--- /dev/null
+/*
+ * Chromium OS cros_ec driver - I2C interface
+ *
+ * Copyright (c) 2012 The Chromium OS Authors.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+/*
+ * The Matrix Keyboard Protocol driver handles talking to the keyboard
+ * controller chip. Mostly this is for keyboard functions, but some other
+ * things have slipped in, so we provide generic services to talk to the
+ * KBC.
+ */
+
+#include <common.h>
+#include <i2c.h>
+#include <cros_ec.h>
+
+#ifdef DEBUG_TRACE
+#define debug_trace(fmt, b...) debug(fmt, #b)
+#else
+#define debug_trace(fmt, b...)
+#endif
+
+int cros_ec_i2c_command(struct cros_ec_dev *dev, uint8_t cmd, int cmd_version,
+ const uint8_t *dout, int dout_len,
+ uint8_t **dinp, int din_len)
+{
+ int old_bus = 0;
+ /* version8, cmd8, arglen8, out8[dout_len], csum8 */
+ int out_bytes = dout_len + 4;
+ /* response8, arglen8, in8[din_len], checksum8 */
+ int in_bytes = din_len + 3;
+ uint8_t *ptr;
+ /* Receive input data, so that args will be dword aligned */
+ uint8_t *in_ptr;
+ int len, csum, ret;
+
+ old_bus = i2c_get_bus_num();
+
+ /*
+ * Sanity-check I/O sizes given transaction overhead in internal
+ * buffers.
+ */
+ if (out_bytes > sizeof(dev->dout)) {
+ debug("%s: Cannot send %d bytes\n", __func__, dout_len);
+ return -1;
+ }
+ if (in_bytes > sizeof(dev->din)) {
+ debug("%s: Cannot receive %d bytes\n", __func__, din_len);
+ return -1;
+ }
+ assert(dout_len >= 0);
+ assert(dinp);
+
+ /*
+ * Copy command and data into output buffer so we can do a single I2C
+ * burst transaction.
+ */
+ ptr = dev->dout;
+
+ /*
+ * in_ptr starts of pointing to a dword-aligned input data buffer.
+ * We decrement it back by the number of header bytes we expect to
+ * receive, so that the first parameter of the resulting input data
+ * will be dword aligned.
+ */
+ in_ptr = dev->din + sizeof(int64_t);
+
+ if (dev->protocol_version != 2) {
+ /* Something we don't support */
+ debug("%s: Protocol version %d unsupported\n",
+ __func__, dev->protocol_version);
+ return -1;
+ }
+
+ *ptr++ = EC_CMD_VERSION0 + cmd_version;
+ *ptr++ = cmd;
+ *ptr++ = dout_len;
+ in_ptr -= 2; /* Expect status, length bytes */
+
+ memcpy(ptr, dout, dout_len);
+ ptr += dout_len;
+
+ *ptr++ = (uint8_t)
+ cros_ec_calc_checksum(dev->dout, dout_len + 3);
+
+ /* Set to the proper i2c bus */
+ if (i2c_set_bus_num(dev->bus_num)) {
+ debug("%s: Cannot change to I2C bus %d\n", __func__,
+ dev->bus_num);
+ return -1;
+ }
+
+ /* Send output data */
+ cros_ec_dump_data("out", -1, dev->dout, out_bytes);
+ ret = i2c_write(dev->addr, 0, 0, dev->dout, out_bytes);
+ if (ret) {
+ debug("%s: Cannot complete I2C write to 0x%x\n",
+ __func__, dev->addr);
+ ret = -1;
+ }
+
+ if (!ret) {
+ ret = i2c_read(dev->addr, 0, 0, in_ptr, in_bytes);
+ if (ret) {
+ debug("%s: Cannot complete I2C read from 0x%x\n",
+ __func__, dev->addr);
+ ret = -1;
+ }
+ }
+
+ /* Return to original bus number */
+ i2c_set_bus_num(old_bus);
+ if (ret)
+ return ret;
+
+ if (*in_ptr != EC_RES_SUCCESS) {
+ debug("%s: Received bad result code %d\n", __func__, *in_ptr);
+ return -(int)*in_ptr;
+ }
+
+ len = in_ptr[1];
+ if (len + 3 > sizeof(dev->din)) {
+ debug("%s: Received length %#02x too large\n",
+ __func__, len);
+ return -1;
+ }
+ csum = cros_ec_calc_checksum(in_ptr, 2 + len);
+ if (csum != in_ptr[2 + len]) {
+ debug("%s: Invalid checksum rx %#02x, calced %#02x\n",
+ __func__, in_ptr[2 + din_len], csum);
+ return -1;
+ }
+ din_len = min(din_len, len);
+ cros_ec_dump_data("in", -1, in_ptr, din_len + 3);
+
+ /* Return pointer to dword-aligned input data, if any */
+ *dinp = dev->din + sizeof(int64_t);
+
+ return din_len;
+}
+
+int cros_ec_i2c_decode_fdt(struct cros_ec_dev *dev, const void *blob)
+{
+ /* Decode interface-specific FDT params */
+ dev->max_frequency = fdtdec_get_int(blob, dev->node,
+ "i2c-max-frequency", 100000);
+ dev->bus_num = i2c_get_bus_num_fdt(dev->parent_node);
+ if (dev->bus_num == -1) {
+ debug("%s: Failed to read bus number\n", __func__);
+ return -1;
+ }
+ dev->addr = fdtdec_get_int(blob, dev->node, "reg", -1);
+ if (dev->addr == -1) {
+ debug("%s: Failed to read device address\n", __func__);
+ return -1;
+ }
+
+ return 0;
+}
+
+/**
+ * Initialize I2C protocol.
+ *
+ * @param dev CROS_EC device
+ * @param blob Device tree blob
+ * @return 0 if ok, -1 on error
+ */
+int cros_ec_i2c_init(struct cros_ec_dev *dev, const void *blob)
+{
+ i2c_init(dev->max_frequency, dev->addr);
+
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff