From: Maud Spierings <[email protected]> The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC with integrated boost controller.
Signed-off-by: Maud Spierings <[email protected]> --- MAINTAINERS | 1 + drivers/video/backlight/Kconfig | 7 + drivers/video/backlight/Makefile | 1 + drivers/video/backlight/max25014.c | 377 +++++++++++++++++++++++++++++++++++++ 4 files changed, 386 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index eb248f4634ac..346a8ede3f71 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15519,6 +15519,7 @@ MAX25014 BACKLIGHT DRIVER M: Maud Spierings <[email protected]> S: Maintained F: Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml +F: drivers/video/backlight/max25014.c MAX31335 RTC DRIVER M: Antoniu Miclaus <[email protected]> diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kconfig index a7a3fbaf7c29..6cd3a1673511 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -282,6 +282,13 @@ config BACKLIGHT_DA9052 help Enable the Backlight Driver for DA9052-BC and DA9053-AA/Bx PMICs. +config BACKLIGHT_MAX25014 + tristate "Backlight driver for the Maxim MAX25014 chip" + depends on I2C + select REGMAP_I2C + help + If you are using a MAX25014 chip as a backlight driver say Y to enable it. + config BACKLIGHT_MAX8925 tristate "Backlight driver for MAX8925" depends on MFD_MAX8925 diff --git a/drivers/video/backlight/Makefile b/drivers/video/backlight/Makefile index 794820a98ed4..21c8313cfb12 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -47,6 +47,7 @@ obj-$(CONFIG_BACKLIGHT_LOCOMO) += locomolcd.o obj-$(CONFIG_BACKLIGHT_LP855X) += lp855x_bl.o obj-$(CONFIG_BACKLIGHT_LP8788) += lp8788_bl.o obj-$(CONFIG_BACKLIGHT_LV5207LP) += lv5207lp.o +obj-$(CONFIG_BACKLIGHT_MAX25014) += max25014.o obj-$(CONFIG_BACKLIGHT_MAX8925) += max8925_bl.o obj-$(CONFIG_BACKLIGHT_MP3309C) += mp3309c.o obj-$(CONFIG_BACKLIGHT_MT6370) += mt6370-backlight.o diff --git a/drivers/video/backlight/max25014.c b/drivers/video/backlight/max25014.c new file mode 100644 index 000000000000..3ee45617261f --- /dev/null +++ b/drivers/video/backlight/max25014.c @@ -0,0 +1,377 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Backlight driver for Maxim MAX25014 + * + * Copyright (C) 2025 GOcontroll B.V. + * Author: Maud Spierings <[email protected]> + */ + +#include <linux/backlight.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/regmap.h> +#include <linux/slab.h> + +#define MAX25014_ISET_DEFAULT_100 11 +#define MAX_BRIGHTNESS 100 +#define MIN_BRIGHTNESS 0 +#define TON_MAX 130720 /* @153Hz */ +#define TON_STEP 1307 /* @153Hz */ +#define TON_MIN 0 + +#define MAX25014_DEV_ID 0x00 +#define MAX25014_REV_ID 0x01 +#define MAX25014_ISET 0x02 +#define MAX25014_IMODE 0x03 +#define MAX25014_TON1H 0x04 +#define MAX25014_TON1L 0x05 +#define MAX25014_TON2H 0x06 +#define MAX25014_TON2L 0x07 +#define MAX25014_TON3H 0x08 +#define MAX25014_TON3L 0x09 +#define MAX25014_TON4H 0x0A +#define MAX25014_TON4L 0x0B +#define MAX25014_TON_1_4_LSB 0x0C +#define MAX25014_SETTING 0x12 +#define MAX25014_DISABLE 0x13 +#define MAX25014_BSTMON 0x14 +#define MAX25014_IOUT1 0x15 +#define MAX25014_IOUT2 0x16 +#define MAX25014_IOUT3 0x17 +#define MAX25014_IOUT4 0x18 +#define MAX25014_OPEN 0x1B +#define MAX25014_SHORTGND 0x1C +#define MAX25014_SHORTED_LED 0x1D +#define MAX25014_MASK 0x1E +#define MAX25014_DIAG 0x1F + +#define MAX25014_ISET_ENA BIT(5) +#define MAX25014_ISET_PSEN BIT(4) +#define MAX25014_IMODE_HDIM BIT(2) +#define MAX25014_SETTING_FPWM GENMASK(6, 4) +#define MAX25014_DISABLE_DIS_MASK GENMASK(3, 0) +#define MAX25014_DIAG_OT BIT(0) +#define MAX25014_DIAG_OTW BIT(1) +#define MAX25014_DIAG_HW_RST BIT(2) +#define MAX25014_DIAG_BSTOV BIT(3) +#define MAX25014_DIAG_BSTUV BIT(4) +#define MAX25014_DIAG_IREFOOR BIT(5) + +struct max25014 { + struct i2c_client *client; + struct backlight_device *bl; + struct regmap *regmap; + struct gpio_desc *enable; + uint32_t iset; + uint8_t strings_mask; +}; + +static const struct regmap_config max25014_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = MAX25014_DIAG, +}; + +static int max25014_initial_power_state(struct max25014 *maxim) +{ + uint32_t val; + int ret; + + ret = regmap_read(maxim->regmap, MAX25014_ISET, &val); + if (ret) + return ret; + + return val & MAX25014_ISET_ENA ? BACKLIGHT_POWER_ON : BACKLIGHT_POWER_OFF; +} + +static int max25014_check_errors(struct max25014 *maxim) +{ + uint32_t val; + uint8_t i; + int ret; + + ret = regmap_read(maxim->regmap, MAX25014_OPEN, &val); + if (ret) + return ret; + if (val) { + dev_err(&maxim->client->dev, "Open led strings detected on:\n"); + for (i = 0; i < 4; i++) { + if (val & 1 << i) + dev_err(&maxim->client->dev, "string %d\n", i + 1); + } + return -EIO; + } + + ret = regmap_read(maxim->regmap, MAX25014_SHORTGND, &val); + if (ret) + return ret; + if (val) { + dev_err(&maxim->client->dev, "Short to ground detected on:\n"); + for (i = 0; i < 4; i++) { + if (val & 1 << i) + dev_err(&maxim->client->dev, "string %d\n", i + 1); + } + return -EIO; + } + + ret = regmap_read(maxim->regmap, MAX25014_SHORTED_LED, &val); + if (ret) + return ret; + if (val) { + dev_err(&maxim->client->dev, "Shorted led detected on:\n"); + for (i = 0; i < 4; i++) { + if (val & 1 << i) + dev_err(&maxim->client->dev, "string %d\n", i + 1); + } + return -EIO; + } + + ret = regmap_read(maxim->regmap, MAX25014_DIAG, &val); + if (ret) + return ret; + /* + * The HW_RST bit always starts at 1 after power up. + * It is reset on first read, does not indicate an error. + */ + if (val && val != MAX25014_DIAG_HW_RST) { + if (val & MAX25014_DIAG_OT) + dev_err(&maxim->client->dev, + "Overtemperature shutdown\n"); + if (val & MAX25014_DIAG_OTW) + dev_err(&maxim->client->dev, + "Chip is getting too hot (>125C)\n"); + if (val & MAX25014_DIAG_BSTOV) + dev_err(&maxim->client->dev, + "Boost converter overvoltage\n"); + if (val & MAX25014_DIAG_BSTUV) + dev_err(&maxim->client->dev, + "Boost converter undervoltage\n"); + if (val & MAX25014_DIAG_IREFOOR) + dev_err(&maxim->client->dev, "IREF out of range\n"); + return -EIO; + } + return 0; +} + +/* + * 1. disable unused strings + * 2. set dim mode + * 3. set setting register + * 4. enable the backlight + */ +static int max25014_configure(struct max25014 *maxim, int initial_state) +{ + uint32_t val; + int ret; + + ret = regmap_read(maxim->regmap, MAX25014_DISABLE, &val); + if (ret) + return ret; + + /* + * Strings can only be disabled when MAX25014_ISET_ENA == 0, check if + * it needs to be changed at all to prevent the backlight flashing when + * it is configured correctly by the bootloader + */ + if (!((val & MAX25014_DISABLE_DIS_MASK) == maxim->strings_mask)) { + if (initial_state == BACKLIGHT_POWER_ON) { + ret = regmap_write(maxim->regmap, MAX25014_ISET, 0); + if (ret) + return ret; + } + ret = regmap_write(maxim->regmap, MAX25014_DISABLE, maxim->strings_mask); + if (ret) + return ret; + } + + ret = regmap_write(maxim->regmap, MAX25014_IMODE, MAX25014_IMODE_HDIM); + if (ret) + return ret; + + ret = regmap_read(maxim->regmap, MAX25014_SETTING, &val); + if (ret) + return ret; + + ret = regmap_write(maxim->regmap, MAX25014_SETTING, + val & ~MAX25014_SETTING_FPWM); + if (ret) + return ret; + + return regmap_write(maxim->regmap, MAX25014_ISET, + maxim->iset | MAX25014_ISET_ENA | + MAX25014_ISET_PSEN); +} + +static int max25014_update_status(struct backlight_device *bl_dev) +{ + struct max25014 *maxim = bl_get_data(bl_dev); + uint32_t reg; + int ret; + + reg = TON_STEP * backlight_get_brightness(bl_dev); + + /* + * 18 bit number lowest, 2 bits in first register, + * next lowest 8 in the L register, next 8 in the H register + * Seemingly setting the strength of only one string controls all of + * them, individual settings don't affect the outcome. + */ + ret = regmap_write(maxim->regmap, MAX25014_TON_1_4_LSB, reg & 0b00000011); + if (ret != 0) + return ret; + ret = regmap_write(maxim->regmap, MAX25014_TON1L, (reg >> 2) & 0b11111111); + if (ret != 0) + return ret; + return regmap_write(maxim->regmap, MAX25014_TON1H, (reg >> 10) & 0b11111111); +} + +static const struct backlight_ops max25014_bl_ops = { + .options = BL_CORE_SUSPENDRESUME, + .update_status = max25014_update_status, +}; + +static int max25014_parse_dt(struct max25014 *maxim, + uint32_t *initial_brightness) +{ + struct device *dev = &maxim->client->dev; + struct device_node *node = dev->of_node; + uint32_t strings[4]; + int res, i; + + res = of_property_count_u32_elems(node, "maxim,strings"); + if (res == 4) { + of_property_read_u32_array(node, "maxim,strings", strings, 4); + for (i = 0; i < 4; i++) { + if (strings[i] == 0) + maxim->strings_mask |= 1 << i; + } + } else { + maxim->strings_mask = 0; + } + + *initial_brightness = 50U; + of_property_read_u32(node, "default-brightness", initial_brightness); + + maxim->iset = MAX25014_ISET_DEFAULT_100; + of_property_read_u32(node, "maxim,iset", &maxim->iset); + + if (maxim->iset > 15) + return dev_err_probe(dev, -EINVAL, + "Invalid iset, should be a value from 0-15, entered was %d\n", + maxim->iset); + + if (*initial_brightness > 100) + return dev_err_probe(dev, -EINVAL, + "Invalid initial brightness, should be a value from 0-100, entered was %d\n", + *initial_brightness); + + return 0; +} + +static int max25014_probe(struct i2c_client *cl) +{ + const struct i2c_device_id *id = i2c_client_get_device_id(cl); + struct backlight_properties props; + uint32_t initial_brightness = 50; + struct backlight_device *bl; + struct max25014 *maxim; + int ret; + + maxim = devm_kzalloc(&cl->dev, sizeof(struct max25014), GFP_KERNEL); + if (!maxim) + return -ENOMEM; + + maxim->client = cl; + + ret = max25014_parse_dt(maxim, &initial_brightness); + if (ret) + return ret; + + ret = devm_regulator_get_enable(&maxim->client->dev, "power"); + if (ret) + return dev_err_probe(&maxim->client->dev, ret, + "failed to get power-supply"); + + maxim->enable = devm_gpiod_get_optional(&maxim->client->dev, "enable", + GPIOD_OUT_HIGH); + if (IS_ERR(maxim->enable)) + return dev_err_probe(&maxim->client->dev, PTR_ERR(maxim->enable), + "failed to get enable gpio\n"); + + /* Datasheet Electrical Characteristics tSTARTUP 2ms */ + fsleep(2000); + + maxim->regmap = devm_regmap_init_i2c(cl, &max25014_regmap_config); + if (IS_ERR(maxim->regmap)) + return dev_err_probe(&maxim->client->dev, PTR_ERR(maxim->regmap), + "failed to initialize the i2c regmap\n"); + + i2c_set_clientdata(cl, maxim); + + ret = max25014_check_errors(maxim); + if (ret) /* error is already reported in the above function */ + return ret; + + ret = max25014_initial_power_state(maxim); + if (ret < 0) + return dev_err_probe(&maxim->client->dev, ret, "Could not get enabled state\n"); + + memset(&props, 0, sizeof(struct backlight_properties)); + props.type = BACKLIGHT_PLATFORM; + props.max_brightness = MAX_BRIGHTNESS; + props.brightness = initial_brightness; + props.scale = BACKLIGHT_SCALE_LINEAR; + props.power = ret; + + ret = max25014_configure(maxim, ret); + if (ret) + return dev_err_probe(&maxim->client->dev, ret, "device config error"); + + bl = devm_backlight_device_register(&maxim->client->dev, id->name, + &maxim->client->dev, maxim, + &max25014_bl_ops, &props); + if (IS_ERR(bl)) + return dev_err_probe(&maxim->client->dev, PTR_ERR(bl), + "failed to register backlight\n"); + + maxim->bl = bl; + + backlight_update_status(maxim->bl); + + return 0; +} + +static void max25014_remove(struct i2c_client *cl) +{ + struct max25014 *maxim = i2c_get_clientdata(cl); + + backlight_device_set_brightness(maxim->bl, 0); + gpiod_set_value_cansleep(maxim->enable, 0); +} + +static const struct of_device_id max25014_dt_ids[] = { + { .compatible = "maxim,max25014", }, + { } +}; +MODULE_DEVICE_TABLE(of, max25014_dt_ids); + +static const struct i2c_device_id max25014_ids[] = { + { "max25014" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, max25014_ids); + +static struct i2c_driver max25014_driver = { + .driver = { + .name = KBUILD_MODNAME, + .of_match_table = of_match_ptr(max25014_dt_ids), + }, + .probe = max25014_probe, + .remove = max25014_remove, + .id_table = max25014_ids, +}; +module_i2c_driver(max25014_driver); + +MODULE_DESCRIPTION("Maxim MAX25014 backlight driver"); +MODULE_AUTHOR("Maud Spierings <[email protected]>"); +MODULE_LICENSE("GPL"); -- 2.52.0
