[U-Boot, 3/3] pmic: allow dump command for non contiguous register maps

[Ian Ray]

From: Martin Fuzzey <martin.fuzzey at flowbird.group>

Some PMICs (such as the DA9063) have non-contiguous register maps.
Attempting to read the non implemented registers returns an error
rather than a dummy value which causes 'pmic dump' to terminate
prematurely.

Fix this by allowing the PMIC driver to return -ENODATA for such
registers, which will then be displayed as '--' by pmic dump.

Use a single error code rather than any error code so that
we can distinguish between a hardware failure reading the PMIC
and a non implemented register known to the driver.

Signed-off-by: Martin Fuzzey <martin.fuzzey at flowbird.group>
---
 cmd/pmic.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/cmd/pmic.c b/cmd/pmic.c
index e46d813..2400bfb 100644
--- a/cmd/pmic.c
+++ b/cmd/pmic.c
@@ -95,7 +95,7 @@ static int do_dump(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 
 	for (reg = 0; reg < pmic_reg_count(dev); reg++) {
 		ret = pmic_reg_read(dev, reg);
-		if (ret < 0) {
+		if (ret < 0 && ret != -ENODATA) {
 			printf("Can't read register: %d\n", reg);
 			return failure(ret);
 		}
@@ -103,7 +103,15 @@ static int do_dump(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		if (!(reg % 16))
 			printf("\n0x%02x: ", reg);
 
-		printf(fmt, ret);
+		if (ret == -ENODATA) {
+			int i;
+
+			for (i = 0; i < priv->trans_len; i++)
+				puts("--");
+			puts(" ");
+		} else {
+			printf(fmt, ret);
+		}
 	}
 	printf("\n");
 
-- 
2.10.1