1 /* 2 * Copyright (C) 2009 3 * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de> 4 * 5 * SPDX-License-Identifier: GPL-2.0+ 6 */ 7 #include <common.h> 8 #include <spi.h> 9 #include <s6e63d6.h> 10 11 /* 12 * Each transfer is performed as: 13 * 1. chip-select active 14 * 2. send 8-bit start code 15 * 3. send 16-bit data 16 * 4. chip-select inactive 17 */ 18 static int send_word(struct s6e63d6 *data, u8 rs, u16 word) 19 { 20 /* 21 * The start byte looks like (binary): 22 * 01110<ID><RS><R/W> 23 * RS is 0 for index or 1 for data, and R/W is 0 for write. 24 */ 25 u32 buf8 = 0x70 | data->id | (rs & 2); 26 u32 buf16 = cpu_to_le16(word); 27 u32 buf_in; 28 int err; 29 30 err = spi_xfer(data->slave, 8, &buf8, &buf_in, SPI_XFER_BEGIN); 31 if (err) 32 return err; 33 34 return spi_xfer(data->slave, 16, &buf16, &buf_in, SPI_XFER_END); 35 } 36 37 /* Index and param differ in Register Select bit */ 38 int s6e63d6_index(struct s6e63d6 *data, u8 idx) 39 { 40 return send_word(data, 0, idx); 41 } 42 43 int s6e63d6_param(struct s6e63d6 *data, u16 param) 44 { 45 return send_word(data, 2, param); 46 } 47 48 int s6e63d6_init(struct s6e63d6 *data) 49 { 50 if (data->id != 0 && data->id != 4) { 51 printf("s6e63d6: invalid ID %u\n", data->id); 52 return 1; 53 } 54 55 data->slave = spi_setup_slave(data->bus, data->cs, 100000, SPI_MODE_3); 56 if (!data->slave) 57 return 1; 58 59 return 0; 60 } 61