1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ST Microelectronics MFD: stmpe's spi client specific driver
4 *
5 * Copyright (C) ST Microelectronics SA 2011
6 *
7 * Author: Viresh Kumar <vireshk@kernel.org> for ST Microelectronics
8 */
9
10 #include <linux/spi/spi.h>
11 #include <linux/interrupt.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/of.h>
15 #include <linux/types.h>
16 #include "stmpe.h"
17
18 #define READ_CMD (1 << 7)
19
spi_reg_read(struct stmpe * stmpe,u8 reg)20 static int spi_reg_read(struct stmpe *stmpe, u8 reg)
21 {
22 struct spi_device *spi = stmpe->client;
23 int status = spi_w8r16(spi, reg | READ_CMD);
24
25 return (status < 0) ? status : status >> 8;
26 }
27
spi_reg_write(struct stmpe * stmpe,u8 reg,u8 val)28 static int spi_reg_write(struct stmpe *stmpe, u8 reg, u8 val)
29 {
30 struct spi_device *spi = stmpe->client;
31 u16 cmd = (val << 8) | reg;
32
33 return spi_write(spi, (const u8 *)&cmd, 2);
34 }
35
spi_block_read(struct stmpe * stmpe,u8 reg,u8 length,u8 * values)36 static int spi_block_read(struct stmpe *stmpe, u8 reg, u8 length, u8 *values)
37 {
38 int ret, i;
39
40 for (i = 0; i < length; i++) {
41 ret = spi_reg_read(stmpe, reg + i);
42 if (ret < 0)
43 return ret;
44 *(values + i) = ret;
45 }
46
47 return 0;
48 }
49
spi_block_write(struct stmpe * stmpe,u8 reg,u8 length,const u8 * values)50 static int spi_block_write(struct stmpe *stmpe, u8 reg, u8 length,
51 const u8 *values)
52 {
53 int ret = 0, i;
54
55 for (i = length; i > 0; i--, reg++) {
56 ret = spi_reg_write(stmpe, reg, *(values + i - 1));
57 if (ret < 0)
58 return ret;
59 }
60
61 return ret;
62 }
63
spi_init(struct stmpe * stmpe)64 static void spi_init(struct stmpe *stmpe)
65 {
66 struct spi_device *spi = stmpe->client;
67
68 spi->bits_per_word = 8;
69
70 /* This register is only present for stmpe811 */
71 if (stmpe->variant->id_val == 0x0811)
72 spi_reg_write(stmpe, STMPE811_REG_SPI_CFG, spi->mode);
73
74 if (spi_setup(spi) < 0)
75 dev_dbg(&spi->dev, "spi_setup failed\n");
76 }
77
78 static struct stmpe_client_info spi_ci = {
79 .read_byte = spi_reg_read,
80 .write_byte = spi_reg_write,
81 .read_block = spi_block_read,
82 .write_block = spi_block_write,
83 .init = spi_init,
84 };
85
86 static int
stmpe_spi_probe(struct spi_device * spi)87 stmpe_spi_probe(struct spi_device *spi)
88 {
89 const struct spi_device_id *id = spi_get_device_id(spi);
90
91 /* don't exceed max specified rate - 1MHz - Limitation of STMPE */
92 if (spi->max_speed_hz > 1000000) {
93 dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
94 (spi->max_speed_hz/1000));
95 return -EINVAL;
96 }
97
98 spi_ci.irq = spi->irq;
99 spi_ci.client = spi;
100 spi_ci.dev = &spi->dev;
101
102 return stmpe_probe(&spi_ci, id->driver_data);
103 }
104
stmpe_spi_remove(struct spi_device * spi)105 static int stmpe_spi_remove(struct spi_device *spi)
106 {
107 struct stmpe *stmpe = spi_get_drvdata(spi);
108
109 return stmpe_remove(stmpe);
110 }
111
112 static const struct of_device_id stmpe_spi_of_match[] = {
113 { .compatible = "st,stmpe610", },
114 { .compatible = "st,stmpe801", },
115 { .compatible = "st,stmpe811", },
116 { .compatible = "st,stmpe1601", },
117 { .compatible = "st,stmpe2401", },
118 { .compatible = "st,stmpe2403", },
119 { /* sentinel */ },
120 };
121 MODULE_DEVICE_TABLE(of, stmpe_spi_of_match);
122
123 static const struct spi_device_id stmpe_spi_id[] = {
124 { "stmpe610", STMPE610 },
125 { "stmpe801", STMPE801 },
126 { "stmpe811", STMPE811 },
127 { "stmpe1601", STMPE1601 },
128 { "stmpe2401", STMPE2401 },
129 { "stmpe2403", STMPE2403 },
130 { }
131 };
132 MODULE_DEVICE_TABLE(spi, stmpe_id);
133
134 static struct spi_driver stmpe_spi_driver = {
135 .driver = {
136 .name = "stmpe-spi",
137 .of_match_table = of_match_ptr(stmpe_spi_of_match),
138 #ifdef CONFIG_PM
139 .pm = &stmpe_dev_pm_ops,
140 #endif
141 },
142 .probe = stmpe_spi_probe,
143 .remove = stmpe_spi_remove,
144 .id_table = stmpe_spi_id,
145 };
146
stmpe_init(void)147 static int __init stmpe_init(void)
148 {
149 return spi_register_driver(&stmpe_spi_driver);
150 }
151 subsys_initcall(stmpe_init);
152
stmpe_exit(void)153 static void __exit stmpe_exit(void)
154 {
155 spi_unregister_driver(&stmpe_spi_driver);
156 }
157 module_exit(stmpe_exit);
158
159 MODULE_LICENSE("GPL v2");
160 MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
161 MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
162