Add a pass-through for the smart battery

Allow to send commands to the smart battery using EC commands when the
battery is connected to an I2C bus behind the EC.

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>

BRANCH=none
BUG=chrome-os-partner:14314
TEST=on Spring, with a kernel including patch to use the pass-through
for the sbs-battery driver, run "power-supply-info" and see the correct
information.

Change-Id: Ie10f1c95afe4a33cf0b55d5a0de7640d5971ebb3
Reviewed-on: https://gerrit.chromium.org/gerrit/41289
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Queue: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>

2 files changed, 112 insertions, 0 deletions

diff --git a/common/smart_battery.c b/common/smart_battery.c
index 0438d6309f..2c4eb32f1f 100644
--- a/common/smart_battery.c
+++ b/common/smart_battery.c
@@ -6,6 +6,7 @@
  */
 
 #include "console.h"
+#include "host_command.h"
 #include "smart_battery.h"
 #include "timer.h"
 #include "util.h"
@@ -278,3 +279,79 @@ DECLARE_CONSOLE_COMMAND(sb, command_sb,
 			"Read/write smart battery data",
 			NULL);
 
+/*****************************************************************************/
+/* Smart battery pass-through
+ */
+#ifdef CONFIG_I2C_PASSTHROUGH
+static int host_command_sb_read_word(struct host_cmd_handler_args *args)
+{
+	int rv;
+	int val;
+	const struct ec_params_sb_rd *p = args->params;
+	struct ec_response_sb_rd_word *r = args->response;
+
+	if (p->reg > 0x1c)
+		return EC_RES_INVALID_PARAM;
+	rv = i2c_read16(I2C_PORT_BATTERY, BATTERY_ADDR, p->reg, &val);
+	if (rv)
+		return EC_RES_ERROR;
+
+	r->value = val;
+	args->response_size = sizeof(struct ec_response_sb_rd_word);
+
+	return EC_RES_SUCCESS;
+}
+DECLARE_HOST_COMMAND(EC_CMD_SB_READ_WORD,
+		     host_command_sb_read_word,
+		     EC_VER_MASK(0));
+
+static int host_command_sb_write_word(struct host_cmd_handler_args *args)
+{
+	int rv;
+	const struct ec_params_sb_wr_word *p = args->params;
+
+	if (p->reg > 0x1c)
+		return EC_RES_INVALID_PARAM;
+	rv = i2c_write16(I2C_PORT_BATTERY, BATTERY_ADDR, p->reg, p->value);
+	if (rv)
+		return EC_RES_ERROR;
+
+	return EC_RES_SUCCESS;
+}
+DECLARE_HOST_COMMAND(EC_CMD_SB_WRITE_WORD,
+		     host_command_sb_write_word,
+		     EC_VER_MASK(0));
+
+static int host_command_sb_read_block(struct host_cmd_handler_args *args)
+{
+	int rv;
+	const struct ec_params_sb_rd *p = args->params;
+	struct ec_response_sb_rd_block *r = args->response;
+
+	if ((p->reg != SB_MANUFACTURER_NAME) &&
+	    (p->reg != SB_DEVICE_NAME) &&
+	    (p->reg != SB_DEVICE_CHEMISTRY) &&
+	    (p->reg != SB_MANUFACTURER_DATA))
+		return EC_RES_INVALID_PARAM;
+	rv = i2c_read_string(I2C_PORT_BATTERY, BATTERY_ADDR, p->reg,
+			     r->data, 32);
+	if (rv)
+		return EC_RES_ERROR;
+
+	args->response_size = sizeof(struct ec_response_sb_rd_block);
+
+	return EC_RES_SUCCESS;
+}
+DECLARE_HOST_COMMAND(EC_CMD_SB_READ_BLOCK,
+		     host_command_sb_read_block,
+		     EC_VER_MASK(0));
+
+static int host_command_sb_write_block(struct host_cmd_handler_args *args)
+{
+	/* Not implemented */
+	return EC_RES_INVALID_COMMAND;
+}
+DECLARE_HOST_COMMAND(EC_CMD_SB_WRITE_BLOCK,
+		     host_command_sb_write_block,
+		     EC_VER_MASK(0));
+#endif
diff --git a/include/ec_commands.h b/include/ec_commands.h
index 02fa46f1bf..54dcbd314a 100644
--- a/include/ec_commands.h
+++ b/include/ec_commands.h
@@ -1261,6 +1261,41 @@ struct ec_params_current_limit {
 } __packed;
 
 /*****************************************************************************/
+/* Smart battery pass-through */
+
+/* Get / Set 16-bit smart battery registers */
+#define EC_CMD_SB_READ_WORD   0xb0
+#define EC_CMD_SB_WRITE_WORD  0xb1
+
+/* Get / Set string smart battery parameters
+ * formatted as SMBUS "block".
+ */
+#define EC_CMD_SB_READ_BLOCK  0xb2
+#define EC_CMD_SB_WRITE_BLOCK 0xb3
+
+struct ec_params_sb_rd {
+	uint8_t reg;
+} __packed;
+
+struct ec_response_sb_rd_word {
+	uint16_t value;
+} __packed;
+
+struct ec_params_sb_wr_word {
+	uint8_t reg;
+	uint16_t value;
+} __packed;
+
+struct ec_response_sb_rd_block {
+	uint8_t data[32];
+} __packed;
+
+struct ec_params_sb_wr_block {
+	uint8_t reg;
+	uint16_t data[32];
+} __packed;
+
+/*****************************************************************************/
 /* System commands */
 
 /*