soc/qcom: rpmh: add RPMh read

Implement support for RPMh reads, these allow reading out the
current votes for RPMh controlled resources such as regulators and
interconnects.

Link: https://patch.msgid.link/20260108-rpmh-regulator-fixes-v1-4-d1b5b300b665@linaro.org
Signed-off-by: Casey Connolly <casey.connolly@linaro.org>

include/soc/qcom/rpmh.h

@@ -13,12 +13,14 @@
 #if IS_ENABLED(CONFIG_QCOM_RPMH)
 int rpmh_write(const struct udevice *dev, enum rpmh_state state,
 	       const struct tcs_cmd *cmd, u32 n);
-
+int rpmh_read(const struct udevice *dev, enum rpmh_state state, struct tcs_cmd *cmd);
 #else
 
 static inline int rpmh_write(const struct device *dev, enum rpmh_state state,
 			     const struct tcs_cmd *cmd, u32 n)
 { return -ENODEV; }
+static inline int rpmh_read(const struct udevice *dev, struct tcs_cmd *cmd)
+{ return -ENODEV; }
 
 #endif /* CONFIG_QCOM_RPMH */
 

include/soc/qcom/tcs.h

@@ -55,6 +55,7 @@ struct tcs_cmd {
  */
 struct tcs_request {
 	enum rpmh_state state;
+	bool is_read;
 	u32 wait_for_compl;
 	u32 num_cmds;
 	struct tcs_cmd *cmds;