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 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
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#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
147static int __init stmpe_init(void)
148{
149	return spi_register_driver(&stmpe_spi_driver);
150}
151subsys_initcall(stmpe_init);
152
153static void __exit stmpe_exit(void)
154{
155	spi_unregister_driver(&stmpe_spi_driver);
156}
157module_exit(stmpe_exit);
158
159MODULE_LICENSE("GPL v2");
160MODULE_DESCRIPTION("STMPE MFD SPI Interface Driver");
161MODULE_AUTHOR("Viresh Kumar <vireshk@kernel.org>");