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
20 static bool enable_crc;
21 module_param(enable_crc, bool, 0444);
22 MODULE_PARM_DESC(enable_crc, "Enable CRC feature for SPI interface");
23
24 DECLARE_CRC8_TABLE(tps6594_spi_crc_table);
25
tps6594_spi_reg_read(void * context,unsigned int reg,unsigned int * val)26 static 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
tps6594_spi_reg_write(void * context,unsigned int reg,unsigned int val)52 static 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
69 static 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
80 static 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 };
86 MODULE_DEVICE_TABLE(of, tps6594_spi_of_match_table);
87
tps6594_spi_probe(struct spi_device * spi)88 static 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->chip_select;
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
118 static 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 };
125 module_spi_driver(tps6594_spi_driver);
126
127 MODULE_AUTHOR("Julien Panis <jpanis@baylibre.com>");
128 MODULE_DESCRIPTION("TPS6594 SPI Interface Driver");
129 MODULE_LICENSE("GPL");
130