diff --git a/drivers/mfd/macsmc.c b/drivers/mfd/macsmc.c
index e6cdae221f1d..e3893e255ce5 100644
--- a/drivers/mfd/macsmc.c
+++ b/drivers/mfd/macsmc.c
@@ -173,7 +173,7 @@ int apple_smc_read(struct apple_smc *smc, smc_key key, void *buf, size_t size)
 }
 EXPORT_SYMBOL(apple_smc_read);
 
-int apple_smc_write(struct apple_smc *smc, smc_key key, void *buf, size_t size)
+int apple_smc_write(struct apple_smc *smc, smc_key key, const void *buf, size_t size)
 {
 	guard(mutex)(&smc->mutex);
 
@@ -181,7 +181,7 @@ int apple_smc_write(struct apple_smc *smc, smc_key key, void *buf, size_t size)
 }
 EXPORT_SYMBOL(apple_smc_write);
 
-int apple_smc_rw(struct apple_smc *smc, smc_key key, void *wbuf, size_t wsize,
+int apple_smc_rw(struct apple_smc *smc, smc_key key, const void *wbuf, size_t wsize,
 		 void *rbuf, size_t rsize)
 {
 	guard(mutex)(&smc->mutex);
@@ -239,7 +239,7 @@ int apple_smc_enter_atomic(struct apple_smc *smc)
 }
 EXPORT_SYMBOL(apple_smc_enter_atomic);
 
-int apple_smc_write_atomic(struct apple_smc *smc, smc_key key, void *buf, size_t size)
+int apple_smc_write_atomic(struct apple_smc *smc, smc_key key, const void *buf, size_t size)
 {
 	guard(spinlock_irqsave)(&smc->lock);
 	u8 result;
diff --git a/include/linux/mfd/macsmc.h b/include/linux/mfd/macsmc.h
index f6f80c33b5cf..cc09ecce0df7 100644
--- a/include/linux/mfd/macsmc.h
+++ b/include/linux/mfd/macsmc.h
@@ -150,7 +150,7 @@ int apple_smc_read(struct apple_smc *smc, smc_key key, void *buf, size_t size);
  *
  * Return: Zero on success, negative errno on error
  */
-int apple_smc_write(struct apple_smc *smc, smc_key key, void *buf, size_t size);
+int apple_smc_write(struct apple_smc *smc, smc_key key, const void *buf, size_t size);
 
 /**
  * apple_smc_enter_atomic - Enter atomic mode to be able to use apple_smc_write_atomic
@@ -177,7 +177,7 @@ int apple_smc_enter_atomic(struct apple_smc *smc);
  *
  * Return: Zero on success, negative errno on error
  */
-int apple_smc_write_atomic(struct apple_smc *smc, smc_key key, void *buf, size_t size);
+int apple_smc_write_atomic(struct apple_smc *smc, smc_key key, const void *buf, size_t size);
 
 /**
  * apple_smc_rw - Write and then read using the given SMC key
@@ -190,7 +190,7 @@ int apple_smc_write_atomic(struct apple_smc *smc, smc_key key, void *buf, size_t
  *
  * Return: Zero on success, negative errno on error
  */
-int apple_smc_rw(struct apple_smc *smc, smc_key key, void *wbuf, size_t wsize,
+int apple_smc_rw(struct apple_smc *smc, smc_key key, const void *wbuf, size_t wsize,
 		 void *rbuf, size_t rsize);
 
 /**