1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * SPI access driver for TI TPS6594/TPS6593/LP8764 PMICs
  4 *
  5 * Copyright (C) 2023 BayLibre Incorporated - https://www.baylibre.com/
  6 */
  7
  8#include <linux/crc8.h>
  9#include <linux/module.h>
 10#include <linux/mod_devicetable.h>
 11#include <linux/of_device.h>
 12#include <linux/regmap.h>
 13#include <linux/spi/spi.h>
 14
 15#include <linux/mfd/tps6594.h>
 16
 17#define TPS6594_SPI_PAGE_SHIFT	5
 18#define TPS6594_SPI_READ_BIT	BIT(4)
 19
 20static bool enable_crc;
 21module_param(enable_crc, bool, 0444);
 22MODULE_PARM_DESC(enable_crc, "Enable CRC feature for SPI interface");
 23
 24DECLARE_CRC8_TABLE(tps6594_spi_crc_table);
 25
 26static int tps6594_spi_reg_read(void *context, unsigned int reg, unsigned int *val)
 27{
 28	struct spi_device *spi = context;
 29	struct tps6594 *tps = spi_get_drvdata(spi);
 30	u8 buf[4] = { 0 };
 31	size_t count_rx = 1;
 32	int ret;
 33
 34	buf[0] = reg;
 35	buf[1] = TPS6594_REG_TO_PAGE(reg) << TPS6594_SPI_PAGE_SHIFT | TPS6594_SPI_READ_BIT;
 36
 37	if (tps->use_crc)
 38		count_rx++;
 39
 40	ret = spi_write_then_read(spi, buf, 2, buf + 2, count_rx);
 41	if (ret < 0)
 42		return ret;
 43
 44	if (tps->use_crc && buf[3] != crc8(tps6594_spi_crc_table, buf, 3, CRC8_INIT_VALUE))
 45		return -EIO;
 46
 47	*val = buf[2];
 48
 49	return 0;
 50}
 51
 52static int tps6594_spi_reg_write(void *context, unsigned int reg, unsigned int val)
 53{
 54	struct spi_device *spi = context;
 55	struct tps6594 *tps = spi_get_drvdata(spi);
 56	u8 buf[4] = { 0 };
 57	size_t count = 3;
 58
 59	buf[0] = reg;
 60	buf[1] = TPS6594_REG_TO_PAGE(reg) << TPS6594_SPI_PAGE_SHIFT;
 61	buf[2] = val;
 62
 63	if (tps->use_crc)
 64		buf[3] = crc8(tps6594_spi_crc_table, buf, count++, CRC8_INIT_VALUE);
 65
 66	return spi_write(spi, buf, count);
 67}
 68
 69static const struct regmap_config tps6594_spi_regmap_config = {
 70	.reg_bits = 16,
 71	.val_bits = 8,
 72	.max_register = TPS6594_REG_DWD_FAIL_CNT_REG,
 73	.volatile_reg = tps6594_is_volatile_reg,
 74	.reg_read = tps6594_spi_reg_read,
 75	.reg_write = tps6594_spi_reg_write,
 76	.use_single_read = true,
 77	.use_single_write = true,
 78};
 79
 80static const struct of_device_id tps6594_spi_of_match_table[] = {
 81	{ .compatible = "ti,tps6594-q1", .data = (void *)TPS6594, },
 82	{ .compatible = "ti,tps6593-q1", .data = (void *)TPS6593, },
 83	{ .compatible = "ti,lp8764-q1",  .data = (void *)LP8764,  },
 84	{}
 85};
 86MODULE_DEVICE_TABLE(of, tps6594_spi_of_match_table);
 87
 88static int tps6594_spi_probe(struct spi_device *spi)
 89{
 90	struct device *dev = &spi->dev;
 91	struct tps6594 *tps;
 92	const struct of_device_id *match;
 93
 94	tps = devm_kzalloc(dev, sizeof(*tps), GFP_KERNEL);
 95	if (!tps)
 96		return -ENOMEM;
 97
 98	spi_set_drvdata(spi, tps);
 99
100	tps->dev = dev;
101	tps->reg = spi_get_chipselect(spi, 0);
102	tps->irq = spi->irq;
103
104	tps->regmap = devm_regmap_init(dev, NULL, spi, &tps6594_spi_regmap_config);
105	if (IS_ERR(tps->regmap))
106		return dev_err_probe(dev, PTR_ERR(tps->regmap), "Failed to init regmap\n");
107
108	match = of_match_device(tps6594_spi_of_match_table, dev);
109	if (!match)
110		return dev_err_probe(dev, -EINVAL, "Failed to find matching chip ID\n");
111	tps->chip_id = (unsigned long)match->data;
112
113	crc8_populate_msb(tps6594_spi_crc_table, TPS6594_CRC8_POLYNOMIAL);
114
115	return tps6594_device_init(tps, enable_crc);
116}
117
118static struct spi_driver tps6594_spi_driver = {
119	.driver	= {
120		.name = "tps6594",
121		.of_match_table = tps6594_spi_of_match_table,
122	},
123	.probe = tps6594_spi_probe,
124};
125module_spi_driver(tps6594_spi_driver);
126
127MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
128MODULE_DESCRIPTION("TPS6594 SPI Interface Driver");
129MODULE_LICENSE("GPL");