1 /* 2 * Chromium OS cros_ec driver - I2C interface 3 * 4 * Copyright (c) 2012 The Chromium OS Authors. 5 * 6 * SPDX-License-Identifier: GPL-2.0+ 7 */ 8 9 /* 10 * The Matrix Keyboard Protocol driver handles talking to the keyboard 11 * controller chip. Mostly this is for keyboard functions, but some other 12 * things have slipped in, so we provide generic services to talk to the 13 * KBC. 14 */ 15 16 #include <common.h> 17 #include <i2c.h> 18 #include <cros_ec.h> 19 20 #ifdef DEBUG_TRACE 21 #define debug_trace(fmt, b...) debug(fmt, #b) 22 #else 23 #define debug_trace(fmt, b...) 24 #endif 25 26 int cros_ec_i2c_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version, 27 const uint8_t *dout, int dout_len, 28 uint8_t **dinp, int din_len) 29 { 30 int old_bus = 0; 31 /* version8, cmd8, arglen8, out8[dout_len], csum8 */ 32 int out_bytes = dout_len + 4; 33 /* response8, arglen8, in8[din_len], checksum8 */ 34 int in_bytes = din_len + 3; 35 uint8_t *ptr; 36 /* Receive input data, so that args will be dword aligned */ 37 uint8_t *in_ptr; 38 int len, csum, ret; 39 40 old_bus = i2c_get_bus_num(); 41 42 /* 43 * Sanity-check I/O sizes given transaction overhead in internal 44 * buffers. 45 */ 46 if (out_bytes > sizeof(dev->dout)) { 47 debug("%s: Cannot send %d bytes\n", __func__, dout_len); 48 return -1; 49 } 50 if (in_bytes > sizeof(dev->din)) { 51 debug("%s: Cannot receive %d bytes\n", __func__, din_len); 52 return -1; 53 } 54 assert(dout_len >= 0); 55 assert(dinp); 56 57 /* 58 * Copy command and data into output buffer so we can do a single I2C 59 * burst transaction. 60 */ 61 ptr = dev->dout; 62 63 /* 64 * in_ptr starts of pointing to a dword-aligned input data buffer. 65 * We decrement it back by the number of header bytes we expect to 66 * receive, so that the first parameter of the resulting input data 67 * will be dword aligned. 68 */ 69 in_ptr = dev->din + sizeof(int64_t); 70 71 if (dev->protocol_version != 2) { 72 /* Something we don't support */ 73 debug("%s: Protocol version %d unsupported\n", 74 __func__, dev->protocol_version); 75 return -1; 76 } 77 78 *ptr++ = EC_CMD_VERSION0 + cmd_version; 79 *ptr++ = cmd; 80 *ptr++ = dout_len; 81 in_ptr -= 2; /* Expect status, length bytes */ 82 83 memcpy(ptr, dout, dout_len); 84 ptr += dout_len; 85 86 *ptr++ = (uint8_t) 87 cros_ec_calc_checksum(dev->dout, dout_len + 3); 88 89 /* Set to the proper i2c bus */ 90 if (i2c_set_bus_num(dev->bus_num)) { 91 debug("%s: Cannot change to I2C bus %d\n", __func__, 92 dev->bus_num); 93 return -1; 94 } 95 96 /* Send output data */ 97 cros_ec_dump_data("out", -1, dev->dout, out_bytes); 98 ret = i2c_write(dev->addr, 0, 0, dev->dout, out_bytes); 99 if (ret) { 100 debug("%s: Cannot complete I2C write to 0x%x\n", 101 __func__, dev->addr); 102 ret = -1; 103 } 104 105 if (!ret) { 106 ret = i2c_read(dev->addr, 0, 0, in_ptr, in_bytes); 107 if (ret) { 108 debug("%s: Cannot complete I2C read from 0x%x\n", 109 __func__, dev->addr); 110 ret = -1; 111 } 112 } 113 114 /* Return to original bus number */ 115 i2c_set_bus_num(old_bus); 116 if (ret) 117 return ret; 118 119 if (*in_ptr != EC_RES_SUCCESS) { 120 debug("%s: Received bad result code %d\n", __func__, *in_ptr); 121 return -(int)*in_ptr; 122 } 123 124 len = in_ptr[1]; 125 if (len + 3 > sizeof(dev->din)) { 126 debug("%s: Received length %#02x too large\n", 127 __func__, len); 128 return -1; 129 } 130 csum = cros_ec_calc_checksum(in_ptr, 2 + len); 131 if (csum != in_ptr[2 + len]) { 132 debug("%s: Invalid checksum rx %#02x, calced %#02x\n", 133 __func__, in_ptr[2 + din_len], csum); 134 return -1; 135 } 136 din_len = min(din_len, len); 137 cros_ec_dump_data("in", -1, in_ptr, din_len + 3); 138 139 /* Return pointer to dword-aligned input data, if any */ 140 *dinp = dev->din + sizeof(int64_t); 141 142 return din_len; 143 } 144 145 int cros_ec_i2c_decode_fdt(struct cros_ec_dev *dev, const void *blob) 146 { 147 /* Decode interface-specific FDT params */ 148 dev->max_frequency = fdtdec_get_int(blob, dev->node, 149 "i2c-max-frequency", 100000); 150 dev->bus_num = i2c_get_bus_num_fdt(dev->parent_node); 151 if (dev->bus_num == -1) { 152 debug("%s: Failed to read bus number\n", __func__); 153 return -1; 154 } 155 dev->addr = fdtdec_get_int(blob, dev->node, "reg", -1); 156 if (dev->addr == -1) { 157 debug("%s: Failed to read device address\n", __func__); 158 return -1; 159 } 160 161 return 0; 162 } 163 164 /** 165 * Initialize I2C protocol. 166 * 167 * @param dev CROS_EC device 168 * @param blob Device tree blob 169 * @return 0 if ok, -1 on error 170 */ 171 int cros_ec_i2c_init(struct cros_ec_dev *dev, const void *blob) 172 { 173 i2c_init(dev->max_frequency, dev->addr); 174 175 return 0; 176 } 177