1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Simple MFD - I2C 4 * 5 * Author(s): 6 * Michael Walle <michael@walle.cc> 7 * Lee Jones <lee.jones@linaro.org> 8 * 9 * This driver creates a single register map with the intention for it to be 10 * shared by all sub-devices. Children can use their parent's device structure 11 * (dev.parent) in order to reference it. 12 * 13 * Once the register map has been successfully initialised, any sub-devices 14 * represented by child nodes in Device Tree or via the MFD cells in this file 15 * will be subsequently registered. 16 */ 17 18 #include <linux/i2c.h> 19 #include <linux/kernel.h> 20 #include <linux/mfd/core.h> 21 #include <linux/module.h> 22 #include <linux/of_platform.h> 23 #include <linux/regmap.h> 24 25 #include "simple-mfd-i2c.h" 26 27 static const struct regmap_config regmap_config_8r_8v = { 28 .reg_bits = 8, 29 .val_bits = 8, 30 }; 31 32 static int simple_mfd_i2c_probe(struct i2c_client *i2c) 33 { 34 const struct simple_mfd_data *simple_mfd_data; 35 const struct regmap_config *regmap_config; 36 struct regmap *regmap; 37 int ret; 38 39 simple_mfd_data = device_get_match_data(&i2c->dev); 40 41 /* If no regmap_config is specified, use the default 8reg and 8val bits */ 42 if (!simple_mfd_data || !simple_mfd_data->regmap_config) 43 regmap_config = ®map_config_8r_8v; 44 else 45 regmap_config = simple_mfd_data->regmap_config; 46 47 regmap = devm_regmap_init_i2c(i2c, regmap_config); 48 if (IS_ERR(regmap)) 49 return PTR_ERR(regmap); 50 51 /* If no MFD cells are spedified, use register the DT child nodes instead */ 52 if (!simple_mfd_data || !simple_mfd_data->mfd_cell) 53 return devm_of_platform_populate(&i2c->dev); 54 55 ret = devm_mfd_add_devices(&i2c->dev, PLATFORM_DEVID_AUTO, 56 simple_mfd_data->mfd_cell, 57 simple_mfd_data->mfd_cell_size, 58 NULL, 0, NULL); 59 if (ret) 60 dev_err(&i2c->dev, "Failed to add child devices\n"); 61 62 return ret; 63 } 64 65 static const struct of_device_id simple_mfd_i2c_of_match[] = { 66 { .compatible = "kontron,sl28cpld" }, 67 {} 68 }; 69 MODULE_DEVICE_TABLE(of, simple_mfd_i2c_of_match); 70 71 static struct i2c_driver simple_mfd_i2c_driver = { 72 .probe_new = simple_mfd_i2c_probe, 73 .driver = { 74 .name = "simple-mfd-i2c", 75 .of_match_table = simple_mfd_i2c_of_match, 76 }, 77 }; 78 module_i2c_driver(simple_mfd_i2c_driver); 79 80 MODULE_AUTHOR("Michael Walle <michael@walle.cc>"); 81 MODULE_DESCRIPTION("Simple MFD - I2C driver"); 82 MODULE_LICENSE("GPL v2"); 83