xref: /openbmc/linux/drivers/mfd/stmpe-spi.c (revision 9ca834bd)
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 void stmpe_spi_remove(struct spi_device *spi)
106 {
107 	struct stmpe *stmpe = spi_get_drvdata(spi);
108 
109 	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 		.pm	= pm_sleep_ptr(&stmpe_dev_pm_ops),
139 	},
140 	.probe		= stmpe_spi_probe,
141 	.remove		= stmpe_spi_remove,
142 	.id_table	= stmpe_spi_id,
143 };
144 
stmpe_init(void)145 static int __init stmpe_init(void)
146 {
147 	return spi_register_driver(&stmpe_spi_driver);
148 }
149 subsys_initcall(stmpe_init);
150 
stmpe_exit(void)151 static void __exit stmpe_exit(void)
152 {
153 	spi_unregister_driver(&stmpe_spi_driver);
154 }
155 module_exit(stmpe_exit);
156 
157 MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
158 MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
159