[PATCH v2 3/3] cmd: rng: Add rng list command

[Weizhao Ouyang]

The 'rng list' command probes all RNG devices and list those devices
that are successfully probed. Also update the help info.

Signed-off-by: Weizhao Ouyang <o451686...@gmail.com>
---
v2: update commit message and rng help info
---
 cmd/rng.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/cmd/rng.c b/cmd/rng.c
index 52f722c7af..b073a6c849 100644
--- a/cmd/rng.c
+++ b/cmd/rng.c
@@ -19,6 +19,22 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, 
char *const argv[])
        struct udevice *dev;
        int ret = CMD_RET_SUCCESS;
 
+       if (argc == 2 && !strcmp(argv[1], "list")) {
+               int idx = 0;
+
+               uclass_foreach_dev_probe(UCLASS_RNG, dev) {
+                       idx++;
+                       printf("RNG #%d - %s\n", dev->seq_, dev->name);
+               }
+
+               if (!idx) {
+                       log_err("No RNG device\n");
+                       return CMD_RET_FAILURE;
+               }
+
+               return CMD_RET_SUCCESS;
+       }
+
        switch (argc) {
        case 1:
                devnum = 0;
@@ -56,12 +72,9 @@ static int do_rng(struct cmd_tbl *cmdtp, int flag, int argc, 
char *const argv[])
        return ret;
 }
 
-U_BOOT_LONGHELP(rng,
-       "[dev [n]]\n"
-       "  - print n random bytes(max 64) read from dev\n");
-
 U_BOOT_CMD(
        rng, 3, 0, do_rng,
        "print bytes from the hardware random number generator",
-       rng_help_text
+       "list         - list all the probed rng devices\n"
+       "rng [dev] [n]    - print n random bytes(max 64) read from dev\n"
 );
-- 
2.39.2