zpa2326_spi.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Murata ZPA2326 SPI pressure and temperature sensor driver
 4 *
 5 * Copyright (c) 2016 Parrot S.A.
 6 *
 7 * Author: Gregor Boirie <gregor.boirie@parrot.com>
 8 */
 9
10#include <linux/module.h>
11#include <linux/regmap.h>
12#include <linux/spi/spi.h>
13#include <linux/mod_devicetable.h>
14#include "zpa2326.h"
15
16/*
17 * read_flag_mask:
18 *   - address bit 7 must be set to request a register read operation
19 *   - address bit 6 must be set to request register address auto increment
20 */
21static const struct regmap_config zpa2326_regmap_spi_config = {
22	.reg_bits       = 8,
23	.val_bits       = 8,
24	.writeable_reg  = zpa2326_isreg_writeable,
25	.readable_reg   = zpa2326_isreg_readable,
26	.precious_reg   = zpa2326_isreg_precious,
27	.max_register   = ZPA2326_TEMP_OUT_H_REG,
28	.read_flag_mask = BIT(7) | BIT(6),
29};
30
31static int zpa2326_probe_spi(struct spi_device *spi)
32{
33	struct regmap *regmap;
34	int            err;
35
36	regmap = devm_regmap_init_spi(spi, &zpa2326_regmap_spi_config);
37	if (IS_ERR(regmap)) {
38		dev_err(&spi->dev, "failed to init registers map");
39		return PTR_ERR(regmap);
40	}
41
42	/*
43	 * Enforce SPI slave settings to prevent from DT misconfiguration.
44	 *
45	 * Clock is idle high. Sampling happens on trailing edge, i.e., rising
46	 * edge. Maximum bus frequency is 1 MHz. Registers are 8 bits wide.
47	 */
48	spi->mode = SPI_MODE_3;
49	spi->max_speed_hz = min(spi->max_speed_hz, 1000000U);
50	err = spi_setup(spi);
51	if (err < 0)
52		return err;
53
54	return zpa2326_probe(&spi->dev, spi_get_device_id(spi)->name,
55			     spi->irq, ZPA2326_DEVICE_ID, regmap);
56}
57
58static void zpa2326_remove_spi(struct spi_device *spi)
59{
60	zpa2326_remove(&spi->dev);
61}
62
63static const struct spi_device_id zpa2326_spi_ids[] = {
64	{ "zpa2326", 0 },
65	{ }
66};
67MODULE_DEVICE_TABLE(spi, zpa2326_spi_ids);
68
69static const struct of_device_id zpa2326_spi_matches[] = {
70	{ .compatible = "murata,zpa2326" },
71	{ }
72};
73MODULE_DEVICE_TABLE(of, zpa2326_spi_matches);
74
75static struct spi_driver zpa2326_spi_driver = {
76	.driver = {
77		.name           = "zpa2326-spi",
78		.of_match_table = zpa2326_spi_matches,
79		.pm             = ZPA2326_PM_OPS,
80	},
81	.probe    = zpa2326_probe_spi,
82	.remove   = zpa2326_remove_spi,
83	.id_table = zpa2326_spi_ids,
84};
85module_spi_driver(zpa2326_spi_driver);
86
87MODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>");
88MODULE_DESCRIPTION("SPI driver for Murata ZPA2326 pressure sensor");
89MODULE_LICENSE("GPL v2");
90MODULE_IMPORT_NS("IIO_ZPA2326");