From nobody Mon Dec 1 22:05:55 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D4EC2F5313; Mon, 1 Dec 2025 11:53:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764590006; cv=none; b=QD7S2Ztv1HySXTGzk/sSdawzxlnZ6AGhukayN/SJvX55ri21b1iOBwykX7q5zBbmDAUTbU+CX5N7ksG6HGgsZ7oYXlvFijsbgWoE3Z6VyKM3bQE+iGfgU5OQZDIhCosStMw5ikBaBpWC5OHT+7KJSHCC+1CxJOPJQcdaXNHmmpE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764590006; c=relaxed/simple; bh=zQlOO9hD9XJ9/sWdtulnqg9yxW21o6psMKGjZwFxyvw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=R6sKCKF9muLzQPUkFunGJOa4UUrv+OqijGeeMhxK02FoV8RwHCz2C5lJqsEoXLb+MtsFXyO2amMg8/iXiEY7kjheKSUVBKCE0p7KOdZRemCnc5pkY9HziSgDyjjKCO4I5CJw7vmitjtL4GM4rAExAOmrs66EhILXA6qDdMVQSA8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GJL9ykar; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GJL9ykar" Received: by smtp.kernel.org (Postfix) with ESMTPS id D5A44C2BC87; Mon, 1 Dec 2025 11:53:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764590005; bh=zQlOO9hD9XJ9/sWdtulnqg9yxW21o6psMKGjZwFxyvw=; h=From:Date:Subject:References:In-Reply-To:To:Cc:Reply-To:From; b=GJL9ykardhMsdOAxs+LPm7jocgWFIq/gd6+eDjZl7JD4T0K7Em6MfcnGWiZJQxkoe dysliHVJd8uK8QdcUngdDg7Wi9AkRTcfLU6cpSWvceSIzu9tF7+4/UH4J4na6idolU gBt+4K10ITVRPqpRcvunKdNXfH8pOs3cnbsvl8INBzuLvMtyhA9rIMG9CF5GzUH6n/ Hx1dL/xF82L7ZZmLmR7SvvCBHHBCLjik/nds77eEffZrjqx/BtISHXP6V7Lea/Pkls SIBF5ypzFV+4F9sUC/TdYvW2x8oBt9UUo9OZBTaWzstYLh7dA0wfqBnqZetsZU9WK6 9LamUBQsw/KWQ== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id BBA3CD116F9; Mon, 1 Dec 2025 11:53:25 +0000 (UTC) From: Maud Spierings via B4 Relay Date: Mon, 01 Dec 2025 12:53:21 +0100 Subject: [PATCH v6 2/4] backlight: add max25014atg backlight Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20251201-max25014-v6-2-88e3ac8112ff@gocontroll.com> References: <20251201-max25014-v6-0-88e3ac8112ff@gocontroll.com> In-Reply-To: <20251201-max25014-v6-0-88e3ac8112ff@gocontroll.com> To: Lee Jones , Daniel Thompson , Jingoo Han , Pavel Machek , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Helge Deller , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Liam Girdwood , Mark Brown Cc: dri-devel@lists.freedesktop.org, linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fbdev@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, Maud Spierings X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=ed25519-sha256; t=1764590004; l=14499; i=maudspierings@gocontroll.com; s=20250214; h=from:subject:message-id; bh=9dik3xIMTaUAsQwBRiAwT596SyTGBbpn9RL3C2HPXk8=; b=ju1M4ANjnLVZzZX8NVoLSqIiK7VA0GtXhQPDvqdOqXTe5VKIor7sXLjImrEhJnpBLazY2lgkl wk9po42+KULBL4EyrpgmrleUVHBkKlNFyKtO/LLNHxC4REHmBa0izlb X-Developer-Key: i=maudspierings@gocontroll.com; a=ed25519; pk=7chUb8XpaTQDvWhzTdHC0YPMkTDloELEC7q94tOUyPg= X-Endpoint-Received: by B4 Relay for maudspierings@gocontroll.com/20250214 with auth_id=341 X-Original-From: Maud Spierings Reply-To: maudspierings@gocontroll.com From: Maud Spierings The Maxim MAX25014 is a 4-channel automotive grade backlight driver IC with integrated boost controller. Signed-off-by: Maud Spierings --- MAINTAINERS | 1 + drivers/video/backlight/Kconfig | 7 + drivers/video/backlight/Makefile | 1 + drivers/video/backlight/max25014.c | 419 +++++++++++++++++++++++++++++++++= ++++ 4 files changed, 428 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index 606ce086f758..d082d3f8cfae 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15265,6 +15265,7 @@ MAX25014 BACKLIGHT DRIVER M: Maud Spierings S: Maintained F: Documentation/devicetree/bindings/leds/backlight/maxim,max25014.yaml +F: drivers/video/backlight/max25014.c =20 MAX31335 RTC DRIVER M: Antoniu Miclaus diff --git a/drivers/video/backlight/Kconfig b/drivers/video/backlight/Kcon= fig index d9374d208cee..d3bb6ccd4185 100644 --- a/drivers/video/backlight/Kconfig +++ b/drivers/video/backlight/Kconfig @@ -262,6 +262,13 @@ config BACKLIGHT_DA9052 help Enable the Backlight Driver for DA9052-BC and DA9053-AA/Bx PMICs. =20 +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/Mak= efile index dfbb169bf6ea..1170d9ec40b8 100644 --- a/drivers/video/backlight/Makefile +++ b/drivers/video/backlight/Makefile @@ -45,6 +45,7 @@ obj-$(CONFIG_BACKLIGHT_LOCOMO) +=3D locomolcd.o obj-$(CONFIG_BACKLIGHT_LP855X) +=3D lp855x_bl.o obj-$(CONFIG_BACKLIGHT_LP8788) +=3D lp8788_bl.o obj-$(CONFIG_BACKLIGHT_LV5207LP) +=3D lv5207lp.o +obj-$(CONFIG_BACKLIGHT_MAX25014) +=3D max25014.o obj-$(CONFIG_BACKLIGHT_MAX8925) +=3D max8925_bl.o obj-$(CONFIG_BACKLIGHT_MP3309C) +=3D mp3309c.o obj-$(CONFIG_BACKLIGHT_MT6370) +=3D mt6370-backlight.o diff --git a/drivers/video/backlight/max25014.c b/drivers/video/backlight/m= ax25014.c new file mode 100644 index 000000000000..7000225752c3 --- /dev/null +++ b/drivers/video/backlight/max25014.c @@ -0,0 +1,419 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Backlight driver for Maxim MAX25014 + * + * Copyright (C) 2025 GOcontroll B.V. + * Author: Maud Spierings + */ + +#include +#include +#include +#include +#include + +#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_SHORT_GND 0x1C +#define MAX25014_SHORT_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; + struct regulator *vin; /* regulator for boost converter Vin rail */ + uint32_t iset; + uint8_t strings_mask; +}; + +static const struct regmap_config max25014_regmap_config =3D { + .reg_bits =3D 8, + .val_bits =3D 8, + .max_register =3D MAX25014_DIAG, +}; + +static int max25014_initial_power_state(struct max25014 *maxim) +{ + uint32_t val; + int ret; + + ret =3D 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 =3D 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 =3D 0; i < 4; i++) { + if (val & 1 << i) + dev_err(&maxim->client->dev, "string %d\n", i + 1); + } + return -EIO; + } + + ret =3D regmap_read(maxim->regmap, MAX25014_SHORT_GND, &val); + if (ret) + return ret; + if (val) { + dev_err(&maxim->client->dev, "Short to ground detected on:\n"); + for (i =3D 0; i < 4; i++) { + if (val & 1 << i) + dev_err(&maxim->client->dev, "string %d\n", i + 1); + } + return -EIO; + } + + ret =3D regmap_read(maxim->regmap, MAX25014_SHORT_GND, &val); + if (ret) + return ret; + if (val) { + dev_err(&maxim->client->dev, "Shorted led detected on:\n"); + for (i =3D 0; i < 4; i++) { + if (val & 1 << i) + dev_err(&maxim->client->dev, "string %d\n", i + 1); + } + return -EIO; + } + + ret =3D 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 !=3D 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; + + /* + * Strings can only be disabled when MAX25014_ISET_ENA =3D=3D 0, check if + * it needs to be changed at all to prevent the backlight flashing when + * it is configured correctly by the bootloader + */ + ret =3D regmap_read(maxim->regmap, MAX25014_DISABLE, &val); + if (ret) + return ret; + + if (!((val & MAX25014_DISABLE_DIS_MASK) =3D=3D maxim->strings_mask)) { + if (initial_state =3D=3D BACKLIGHT_POWER_ON) { + ret =3D regmap_write(maxim->regmap, MAX25014_ISET, 0); + if (ret) + return ret; + } + ret =3D regmap_write(maxim->regmap, MAX25014_DISABLE, maxim->strings_mas= k); + if (ret) + return ret; + } + + ret =3D regmap_write(maxim->regmap, MAX25014_IMODE, MAX25014_IMODE_HDIM); + if (ret) + return ret; + + ret =3D regmap_read(maxim->regmap, MAX25014_SETTING, &val); + if (ret) + return ret; + + ret =3D regmap_write(maxim->regmap, MAX25014_SETTING, + val & ~MAX25014_SETTING_FPWM); + if (ret) + return ret; + + ret =3D regmap_write(maxim->regmap, MAX25014_ISET, + maxim->iset | MAX25014_ISET_ENA | + MAX25014_ISET_PSEN); + return ret; +} + +static int max25014_update_status(struct backlight_device *bl_dev) +{ + struct max25014 *maxim =3D bl_get_data(bl_dev); + uint32_t reg; + int ret; + + if (backlight_is_blank(maxim->bl)) + bl_dev->props.brightness =3D 0; + + reg =3D TON_STEP * bl_dev->props.brightness; + + /* + * 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 =3D regmap_write(maxim->regmap, MAX25014_TON_1_4_LSB, reg & 0b0000001= 1); + if (ret !=3D 0) + return ret; + ret =3D regmap_write(maxim->regmap, MAX25014_TON1L, (reg >> 2) & 0b111111= 11); + if (ret !=3D 0) + return ret; + return regmap_write(maxim->regmap, MAX25014_TON1H, (reg >> 10) & 0b111111= 11); +} + +static const struct backlight_ops max25014_bl_ops =3D { + .options =3D BL_CORE_SUSPENDRESUME, + .update_status =3D max25014_update_status, +}; + +static int max25014_parse_dt(struct max25014 *maxim, + uint32_t *initial_brightness) +{ + struct device *dev =3D &maxim->client->dev; + struct device_node *node =3D dev->of_node; + struct fwnode_handle *child; + uint32_t strings[4]; + int res, i; + + if (!node) + return dev_err_probe(dev, -EINVAL, "no platform data\n"); + + child =3D device_get_next_child_node(dev, NULL); + if (child) { + res =3D fwnode_property_count_u32(child, "led-sources"); + if (res > 0) { + fwnode_property_read_u32_array(child, "led-sources", + strings, res); + + /* set all strings as disabled, then enable those in led-sources*/ + maxim->strings_mask =3D 0xf; + for (i =3D 0; i < res; i++) { + if (strings[i] <=3D 4) + maxim->strings_mask &=3D ~BIT(strings[i]); + } + } + + fwnode_property_read_u32(child, "default-brightness", + initial_brightness); + + fwnode_handle_put(child); + } + + maxim->iset =3D 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, entere= d was %d\n", + *initial_brightness); + + return 0; +} + +static int max25014_probe(struct i2c_client *cl) +{ + const struct i2c_device_id *id =3D i2c_client_get_device_id(cl); + struct backlight_properties props; + uint32_t initial_brightness =3D 50; + struct backlight_device *bl; + struct max25014 *maxim; + int ret; + + maxim =3D devm_kzalloc(&cl->dev, sizeof(struct max25014), GFP_KERNEL); + if (!maxim) + return -ENOMEM; + + maxim->client =3D cl; + + ret =3D max25014_parse_dt(maxim, &initial_brightness); + if (ret) + return ret; + + maxim->vin =3D devm_regulator_get(&maxim->client->dev, "power"); + if (IS_ERR(maxim->vin)) { + return dev_err_probe(&maxim->client->dev, PTR_ERR(maxim->vin), + "failed to get power-supply"); + } + + ret =3D regulator_enable(maxim->vin); + if (ret) + return dev_err_probe(&maxim->client->dev, ret, + "failed to enable power-supply\n"); + + maxim->enable =3D devm_gpiod_get_optional(&maxim->client->dev, "enable", + GPIOD_OUT_HIGH); + if (IS_ERR(maxim->enable)) { + ret =3D dev_err_probe(&maxim->client->dev, PTR_ERR(maxim->enable), + "failed to get enable gpio\n"); + goto disable_vin; + } + + /* Datasheet Electrical Characteristics tSTARTUP 2ms */ + fsleep(2000); + + maxim->regmap =3D devm_regmap_init_i2c(cl, &max25014_regmap_config); + if (IS_ERR(maxim->regmap)) { + ret =3D dev_err_probe(&maxim->client->dev, PTR_ERR(maxim->regmap), + "failed to initialize the i2c regmap\n"); + goto disable_full; + } + + i2c_set_clientdata(cl, maxim); + + ret =3D max25014_check_errors(maxim); + if (ret) { /* error is already reported in the above function */ + goto disable_full; + } + + ret =3D max25014_initial_power_state(maxim); + if (ret < 0) { + dev_err_probe(&maxim->client->dev, ret, "Could not get enabled state\n"); + goto disable_full; + } + + memset(&props, 0, sizeof(struct backlight_properties)); + props.type =3D BACKLIGHT_PLATFORM; + props.max_brightness =3D MAX_BRIGHTNESS; + props.brightness =3D initial_brightness; + props.scale =3D BACKLIGHT_SCALE_LINEAR; + props.power =3D ret; + + ret =3D max25014_configure(maxim, ret); + if (ret) { + dev_err_probe(&maxim->client->dev, ret, "device config error"); + goto disable_full; + } + + bl =3D devm_backlight_device_register(&maxim->client->dev, id->name, + &maxim->client->dev, maxim, + &max25014_bl_ops, &props); + if (IS_ERR(bl)) { + ret =3D dev_err_probe(&maxim->client->dev, PTR_ERR(bl), + "failed to register backlight\n"); + goto disable_full; + } + + maxim->bl =3D bl; + + backlight_update_status(maxim->bl); + + return 0; + +disable_full: + gpiod_set_value_cansleep(maxim->enable, 0); +disable_vin: + regulator_disable(maxim->vin); + return ret; +} + +static void max25014_remove(struct i2c_client *cl) +{ + struct max25014 *maxim =3D i2c_get_clientdata(cl); + + maxim->bl->props.brightness =3D 0; + max25014_update_status(maxim->bl); + gpiod_set_value_cansleep(maxim->enable, 0); + regulator_disable(maxim->vin); +} + +static const struct of_device_id max25014_dt_ids[] =3D { + { .compatible =3D "maxim,max25014", }, + { } +}; +MODULE_DEVICE_TABLE(of, max25014_dt_ids); + +static const struct i2c_device_id max25014_ids[] =3D { + { "max25014" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, max25014_ids); + +static struct i2c_driver max25014_driver =3D { + .driver =3D { + .name =3D KBUILD_MODNAME, + .of_match_table =3D of_match_ptr(max25014_dt_ids), + }, + .probe =3D max25014_probe, + .remove =3D max25014_remove, + .id_table =3D max25014_ids, +}; +module_i2c_driver(max25014_driver); + +MODULE_DESCRIPTION("Maxim MAX25014 backlight driver"); +MODULE_AUTHOR("Maud Spierings "); +MODULE_LICENSE("GPL"); --=20 2.52.0