[PATCH V6 2/5] mfd: bq257xx: Add support for BQ25703A core driver

[Chris Morgan <macroalpha82@gmail.com>]

From: Chris Morgan <macromorgan@hotmail.com>

The Texas Instruments BQ25703A is an integrated charger manager and
boost converter.

The MFD driver initalizes the device for the regulator driver
and power supply driver.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/mfd/Kconfig         |  11 ++++
 drivers/mfd/Makefile        |   1 +
 drivers/mfd/bq257xx.c       |  97 +++++++++++++++++++++++++++++++++
 include/linux/mfd/bq257xx.h | 104 ++++++++++++++++++++++++++++++++++++
 4 files changed, 213 insertions(+)
 create mode 100644 drivers/mfd/bq257xx.c
 create mode 100644 include/linux/mfd/bq257xx.h

diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 425c5fba6cb1..768417c97339 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1641,6 +1641,17 @@ config MFD_TI_LMU
 	  LM36274.  It consists of backlight, LED and regulator driver.
 	  It provides consistent device controls for lighting functions.
 
+config MFD_BQ257XX
+	tristate "TI BQ257XX Buck/Boost Charge Controller"
+	depends on I2C
+	select MFD_CORE
+	select REGMAP_I2C
+	help
+	  Support Texas Instruments BQ25703 Buck/Boost converter with
+	  charge controller. It consists of regulators that provide
+	  system voltage and OTG voltage, and a charger manager for
+	  batteries containing one or more cells.
+
 config MFD_OMAP_USB_HOST
 	bool "TI OMAP USBHS core and TLL driver"
 	depends on USB_EHCI_HCD_OMAP || USB_OHCI_HCD_OMAP3
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index f7bdedd5a66d..3d700374a42d 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_MFD_SM501)		+= sm501.o
 obj-$(CONFIG_ARCH_BCM2835)	+= bcm2835-pm.o
 obj-$(CONFIG_MFD_BCM590XX)	+= bcm590xx.o
 obj-$(CONFIG_MFD_BD9571MWV)	+= bd9571mwv.o
+obj-$(CONFIG_MFD_BQ257XX)	+= bq257xx.o
 obj-$(CONFIG_MFD_CGBC)		+= cgbc-core.o
 obj-$(CONFIG_MFD_CROS_EC_DEV)	+= cros_ec_dev.o
 obj-$(CONFIG_MFD_CS42L43)	+= cs42l43.o
diff --git a/drivers/mfd/bq257xx.c b/drivers/mfd/bq257xx.c
new file mode 100644
index 000000000000..ac4485a2cc60
--- /dev/null
+++ b/drivers/mfd/bq257xx.c
@@ -0,0 +1,97 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * BQ257XX Core Driver
+ * Copyright (C) 2025 Chris Morgan <macromorgan@hotmail.com>
+ */
+
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/mfd/bq257xx.h>
+#include <linux/mfd/core.h>
+#include <linux/regmap.h>
+
+static const struct regmap_range bq25703_readonly_reg_ranges[] = {
+	regmap_reg_range(BQ25703_CHARGER_STATUS, BQ25703_MANUFACT_DEV_ID),
+};
+
+static const struct regmap_access_table bq25703_writeable_regs = {
+	.no_ranges = bq25703_readonly_reg_ranges,
+	.n_no_ranges = ARRAY_SIZE(bq25703_readonly_reg_ranges),
+};
+
+static const struct regmap_range bq25703_volatile_reg_ranges[] = {
+	regmap_reg_range(BQ25703_CHARGE_OPTION_0, BQ25703_IIN_HOST),
+	regmap_reg_range(BQ25703_CHARGER_STATUS, BQ25703_ADC_OPTION),
+};
+
+static const struct regmap_access_table bq25703_volatile_regs = {
+	.yes_ranges = bq25703_volatile_reg_ranges,
+	.n_yes_ranges = ARRAY_SIZE(bq25703_volatile_reg_ranges),
+};
+
+static const struct regmap_config bq25703_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.max_register = BQ25703_ADC_OPTION,
+	.cache_type = REGCACHE_RBTREE,
+	.wr_table = &bq25703_writeable_regs,
+	.volatile_table = &bq25703_volatile_regs,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
+static int bq257xx_probe(struct i2c_client *client)
+{
+	struct bq257xx_device *ddata;
+	static const struct mfd_cell cells[] = {
+		MFD_CELL_NAME("bq257xx-regulator"),
+		MFD_CELL_NAME("bq257xx-charger"),
+	};
+	int ret;
+
+	ddata = devm_kzalloc(&client->dev, sizeof(*ddata), GFP_KERNEL);
+	if (!ddata)
+		return -ENOMEM;
+
+	ddata->client = client;
+	ddata->regmap = devm_regmap_init_i2c(client, &bq25703_regmap_config);
+	if (IS_ERR(ddata->regmap)) {
+		return dev_err_probe(&client->dev, PTR_ERR(ddata->regmap),
+				     "Failed to allocate register map\n");
+	}
+
+	i2c_set_clientdata(client, ddata);
+
+	ret = devm_mfd_add_devices(&client->dev, PLATFORM_DEVID_AUTO,
+				   cells, ARRAY_SIZE(cells), NULL, 0, NULL);
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to register child devices\n");
+
+	return ret;
+}
+
+static const struct i2c_device_id bq257xx_i2c_ids[] = {
+	{ "bq25703a" },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, bq257xx_i2c_ids);
+
+static const struct of_device_id bq257xx_of_match[] = {
+	{ .compatible = "ti,bq25703a" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, bq257xx_of_match);
+
+static struct i2c_driver bq257xx_driver = {
+	.driver = {
+		.name = "bq257xx",
+		.of_match_table = bq257xx_of_match,
+	},
+	.probe = bq257xx_probe,
+	.id_table = bq257xx_i2c_ids,
+};
+module_i2c_driver(bq257xx_driver);
+
+MODULE_DESCRIPTION("bq257xx buck/boost/charger driver");
+MODULE_AUTHOR("Chris Morgan <macromorgan@hotmail.com>");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/bq257xx.h b/include/linux/mfd/bq257xx.h
new file mode 100644
index 000000000000..1d6ddc7fb09f
--- /dev/null
+++ b/include/linux/mfd/bq257xx.h
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Register definitions for TI BQ257XX
+ * Copyright (C) 2020 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+#define BQ25703_CHARGE_OPTION_0			0x00
+#define BQ25703_CHARGE_CURRENT			0x02
+#define BQ25703_MAX_CHARGE_VOLT			0x04
+#define BQ25703_OTG_VOLT			0x06
+#define BQ25703_OTG_CURRENT			0x08
+#define BQ25703_INPUT_VOLTAGE			0x0a
+#define BQ25703_MIN_VSYS			0x0c
+#define BQ25703_IIN_HOST			0x0e
+#define BQ25703_CHARGER_STATUS			0x20
+#define BQ25703_PROCHOT_STATUS			0x22
+#define BQ25703_IIN_DPM				0x24
+#define BQ25703_ADCIBAT_CHG			0x28
+#define BQ25703_ADCIINCMPIN			0x2a
+#define BQ25703_ADCVSYSVBAT			0x2c
+#define BQ25703_MANUFACT_DEV_ID			0x2e
+#define BQ25703_CHARGE_OPTION_1			0x30
+#define BQ25703_CHARGE_OPTION_2			0x32
+#define BQ25703_CHARGE_OPTION_3			0x34
+#define BQ25703_ADC_OPTION			0x3a
+
+#define BQ25703_EN_LWPWR			BIT(15)
+#define BQ25703_WDTMR_ADJ_MASK			GENMASK(14, 13)
+#define BQ25703_WDTMR_DISABLE			0
+#define BQ25703_WDTMR_5_SEC			1
+#define BQ25703_WDTMR_88_SEC			2
+#define BQ25703_WDTMR_175_SEC			3
+
+#define BQ25703_ICHG_MASK			GENMASK(12, 6)
+#define BQ25703_ICHG_STEP_UA			64000
+#define BQ25703_ICHG_MIN_UA			64000
+#define BQ25703_ICHG_MAX_UA			8128000
+
+#define BQ25703_MAX_CHARGE_VOLT_MASK		GENMASK(15, 4)
+#define BQ25703_VBATREG_STEP_UV			16000
+#define BQ25703_VBATREG_MIN_UV			1024000
+#define BQ25703_VBATREG_MAX_UV			19200000
+
+#define BQ25703_OTG_VOLT_MASK			GENMASK(13, 6)
+#define BQ25703_OTG_VOLT_STEP_UV		64000
+#define BQ25703_OTG_VOLT_MIN_UV			4480000
+#define BQ25703_OTG_VOLT_MAX_UV			20800000
+#define BQ25703_OTG_VOLT_NUM_VOLT		256
+
+#define BQ25703_OTG_CUR_MASK			GENMASK(14, 8)
+#define BQ25703_OTG_CUR_STEP_UA			50000
+#define BQ25703_OTG_CUR_MAX_UA			6350000
+
+#define BQ25703_MINVSYS_MASK			GENMASK(13, 8)
+#define BQ25703_MINVSYS_STEP_UV			256000
+#define BQ25703_MINVSYS_MIN_UV			1024000
+#define BQ25703_MINVSYS_MAX_UV			16128000
+
+#define BQ25703_STS_AC_STAT			BIT(15)
+#define BQ25703_STS_IN_FCHRG			BIT(10)
+#define BQ25703_STS_IN_PCHRG			BIT(9)
+#define BQ25703_STS_FAULT_ACOV			BIT(7)
+#define BQ25703_STS_FAULT_BATOC			BIT(6)
+#define BQ25703_STS_FAULT_ACOC			BIT(5)
+
+#define BQ25703_IINDPM_MASK			GENMASK(14, 8)
+#define BQ25703_IINDPM_STEP_UA			50000
+#define BQ25703_IINDPM_MIN_UA			50000
+#define BQ25703_IINDPM_MAX_UA			6400000
+#define BQ25703_IINDPM_DEFAULT_UA		3300000
+#define BQ25703_IINDPM_OFFSET_UA		50000
+
+#define BQ25703_ADCIBAT_DISCHG_MASK		GENMASK(6, 0)
+#define BQ25703_ADCIBAT_CHG_MASK		GENMASK(14, 8)
+#define BQ25703_ADCIBAT_CHG_STEP_UA		64000
+#define BQ25703_ADCIBAT_DIS_STEP_UA		256000
+
+#define BQ25703_ADCIIN				GENMASK(15, 8)
+#define BQ25703_ADCIINCMPIN_STEP		50000
+
+#define BQ25703_ADCVSYS_MASK			GENMASK(15, 8)
+#define BQ25703_ADCVBAT_MASK			GENMASK(7, 0)
+#define BQ25703_ADCVSYSVBAT_OFFSET_UV		2880000
+#define BQ25703_ADCVSYSVBAT_STEP		64000
+
+#define BQ25703_ADC_CH_MASK			GENMASK(7, 0)
+#define BQ25703_ADC_CONV_EN			BIT(15)
+#define BQ25703_ADC_START			BIT(14)
+#define BQ25703_ADC_FULL_SCALE			BIT(13)
+#define BQ25703_ADC_CMPIN_EN			BIT(7)
+#define BQ25703_ADC_VBUS_EN			BIT(6)
+#define BQ25703_ADC_PSYS_EN			BIT(5)
+#define BQ25703_ADC_IIN_EN			BIT(4)
+#define BQ25703_ADC_IDCHG_EN			BIT(3)
+#define BQ25703_ADC_ICHG_EN			BIT(2)
+#define BQ25703_ADC_VSYS_EN			BIT(1)
+#define BQ25703_ADC_VBAT_EN			BIT(0)
+
+#define BQ25703_EN_OTG_MASK			BIT(12)
+
+struct bq257xx_device {
+	struct i2c_client *client;
+	struct regmap *regmap;
+};
-- 
2.43.0