1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * AD714X CapTouch Programmable Controller driver (SPI bus)
  4 *
  5 * Copyright 2009-2011 Analog Devices Inc.
  6 */
  7
  8#include <linux/input.h>	/* BUS_SPI */
  9#include <linux/module.h>
 10#include <linux/spi/spi.h>
 11#include <linux/pm.h>
 12#include <linux/types.h>
 13#include "ad714x.h"
 14
 15#define AD714x_SPI_CMD_PREFIX      0xE000   /* bits 15:11 */
 16#define AD714x_SPI_READ            BIT(10)
 17
 18static int __maybe_unused ad714x_spi_suspend(struct device *dev)
 19{
 20	return ad714x_disable(spi_get_drvdata(to_spi_device(dev)));
 21}
 22
 23static int __maybe_unused ad714x_spi_resume(struct device *dev)
 24{
 25	return ad714x_enable(spi_get_drvdata(to_spi_device(dev)));
 26}
 27
 28static SIMPLE_DEV_PM_OPS(ad714x_spi_pm, ad714x_spi_suspend, ad714x_spi_resume);
 29
 30static int ad714x_spi_read(struct ad714x_chip *chip,
 31			   unsigned short reg, unsigned short *data, size_t len)
 32{
 33	struct spi_device *spi = to_spi_device(chip->dev);
 34	struct spi_message message;
 35	struct spi_transfer xfer[2];
 36	int i;
 37	int error;
 38
 39	spi_message_init(&message);
 40	memset(xfer, 0, sizeof(xfer));
 41
 42	chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX |
 43					AD714x_SPI_READ | reg);
 44	xfer[0].tx_buf = &chip->xfer_buf[0];
 45	xfer[0].len = sizeof(chip->xfer_buf[0]);
 46	spi_message_add_tail(&xfer[0], &message);
 47
 48	xfer[1].rx_buf = &chip->xfer_buf[1];
 49	xfer[1].len = sizeof(chip->xfer_buf[1]) * len;
 50	spi_message_add_tail(&xfer[1], &message);
 51
 52	error = spi_sync(spi, &message);
 53	if (unlikely(error)) {
 54		dev_err(chip->dev, "SPI read error: %d\n", error);
 55		return error;
 56	}
 57
 58	for (i = 0; i < len; i++)
 59		data[i] = be16_to_cpu(chip->xfer_buf[i + 1]);
 60
 61	return 0;
 62}
 63
 64static int ad714x_spi_write(struct ad714x_chip *chip,
 65			    unsigned short reg, unsigned short data)
 66{
 67	struct spi_device *spi = to_spi_device(chip->dev);
 68	int error;
 69
 70	chip->xfer_buf[0] = cpu_to_be16(AD714x_SPI_CMD_PREFIX | reg);
 71	chip->xfer_buf[1] = cpu_to_be16(data);
 72
 73	error = spi_write(spi, (u8 *)chip->xfer_buf,
 74			  2 * sizeof(*chip->xfer_buf));
 75	if (unlikely(error)) {
 76		dev_err(chip->dev, "SPI write error: %d\n", error);
 77		return error;
 78	}
 79
 80	return 0;
 81}
 82
 83static int ad714x_spi_probe(struct spi_device *spi)
 84{
 85	struct ad714x_chip *chip;
 86	int err;
 87
 88	spi->bits_per_word = 8;
 89	err = spi_setup(spi);
 90	if (err < 0)
 91		return err;
 92
 93	chip = ad714x_probe(&spi->dev, BUS_SPI, spi->irq,
 94			    ad714x_spi_read, ad714x_spi_write);
 95	if (IS_ERR(chip))
 96		return PTR_ERR(chip);
 97
 98	spi_set_drvdata(spi, chip);
 99
100	return 0;
101}
102
103static struct spi_driver ad714x_spi_driver = {
104	.driver = {
105		.name	= "ad714x_captouch",
106		.pm	= &ad714x_spi_pm,
107	},
108	.probe		= ad714x_spi_probe,
109};
110
111module_spi_driver(ad714x_spi_driver);
112
113MODULE_DESCRIPTION("Analog Devices AD714X Capacitance Touch Sensor SPI Bus Driver");
114MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
115MODULE_LICENSE("GPL");