linux/drivers/mfd/rohm-bd96801.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2024 ROHM Semiconductors
 *
 * ROHM BD96801 PMIC driver
 *
 * This version of the "BD86801 scalable PMIC"'s driver supports only very
 * basic set of the PMIC features. Most notably, there is no support for
 * the ERRB interrupt and the configurations which should be done when the
 * PMIC is in STBY mode.
 *
 * Supporting the ERRB interrupt would require dropping the regmap-IRQ
 * usage or working around (or accepting a presense of) a naming conflict
 * in debugFS IRQs.
 *
 * Being able to reliably do the configurations like changing the
 * regulator safety limits (like limits for the over/under -voltages, over
 * current, thermal protection) would require the configuring driver to be
 * synchronized with entity causing the PMIC state transitions. Eg, one
 * should be able to ensure the PMIC is in STBY state when the
 * configurations are applied to the hardware. How and when the PMIC state
 * transitions are to be done is likely to be very system specific, as will
 * be the need to configure these safety limits. Hence it's not simple to
 * come up with a generic solution.
 *
 * Users who require the ERRB handling and STBY state configurations can
 * have a look at the original RFC:
 * https://lore.kernel.org/all/[email protected]/
 * which implements a workaround to debugFS naming conflict and some of
 * the safety limit configurations - but leaves the state change handling
 * and synchronization to be implemented.
 *
 * It would be great to hear (and receive a patch!) if you implement the
 * STBY configuration support or a proper fix to the debugFS naming
 * conflict in your downstream driver ;)
 */

#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/types.h>

#include <linux/mfd/rohm-bd96801.h>
#include <linux/mfd/rohm-generic.h>

static const struct resource regulator_intb_irqs[] = …;

static const struct resource wdg_intb_irqs[] = …;

static struct mfd_cell bd96801_cells[] = …;

static const struct regmap_range bd96801_volatile_ranges[] = …;

static const struct regmap_access_table volatile_regs = …;

static const struct regmap_irq bd96801_intb_irqs[] = …;

static struct regmap_irq_chip bd96801_irq_chip_intb = …;

static const struct regmap_config bd96801_regmap_config = …;

static int bd96801_i2c_probe(struct i2c_client *i2c)
{ … }

static const struct of_device_id bd96801_of_match[] = …;
MODULE_DEVICE_TABLE(of, bd96801_of_match);

static struct i2c_driver bd96801_i2c_driver = …;

static int __init bd96801_i2c_init(void)
{ … }

/* Initialise early so consumer devices can complete system boot */
subsys_initcall(bd96801_i2c_init);

static void __exit bd96801_i2c_exit(void)
{ … }
module_exit(bd96801_i2c_exit);

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;