regulator: new API for voltage reference supplies

Merge series from David Lechner <[email protected]>:

In the IIO subsystem, we noticed a pattern in many drivers where we need
to get, enable and get the voltage of a supply that provides a reference
voltage. In these cases, we only need the voltage and not a handle to
the regulator. Another common pattern is for chips to have an internal
reference voltage that is used when an external reference is not
available. There are also a few drivers outside of IIO that do the same.

So we would like to propose a new regulator consumer API to handle these
specific cases to avoid repeating the same boilerplate code in multiple
drivers.

As an example of how these functions are used, I have included a few
patches to consumer drivers. But to avoid a giant patch bomb, I have
omitted the iio/adc and iio/dac patches I have prepared from this
series. I will send those separately but these will add 36 more users
of devm_regulator_get_enable_read_voltage() in addition to the 6 here.
In total, this will eliminate nearly 1000 lines of similar code and will
simplify writing and reviewing new drivers in the future.

1 files changed, 26 insertions, 27 deletions

diff --git a/tools/testing/selftests/exec/recursion-depth.c b/tools/testing/selftests/exec/recursion-depth.c
index 2dbd5bc45b3e..b2f37d86a5f6 100644
--- a/tools/testing/selftests/exec/recursion-depth.c
+++ b/tools/testing/selftests/exec/recursion-depth.c
@@ -23,45 +23,44 @@
 #include <fcntl.h>
 #include <sys/mount.h>
 #include <unistd.h>
+#include "../kselftest.h"
 
 int main(void)
 {
+	int fd, rv;
+
+	ksft_print_header();
+	ksft_set_plan(1);
+
 	if (unshare(CLONE_NEWNS) == -1) {
 		if (errno == ENOSYS || errno == EPERM) {
-			fprintf(stderr, "error: unshare, errno %d\n", errno);
-			return 4;
+			ksft_test_result_skip("error: unshare, errno %d\n", errno);
+			ksft_finished();
 		}
-		fprintf(stderr, "error: unshare, errno %d\n", errno);
-		return 1;
-	}
-	if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
-		fprintf(stderr, "error: mount '/', errno %d\n", errno);
-		return 1;
+		ksft_exit_fail_msg("error: unshare, errno %d\n", errno);
 	}
+
+	if (mount(NULL, "/", NULL, MS_PRIVATE | MS_REC, NULL) == -1)
+		ksft_exit_fail_msg("error: mount '/', errno %d\n", errno);
+
 	/* Require "exec" filesystem. */
-	if (mount(NULL, "/tmp", "ramfs", 0, NULL) == -1) {
-		fprintf(stderr, "error: mount ramfs, errno %d\n", errno);
-		return 1;
-	}
+	if (mount(NULL, "/tmp", "ramfs", 0, NULL) == -1)
+		ksft_exit_fail_msg("error: mount ramfs, errno %d\n", errno);
 
 #define FILENAME "/tmp/1"
 
-	int fd = creat(FILENAME, 0700);
-	if (fd == -1) {
-		fprintf(stderr, "error: creat, errno %d\n", errno);
-		return 1;
-	}
+	fd = creat(FILENAME, 0700);
+	if (fd == -1)
+		ksft_exit_fail_msg("error: creat, errno %d\n", errno);
+
 #define S "#!" FILENAME "\n"
-	if (write(fd, S, strlen(S)) != strlen(S)) {
-		fprintf(stderr, "error: write, errno %d\n", errno);
-		return 1;
-	}
+	if (write(fd, S, strlen(S)) != strlen(S))
+		ksft_exit_fail_msg("error: write, errno %d\n", errno);
+
 	close(fd);
 
-	int rv = execve(FILENAME, NULL, NULL);
-	if (rv == -1 && errno == ELOOP) {
-		return 0;
-	}
-	fprintf(stderr, "error: execve, rv %d, errno %d\n", rv, errno);
-	return 1;
+	rv = execve(FILENAME, NULL, NULL);
+	ksft_test_result(rv == -1 && errno == ELOOP,
+			 "execve failed as expected (ret %d, errno %d)\n", rv, errno);
+	ksft_finished();
 }