mfd: cros_ec: Add I2C passthru protection API

Prevent direct i2c access to device behind EC when not in development mode.
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Acked-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Acked-by: Benson Leung <bleung@chromium.org>
Reviewed-by: Fabien Lahoudere <fabien.lahoudere@collabora.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

include/linux/mfd/cros_ec_commands.h

@@ -4316,6 +4316,28 @@ struct ec_params_entering_mode {
 #define VBOOT_MODE_DEVELOPER 1
 #define VBOOT_MODE_RECOVERY  2
 
+/*****************************************************************************/
+/*
+ * I2C passthru protection command: Protects I2C tunnels against access on
+ * certain addresses (board-specific).
+ */
+#define EC_CMD_I2C_PASSTHRU_PROTECT 0x00B7
+
+enum ec_i2c_passthru_protect_subcmd {
+	EC_CMD_I2C_PASSTHRU_PROTECT_STATUS = 0x0,
+	EC_CMD_I2C_PASSTHRU_PROTECT_ENABLE = 0x1,
+};
+
+struct ec_params_i2c_passthru_protect {
+	uint8_t subcmd;
+	uint8_t port;		/* I2C port number */
+} __ec_align1;
+
+struct ec_response_i2c_passthru_protect {
+	uint8_t status;		/* Status flags (0: unlocked, 1: locked) */
+} __ec_align1;
+
+
 /*****************************************************************************/
 /*
  * HDMI CEC commands