| Dirk Eibach | 486cad0 | 2011-10-03 23:13:51 +0000 | [diff] [blame] | 1 | /* |
| 2 | * (C) Copyright 2011 |
| 3 | * Dirk Eibach, Guntermann & Drunck GmbH, eibach@gdsys.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 | |
| 24 | /* |
| 25 | * Driver for NXP's pca9698 40 bit I2C gpio expander |
| 26 | */ |
| 27 | |
| 28 | #include <common.h> |
| 29 | #include <i2c.h> |
| 30 | #include <pca9698.h> |
| 31 | |
| 32 | /* |
| 33 | * The pca9698 registers |
| 34 | */ |
| 35 | |
| 36 | #define PCA9698_REG_INPUT 0x00 |
| 37 | #define PCA9698_REG_OUTPUT 0x08 |
| 38 | #define PCA9698_REG_POLARITY 0x10 |
| 39 | #define PCA9698_REG_CONFIG 0x18 |
| 40 | |
| 41 | #define PCA9698_BUFFER_SIZE 5 |
| 42 | |
| 43 | static int pca9698_read40(u8 chip, u8 offset, u8 *buffer) |
| 44 | { |
| 45 | u8 command = offset | 0x80; /* autoincrement */ |
| 46 | |
| 47 | return i2c_read(chip, command, 1, buffer, PCA9698_BUFFER_SIZE); |
| 48 | } |
| 49 | |
| 50 | static int pca9698_write40(u8 chip, u8 offset, u8 *buffer) |
| 51 | { |
| 52 | u8 command = offset | 0x80; /* autoincrement */ |
| 53 | |
| 54 | return i2c_write(chip, command, 1, buffer, PCA9698_BUFFER_SIZE); |
| 55 | } |
| 56 | |
| 57 | static void pca9698_set_bit(unsigned gpio, u8 *buffer, unsigned value) |
| 58 | { |
| 59 | unsigned byte = gpio / 8; |
| 60 | unsigned bit = gpio % 8; |
| 61 | |
| 62 | if (value) |
| 63 | buffer[byte] |= (1 << bit); |
| 64 | else |
| 65 | buffer[byte] &= ~(1 << bit); |
| 66 | } |
| 67 | |
| 68 | int pca9698_direction_input(u8 chip, unsigned offset) |
| 69 | { |
| 70 | u8 data[PCA9698_BUFFER_SIZE]; |
| 71 | int res; |
| 72 | |
| 73 | res = pca9698_read40(chip, PCA9698_REG_CONFIG, data); |
| 74 | if (res) |
| 75 | return res; |
| 76 | |
| 77 | pca9698_set_bit(offset, data, 1); |
| 78 | return pca9698_write40(chip, PCA9698_REG_CONFIG, data); |
| 79 | } |
| 80 | |
| 81 | int pca9698_direction_output(u8 chip, unsigned offset) |
| 82 | { |
| 83 | u8 data[PCA9698_BUFFER_SIZE]; |
| 84 | int res; |
| 85 | |
| 86 | res = pca9698_read40(chip, PCA9698_REG_CONFIG, data); |
| 87 | if (res) |
| 88 | return res; |
| 89 | |
| 90 | pca9698_set_bit(offset, data, 0); |
| 91 | return pca9698_write40(chip, PCA9698_REG_CONFIG, data); |
| 92 | } |
| 93 | |
| 94 | int pca9698_get_input(u8 chip, unsigned offset) |
| 95 | { |
| 96 | unsigned config_byte = offset / 8; |
| 97 | unsigned config_bit = offset % 8; |
| 98 | unsigned value; |
| 99 | u8 data[PCA9698_BUFFER_SIZE]; |
| 100 | int res; |
| 101 | |
| 102 | res = pca9698_read40(chip, PCA9698_REG_INPUT, data); |
| 103 | if (res) |
| 104 | return -1; |
| 105 | |
| 106 | value = data[config_byte] & (1 << config_bit); |
| 107 | |
| 108 | return !!value; |
| 109 | } |
| 110 | |
| 111 | int pca9698_set_output(u8 chip, unsigned offset, int value) |
| 112 | { |
| 113 | u8 data[PCA9698_BUFFER_SIZE]; |
| 114 | int res; |
| 115 | |
| 116 | res = pca9698_read40(chip, PCA9698_REG_OUTPUT, data); |
| 117 | if (res) |
| 118 | return res; |
| 119 | |
| 120 | memset(data, sizeof(data), 0); |
| 121 | pca9698_set_bit(offset, data, value); |
| 122 | return pca9698_write40(chip, PCA9698_REG_OUTPUT, data); |
| 123 | } |