[PATCH v2] cmd: adc: Add support for storing ADC result in env variable

[Marek Vasut]

Add the ability to save ADC conversion result in an environment
variable. This is useful for further arbitrary processing by the
U-Boot scripts.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Fabrice Gasnier <fabrice.gasnier at foss.st.com>
Cc: Patrice Chotard <patrice.chotard at foss.st.com>
Cc: Patrick Delaunay <patrick.delaunay at foss.st.com>
Cc: Simon Glass <sjg at chromium.org>
---
V2: - Fix up commit message
    - Call adc_raw_to_uV() only once
---
 cmd/adc.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/cmd/adc.c b/cmd/adc.c
index 75739bc8eed..8de9121cad6 100644
--- a/cmd/adc.c
+++ b/cmd/adc.c
@@ -71,13 +71,17 @@ static int do_adc_info(struct cmd_tbl *cmdtp, int flag, int argc,
 static int do_adc_single(struct cmd_tbl *cmdtp, int flag, int argc,
 			 char *const argv[])
 {
+	char *varname = NULL;
 	struct udevice *dev;
 	unsigned int data;
-	int ret, uV;
+	int ret, uV, val;
 
 	if (argc < 3)
 		return CMD_RET_USAGE;
 
+	if (argc >= 3)
+		varname = argv[2];
+
 	ret = adc_channel_single_shot(argv[1], simple_strtol(argv[2], NULL, 0),
 				      &data);
 	if (ret) {
@@ -87,10 +91,16 @@ static int do_adc_single(struct cmd_tbl *cmdtp, int flag, int argc,
 	}
 
 	ret = uclass_get_device_by_name(UCLASS_ADC, argv[1], &dev);
-	if (!ret && !adc_raw_to_uV(dev, data, &uV))
+	if (!ret && !adc_raw_to_uV(dev, data, &uV)) {
+		val = uV;
 		printf("%u, %d uV\n", data, uV);
-	else
+	} else {
+		val = data;
 		printf("%u\n", data);
+	}
+
+	if (varname)
+		env_set_ulong(varname, val);
 
 	return CMD_RET_SUCCESS;
 }
@@ -149,7 +159,7 @@ static int do_adc_scan(struct cmd_tbl *cmdtp, int flag, int argc,
 static char adc_help_text[] =
 	"list - list ADC devices\n"
 	"adc info <name> - Get ADC device info\n"
-	"adc single <name> <channel> - Get Single data of ADC device channel\n"
+	"adc single <name> <channel> [varname] - Get Single data of ADC device channel\n"
 	"adc scan <name> [channel mask] - Scan all [or masked] ADC channels";
 
 U_BOOT_CMD_WITH_SUBCMDS(adc, "ADC sub-system", adc_help_text,
-- 
2.35.1