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
  35 enum spi_direction {
  36         SPI_DIR_RX,
  37         SPI_DIR_TX
  38 };
  39
  40 static int spi_xmit(struct spi_device *spi_dev, void *addr, const int len,
  41                                                         enum spi_direction dir)
  42 {
  43         struct spi_message msg;
  44         int r;
  45         struct spi_transfer xfer = {
  46                 .len    = len,
  47         };
  48
  49         if (dir == SPI_DIR_TX)
  50                 xfer.tx_buf = addr;
  51         else
  52                 xfer.rx_buf = addr;
  53
  54         if (spi_dev == NULL) {
  55                 dev_err(&spi_dev->dev, "SPI device is uninitialized\n");
  56                 return -ENODEV;
  57         }
  58
  59         spi_message_init(&msg);
  60         spi_message_add_tail(&xfer, &msg);
  61
  62         r = spi_sync(spi_dev, &msg);
  63         if (r < 0)
  64                 dev_err(&spi_dev->dev, "%s spi_sync failed %d\n", __func__, r);
  65
  66         return r;
  67 }
  68
  69 int s5c73m3_spi_write(struct s5c73m3 *state, const void *addr,
  70                       const unsigned int len, const unsigned int tx_size)
  71 {
  72         struct spi_device *spi_dev = state->spi_dev;
  73         u32 count = len / tx_size;
  74         u32 extra = len % tx_size;
  75         unsigned int i, j = 0;
  76         u8 padding[32];
  77         int r = 0;
  78
  79         memset(padding, 0, sizeof(padding));
  80
  81         for (i = 0; i < count; i++) {
  82                 r = spi_xmit(spi_dev, (void *)addr + j, tx_size, SPI_DIR_TX);
  83                 if (r < 0)
  84                         return r;
  85                 j += tx_size;
  86         }
  87
  88         if (extra > 0) {
  89                 r = spi_xmit(spi_dev, (void *)addr + j, extra, SPI_DIR_TX);
  90                 if (r < 0)
  91                         return r;
  92         }
  93
  94         return spi_xmit(spi_dev, padding, sizeof(padding), SPI_DIR_TX);
  95 }
  96
  97 int s5c73m3_spi_read(struct s5c73m3 *state, void *addr,
  98                      const unsigned int len, const unsigned int tx_size)
  99 {
 100         struct spi_device *spi_dev = state->spi_dev;
 101         u32 count = len / tx_size;
 102         u32 extra = len % tx_size;
 103         unsigned int i, j = 0;
 104         int r = 0;
 105
 106         for (i = 0; i < count; i++) {
 107                 r = spi_xmit(spi_dev, addr + j, tx_size, SPI_DIR_RX);
 108                 if (r < 0)
 109                         return r;
 110                 j += tx_size;
 111         }
 112
 113         if (extra > 0)
 114                 return spi_xmit(spi_dev, addr + j, extra, SPI_DIR_RX);
 115
 116         return 0;
 117 }
 118
 119 static int s5c73m3_spi_probe(struct spi_device *spi)
 120 {
 121         int r;
 122         struct s5c73m3 *state = container_of(spi->dev.driver, struct s5c73m3,
 123                                              spidrv.driver);
 124         spi->bits_per_word = 32;
 125
 126         r = spi_setup(spi);
 127         if (r < 0) {
 128                 dev_err(&spi->dev, "spi_setup() failed\n");
 129                 return r;
 130         }
 131
 132         mutex_lock(&state->lock);
 133         state->spi_dev = spi;
 134         mutex_unlock(&state->lock);
 135
 136         v4l2_info(&state->sensor_sd, "S5C73M3 SPI probed successfully\n");
 137         return 0;
 138 }
 139
 140 static int s5c73m3_spi_remove(struct spi_device *spi)
 141 {
 142         return 0;
 143 }
 144
 145 int s5c73m3_register_spi_driver(struct s5c73m3 *state)
 146 {
 147         struct spi_driver *spidrv = &state->spidrv;
 148
 149         spidrv->remove = s5c73m3_spi_remove;
 150         spidrv->probe = s5c73m3_spi_probe;
 151         spidrv->driver.name = S5C73M3_SPI_DRV_NAME;
 152         spidrv->driver.bus = &spi_bus_type;
 153         spidrv->driver.owner = THIS_MODULE;
 154         spidrv->driver.of_match_table = s5c73m3_spi_ids;
 155
 156         return spi_register_driver(spidrv);
 157 }
 158
 159 void s5c73m3_unregister_spi_driver(struct s5c73m3 *state)
 160 {
 161         spi_unregister_driver(&state->spidrv);
 162 }