drivers/media/i2c/s5c73m3/s5c73m3-spi.c

   1 /*
   2  * Samsung LSI S5C73M3 8M pixel camera driver
   3  *
   4  * Copyright (C) 2012, Samsung Electronics, Co., Ltd.
   5  * Sylwester Nawrocki <s.nawrocki@samsung.com>
   6  * Andrzej Hajda <a.hajda@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU General Public License
  10  * version 2 as published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/sizes.h>
  19 #include <linux/delay.h>
  20 #include <linux/init.h>
  21 #include <linux/media.h>
  22 #include <linux/module.h>
  23 #include <linux/slab.h>
  24 #include <linux/spi/spi.h>
  25
  26 #include "s5c73m3.h"
  27
  28 #define S5C73M3_SPI_DRV_NAME "S5C73M3-SPI"
  29
  30 static const struct of_device_id s5c73m3_spi_ids[] = {
  31         { .compatible = "samsung,s5c73m3" },
  32         { }
  33 };
  34 MODULE_DEVICE_TABLE(of, s5c73m3_spi_ids);
  35
  36 enum spi_direction {
  37         SPI_DIR_RX,
  38         SPI_DIR_TX
  39 };
  40
  41 static int spi_xmit(struct spi_device *spi_dev, void *addr, const int len,
  42                                                         enum spi_direction dir)
  43 {
  44         struct spi_message msg;
  45         int r;
  46         struct spi_transfer xfer = {
  47                 .len    = len,
  48         };
  49
  50         if (dir == SPI_DIR_TX)
  51                 xfer.tx_buf = addr;
  52         else
  53                 xfer.rx_buf = addr;
  54
  55         if (spi_dev == NULL) {
  56                 pr_err("SPI device is uninitialized\n");
  57                 return -ENODEV;
  58         }
  59
  60         spi_message_init(&msg);
  61         spi_message_add_tail(&xfer, &msg);
  62
  63         r = spi_sync(spi_dev, &msg);
  64         if (r < 0)
  65                 dev_err(&spi_dev->dev, "%s spi_sync failed %d\n", __func__, r);
  66
  67         return r;
  68 }
  69
  70 int s5c73m3_spi_write(struct s5c73m3 *state, const void *addr,
  71                       const unsigned int len, const unsigned int tx_size)
  72 {
  73         struct spi_device *spi_dev = state->spi_dev;
  74         u32 count = len / tx_size;
  75         u32 extra = len % tx_size;
  76         unsigned int i, j = 0;
  77         u8 padding[32];
  78         int r = 0;
  79
  80         memset(padding, 0, sizeof(padding));
  81
  82         for (i = 0; i < count; i++) {
  83                 r = spi_xmit(spi_dev, (void *)addr + j, tx_size, SPI_DIR_TX);
  84                 if (r < 0)
  85                         return r;
  86                 j += tx_size;
  87         }
  88
  89         if (extra > 0) {
  90                 r = spi_xmit(spi_dev, (void *)addr + j, extra, SPI_DIR_TX);
  91                 if (r < 0)
  92                         return r;
  93         }
  94
  95         return spi_xmit(spi_dev, padding, sizeof(padding), SPI_DIR_TX);
  96 }
  97
  98 int s5c73m3_spi_read(struct s5c73m3 *state, void *addr,
  99                      const unsigned int len, const unsigned int tx_size)
 100 {
 101         struct spi_device *spi_dev = state->spi_dev;
 102         u32 count = len / tx_size;
 103         u32 extra = len % tx_size;
 104         unsigned int i, j = 0;
 105         int r = 0;
 106
 107         for (i = 0; i < count; i++) {
 108                 r = spi_xmit(spi_dev, addr + j, tx_size, SPI_DIR_RX);
 109                 if (r < 0)
 110                         return r;
 111                 j += tx_size;
 112         }
 113
 114         if (extra > 0)
 115                 return spi_xmit(spi_dev, addr + j, extra, SPI_DIR_RX);
 116
 117         return 0;
 118 }
 119
 120 static int s5c73m3_spi_probe(struct spi_device *spi)
 121 {
 122         int r;
 123         struct s5c73m3 *state = container_of(spi->dev.driver, struct s5c73m3,
 124                                              spidrv.driver);
 125         spi->bits_per_word = 32;
 126
 127         r = spi_setup(spi);
 128         if (r < 0) {
 129                 dev_err(&spi->dev, "spi_setup() failed\n");
 130                 return r;
 131         }
 132
 133         mutex_lock(&state->lock);
 134         state->spi_dev = spi;
 135         mutex_unlock(&state->lock);
 136
 137         v4l2_info(&state->sensor_sd, "S5C73M3 SPI probed successfully\n");
 138         return 0;
 139 }
 140
 141 static int s5c73m3_spi_remove(struct spi_device *spi)
 142 {
 143         return 0;
 144 }
 145
 146 int s5c73m3_register_spi_driver(struct s5c73m3 *state)
 147 {
 148         struct spi_driver *spidrv = &state->spidrv;
 149
 150         spidrv->remove = s5c73m3_spi_remove;
 151         spidrv->probe = s5c73m3_spi_probe;
 152         spidrv->driver.name = S5C73M3_SPI_DRV_NAME;
 153         spidrv->driver.of_match_table = s5c73m3_spi_ids;
 154
 155         return spi_register_driver(spidrv);
 156 }
 157
 158 void s5c73m3_unregister_spi_driver(struct s5c73m3 *state)
 159 {
 160         spi_unregister_driver(&state->spidrv);
 161 }