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 */ 34 static 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 */ 54 int s6e63d6_index(struct s6e63d6 *data, u8 idx) 55 { 56 return send_word(data, 0, idx); 57 } 58 59 int s6e63d6_param(struct s6e63d6 *data, u16 param) 60 { 61 return send_word(data, 2, param); 62 } 63 64 int 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