text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * Maxim MAX77714 Core Driver
   *
   * Copyright (C) 2022 Luca Ceresoli
   * Author: Luca Ceresoli <luca@lucaceresoli.net>
   */
  
  #include <linux/i2c.h>
  #include <linux/interrupt.h>
  #include <linux/mfd/core.h>
  #include <linux/mfd/max77714.h>
  #include <linux/module.h>
  #include <linux/of.h>
  #include <linux/regmap.h>
  
  static const struct mfd_cell max77714_cells[] = {
  	{ .name = "max77714-watchdog" },
  	{ .name = "max77714-rtc" },
  };
  
  static const struct regmap_range max77714_readable_ranges[] = {
  	regmap_reg_range(MAX77714_INT_TOP,     MAX77714_INT_TOP),
  	regmap_reg_range(MAX77714_INT_TOPM,    MAX77714_INT_TOPM),
  	regmap_reg_range(MAX77714_32K_STATUS,  MAX77714_32K_CONFIG),
  	regmap_reg_range(MAX77714_CNFG_GLBL2,  MAX77714_CNFG2_ONOFF),
  };
  
  static const struct regmap_range max77714_writable_ranges[] = {
  	regmap_reg_range(MAX77714_INT_TOPM,    MAX77714_INT_TOPM),
  	regmap_reg_range(MAX77714_32K_CONFIG,  MAX77714_32K_CONFIG),
  	regmap_reg_range(MAX77714_CNFG_GLBL2,  MAX77714_CNFG2_ONOFF),
  };
  
  static const struct regmap_access_table max77714_readable_table = {
  	.yes_ranges = max77714_readable_ranges,
  	.n_yes_ranges = ARRAY_SIZE(max77714_readable_ranges),
  };
  
  static const struct regmap_access_table max77714_writable_table = {
  	.yes_ranges = max77714_writable_ranges,
  	.n_yes_ranges = ARRAY_SIZE(max77714_writable_ranges),
  };
  
  static const struct regmap_config max77714_regmap_config = {
  	.reg_bits = 8,
  	.val_bits = 8,
  	.max_register = MAX77714_CNFG2_ONOFF,
  	.rd_table = &max77714_readable_table,
  	.wr_table = &max77714_writable_table,
  };
  
  static const struct regmap_irq max77714_top_irqs[] = {
  	REGMAP_IRQ_REG(MAX77714_IRQ_TOP_ONOFF,   0, MAX77714_INT_TOP_ONOFF),
  	REGMAP_IRQ_REG(MAX77714_IRQ_TOP_RTC,     0, MAX77714_INT_TOP_RTC),
  	REGMAP_IRQ_REG(MAX77714_IRQ_TOP_GPIO,    0, MAX77714_INT_TOP_GPIO),
  	REGMAP_IRQ_REG(MAX77714_IRQ_TOP_LDO,     0, MAX77714_INT_TOP_LDO),
  	REGMAP_IRQ_REG(MAX77714_IRQ_TOP_SD,      0, MAX77714_INT_TOP_SD),
  	REGMAP_IRQ_REG(MAX77714_IRQ_TOP_GLBL,    0, MAX77714_INT_TOP_GLBL),
  };
  
  static const struct regmap_irq_chip max77714_irq_chip = {
  	.name			= "max77714-pmic",
  	.status_base		= MAX77714_INT_TOP,
  	.mask_base		= MAX77714_INT_TOPM,
  	.num_regs		= 1,
  	.irqs			= max77714_top_irqs,
  	.num_irqs		= ARRAY_SIZE(max77714_top_irqs),
  };
  
  /*
   * MAX77714 initially uses the internal, low precision oscillator. Enable
   * the external oscillator by setting the XOSC_RETRY bit. If the external
   * oscillator is not OK (probably not installed) this has no effect.
   */
  static int max77714_setup_xosc(struct device *dev, struct regmap *regmap)
  {
  	/* Internal Crystal Load Capacitance, indexed by value of 32KLOAD bits */
  	static const unsigned int load_cap[4] = {0, 10, 12, 22}; /* pF */
  	unsigned int load_cap_idx;
  	unsigned int status;
  	int err;
  
  	err = regmap_update_bits(regmap, MAX77714_32K_CONFIG,
  				 MAX77714_32K_CONFIG_XOSC_RETRY,
  				 MAX77714_32K_CONFIG_XOSC_RETRY);
  	if (err)
  		return dev_err_probe(dev, err, "Failed to configure the external oscillator\n");
  
  	err = regmap_read(regmap, MAX77714_32K_STATUS, &status);
  	if (err)
  		return dev_err_probe(dev, err, "Failed to read external oscillator status\n");
  
  	load_cap_idx = (status >> MAX77714_32K_STATUS_32KLOAD_SHF)
  		& MAX77714_32K_STATUS_32KLOAD_MSK;
  
  	dev_info(dev, "Using %s oscillator, %d pF load cap\n",
  		 status & MAX77714_32K_STATUS_32KSOURCE ? "internal" : "external",
  		 load_cap[load_cap_idx]);
  
  	return 0;
  }
  
  static int max77714_probe(struct i2c_client *client)
  {
  	struct device *dev = &client->dev;
  	struct regmap *regmap;
  	struct regmap_irq_chip_data *irq_data;
  	int err;
  
  	regmap = devm_regmap_init_i2c(client, &max77714_regmap_config);
  	if (IS_ERR(regmap))
  		return dev_err_probe(dev, PTR_ERR(regmap),
  				     "Failed to initialise regmap\n");
  
  	err = max77714_setup_xosc(dev, regmap);
  	if (err)
  		return err;
  
  	err = devm_regmap_add_irq_chip(dev, regmap, client->irq,
  				       IRQF_ONESHOT | IRQF_SHARED, 0,
  				       &max77714_irq_chip, &irq_data);
  	if (err)
  		return dev_err_probe(dev, err, "Failed to add PMIC IRQ chip\n");
  
  	err =  devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
  				    max77714_cells, ARRAY_SIZE(max77714_cells),
  				    NULL, 0, NULL);
  	if (err)
  		return dev_err_probe(dev, err, "Failed to register child devices\n");
  
  	return 0;
  }
  
  static const struct of_device_id max77714_dt_match[] = {
  	{ .compatible = "maxim,max77714" },
  	{},
  };
  MODULE_DEVICE_TABLE(of, max77714_dt_match);
  
  static struct i2c_driver max77714_driver = {
  	.driver = {
  		.name = "max77714",
  		.of_match_table = max77714_dt_match,
  	},
  	.probe_new = max77714_probe,
  };
  module_i2c_driver(max77714_driver);
  
  MODULE_DESCRIPTION("Maxim MAX77714 MFD core driver");
  MODULE_AUTHOR("Luca Ceresoli <luca@lucaceresoli.net>");
  MODULE_LICENSE("GPL");
  