iio/pressure/zpa2326_spi.c

03b262f2SGregor Boirie/*
03b262f2SGregor Boirie * Murata ZPA2326 SPI pressure and temperature sensor driver
03b262f2SGregor Boirie *
03b262f2SGregor Boirie * Copyright (c) 2016 Parrot S.A.
03b262f2SGregor Boirie *
03b262f2SGregor Boirie * Author: Gregor Boirie <gregor.boirie@parrot.com>
03b262f2SGregor Boirie *
03b262f2SGregor Boirie * This program is free software; you can redistribute it and/or modify it
03b262f2SGregor Boirie * under the terms of the GNU General Public License version 2 as published by
03b262f2SGregor Boirie * the Free Software Foundation.
03b262f2SGregor Boirie *
03b262f2SGregor Boirie * This program is distributed in the hope that it will be useful, but WITHOUT
03b262f2SGregor Boirie * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
03b262f2SGregor Boirie * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
03b262f2SGregor Boirie * more details.
03b262f2SGregor Boirie */
03b262f2SGregor Boirie
03b262f2SGregor Boirie#include <linux/module.h>
03b262f2SGregor Boirie#include <linux/regmap.h>
03b262f2SGregor Boirie#include <linux/spi/spi.h>
03b262f2SGregor Boirie#include <linux/of_device.h>
03b262f2SGregor Boirie#include "zpa2326.h"
03b262f2SGregor Boirie
03b262f2SGregor Boirie/*
03b262f2SGregor Boirie * read_flag_mask:
03b262f2SGregor Boirie *   - address bit 7 must be set to request a register read operation
03b262f2SGregor Boirie *   - address bit 6 must be set to request register address auto increment
03b262f2SGregor Boirie */
03b262f2SGregor Boiriestatic const struct regmap_config zpa2326_regmap_spi_config = {
03b262f2SGregor Boirie	.reg_bits       = 8,
03b262f2SGregor Boirie	.val_bits       = 8,
03b262f2SGregor Boirie	.writeable_reg  = zpa2326_isreg_writeable,
03b262f2SGregor Boirie	.readable_reg   = zpa2326_isreg_readable,
03b262f2SGregor Boirie	.precious_reg   = zpa2326_isreg_precious,
03b262f2SGregor Boirie	.max_register   = ZPA2326_TEMP_OUT_H_REG,
03b262f2SGregor Boirie	.read_flag_mask = BIT(7) | BIT(6),
03b262f2SGregor Boirie	.cache_type     = REGCACHE_NONE,
03b262f2SGregor Boirie};
03b262f2SGregor Boirie
03b262f2SGregor Boiriestatic int zpa2326_probe_spi(struct spi_device *spi)
03b262f2SGregor Boirie{
03b262f2SGregor Boirie	struct regmap *regmap;
03b262f2SGregor Boirie	int            err;
03b262f2SGregor Boirie
03b262f2SGregor Boirie	regmap = devm_regmap_init_spi(spi, &zpa2326_regmap_spi_config);
03b262f2SGregor Boirie	if (IS_ERR(regmap)) {
03b262f2SGregor Boirie		dev_err(&spi->dev, "failed to init registers map");
03b262f2SGregor Boirie		return PTR_ERR(regmap);
03b262f2SGregor Boirie	}
03b262f2SGregor Boirie
03b262f2SGregor Boirie	/*
03b262f2SGregor Boirie	 * Enforce SPI slave settings to prevent from DT misconfiguration.
03b262f2SGregor Boirie	 *
03b262f2SGregor Boirie	 * Clock is idle high. Sampling happens on trailing edge, i.e., rising
03b262f2SGregor Boirie	 * edge. Maximum bus frequency is 1 MHz. Registers are 8 bits wide.
03b262f2SGregor Boirie	 */
03b262f2SGregor Boirie	spi->mode = SPI_MODE_3;
03b262f2SGregor Boirie	spi->max_speed_hz = min(spi->max_speed_hz, 1000000U);
03b262f2SGregor Boirie	spi->bits_per_word = 8;
03b262f2SGregor Boirie	err = spi_setup(spi);
03b262f2SGregor Boirie	if (err < 0)
03b262f2SGregor Boirie		return err;
03b262f2SGregor Boirie
03b262f2SGregor Boirie	return zpa2326_probe(&spi->dev, spi_get_device_id(spi)->name,
03b262f2SGregor Boirie			     spi->irq, ZPA2326_DEVICE_ID, regmap);
03b262f2SGregor Boirie}
03b262f2SGregor Boirie
03b262f2SGregor Boiriestatic int zpa2326_remove_spi(struct spi_device *spi)
03b262f2SGregor Boirie{
03b262f2SGregor Boirie	zpa2326_remove(&spi->dev);
03b262f2SGregor Boirie
03b262f2SGregor Boirie	return 0;
03b262f2SGregor Boirie}
03b262f2SGregor Boirie
03b262f2SGregor Boiriestatic const struct spi_device_id zpa2326_spi_ids[] = {
03b262f2SGregor Boirie	{ "zpa2326", 0 },
03b262f2SGregor Boirie	{ },
03b262f2SGregor Boirie};
03b262f2SGregor BoirieMODULE_DEVICE_TABLE(spi, zpa2326_spi_ids);
03b262f2SGregor Boirie
03b262f2SGregor Boirie#if defined(CONFIG_OF)
03b262f2SGregor Boiriestatic const struct of_device_id zpa2326_spi_matches[] = {
03b262f2SGregor Boirie	{ .compatible = "murata,zpa2326" },
03b262f2SGregor Boirie	{ }
03b262f2SGregor Boirie};
03b262f2SGregor BoirieMODULE_DEVICE_TABLE(of, zpa2326_spi_matches);
03b262f2SGregor Boirie#endif
03b262f2SGregor Boirie
03b262f2SGregor Boiriestatic struct spi_driver zpa2326_spi_driver = {
03b262f2SGregor Boirie	.driver = {
03b262f2SGregor Boirie		.name           = "zpa2326-spi",
03b262f2SGregor Boirie		.of_match_table = of_match_ptr(zpa2326_spi_matches),
03b262f2SGregor Boirie		.pm             = ZPA2326_PM_OPS,
03b262f2SGregor Boirie	},
03b262f2SGregor Boirie	.probe    = zpa2326_probe_spi,
03b262f2SGregor Boirie	.remove   = zpa2326_remove_spi,
03b262f2SGregor Boirie	.id_table = zpa2326_spi_ids,
03b262f2SGregor Boirie};
03b262f2SGregor Boiriemodule_spi_driver(zpa2326_spi_driver);
03b262f2SGregor Boirie
03b262f2SGregor BoirieMODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>");
03b262f2SGregor BoirieMODULE_DESCRIPTION("SPI driver for Murata ZPA2326 pressure sensor");
03b262f2SGregor BoirieMODULE_LICENSE("GPL v2");