cmd: adc: add an option to scan some or all available channels

Add new option to 'adc' command to do a single scan of:
- some channel(s), using mask argument
- all channels available on an ADC device (when optional mask is omitted).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/adc.c b/cmd/adc.c
index 7360a96..2d635ac 100644
--- a/cmd/adc.c
+++ b/cmd/adc.c
@@ -95,10 +95,62 @@
 	return CMD_RET_SUCCESS;
 }
 
+static int do_adc_scan(cmd_tbl_t *cmdtp, int flag, int argc,
+		       char *const argv[])
+{
+	struct adc_channel ch[ADC_MAX_CHANNEL];
+	struct udevice *dev;
+	unsigned int ch_mask;
+	int i, chan, ret, uV;
+
+	if (argc < 2)
+		return CMD_RET_USAGE;
+
+	ret = uclass_get_device_by_name(UCLASS_ADC, argv[1], &dev);
+	if (ret) {
+		pr_err("Can't get the ADC %s: %d\n", argv[1], ret);
+		return CMD_RET_FAILURE;
+	}
+
+	switch (argc) {
+	case 3:
+		ch_mask = simple_strtoul(argv[2], NULL, 0);
+		if (ch_mask)
+			break;
+	case 2:
+		ret = adc_channel_mask(dev, &ch_mask);
+		if (ret) {
+			pr_err("Can't get mask for %s: %d\n", dev->name, ret);
+			return CMD_RET_FAILURE;
+		}
+		break;
+	}
+
+	ret = adc_channels_single_shot(dev->name, ch_mask, ch);
+	if (ret) {
+		pr_err("Can't get single shot for %s (chans mask: 0x%x): %d\n",
+		       dev->name, ch_mask, ret);
+		return CMD_RET_FAILURE;
+	}
+
+	for (chan = 0, i = 0; chan < ADC_MAX_CHANNEL; chan++) {
+		if (!(ch_mask & ADC_CHANNEL(chan)))
+			continue;
+		if (!adc_raw_to_uV(dev, ch[i].data, &uV))
+			printf("[%02d]: %u, %d uV\n", ch[i].id, ch[i].data, uV);
+		else
+			printf("[%02d]: %u\n", ch[i].id, ch[i].data);
+		i++;
+	}
+
+	return CMD_RET_SUCCESS;
+}
+
 static cmd_tbl_t cmd_adc_sub[] = {
 	U_BOOT_CMD_MKENT(list, 1, 1, do_adc_list, "", ""),
 	U_BOOT_CMD_MKENT(info, 2, 1, do_adc_info, "", ""),
 	U_BOOT_CMD_MKENT(single, 3, 1, do_adc_single, "", ""),
+	U_BOOT_CMD_MKENT(scan, 3, 1, do_adc_scan, "", ""),
 };
 
 static int do_adc(cmd_tbl_t *cmdtp, int flag, int argc,
@@ -124,6 +176,7 @@
 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";
+	"adc single <name> <channel> - Get Single data of ADC device channel\n"
+	"adc scan <name> [channel mask] - Scan all [or masked] ADC channels";
 
 U_BOOT_CMD(adc, 4, 1, do_adc, "ADC sub-system", adc_help_text);