mfd: bq257xx: Add support for BQ25703A core driver

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

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

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
Link: https://lore.kernel.org/r/20250904160530.66178-3-macroalpha82@gmail.com
Signed-off-by: Lee Jones <lee@kernel.org>

3 files changed, 111 insertions, 0 deletions

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..e9d49dac0a16
--- /dev/null
+++ b/drivers/mfd/bq257xx.c
@@ -0,0 +1,99 @@
+// 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_MAPLE,
+	.wr_table = &bq25703_writeable_regs,
+	.volatile_table = &bq25703_volatile_regs,
+	.val_format_endian = REGMAP_ENDIAN_LITTLE,
+};
+
+static const struct mfd_cell cells[] = {
+	MFD_CELL_NAME("bq257xx-regulator"),
+	MFD_CELL_NAME("bq257xx-charger"),
+};
+
+static int bq257xx_probe(struct i2c_client *client)
+{
+	struct bq257xx_device *ddata;
+	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");