/*
 * Motorola CPCAP PMIC core driver
 *
 * Copyright (C) 2016 Tony Lindgren <tony@atomide.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/regmap.h>
#include <linux/sysfs.h>

#include <linux/mfd/motorola-cpcap.h>
#include <linux/spi/spi.h>

#define CPCAP_NR_IRQ_REG_BANKS	6
#define CPCAP_NR_IRQ_CHIPS	3
#define CPCAP_REGISTER_SIZE	4
#define CPCAP_REGISTER_BITS	16

struct cpcap_ddata {
	struct spi_device *spi;
	struct regmap_irq *irqs;
	struct regmap_irq_chip_data *irqdata[CPCAP_NR_IRQ_CHIPS];
	const struct regmap_config *regmap_conf;
	struct regmap *regmap;
};

static int cpcap_sense_irq(struct regmap *regmap, int irq)
{
	int regnum = irq / CPCAP_REGISTER_BITS;
	int mask = BIT(irq % CPCAP_REGISTER_BITS);
	int reg = CPCAP_REG_INTS1 + (regnum * CPCAP_REGISTER_SIZE);
	int err, val;

	if (reg < CPCAP_REG_INTS1 || reg > CPCAP_REG_INTS4)
		return -EINVAL;

	err = regmap_read(regmap, reg, &val);
	if (err)
		return err;

	return !!(val & mask);
}

int cpcap_sense_virq(struct regmap *regmap, int virq)
{
	struct regmap_irq_chip_data *d = irq_get_chip_data(virq);
	int irq_base = regmap_irq_chip_get_base(d);

	return cpcap_sense_irq(regmap, virq - irq_base);
}
EXPORT_SYMBOL_GPL(cpcap_sense_virq);

static int cpcap_check_revision(struct cpcap_ddata *cpcap)
{
	u16 vendor, rev;
	int ret;

	ret = cpcap_get_vendor(&cpcap->spi->dev, cpcap->regmap, &vendor);
	if (ret)
		return ret;

	ret = cpcap_get_revision(&cpcap->spi->dev, cpcap->regmap, &rev);
	if (ret)
		return ret;

	dev_info(&cpcap->spi->dev, "CPCAP vendor: %s rev: %i.%i (%x)\n",
		 vendor == CPCAP_VENDOR_ST ? "ST" : "TI",
		 CPCAP_REVISION_MAJOR(rev), CPCAP_REVISION_MINOR(rev),
		 rev);

	if (rev < CPCAP_REVISION_2_1) {
		dev_info(&cpcap->spi->dev,
			 "Please add old CPCAP revision support as needed\n");
		return -ENODEV;
	}

	return 0;
}

/*
 * First two irq chips are the two private macro interrupt chips, the third
 * irq chip is for register banks 1 - 4 and is available for drivers to use.
 */
static struct regmap_irq_chip cpcap_irq_chip[CPCAP_NR_IRQ_CHIPS] = {
	{
		.name = "cpcap-m2",
		.num_regs = 1,
		.status_base = CPCAP_REG_MI1,
		.ack_base = CPCAP_REG_MI1,
		.mask_base = CPCAP_REG_MIM1,
		.use_ack = true,
		.ack_invert = true,
	},
	{
		.name = "cpcap-m2",
		.num_regs = 1,
		.status_base = CPCAP_REG_MI2,
		.ack_base = CPCAP_REG_MI2,
		.mask_base = CPCAP_REG_MIM2,
		.use_ack = true,
		.ack_invert = true,
	},
	{
		.name = "cpcap1-4",
		.num_regs = 4,
		.status_base = CPCAP_REG_INT1,
		.ack_base = CPCAP_REG_INT1,
		.mask_base = CPCAP_REG_INTM1,
		.use_ack = true,
		.ack_invert = true,
	},
};

static void cpcap_init_one_regmap_irq(struct cpcap_ddata *cpcap,
				      struct regmap_irq *rirq,
				      int irq_base, int irq)
{
	unsigned int reg_offset;
	unsigned int bit, mask;

	reg_offset = irq - irq_base;
	reg_offset /= cpcap->regmap_conf->val_bits;
	reg_offset *= cpcap->regmap_conf->reg_stride;

	bit = irq % cpcap->regmap_conf->val_bits;
	mask = (1 << bit);

	rirq->reg_offset = reg_offset;
	rirq->mask = mask;
}

static int cpcap_init_irq_chip(struct cpcap_ddata *cpcap, int irq_chip,
			       int irq_start, int nr_irqs)
{
	struct regmap_irq_chip *chip = &cpcap_irq_chip[irq_chip];
	int i, ret;

	for (i = irq_start; i < irq_start + nr_irqs; i++) {
		struct regmap_irq *rirq = &cpcap->irqs[i];

		cpcap_init_one_regmap_irq(cpcap, rirq, irq_start, i);
	}
	chip->irqs = &cpcap->irqs[irq_start];
	chip->num_irqs = nr_irqs;
	chip->irq_drv_data = cpcap;

	ret = devm_regmap_add_irq_chip(&cpcap->spi->dev, cpcap->regmap,
				       cpcap->spi->irq,
				       irq_get_trigger_type(cpcap->spi->irq) |
				       IRQF_SHARED, -1,
				       chip, &cpcap->irqdata[irq_chip]);
	if (ret) {
		dev_err(&cpcap->spi->dev, "could not add irq chip %i: %i\n",
			irq_chip, ret);
		return ret;
	}

	return 0;
}

static int cpcap_init_irq(struct cpcap_ddata *cpcap)
{
	int ret;

	cpcap->irqs = devm_kzalloc(&cpcap->spi->dev,
				   sizeof(*cpcap->irqs) *
				   CPCAP_NR_IRQ_REG_BANKS *
				   cpcap->regmap_conf->val_bits,
				   GFP_KERNEL);
	if (!cpcap->irqs)
		return -ENOMEM;

	ret = cpcap_init_irq_chip(cpcap, 0, 0, 16);
	if (ret)
		return ret;

	ret = cpcap_init_irq_chip(cpcap, 1, 16, 16);
	if (ret)
		return ret;

	ret = cpcap_init_irq_chip(cpcap, 2, 32, 64);
	if (ret)
		return ret;

	enable_irq_wake(cpcap->spi->irq);

	return 0;
}

static const struct of_device_id cpcap_of_match[] = {
	{ .compatible = "motorola,cpcap", },
	{ .compatible = "st,6556002", },
	{},
};
MODULE_DEVICE_TABLE(of, cpcap_of_match);

static const struct regmap_config cpcap_regmap_config = {
	.reg_bits = 16,
	.reg_stride = 4,
	.pad_bits = 0,
	.val_bits = 16,
	.write_flag_mask = 0x8000,
	.max_register = CPCAP_REG_ST_TEST2,
	.cache_type = REGCACHE_NONE,
	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
	.val_format_endian = REGMAP_ENDIAN_LITTLE,
};

static int cpcap_probe(struct spi_device *spi)
{
	const struct of_device_id *match;
	struct cpcap_ddata *cpcap;
	int ret;

	match = of_match_device(of_match_ptr(cpcap_of_match), &spi->dev);
	if (!match)
		return -ENODEV;

	cpcap = devm_kzalloc(&spi->dev, sizeof(*cpcap), GFP_KERNEL);
	if (!cpcap)
		return -ENOMEM;

	cpcap->spi = spi;
	spi_set_drvdata(spi, cpcap);

	spi->bits_per_word = 16;
	spi->mode = SPI_MODE_0 | SPI_CS_HIGH;

	ret = spi_setup(spi);
	if (ret)
		return ret;

	cpcap->regmap_conf = &cpcap_regmap_config;
	cpcap->regmap = devm_regmap_init_spi(spi, &cpcap_regmap_config);
	if (IS_ERR(cpcap->regmap)) {
		ret = PTR_ERR(cpcap->regmap);
		dev_err(&cpcap->spi->dev, "Failed to initialize regmap: %d\n",
			ret);

		return ret;
	}

	ret = cpcap_check_revision(cpcap);
	if (ret) {
		dev_err(&cpcap->spi->dev, "Failed to detect CPCAP: %i\n", ret);
		return ret;
	}

	ret = cpcap_init_irq(cpcap);
	if (ret)
		return ret;

	return devm_of_platform_populate(&cpcap->spi->dev);
}

static struct spi_driver cpcap_driver = {
	.driver = {
		.name = "cpcap-core",
		.of_match_table = cpcap_of_match,
	},
	.probe = cpcap_probe,
};
module_spi_driver(cpcap_driver);

MODULE_ALIAS("platform:cpcap");
MODULE_DESCRIPTION("CPCAP driver");
MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
MODULE_LICENSE("GPL v2");