// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Core driver for STw4810/STw4811
   *
   * Copyright (C) 2013 ST-Ericsson SA
   * Written on behalf of Linaro for ST-Ericsson
   *
   * Author: Linus Walleij <linus.walleij@linaro.org>

   */
  
  #include <linux/err.h>
  #include <linux/i2c.h>
  #include <linux/init.h>
  #include <linux/mfd/core.h>
  #include <linux/mfd/stw481x.h>
  #include <linux/module.h>
  #include <linux/regmap.h>
  #include <linux/spinlock.h>
  #include <linux/slab.h>
  
  /*
   * This driver can only access the non-USB portions of STw4811, the register
   * range 0x00-0x10 dealing with USB is bound to the two special I2C pins used
   * for USB control.
   */
  
  /* Registers inside the power control address space */
  #define STW_PC_VCORE_SEL	0x05U
  #define STW_PC_VAUX_SEL		0x06U
  #define STW_PC_VPLL_SEL		0x07U
  
  /**
   * stw481x_get_pctl_reg() - get a power control register
   * @stw481x: handle to the stw481x chip
   * @reg: power control register to fetch
   *
   * The power control registers is a set of one-time-programmable registers
   * in its own register space, accessed by writing addess bits to these
   * two registers: bits 7,6,5 of PCTL_REG_LO corresponds to the 3 LSBs of
   * the address and bits 8,9 of PCTL_REG_HI corresponds to the 2 MSBs of
   * the address, forming an address space of 5 bits, i.e. 32 registers
   * 0x00 ... 0x1f can be obtained.
   */
  static int stw481x_get_pctl_reg(struct stw481x *stw481x, u8 reg)
  {
  	u8 msb = (reg >> 3) & 0x03;
  	u8 lsb = (reg << 5) & 0xe0;
  	unsigned int val;
  	u8 vrfy;
  	int ret;
  
  	ret = regmap_write(stw481x->map, STW_PCTL_REG_HI, msb);
  	if (ret)
  		return ret;
  	ret = regmap_write(stw481x->map, STW_PCTL_REG_LO, lsb);
  	if (ret)
  		return ret;
  	ret = regmap_read(stw481x->map, STW_PCTL_REG_HI, &val);
  	if (ret)
  		return ret;
  	vrfy = (val & 0x03) << 3;
  	ret = regmap_read(stw481x->map, STW_PCTL_REG_LO, &val);
  	if (ret)
  		return ret;
  	vrfy |= ((val >> 5) & 0x07);
  	if (vrfy != reg)
  		return -EIO;
  	return (val >> 1) & 0x0f;
  }
  
  static int stw481x_startup(struct stw481x *stw481x)
  {
  	/* Voltages multiplied by 100 */

  	static const u8 vcore_val[] = {
  		100, 105, 110, 115, 120, 122, 124, 126, 128,
  		130, 132, 134, 136, 138, 140, 145
  	};
  	static const u8 vpll_val[] = { 105, 120, 130, 180 };
  	static const u8 vaux_val[] = { 15, 18, 25, 28 };

  	u8 vcore;
  	u8 vcore_slp;
  	u8 vpll;
  	u8 vaux;
  	bool vaux_en;
  	bool it_warn;
  	int ret;
  	unsigned int val;
  
  	ret = regmap_read(stw481x->map, STW_CONF1, &val);
  	if (ret)
  		return ret;
  	vaux_en = !!(val & STW_CONF1_PDN_VAUX);
  	it_warn = !!(val & STW_CONF1_IT_WARN);
  
  	dev_info(&stw481x->client->dev, "voltages %s
  ",
  		(val & STW_CONF1_V_MONITORING) ? "OK" : "LOW");
  	dev_info(&stw481x->client->dev, "MMC level shifter %s
  ",
  		(val & STW_CONF1_MMC_LS_STATUS) ? "high impedance" : "ON");
  	dev_info(&stw481x->client->dev, "VMMC: %s
  ",
  		(val & STW_CONF1_PDN_VMMC) ? "ON" : "disabled");
  
  	dev_info(&stw481x->client->dev, "STw481x power control registers:
  ");
  
  	ret = stw481x_get_pctl_reg(stw481x, STW_PC_VCORE_SEL);
  	if (ret < 0)
  		return ret;
  	vcore = ret & 0x0f;
  
  	ret = stw481x_get_pctl_reg(stw481x, STW_PC_VAUX_SEL);
  	if (ret < 0)
  		return ret;
  	vaux = (ret >> 2) & 3;
  	vpll = (ret >> 4) & 1; /* Save bit 4 */
  
  	ret = stw481x_get_pctl_reg(stw481x, STW_PC_VPLL_SEL);
  	if (ret < 0)
  		return ret;
  	vpll |= (ret >> 1) & 2;
  
  	dev_info(&stw481x->client->dev, "VCORE: %u.%uV %s
  ",
  		vcore_val[vcore] / 100, vcore_val[vcore] % 100,
  		(ret & 4) ? "ON" : "OFF");
  
  	dev_info(&stw481x->client->dev, "VPLL:  %u.%uV %s
  ",
  		vpll_val[vpll] / 100, vpll_val[vpll] % 100,
  		(ret & 0x10) ? "ON" : "OFF");
  
  	dev_info(&stw481x->client->dev, "VAUX:  %u.%uV %s
  ",
  		vaux_val[vaux] / 10, vaux_val[vaux] % 10,
  		vaux_en ? "ON" : "OFF");
  
  	ret = regmap_read(stw481x->map, STW_CONF2, &val);
  	if (ret)
  		return ret;
  
  	dev_info(&stw481x->client->dev, "TWARN: %s threshold, %s
  ",
  		it_warn ? "below" : "above",
  		(val & STW_CONF2_MASK_TWARN) ?
  		 "enabled" : "mask through VDDOK");
  	dev_info(&stw481x->client->dev, "VMMC: %s
  ",
  		(val & STW_CONF2_VMMC_EXT) ? "internal" : "external");
  	dev_info(&stw481x->client->dev, "IT WAKE UP: %s
  ",
  		(val & STW_CONF2_MASK_IT_WAKE_UP) ? "enabled" : "masked");
  	dev_info(&stw481x->client->dev, "GPO1: %s
  ",
  		(val & STW_CONF2_GPO1) ? "low" : "high impedance");
  	dev_info(&stw481x->client->dev, "GPO2: %s
  ",
  		(val & STW_CONF2_GPO2) ? "low" : "high impedance");
  
  	ret = regmap_read(stw481x->map, STW_VCORE_SLEEP, &val);
  	if (ret)
  		return ret;
  	vcore_slp = val & 0x0f;
  	dev_info(&stw481x->client->dev, "VCORE SLEEP: %u.%uV
  ",
  		vcore_val[vcore_slp] / 100, vcore_val[vcore_slp] % 100);
  
  	return 0;
  }
  
  /*
   * MFD cells - we have one cell which is selected operation
   * mode, and we always have a GPIO cell.
   */
  static struct mfd_cell stw481x_cells[] = {
  	{
  		.of_compatible = "st,stw481x-vmmc",
  		.name = "stw481x-vmmc-regulator",
  		.id = -1,
  	},
  };

  static const struct regmap_config stw481x_regmap_config = {

  	.reg_bits = 8,
  	.val_bits = 8,
  };
  
  static int stw481x_probe(struct i2c_client *client,
  			 const struct i2c_device_id *id)
  {
  	struct stw481x			*stw481x;
  	int ret;
  	int i;
  
  	stw481x = devm_kzalloc(&client->dev, sizeof(*stw481x), GFP_KERNEL);
  	if (!stw481x)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, stw481x);
  	stw481x->client = client;
  	stw481x->map = devm_regmap_init_i2c(client, &stw481x_regmap_config);

  	if (IS_ERR(stw481x->map)) {
  		ret = PTR_ERR(stw481x->map);
  		dev_err(&client->dev, "Failed to allocate register map: %d
  ",
  			ret);
  		return ret;
  	}

  
  	ret = stw481x_startup(stw481x);
  	if (ret) {
  		dev_err(&client->dev, "chip initialization failed
  ");
  		return ret;
  	}
  
  	/* Set up and register the platform devices. */
  	for (i = 0; i < ARRAY_SIZE(stw481x_cells); i++) {
  		/* One state holder for all drivers, this is simple */
  		stw481x_cells[i].platform_data = stw481x;
  		stw481x_cells[i].pdata_size = sizeof(*stw481x);
  	}

  	ret = devm_mfd_add_devices(&client->dev, 0, stw481x_cells,
  				   ARRAY_SIZE(stw481x_cells), NULL, 0, NULL);

  	if (ret)
  		return ret;
  
  	dev_info(&client->dev, "initialized STw481x device
  ");
  
  	return ret;
  }

  /*
   * This ID table is completely unused, as this is a pure
   * device-tree probed driver, but it has to be here due to
   * the structure of the I2C core.
   */
  static const struct i2c_device_id stw481x_id[] = {
  	{ "stw481x", 0 },
  	{ },
  };

  MODULE_DEVICE_TABLE(i2c, stw481x_id);

  
  static const struct of_device_id stw481x_match[] = {
  	{ .compatible = "st,stw4810", },
  	{ .compatible = "st,stw4811", },
  	{ },
  };
  MODULE_DEVICE_TABLE(of, stw481x_match);
  
  static struct i2c_driver stw481x_driver = {
  	.driver = {
  		.name	= "stw481x",
  		.of_match_table = stw481x_match,
  	},
  	.probe		= stw481x_probe,

  	.id_table	= stw481x_id,
  };
  
  module_i2c_driver(stw481x_driver);
  
  MODULE_AUTHOR("Linus Walleij");
  MODULE_DESCRIPTION("STw481x PMIC driver");
  MODULE_LICENSE("GPL v2");