iio: imu: inv_icm42600: add I2C driver for inv_icm42600 driver

Add I2C driver for InvenSense ICM-426xxx devices.

Configure bus signal slew rates as indicated in the datasheet.
Signed-off-by: Jean-Baptiste Maneyrol <jmaneyrol@invensense.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/inv_icm42600/inv_icm42600_i2c.c

+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2020 InvenSense, Inc.
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/i2c.h>
+#include <linux/regmap.h>
+#include <linux/property.h>
+
+#include "inv_icm42600.h"
+
+static int inv_icm42600_i2c_bus_setup(struct inv_icm42600_state *st)
+{
+	unsigned int mask, val;
+	int ret;
+
+	/* setup interface registers */
+	ret = regmap_update_bits(st->map, INV_ICM42600_REG_INTF_CONFIG6,
+				 INV_ICM42600_INTF_CONFIG6_MASK,
+				 INV_ICM42600_INTF_CONFIG6_I3C_EN);
+	if (ret)
+		return ret;
+
+	ret = regmap_update_bits(st->map, INV_ICM42600_REG_INTF_CONFIG4,
+				 INV_ICM42600_INTF_CONFIG4_I3C_BUS_ONLY, 0);
+	if (ret)
+		return ret;
+
+	/* set slew rates for I2C and SPI */
+	mask = INV_ICM42600_DRIVE_CONFIG_I2C_MASK |
+	       INV_ICM42600_DRIVE_CONFIG_SPI_MASK;
+	val = INV_ICM42600_DRIVE_CONFIG_I2C(INV_ICM42600_SLEW_RATE_12_36NS) |
+	      INV_ICM42600_DRIVE_CONFIG_SPI(INV_ICM42600_SLEW_RATE_12_36NS);
+	ret = regmap_update_bits(st->map, INV_ICM42600_REG_DRIVE_CONFIG,
+				 mask, val);
+	if (ret)
+		return ret;
+
+	/* disable SPI bus */
+	return regmap_update_bits(st->map, INV_ICM42600_REG_INTF_CONFIG0,
+				  INV_ICM42600_INTF_CONFIG0_UI_SIFS_CFG_MASK,
+				  INV_ICM42600_INTF_CONFIG0_UI_SIFS_CFG_SPI_DIS);
+}
+
+static int inv_icm42600_probe(struct i2c_client *client)
+{
+	const void *match;
+	enum inv_icm42600_chip chip;
+	struct regmap *regmap;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
+		return -ENOTSUPP;
+
+	match = device_get_match_data(&client->dev);
+	if (!match)
+		return -EINVAL;
+	chip = (enum inv_icm42600_chip)match;
+
+	regmap = devm_regmap_init_i2c(client, &inv_icm42600_regmap_config);
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+
+	return inv_icm42600_core_probe(regmap, chip, inv_icm42600_i2c_bus_setup);
+}
+
+static const struct of_device_id inv_icm42600_of_matches[] = {
+	{
+		.compatible = "invensense,icm42600",
+		.data = (void *)INV_CHIP_ICM42600,
+	}, {
+		.compatible = "invensense,icm42602",
+		.data = (void *)INV_CHIP_ICM42602,
+	}, {
+		.compatible = "invensense,icm42605",
+		.data = (void *)INV_CHIP_ICM42605,
+	}, {
+		.compatible = "invensense,icm42622",
+		.data = (void *)INV_CHIP_ICM42622,
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, inv_icm42600_of_matches);
+
+static struct i2c_driver inv_icm42600_driver = {
+	.driver = {
+		.name = "inv-icm42600-i2c",
+		.of_match_table = inv_icm42600_of_matches,
+		.pm = &inv_icm42600_pm_ops,
+	},
+	.probe_new = inv_icm42600_probe,
+};
+module_i2c_driver(inv_icm42600_driver);
+
+MODULE_AUTHOR("InvenSense, Inc.");
+MODULE_DESCRIPTION("InvenSense ICM-426xx I2C driver");
+MODULE_LICENSE("GPL");