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");
130