LXR uboot/drivers/video/s6e63d6.c

   1/*
   2 * Copyright (C) 2009
   3 * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
   4 *
   5 * See file CREDITS for list of people who contributed to this
   6 * project.
   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 as
  10 * published by the Free Software Foundation; either version 2 of
  11 * the License, or (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21 * MA 02111-1307 USA
  22 */
  23#include <common.h>
  24#include <spi.h>
  25#include <s6e63d6.h>
  26
  27/*
  28 * Each transfer is performed as:
  29 * 1. chip-select active
  30 * 2. send 8-bit start code
  31 * 3. send 16-bit data
  32 * 4. chip-select inactive
  33 */
  34static int send_word(struct s6e63d6 *data, u8 rs, u16 word)
  35{
  36        /*
  37         * The start byte looks like (binary):
  38         * 01110<ID><RS><R/W>
  39         * RS is 0 for index or 1 for data, and R/W is 0 for write.
  40         */
  41        u32 buf8 = 0x70 | data->id | (rs & 2);
  42        u32 buf16 = cpu_to_le16(word);
  43        u32 buf_in;
  44        int err;
  45
  46        err = spi_xfer(data->slave, 8, &buf8, &buf_in, SPI_XFER_BEGIN);
  47        if (err)
  48                return err;
  49
  50        return spi_xfer(data->slave, 16, &buf16, &buf_in, SPI_XFER_END);
  51}
  52
  53/* Index and param differ in Register Select bit */
  54int s6e63d6_index(struct s6e63d6 *data, u8 idx)
  55{
  56        return send_word(data, 0, idx);
  57}
  58
  59int s6e63d6_param(struct s6e63d6 *data, u16 param)
  60{
  61        return send_word(data, 2, param);
  62}
  63
  64int s6e63d6_init(struct s6e63d6 *data)
  65{
  66        if (data->id != 0 && data->id != 4) {
  67                printf("s6e63d6: invalid ID %u\n", data->id);
  68                return 1;
  69        }
  70
  71        data->slave = spi_setup_slave(data->bus, data->cs, 100000, SPI_MODE_3);
  72        if (!data->slave)
  73                return 1;
  74
  75        return 0;
  76}
  77