Gregor Boirie | 03b262f | 2016-09-13 14:23:14 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Murata ZPA2326 SPI pressure and temperature sensor driver |
| 3 | * |
| 4 | * Copyright (c) 2016 Parrot S.A. |
| 5 | * |
| 6 | * Author: Gregor Boirie <gregor.boirie@parrot.com> |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or modify it |
| 9 | * under the terms of the GNU General Public License version 2 as published by |
| 10 | * the Free Software Foundation. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, but WITHOUT |
| 13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
| 15 | * more details. |
| 16 | */ |
| 17 | |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/regmap.h> |
| 20 | #include <linux/spi/spi.h> |
| 21 | #include <linux/of_device.h> |
| 22 | #include "zpa2326.h" |
| 23 | |
| 24 | /* |
| 25 | * read_flag_mask: |
| 26 | * - address bit 7 must be set to request a register read operation |
| 27 | * - address bit 6 must be set to request register address auto increment |
| 28 | */ |
| 29 | static const struct regmap_config zpa2326_regmap_spi_config = { |
| 30 | .reg_bits = 8, |
| 31 | .val_bits = 8, |
| 32 | .writeable_reg = zpa2326_isreg_writeable, |
| 33 | .readable_reg = zpa2326_isreg_readable, |
| 34 | .precious_reg = zpa2326_isreg_precious, |
| 35 | .max_register = ZPA2326_TEMP_OUT_H_REG, |
| 36 | .read_flag_mask = BIT(7) | BIT(6), |
| 37 | .cache_type = REGCACHE_NONE, |
| 38 | }; |
| 39 | |
| 40 | static int zpa2326_probe_spi(struct spi_device *spi) |
| 41 | { |
| 42 | struct regmap *regmap; |
| 43 | int err; |
| 44 | |
| 45 | regmap = devm_regmap_init_spi(spi, &zpa2326_regmap_spi_config); |
| 46 | if (IS_ERR(regmap)) { |
| 47 | dev_err(&spi->dev, "failed to init registers map"); |
| 48 | return PTR_ERR(regmap); |
| 49 | } |
| 50 | |
| 51 | /* |
| 52 | * Enforce SPI slave settings to prevent from DT misconfiguration. |
| 53 | * |
| 54 | * Clock is idle high. Sampling happens on trailing edge, i.e., rising |
| 55 | * edge. Maximum bus frequency is 1 MHz. Registers are 8 bits wide. |
| 56 | */ |
| 57 | spi->mode = SPI_MODE_3; |
| 58 | spi->max_speed_hz = min(spi->max_speed_hz, 1000000U); |
| 59 | spi->bits_per_word = 8; |
| 60 | err = spi_setup(spi); |
| 61 | if (err < 0) |
| 62 | return err; |
| 63 | |
| 64 | return zpa2326_probe(&spi->dev, spi_get_device_id(spi)->name, |
| 65 | spi->irq, ZPA2326_DEVICE_ID, regmap); |
| 66 | } |
| 67 | |
| 68 | static int zpa2326_remove_spi(struct spi_device *spi) |
| 69 | { |
| 70 | zpa2326_remove(&spi->dev); |
| 71 | |
| 72 | return 0; |
| 73 | } |
| 74 | |
| 75 | static const struct spi_device_id zpa2326_spi_ids[] = { |
| 76 | { "zpa2326", 0 }, |
| 77 | { }, |
| 78 | }; |
| 79 | MODULE_DEVICE_TABLE(spi, zpa2326_spi_ids); |
| 80 | |
| 81 | #if defined(CONFIG_OF) |
| 82 | static const struct of_device_id zpa2326_spi_matches[] = { |
| 83 | { .compatible = "murata,zpa2326" }, |
| 84 | { } |
| 85 | }; |
| 86 | MODULE_DEVICE_TABLE(of, zpa2326_spi_matches); |
| 87 | #endif |
| 88 | |
| 89 | static struct spi_driver zpa2326_spi_driver = { |
| 90 | .driver = { |
| 91 | .name = "zpa2326-spi", |
| 92 | .of_match_table = of_match_ptr(zpa2326_spi_matches), |
| 93 | .pm = ZPA2326_PM_OPS, |
| 94 | }, |
| 95 | .probe = zpa2326_probe_spi, |
| 96 | .remove = zpa2326_remove_spi, |
| 97 | .id_table = zpa2326_spi_ids, |
| 98 | }; |
| 99 | module_spi_driver(zpa2326_spi_driver); |
| 100 | |
| 101 | MODULE_AUTHOR("Gregor Boirie <gregor.boirie@parrot.com>"); |
| 102 | MODULE_DESCRIPTION("SPI driver for Murata ZPA2326 pressure sensor"); |
| 103 | MODULE_LICENSE("GPL v2"); |