cmd: Add a mux command

This command lets the user list, select, and deselect mux controllers
introduced with the mux framework on the fly. It has 3 subcommands:
list, select, and deselect.

List: Lists all the mux present on the system. The muxes are listed for
each chip. The chip is identified by its device name. Each chip can have
a number of mux controllers. Each is listed in sequence and is assigned
a sequential ID based on its position in the mux chip. It lists details
like ID, whether the mux is currently selected or not, the current
state, the idle state, and the number of states.

A sample output would look something like:

=> mux list
a-mux-controller:
	ID	Selected	Current State	Idle State	Num States
	0	no        	unknown   	as-is     	0x4
	1	no        	0x2       	0x2       	0x10
	2	no        	0x73      	0x73      	0x100

another-mux-controller:
	ID	Selected	Current State	Idle State	Num States
        0       no              0x1             0x1             0x4
        1       no              0x2             0x2             0x4

Select: Selects a given mux and puts it in the specified state. This
subcommand takes 3 arguments: mux chip, mux ID, state to set
the mux in. The arguments mux chip and mux ID are used to identify which
mux needs to be selected, and then it is selected to the given state.
The mux needs to be deselected before it can be selected again in
another state. The state should be a hexadecimal number.

For example:
=> mux list
a-mux-controller:
        ID      Selected        Current State   Idle State      Num States
        0       no              0x1             0x1             0x4
        1       no              0x1             0x1             0x4
=> mux select a-mux-controller 0 0x3
=> mux list
a-mux-controller:
        ID      Selected        Current State   Idle State      Num States
        0       yes             0x3             0x1             0x4
        1       no              0x1             0x1             0x4

Deselect: Deselects a given mux and puts it in its idle state. This
subcommand takes 2 arguments: the mux chip and mux ID to identify which
mux needs to be deselected. So in the above example, we can deselect mux
0 using:

=> mux deselect a-mux-controller 0
=> mux list
a-mux-controller:
        ID      Selected        Current State   Idle State      Num States
        0       no              0x1             0x1             0x4
        1       no              0x1             0x1             0x4

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

3 files changed, 191 insertions, 0 deletions

diff --git a/cmd/Kconfig b/cmd/Kconfig
index 11f299da2b..58864f6448 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1081,6 +1081,12 @@ config CMD_MTD
 	help
 	  MTD commands support.
 
+config CMD_MUX
+	bool "mux"
+	depends on MULTIPLEXER
+	help
+	 List, select, and deselect mux controllers on the fly.
+
 config CMD_NAND
 	bool "nand"
 	default y if NAND_SUNXI
diff --git a/cmd/Makefile b/cmd/Makefile
index da4e0600b2..0cbee6c2f8 100644
--- a/cmd/Makefile
+++ b/cmd/Makefile
@@ -105,6 +105,7 @@ obj-$(CONFIG_CMD_CLONE) += clone.o
 ifneq ($(CONFIG_CMD_NAND)$(CONFIG_CMD_SF),)
 obj-y += legacy-mtd-utils.o
 endif
+obj-$(CONFIG_CMD_MUX) += mux.o
 obj-$(CONFIG_CMD_NAND) += nand.o
 obj-$(CONFIG_CMD_NET) += net.o
 obj-$(CONFIG_CMD_NVEDIT_EFI) += nvedit_efi.o
diff --git a/cmd/mux.c b/cmd/mux.c
new file mode 100644
index 0000000000..833266f08b
--- /dev/null
+++ b/cmd/mux.c
@@ -0,0 +1,184 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * List, select, and deselect mux controllers on the fly.
+ *
+ * Copyright (c) 2020 Texas Instruments Inc.
+ * Author: Pratyush Yadav <p.yadav@ti.com>
+ */
+
+#include <common.h>
+#include <command.h>
+#include <errno.h>
+#include <dm.h>
+#include <dm/device_compat.h>
+#include <mux.h>
+#include <mux-internal.h>
+#include <linux/err.h>
+#include <dt-bindings/mux/mux.h>
+
+#define COLUMN_SIZE 16
+
+/*
+ * Print a member of a column. The total size of the text printed, including
+ * trailing whitespace, will always be COLUMN_SIZE.
+ */
+#define PRINT_COLUMN(fmt, args...) do {					\
+	char buf[COLUMN_SIZE + 1];					\
+	snprintf(buf, COLUMN_SIZE + 1, fmt, ##args);			\
+	printf("%-*s", COLUMN_SIZE, buf);				\
+} while (0)
+
+/*
+ * Find a mux based on its device name in argv[1] and index in the chip in
+ * argv[2].
+ */
+static struct mux_control *cmd_mux_find(char *const argv[])
+{
+	struct udevice *dev;
+	struct mux_chip *chip;
+	int ret;
+	unsigned long id;
+
+	ret = strict_strtoul(argv[2], 10, &id);
+	if (ret)
+		return ERR_PTR(ret);
+
+	ret = uclass_get_device_by_name(UCLASS_MUX, argv[1], &dev);
+	if (ret)
+		return ERR_PTR(ret);
+
+	chip = dev_get_uclass_priv(dev);
+	if (!chip)
+		return ERR_PTR(ret);
+
+	if (id >= chip->controllers)
+		return ERR_PTR(-EINVAL);
+
+	return &chip->mux[id];
+}
+
+/*
+ * Print the details of a mux. The columns printed correspond to: "Selected",
+ * "Current State", "Idle State", and "Num States".
+ */
+static void print_mux(struct mux_control *mux)
+{
+	PRINT_COLUMN("%s", mux->in_use ? "yes" : "no");
+
+	if (mux->cached_state == MUX_IDLE_AS_IS)
+		PRINT_COLUMN("%s", "unknown");
+	else
+		PRINT_COLUMN("0x%x", mux->cached_state);
+
+	if (mux->idle_state == MUX_IDLE_AS_IS)
+		PRINT_COLUMN("%s", "as-is");
+	else if (mux->idle_state == MUX_IDLE_DISCONNECT)
+		PRINT_COLUMN("%s", "disconnect");
+	else
+		PRINT_COLUMN("0x%x", mux->idle_state);
+
+	PRINT_COLUMN("0x%x", mux->states);
+
+	printf("\n");
+}
+
+static int do_mux_list(struct cmd_tbl *cmdtp, int flag, int argc,
+		       char *const argv[])
+{
+	struct udevice *dev;
+	struct mux_chip *chip;
+	int j;
+
+	for (uclass_first_device(UCLASS_MUX, &dev);
+	     dev;
+	     uclass_next_device(&dev)) {
+		chip = dev_get_uclass_priv(dev);
+		if (!chip) {
+			dev_err(dev, "can't find mux chip\n");
+			continue;
+		}
+
+		printf("%s:\n", dev->name);
+
+		printf("    ");
+		PRINT_COLUMN("ID");
+		PRINT_COLUMN("Selected");
+		PRINT_COLUMN("Current State");
+		PRINT_COLUMN("Idle State");
+		PRINT_COLUMN("Num States");
+		printf("\n");
+		for (j = 0; j < chip->controllers; j++) {
+			printf("    ");
+			PRINT_COLUMN("%d", j);
+			print_mux(&chip->mux[j]);
+		}
+		printf("\n");
+	}
+
+	return 0;
+}
+
+static int do_mux_select(struct cmd_tbl *cmdtp, int flag, int argc,
+			 char *const argv[])
+{
+	struct mux_control *mux;
+	int ret;
+	unsigned long state;
+
+	if (argc != 4)
+		return CMD_RET_USAGE;
+
+	mux = cmd_mux_find(argv);
+	if (IS_ERR_OR_NULL(mux)) {
+		printf("Failed to find the specified mux\n");
+		return CMD_RET_FAILURE;
+	}
+
+	ret = strict_strtoul(argv[3], 16, &state);
+	if (ret) {
+		printf("Invalid state\n");
+		return CMD_RET_FAILURE;
+	}
+
+	ret = mux_control_select(mux, state);
+	if (ret) {
+		printf("Failed to select requested state\n");
+		return CMD_RET_FAILURE;
+	}
+
+	return CMD_RET_SUCCESS;
+}
+
+static int do_mux_deselect(struct cmd_tbl *cmdtp, int flag, int argc,
+			   char *const argv[])
+{
+	struct mux_control *mux;
+	int ret;
+
+	if (argc != 3)
+		return CMD_RET_USAGE;
+
+	mux = cmd_mux_find(argv);
+	if (IS_ERR_OR_NULL(mux)) {
+		printf("Failed to find the specified mux\n");
+		return CMD_RET_FAILURE;
+	}
+
+	ret = mux_control_deselect(mux);
+	if (ret) {
+		printf("Failed to deselect mux\n");
+		return CMD_RET_FAILURE;
+	}
+
+	return CMD_RET_SUCCESS;
+}
+
+static char mux_help_text[] =
+	"list - List all Muxes and their states\n"
+	"select <chip> <id> <state> - Select the given mux state\n"
+	"deselect <chip> <id> - Deselect the given mux and reset it to its idle state";
+
+U_BOOT_CMD_WITH_SUBCMDS(mux, "List, select, and deselect muxes", mux_help_text,
+			U_BOOT_SUBCMD_MKENT(list, 1, 1, do_mux_list),
+			U_BOOT_SUBCMD_MKENT(select, 4, 0, do_mux_select),
+			U_BOOT_SUBCMD_MKENT(deselect, 3, 0, do_mux_deselect));