drivers/input/misc/adxl34x-spi.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * ADLX345/346 Three-Axis Digital Accelerometers (SPI Interface)
   4  *
   5  * Enter bugs at http://blackfin.uclinux.org/
   6  *
   7  * Copyright (C) 2009 Michael Hennerich, Analog Devices Inc.
   8  */
   9
  10 #include <linux/input.h>        /* BUS_SPI */
  11 #include <linux/module.h>
  12 #include <linux/spi/spi.h>
  13 #include <linux/pm.h>
  14 #include <linux/types.h>
  15 #include "adxl34x.h"
  16
  17 #define MAX_SPI_FREQ_HZ         5000000
  18 #define MAX_FREQ_NO_FIFODELAY   1500000
  19 #define ADXL34X_CMD_MULTB       (1 << 6)
  20 #define ADXL34X_CMD_READ        (1 << 7)
  21 #define ADXL34X_WRITECMD(reg)   (reg & 0x3F)
  22 #define ADXL34X_READCMD(reg)    (ADXL34X_CMD_READ | (reg & 0x3F))
  23 #define ADXL34X_READMB_CMD(reg) (ADXL34X_CMD_READ | ADXL34X_CMD_MULTB \
  24                                         | (reg & 0x3F))
  25
  26 static int adxl34x_spi_read(struct device *dev, unsigned char reg)
  27 {
  28         struct spi_device *spi = to_spi_device(dev);
  29         unsigned char cmd;
  30
  31         cmd = ADXL34X_READCMD(reg);
  32
  33         return spi_w8r8(spi, cmd);
  34 }
  35
  36 static int adxl34x_spi_write(struct device *dev,
  37                              unsigned char reg, unsigned char val)
  38 {
  39         struct spi_device *spi = to_spi_device(dev);
  40         unsigned char buf[2];
  41
  42         buf[0] = ADXL34X_WRITECMD(reg);
  43         buf[1] = val;
  44
  45         return spi_write(spi, buf, sizeof(buf));
  46 }
  47
  48 static int adxl34x_spi_read_block(struct device *dev,
  49                                   unsigned char reg, int count,
  50                                   void *buf)
  51 {
  52         struct spi_device *spi = to_spi_device(dev);
  53         ssize_t status;
  54
  55         reg = ADXL34X_READMB_CMD(reg);
  56         status = spi_write_then_read(spi, &reg, 1, buf, count);
  57
  58         return (status < 0) ? status : 0;
  59 }
  60
  61 static const struct adxl34x_bus_ops adxl34x_spi_bops = {
  62         .bustype        = BUS_SPI,
  63         .write          = adxl34x_spi_write,
  64         .read           = adxl34x_spi_read,
  65         .read_block     = adxl34x_spi_read_block,
  66 };
  67
  68 static int adxl34x_spi_probe(struct spi_device *spi)
  69 {
  70         struct adxl34x *ac;
  71
  72         /* don't exceed max specified SPI CLK frequency */
  73         if (spi->max_speed_hz > MAX_SPI_FREQ_HZ) {
  74                 dev_err(&spi->dev, "SPI CLK %d Hz too fast\n", spi->max_speed_hz);
  75                 return -EINVAL;
  76         }
  77
  78         ac = adxl34x_probe(&spi->dev, spi->irq,
  79                            spi->max_speed_hz > MAX_FREQ_NO_FIFODELAY,
  80                            &adxl34x_spi_bops);
  81
  82         if (IS_ERR(ac))
  83                 return PTR_ERR(ac);
  84
  85         spi_set_drvdata(spi, ac);
  86
  87         return 0;
  88 }
  89
  90 static struct spi_driver adxl34x_driver = {
  91         .driver = {
  92                 .name = "adxl34x",
  93                 .dev_groups = adxl34x_groups,
  94                 .pm = pm_sleep_ptr(&adxl34x_pm),
  95         },
  96         .probe   = adxl34x_spi_probe,
  97 };
  98
  99 module_spi_driver(adxl34x_driver);
 100
 101 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 102 MODULE_DESCRIPTION("ADXL345/346 Three-Axis Digital Accelerometer SPI Bus Driver");
 103 MODULE_LICENSE("GPL");