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 enum spi_direction {
  31         SPI_DIR_RX,
  32         SPI_DIR_TX
  33 };
  34
  35 static int spi_xmit(struct spi_device *spi_dev, void *addr, const int len,
  36                                                         enum spi_direction dir)
  37 {
  38         struct spi_message msg;
  39         int r;
  40         struct spi_transfer xfer = {
  41                 .len    = len,
  42         };
  43
  44         if (dir == SPI_DIR_TX)
  45                 xfer.tx_buf = addr;
  46         else
  47                 xfer.rx_buf = addr;
  48
  49         if (spi_dev == NULL) {
  50                 dev_err(&spi_dev->dev, "SPI device is uninitialized\n");
  51                 return -ENODEV;
  52         }
  53
  54         spi_message_init(&msg);
  55         spi_message_add_tail(&xfer, &msg);
  56
  57         r = spi_sync(spi_dev, &msg);
  58         if (r < 0)
  59                 dev_err(&spi_dev->dev, "%s spi_sync failed %d\n", __func__, r);
  60
  61         return r;
  62 }
  63
  64 int s5c73m3_spi_write(struct s5c73m3 *state, const void *addr,
  65                       const unsigned int len, const unsigned int tx_size)
  66 {
  67         struct spi_device *spi_dev = state->spi_dev;
  68         u32 count = len / tx_size;
  69         u32 extra = len % tx_size;
  70         unsigned int i, j = 0;
  71         u8 padding[32];
  72         int r = 0;
  73
  74         memset(padding, 0, sizeof(padding));
  75
  76         for (i = 0; i < count; i++) {
  77                 r = spi_xmit(spi_dev, (void *)addr + j, tx_size, SPI_DIR_TX);
  78                 if (r < 0)
  79                         return r;
  80                 j += tx_size;
  81         }
  82
  83         if (extra > 0) {
  84                 r = spi_xmit(spi_dev, (void *)addr + j, extra, SPI_DIR_TX);
  85                 if (r < 0)
  86                         return r;
  87         }
  88
  89         return spi_xmit(spi_dev, padding, sizeof(padding), SPI_DIR_TX);
  90 }
  91
  92 int s5c73m3_spi_read(struct s5c73m3 *state, void *addr,
  93                      const unsigned int len, const unsigned int tx_size)
  94 {
  95         struct spi_device *spi_dev = state->spi_dev;
  96         u32 count = len / tx_size;
  97         u32 extra = len % tx_size;
  98         unsigned int i, j = 0;
  99         int r = 0;
 100
 101         for (i = 0; i < count; i++) {
 102                 r = spi_xmit(spi_dev, addr + j, tx_size, SPI_DIR_RX);
 103                 if (r < 0)
 104                         return r;
 105                 j += tx_size;
 106         }
 107
 108         if (extra > 0)
 109                 return spi_xmit(spi_dev, addr + j, extra, SPI_DIR_RX);
 110
 111         return 0;
 112 }
 113
 114 static int s5c73m3_spi_probe(struct spi_device *spi)
 115 {
 116         int r;
 117         struct s5c73m3 *state = container_of(spi->dev.driver, struct s5c73m3,
 118                                              spidrv.driver);
 119         spi->bits_per_word = 32;
 120
 121         r = spi_setup(spi);
 122         if (r < 0) {
 123                 dev_err(&spi->dev, "spi_setup() failed\n");
 124                 return r;
 125         }
 126
 127         mutex_lock(&state->lock);
 128         state->spi_dev = spi;
 129         mutex_unlock(&state->lock);
 130
 131         v4l2_info(&state->sensor_sd, "S5C73M3 SPI probed successfully\n");
 132         return 0;
 133 }
 134
 135 static int s5c73m3_spi_remove(struct spi_device *spi)
 136 {
 137         return 0;
 138 }
 139
 140 int s5c73m3_register_spi_driver(struct s5c73m3 *state)
 141 {
 142         struct spi_driver *spidrv = &state->spidrv;
 143
 144         spidrv->remove = s5c73m3_spi_remove;
 145         spidrv->probe = s5c73m3_spi_probe;
 146         spidrv->driver.name = S5C73M3_SPI_DRV_NAME;
 147         spidrv->driver.bus = &spi_bus_type;
 148         spidrv->driver.owner = THIS_MODULE;
 149
 150         return spi_register_driver(spidrv);
 151 }
 152
 153 void s5c73m3_unregister_spi_driver(struct s5c73m3 *state)
 154 {
 155         spi_unregister_driver(&state->spidrv);
 156 }