &lp3943_led_api);

dts/bindings/led/ti,lp3943.yaml

@@ -0,0 +1,17 @@
+---
+title: TI LP3943 LED Driver
+id: ti,lp3943
+version: 0.1
+
+description: TI LP3943 LED binding
+
+inherits:
+    !include i2c-device.yaml
+
+properties:
+    compatible:
+      type: string
+      category: required
+      description: compatible strings
+      constraint: "ti,lp3943"
+...