adgs1408.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * ADGS1408/ADGS1409 SPI MUX driver
  4 *
  5 * Copyright 2018 Analog Devices Inc.
  6 */
  7
  8#include <linux/err.h>
  9#include <linux/mod_devicetable.h>
 10#include <linux/module.h>
 11#include <linux/mux/driver.h>
 12#include <linux/property.h>
 13#include <linux/spi/spi.h>
 14
 15#define ADGS1408_SW_DATA       (0x01)
 16#define ADGS1408_REG_READ(reg) ((reg) | 0x80)
 17#define ADGS1408_DISABLE       (0x00)
 18#define ADGS1408_MUX(state)    (((state) << 1) | 1)
 19
 20enum adgs1408_chip_id {
 21	ADGS1408 = 1,
 22	ADGS1409,
 23};
 24
 25static int adgs1408_spi_reg_write(struct spi_device *spi,
 26				  u8 reg_addr, u8 reg_data)
 27{
 28	u8 tx_buf[2];
 29
 30	tx_buf[0] = reg_addr;
 31	tx_buf[1] = reg_data;
 32
 33	return spi_write_then_read(spi, tx_buf, sizeof(tx_buf), NULL, 0);
 34}
 35
 36static int adgs1408_set(struct mux_control *mux, int state)
 37{
 38	struct spi_device *spi = to_spi_device(mux->chip->dev.parent);
 39	u8 reg;
 40
 41	if (state == MUX_IDLE_DISCONNECT)
 42		reg = ADGS1408_DISABLE;
 43	else
 44		reg = ADGS1408_MUX(state);
 45
 46	return adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, reg);
 47}
 48
 49static const struct mux_control_ops adgs1408_ops = {
 50	.set = adgs1408_set,
 51};
 52
 53static int adgs1408_probe(struct spi_device *spi)
 54{
 55	struct device *dev = &spi->dev;
 56	enum adgs1408_chip_id chip_id;
 57	struct mux_chip *mux_chip;
 58	struct mux_control *mux;
 59	s32 idle_state;
 60	int ret;
 61
 62	chip_id = (kernel_ulong_t)spi_get_device_match_data(spi);
 63
 64	mux_chip = devm_mux_chip_alloc(dev, 1, 0);
 65	if (IS_ERR(mux_chip))
 66		return PTR_ERR(mux_chip);
 67
 68	mux_chip->ops = &adgs1408_ops;
 69
 70	ret = adgs1408_spi_reg_write(spi, ADGS1408_SW_DATA, ADGS1408_DISABLE);
 71	if (ret < 0)
 72		return ret;
 73
 74	ret = device_property_read_u32(dev, "idle-state", (u32 *)&idle_state);
 75	if (ret < 0)
 76		idle_state = MUX_IDLE_AS_IS;
 77
 78	mux = mux_chip->mux;
 79
 80	if (chip_id == ADGS1408)
 81		mux->states = 8;
 82	else
 83		mux->states = 4;
 84
 85	switch (idle_state) {
 86	case MUX_IDLE_DISCONNECT:
 87	case MUX_IDLE_AS_IS:
 88	case 0 ... 7:
 89		/* adgs1409 supports only 4 states */
 90		if (idle_state < mux->states) {
 91			mux->idle_state = idle_state;
 92			break;
 93		}
 94		fallthrough;
 95	default:
 96		dev_err(dev, "invalid idle-state %d\n", idle_state);
 97		return -EINVAL;
 98	}
 99
100	return devm_mux_chip_register(dev, mux_chip);
101}
102
103static const struct spi_device_id adgs1408_spi_id[] = {
104	{ "adgs1408", ADGS1408 },
105	{ "adgs1409", ADGS1409 },
106	{ }
107};
108MODULE_DEVICE_TABLE(spi, adgs1408_spi_id);
109
110static const struct of_device_id adgs1408_of_match[] = {
111	{ .compatible = "adi,adgs1408", .data = (void *)ADGS1408, },
112	{ .compatible = "adi,adgs1409", .data = (void *)ADGS1409, },
113	{ }
114};
115MODULE_DEVICE_TABLE(of, adgs1408_of_match);
116
117static struct spi_driver adgs1408_driver = {
118	.driver = {
119		.name = "adgs1408",
120		.of_match_table = adgs1408_of_match,
121	},
122	.probe = adgs1408_probe,
123	.id_table = adgs1408_spi_id,
124};
125module_spi_driver(adgs1408_driver);
126
127MODULE_AUTHOR("Mircea Caprioru <mircea.caprioru@analog.com>");
128MODULE_DESCRIPTION("Analog Devices ADGS1408 MUX driver");
129MODULE_LICENSE("GPL");