1  /*
  2   * generic I2C slave access interface
  3   *
  4   * Copyright 2014-2016 Mikeqin <Fengling.Qin@gmail.com>
  5   * Copyright 2014 Zefir Kurtisi <zefir.kurtisi@gmail.com>
  6   *
  7   * This program is free software; you can redistribute it and/or modify it
  8   * under the terms of the GNU General Public License as published by the Free
  9   * Software Foundation; either version 3 of the License, or (at your option)
 10   * any later version.  See COPYING for more details.
 11   */
 12  
 13  #include <sys/ioctl.h>
 14  #include <errno.h>
 15  #include <string.h>
 16  #include <stdio.h>
 17  #include <stdlib.h>
 18  #include <unistd.h>
 19  #include <linux/i2c.h>
 20  #include <linux/i2c-dev.h>
 21  
 22  #include <stdint.h>
 23  #include <stdbool.h>
 24  #include <fcntl.h>
 25  #include <assert.h>
 26  
 27  #include "miner.h"
 28  #include "i2c-context.h"
 29  
 30  static bool i2c_slave_write(struct i2c_ctx *ctx, uint8_t reg, uint8_t val)
 31  {
 32  	union i2c_smbus_data data;
 33  	data.byte = val;
 34  
 35  	struct i2c_smbus_ioctl_data args;
 36  
 37  	args.read_write = I2C_SMBUS_WRITE;
 38  	args.command = reg;
 39  	args.size = I2C_SMBUS_BYTE_DATA;
 40  	args.data = &data;
 41  
 42  	if (ioctl(ctx->file, I2C_SMBUS, &args) == -1) {
 43  		applog(LOG_INFO, "i2c 0x%02x: failed to write to fdesc %d: %s",
 44  		       ctx->addr, ctx->file, strerror(errno));
 45  		return false;
 46  	}
 47  	applog(LOG_DEBUG, "I2C-W(0x%02x/0x%02x)=0x%02x", ctx->addr, reg, val);
 48  	return true;
 49  }
 50  
 51  static bool i2c_slave_read(struct i2c_ctx *ctx, uint8_t reg, uint8_t *val)
 52  {
 53  	union i2c_smbus_data data;
 54  	struct i2c_smbus_ioctl_data args;
 55  
 56  	args.read_write = I2C_SMBUS_READ;
 57  	args.command = reg;
 58  	args.size = I2C_SMBUS_BYTE_DATA;
 59  	args.data = &data;
 60  
 61  	if (ioctl(ctx->file, I2C_SMBUS, &args) == -1) {
 62  		applog(LOG_INFO, "i2c 0x%02x: failed to read from fdesc %d: %s",
 63  		       ctx->addr, ctx->file, strerror(errno));
 64  		return false;
 65  	}
 66  	*val = data.byte;
 67  	applog(LOG_DEBUG, "I2C-R(0x%02x/0x%02x)=0x%02x", ctx->addr, reg, *val);
 68  	return true;
 69  }
 70  
 71  static bool i2c_slave_write_raw(struct i2c_ctx *ctx, uint8_t *buf, uint32_t len)
 72  {
 73  	/* SMBus cann't support write bytes > 32, use plain i2c write */
 74  	if (len != write(ctx->file, buf, len)) {
 75  		applog(LOG_INFO, "i2c 0x%02x: failed to write raw to fdesc %d: %s",
 76  		       ctx->addr, ctx->file, strerror(errno));
 77  		return false;
 78  	}
 79  	applog(LOG_DEBUG, "I2C-W-RAW(0x%02x)", ctx->addr);
 80  	return true;
 81  }
 82  
 83  static bool i2c_slave_read_raw(struct i2c_ctx *ctx, uint8_t *buf, uint32_t len)
 84  {
 85  	/* SMBus cann't support read bytes > 32, use plain i2c read */
 86  	if (len != read(ctx->file, buf, len)) {
 87  		applog(LOG_INFO, "i2c 0x%02x: failed to read raw from fdesc %d: %s",
 88  		       ctx->addr, ctx->file, strerror(errno));
 89  		return false;
 90  	}
 91  	applog(LOG_DEBUG, "I2C-R-RAW(0x%02x)", ctx->addr);
 92  	return true;
 93  }
 94  
 95  static void i2c_slave_exit(struct i2c_ctx *ctx)
 96  {
 97  	if (ctx->file == -1)
 98  		return;
 99  	close(ctx->file);
100  	free(ctx);
101  }
102  
103  extern struct i2c_ctx *i2c_slave_open(char *i2c_bus, uint8_t slave_addr)
104  {
105  	int file = open(i2c_bus, O_RDWR);
106  	if (file < 0) {
107  		applog(LOG_INFO, "Failed to open %s: %s", i2c_bus, strerror(errno));
108  		return NULL;
109  	}
110  
111  	if (ioctl(file, I2C_SLAVE, slave_addr) < 0) {
112  		close(file);
113  		return NULL;
114  	}
115  	struct i2c_ctx *ctx = malloc(sizeof(*ctx));
116  	assert(ctx != NULL);
117  
118  	ctx->addr = slave_addr;
119  	ctx->file = file;
120  	ctx->exit = i2c_slave_exit;
121  	ctx->read = i2c_slave_read;
122  	ctx->write = i2c_slave_write;
123  	ctx->read_raw = i2c_slave_read_raw;
124  	ctx->write_raw = i2c_slave_write_raw;
125  	return ctx;
126  }
127