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 */
21 static 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 .cache_type = REGCACHE_NONE,
30 };
31
zpa2326_probe_spi(struct spi_device * spi)32 static int zpa2326_probe_spi(struct spi_device *spi)
33 {
34 struct regmap *regmap;
35 int err;
36
37 regmap = devm_regmap_init_spi(spi, &zpa2326_regmap_spi_config);
38 if (IS_ERR(regmap)) {
39 dev_err(&spi->dev, "failed to init registers map");
40 return PTR_ERR(regmap);
41 }
42
43 /*
44 * Enforce SPI slave settings to prevent from DT misconfiguration.
45 *
46 * Clock is idle high. Sampling happens on trailing edge, i.e., rising
47 * edge. Maximum bus frequency is 1 MHz. Registers are 8 bits wide.
48 */
49 spi->mode = SPI_MODE_3;
50 spi->max_speed_hz = min(spi->max_speed_hz, 1000000U);
51 spi->bits_per_word = 8;
52 err = spi_setup(spi);
53 if (err < 0)
54 return err;
55
56 return zpa2326_probe(&spi->dev, spi_get_device_id(spi)->name,
57 spi->irq, ZPA2326_DEVICE_ID, regmap);
58 }
59
zpa2326_remove_spi(struct spi_device * spi)60 static int zpa2326_remove_spi(struct spi_device *spi)
61 {
62 zpa2326_remove(&spi->dev);
63
64 return 0;
65 }
66
67 static const struct spi_device_id zpa2326_spi_ids[] = {
68 { "zpa2326", 0 },
69 { },
70 };
71 MODULE_DEVICE_TABLE(spi, zpa2326_spi_ids);
72
73 static const struct of_device_id zpa2326_spi_matches[] = {
74 { .compatible = "murata,zpa2326" },
75 { }
76 };
77 MODULE_DEVICE_TABLE(of, zpa2326_spi_matches);
78
79 static struct spi_driver zpa2326_spi_driver = {
80 .driver = {
81 .name = "zpa2326-spi",
82 .of_match_table = zpa2326_spi_matches,
83 .pm = ZPA2326_PM_OPS,
84 },
85 .probe = zpa2326_probe_spi,
86 .remove = zpa2326_remove_spi,
87 .id_table = zpa2326_spi_ids,
88 };
89 module_spi_driver(zpa2326_spi_driver);
90
91 MODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>");
92 MODULE_DESCRIPTION("SPI driver for Murata ZPA2326 pressure sensor");
93 MODULE_LICENSE("GPL v2");
94