w1: add command for onewire protocol

Add basic command for bus information and read for onewire
bus using Dallas 1-Wire protocol.

Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>

cmd/Kconfig

@@ -832,6 +832,13 @@ config CMD_I2C
 	help
 	  I2C support.
 
+config CMD_W1
+	depends on W1
+	default y if W1
+	bool "w1 - Support for Dallas 1-Wire protocol"
+	help
+	  Dallas 1-wire protocol support
+
 config CMD_LOADB
 	bool "loadb"
 	default y

cmd/Makefile

@@ -146,6 +146,7 @@ obj-$(CONFIG_CMD_THOR_DOWNLOAD) += thordown.o
 obj-$(CONFIG_CMD_XIMG) += ximg.o
 obj-$(CONFIG_CMD_YAFFS2) += yaffs2.o
 obj-$(CONFIG_CMD_SPL) += spl.o
+obj-$(CONFIG_CMD_W1) += w1.o
 obj-$(CONFIG_CMD_ZIP) += zip.o
 obj-$(CONFIG_CMD_ZFS) += zfs.o
 

cmd/w1.c

@@ -0,0 +1,126 @@
+/* SPDX-License-Identifier: GPL-2.0+
+ *
+ * (C) Copyright 2018
+ * Microchip Technology, Inc.
+ * Eugen Hristev <eugen.hristev@microchip.com>
+ */
+#include <common.h>
+#include <command.h>
+#include <w1.h>
+#include <w1-eeprom.h>
+#include <dm/device-internal.h>
+
+static int w1_bus(void)
+{
+	struct udevice *bus, *dev;
+	int ret;
+
+	ret = w1_get_bus(0, &bus);
+	if (ret) {
+		printf("one wire interface not found\n");
+		return CMD_RET_FAILURE;
+	}
+	printf("Bus %d:\t%s", bus->seq, bus->name);
+	if (device_active(bus))
+		printf("  (active)");
+	printf("\n");
+
+	for (device_find_first_child(bus, &dev);
+	     dev;
+	     device_find_next_child(&dev)) {
+		ret = device_probe(dev);
+
+		printf("\t%s (%d) uclass %s : ", dev->name, dev->seq,
+		       dev->uclass->uc_drv->name);
+
+		if (ret)
+			printf("device error\n");
+		else
+			printf("family 0x%x\n", w1_get_device_family(dev));
+	}
+	return CMD_RET_SUCCESS;
+}
+
+static int w1_read(int argc, char *const argv[])
+{
+	int bus_n = 0, dev_n = 0, offset = 0, len = 512;
+	int i;
+	struct udevice *bus, *dev;
+	int ret;
+	u8 buf[512];
+
+	if (argc > 2)
+		bus_n = simple_strtoul(argv[2], NULL, 10);
+
+	if (argc > 3)
+		dev_n = simple_strtoul(argv[3], NULL, 10);
+
+	if (argc > 4)
+		offset = simple_strtoul(argv[4], NULL, 10);
+
+	if (argc > 5)
+		len = simple_strtoul(argv[5], NULL, 10);
+
+	if (len > 512) {
+		printf("len needs to be <= 512\n");
+		return CMD_RET_FAILURE;
+	}
+
+	ret = w1_get_bus(bus_n, &bus);
+	if (ret) {
+		printf("one wire interface not found\n");
+		return CMD_RET_FAILURE;
+	}
+
+	for (device_find_first_child(bus, &dev), i = 0;
+	   dev && i <= dev_n;
+	   device_find_next_child(&dev), i++) {
+		ret = device_probe(dev);
+		if (!ret && i == dev_n)
+			break;
+	}
+
+	if (i != dev_n || ret || !dev) {
+		printf("invalid dev\n");
+		return CMD_RET_FAILURE;
+	}
+
+	if (strcmp(dev->uclass->uc_drv->name, "w1_eeprom")) {
+		printf("the device present on the interface is of unknown device class\n");
+		return CMD_RET_FAILURE;
+	}
+
+	ret = w1_eeprom_read_buf(dev, offset, (u8 *)buf, len);
+	if (ret) {
+		printf("error reading device %s\n", dev->name);
+		return CMD_RET_FAILURE;
+	}
+
+	for (i = 0; i < len; i++)
+		printf("%x", buf[i]);
+	printf("\n");
+
+	return CMD_RET_SUCCESS;
+}
+
+int do_w1(cmd_tbl_t *cmdtp, int flag, int argc, char *const argv[])
+{
+	if (argc < 2)
+		return CMD_RET_USAGE;
+
+	if (!strcmp(argv[1], "bus"))
+		return w1_bus();
+
+	if (!strcmp(argv[1], "read"))
+		return w1_read(argc, argv);
+
+	return CMD_RET_SUCCESS;
+}
+
+U_BOOT_CMD(w1, 6, 0, do_w1,
+	   "onewire interface utility commands",
+	   "bus - show onewire bus info (all)\n"
+	   "w1 read [<bus> [<dev> [offset [length]]]]"
+	   "    - read from onewire device 'dev' on onewire bus 'bus'"
+	   " starting from offset 'offset' and length 'length'\n"
+	   "      defaults: bus 0, dev 0, offset 0, length 512 bytes.");