cmd: add temperature command

Currently, there is no way for users to check the readings from thermal
sensors from U-boot console, only some boards print it during boot.

So, lets add a simple "temperature" command that allows listing thermal
uclass devices and getting their value.

Note that the thermal devices are intenionally probed if list is used as
almost always they will not get probed otherwise and there is no way for
users to manually call probe on a certain device from console.

Assumption is made that temperature is returned in degrees C and not
milidegrees like in Linux as this is what most drivers seem to return.

Signed-off-by: Robert Marko <robert.marko@sartura.hr>
Reviewed-by: Simon Glass <sjg@chromium.org>

cmd/Kconfig

@@ -1454,6 +1454,12 @@ config DEFAULT_SPI_MODE
 	depends on CMD_SPI
 	default 0
 
+config CMD_TEMPERATURE
+	bool "temperature - display the temperature from thermal sensors"
+	depends on DM_THERMAL
+	help
+	  Provides a way to list thermal sensors and to get their readings.
+
 config CMD_TSI148
 	bool "tsi148 - Command to access tsi148 device"
 	help

cmd/Makefile

@@ -156,6 +156,7 @@ obj-$(CONFIG_CMD_STRINGS) += strings.o
 obj-$(CONFIG_CMD_SMC) += smccc.o
 obj-$(CONFIG_CMD_SYSBOOT) += sysboot.o
 obj-$(CONFIG_CMD_STACKPROTECTOR_TEST) += stackprot_test.o
+obj-$(CONFIG_CMD_TEMPERATURE) += temperature.o
 obj-$(CONFIG_CMD_TERMINAL) += terminal.o
 obj-$(CONFIG_CMD_TIME) += time.o
 obj-$(CONFIG_CMD_TIMER) += timer.o

cmd/temperature.c

@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+/*
+ * Copyright (c) 2022 Sartura Ltd.
+ * Written by Robert Marko <robert.marko@sartura.hr>
+ */
+
+#include <common.h>
+#include <command.h>
+#include <dm.h>
+#include <thermal.h>
+
+#define LIMIT_DEVNAME	30
+
+static int do_get(struct cmd_tbl *cmdtp, int flag, int argc,
+		  char *const argv[])
+{
+	struct udevice *dev;
+	int ret, temp;
+
+	if (argc < 2) {
+		printf("thermal device not selected\n");
+		return CMD_RET_FAILURE;
+	}
+
+	ret = uclass_get_device_by_name(UCLASS_THERMAL, argv[1], &dev);
+	if (ret) {
+		printf("thermal device not found\n");
+		return CMD_RET_FAILURE;
+	}
+
+	ret = thermal_get_temp(dev, &temp);
+	if (ret)
+		return CMD_RET_FAILURE;
+
+	printf("%s: %d C\n", dev->name, temp);
+
+	return CMD_RET_SUCCESS;
+}
+
+static int do_list(struct cmd_tbl *cmdtp, int flag, int argc,
+		   char *const argv[])
+{
+	struct udevice *dev;
+
+	printf("| %-*.*s| %-*.*s| %s\n",
+	       LIMIT_DEVNAME, LIMIT_DEVNAME, "Device",
+	       LIMIT_DEVNAME, LIMIT_DEVNAME, "Driver",
+	       "Parent");
+
+	uclass_foreach_dev_probe(UCLASS_THERMAL, dev) {
+		printf("| %-*.*s| %-*.*s| %s\n",
+		       LIMIT_DEVNAME, LIMIT_DEVNAME, dev->name,
+		       LIMIT_DEVNAME, LIMIT_DEVNAME, dev->driver->name,
+		       dev->parent->name);
+	}
+
+	return CMD_RET_SUCCESS;
+}
+
+static struct cmd_tbl temperature_subcmd[] = {
+	U_BOOT_CMD_MKENT(list, 1, 1, do_list, "", ""),
+	U_BOOT_CMD_MKENT(get, 2, 1, do_get, "", ""),
+};
+
+static int do_temperature(struct cmd_tbl *cmdtp, int flag, int argc,
+			  char *const argv[])
+{
+	struct cmd_tbl *cmd;
+
+	argc--;
+	argv++;
+
+	cmd = find_cmd_tbl(argv[0], temperature_subcmd, ARRAY_SIZE(temperature_subcmd));
+	if (!cmd || argc > cmd->maxargs)
+		return CMD_RET_USAGE;
+
+	return cmd->cmd(cmdtp, flag, argc, argv);
+}
+
+U_BOOT_CMD(temperature, CONFIG_SYS_MAXARGS, 1, do_temperature,
+	   "thermal sensor temperature",
+	   "list\t\tshow list of temperature sensors\n"
+	   "get [thermal device name]\tprint temperature in degrees C"
+);