test: pinmux: Add test for pin muxing

This extends the pinctrl-sandbox driver to support pin muxing, and adds a
test for that behaviour. The test is done in C and not python (like the
existing tests for the pinctrl uclass) because it needs to call
pinctrl_select_state.  Another option could be to add a command that
invokes pinctrl_select_state and then test everything in
test/py/tests/test_pinmux.py.

The pinctrl-sandbox driver now mimics the way that many pinmux devices
work.  There are two groups of pins which are muxed together, as well as
four pins which are muxed individually. I have tried to test all normal
paths. However, very few error cases are explicitly checked for.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/dm/Makefile b/test/dm/Makefile
index 70ba1b6..e2b0798 100644
--- a/test/dm/Makefile
+++ b/test/dm/Makefile
@@ -81,4 +81,7 @@
 obj-$(CONFIG_SIMPLE_PM_BUS) += simple-pm-bus.o
 obj-$(CONFIG_RESET_SYSCON) += syscon-reset.o
 obj-$(CONFIG_SCMI_FIRMWARE) += scmi.o
+ifneq ($(CONFIG_PINMUX),)
+obj-$(CONFIG_PINCONF) += pinmux.o
+endif
 endif
diff --git a/test/dm/pinmux.c b/test/dm/pinmux.c
new file mode 100644
index 0000000..047184d
--- /dev/null
+++ b/test/dm/pinmux.c
@@ -0,0 +1,57 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2020 Sean Anderson <seanga2@gmail.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/pinctrl.h>
+#include <dm/test.h>
+#include <test/ut.h>
+
+static int dm_test_pinmux(struct unit_test_state *uts)
+{
+	char buf[64];
+	struct udevice *dev;
+
+#define test_muxing(selector, expected) do { \
+	ut_assertok(pinctrl_get_pin_muxing(dev, selector, buf, sizeof(buf))); \
+	ut_asserteq_str(expected, (char *)&buf); \
+} while (0)
+
+	ut_assertok(uclass_get_device_by_name(UCLASS_PINCTRL, "pinctrl", &dev));
+	test_muxing(0, "UART TX.");
+	test_muxing(1, "UART RX.");
+	test_muxing(2, "I2S SCK.");
+	test_muxing(3, "I2S SD.");
+	test_muxing(4, "I2S WS.");
+	test_muxing(5, "GPIO0 bias-pull-up input-disable.");
+	test_muxing(6, "GPIO1 drive-open-drain.");
+	test_muxing(7, "GPIO2 bias-pull-down input-enable.");
+	test_muxing(8, "GPIO3 bias-disable.");
+
+	ut_assertok(pinctrl_select_state(dev, "alternate"));
+	test_muxing(0, "I2C SCL drive-open-drain.");
+	test_muxing(1, "I2C SDA drive-open-drain.");
+	test_muxing(2, "SPI SCLK.");
+	test_muxing(3, "SPI MOSI.");
+	test_muxing(4, "SPI MISO.");
+	test_muxing(5, "SPI CS0.");
+	test_muxing(6, "SPI CS1.");
+	test_muxing(7, "GPIO2 bias-pull-down input-enable.");
+	test_muxing(8, "GPIO3 bias-disable.");
+
+	ut_assertok(pinctrl_select_state(dev, "0"));
+	test_muxing(0, "I2C SCL drive-open-drain.");
+	test_muxing(1, "I2C SDA drive-open-drain.");
+	test_muxing(2, "I2S SCK.");
+	test_muxing(3, "I2S SD.");
+	test_muxing(4, "I2S WS.");
+	test_muxing(5, "GPIO0 bias-pull-up input-disable.");
+	test_muxing(6, "GPIO1 drive-open-drain.");
+	test_muxing(7, "GPIO2 bias-pull-down input-enable.");
+	test_muxing(8, "GPIO3 bias-disable.");
+
+	return 0;
+}
+DM_TEST(dm_test_pinmux, UT_TESTF_SCAN_FDT);