drivers/iio/pressure/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  */
  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
  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
  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");