xref: /kernel/linux/linux-6.6/drivers/mfd/stmpe-spi.c (revision 62306a36) 
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
20static 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
28static 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
36static 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
50static 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
64static 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
78static 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
86static int
87stmpe_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
105static void stmpe_spi_remove(struct spi_device *spi)
106{
107	struct stmpe *stmpe = spi_get_drvdata(spi);
108
109	stmpe_remove(stmpe);
110}
111
112static 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};
121MODULE_DEVICE_TABLE(of, stmpe_spi_of_match);
122
123static 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};
132MODULE_DEVICE_TABLE(spi, stmpe_id);
133
134static 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
145static int __init stmpe_init(void)
146{
147	return spi_register_driver(&stmpe_spi_driver);
148}
149subsys_initcall(stmpe_init);
150
151static void __exit stmpe_exit(void)
152{
153	spi_unregister_driver(&stmpe_spi_driver);
154}
155module_exit(stmpe_exit);
156
157MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
158MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");
159