2 * Chromium OS cros_ec driver - I2C interface
4 * Copyright (c) 2012 The Chromium OS Authors.
6 * SPDX-License-Identifier: GPL-2.0+
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
21 #define debug_trace(fmt, b...) debug(fmt, #b)
23 #define debug_trace(fmt, b...)
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)
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;
36 /* Receive input data, so that args will be dword aligned */
40 old_bus = i2c_get_bus_num();
43 * Sanity-check I/O sizes given transaction overhead in internal
46 if (out_bytes > sizeof(dev->dout)) {
47 debug("%s: Cannot send %d bytes\n", __func__, dout_len);
50 if (in_bytes > sizeof(dev->din)) {
51 debug("%s: Cannot receive %d bytes\n", __func__, din_len);
54 assert(dout_len >= 0);
58 * Copy command and data into output buffer so we can do a single I2C
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.
69 in_ptr = dev->din + sizeof(int64_t);
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);
78 *ptr++ = EC_CMD_VERSION0 + cmd_version;
81 in_ptr -= 2; /* Expect status, length bytes */
83 memcpy(ptr, dout, dout_len);
87 cros_ec_calc_checksum(dev->dout, dout_len + 3);
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__,
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);
100 debug("%s: Cannot complete I2C write to 0x%x\n",
101 __func__, dev->addr);
106 ret = i2c_read(dev->addr, 0, 0, in_ptr, in_bytes);
108 debug("%s: Cannot complete I2C read from 0x%x\n",
109 __func__, dev->addr);
114 /* Return to original bus number */
115 i2c_set_bus_num(old_bus);
119 if (*in_ptr != EC_RES_SUCCESS) {
120 debug("%s: Received bad result code %d\n", __func__, *in_ptr);
121 return -(int)*in_ptr;
125 if (len + 3 > sizeof(dev->din)) {
126 debug("%s: Received length %#02x too large\n",
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);
136 din_len = min(din_len, len);
137 cros_ec_dump_data("in", -1, in_ptr, din_len + 3);
139 /* Return pointer to dword-aligned input data, if any */
140 *dinp = dev->din + sizeof(int64_t);
145 int cros_ec_i2c_decode_fdt(struct cros_ec_dev *dev, const void *blob)
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__);
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__);
165 * Initialize I2C protocol.
167 * @param dev CROS_EC device
168 * @param blob Device tree blob
169 * @return 0 if ok, -1 on error
171 int cros_ec_i2c_init(struct cros_ec_dev *dev, const void *blob)
173 i2c_init(dev->max_frequency, dev->addr);