zephyr: add initial gpio shim

Add the gpioget and gpioset commands to zephyr build. This requires
a minimum set of platform/ec gpio_ API functions. Add the minimum set of
gpio_ functions. More can be added later depending on future uses

BRANCH=none
BUG=b:169935802
TEST=verify gpioget and gpioset console command work on volteer
TEST=verify that posix-ec compiles without any named_gpios in DT

Change-Id: Ie6f0b4505aa17c50c01b71fc4ea5b59393f39fce
Signed-off-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2488141
Reviewed-by: Jack Rosenthal <jrosenth@chromium.org>
Commit-Queue: Jack Rosenthal <jrosenth@chromium.org>

7 files changed, 232 insertions, 16 deletions

diff --git a/include/gpio.h b/include/gpio.h
index 92c851f91a..3fa091f4bd 100644
--- a/include/gpio.h
+++ b/include/gpio.h
@@ -11,24 +11,59 @@
 #include "common.h"
 #include "console.h"
 
-/* Flag definitions for gpio_info and gpio_alt_func */
+
+/*
+ * If compiling with Zephyr, include the GPIO_ definitions to deal with name
+ * conflicts
+ */
+#ifdef CONFIG_ZEPHYR
+#include <drivers/gpio.h>
+
+/* Validate that Zephyr's definition are the same for overlapping defines */
+#if GPIO_OPEN_DRAIN != (BIT(1) | BIT(2))
+#error GPIO_OPEN_DRAIN values are not the same!
+#elif GPIO_PULL_UP != BIT(4)
+#error GPIO_PULL_UP values are not the same!
+#elif GPIO_PULL_DOWN != BIT(5)
+#error GPIO_PULL_DOWN values are not the same!
+#elif GPIO_INPUT != BIT(8)
+#error GPIO_INPUT values are not the same!
+#elif GPIO_OUTPUT != BIT(9)
+#error GPIO_PULL_DOWN values are not the same!
+#endif
+
+/* Otherwise define overlapping GPIO_ flags ourselves */
+#else /* !CONFIG_ZEPHYR */
+#define GPIO_OPEN_DRAIN    (BIT(1) | BIT(2))  /* Output type is open-drain */
+#define GPIO_PULL_UP       BIT(4)  /* Enable on-chip pullup */
+#define GPIO_PULL_DOWN     BIT(5)  /* Enable on-chip pulldown */
+#define GPIO_INPUT         BIT(8)  /* Input */
+#define GPIO_OUTPUT        BIT(9)  /* Output */
+#endif /* CONFIG_ZEPHYR */
+
+/*
+ * All flags supported by gpio_info expect GPIO_ANALOG
+ *
+ * Only 4 flags are supported by gpio_alt_func:
+ *   GPIO_OPEN_DRAIN
+ *   GPIO_PULL_UP
+ *   GPIO_PULL_DOWN
+ *   GPIO_PULL_ANALOG
+ */
 #define GPIO_FLAG_NONE     0       /* No flag needed, default setting */
-/* The following are valid for both gpio_info and gpio_alt_func: */
-#define GPIO_OPEN_DRAIN    BIT(0)  /* Output type is open-drain */
-#define GPIO_PULL_UP       BIT(1)  /* Enable on-chip pullup */
-#define GPIO_PULL_DOWN     BIT(2)  /* Enable on-chip pulldown */
-/* The following are valid for gpio_alt_func only */
-#define GPIO_ANALOG        BIT(3)  /* Set pin to analog-mode */
-/* The following are valid for gpio_info only */
-#define GPIO_INPUT         BIT(4)  /* Input */
-#define GPIO_OUTPUT        BIT(5)  /* Output */
+#define GPIO_ANALOG        BIT(0)  /* Set pin to analog-mode */
+/* GPIO_OPEN_DRAIN         BIT(1) | BIT(2)  Output type is open-drain */
+#define GPIO_DEFAULT       BIT(3) /* Don't set up on boot */
+/* GPIO_PULL_UP            BIT(4)    Enable on-chip pullup */
+/* GPIO_PULL_DOWN          BIT(5)    Enable on-chip pulldown */
 #define GPIO_LOW           BIT(6)  /* If GPIO_OUTPUT, set level low */
 #define GPIO_HIGH          BIT(7)  /* If GPIO_OUTPUT, set level high */
-#define GPIO_INT_F_RISING  BIT(8)  /* Interrupt on rising edge */
-#define GPIO_INT_F_FALLING BIT(9)  /* Interrupt on falling edge */
-#define GPIO_INT_F_LOW     BIT(11) /* Interrupt on low level */
-#define GPIO_INT_F_HIGH    BIT(12) /* Interrupt on high level */
-#define GPIO_DEFAULT       BIT(13) /* Don't set up on boot */
+/* GPIO_INPUT              BIT(8)     Input */
+/* GPIO_OUTPUT             BIT(9)     Output */
+#define GPIO_INT_F_RISING  BIT(10) /* Interrupt on rising edge */
+#define GPIO_INT_F_FALLING BIT(11) /* Interrupt on falling edge */
+#define GPIO_INT_F_LOW     BIT(12) /* Interrupt on low level */
+#define GPIO_INT_F_HIGH    BIT(13) /* Interrupt on high level */
 #define GPIO_INT_DSLEEP    BIT(14) /* Interrupt in deep sleep */
 #define GPIO_INT_SHARED    BIT(15) /* Shared among multiple pins */
 #define GPIO_SEL_1P8V      BIT(16) /* Support 1.8v */
diff --git a/zephyr/CMakeLists.txt b/zephyr/CMakeLists.txt
index 60eca34519..cac731a2bc 100644
--- a/zephyr/CMakeLists.txt
+++ b/zephyr/CMakeLists.txt
@@ -37,3 +37,4 @@ add_subdirectory_ifdef(CONFIG_PLATFORM_EC "shim/src")
 # Shimmed modules
 zephyr_sources_ifdef(CONFIG_PLATFORM_EC "${PLATFORM_EC}/common/base32.c")
 zephyr_sources_ifdef(CONFIG_PLATFORM_EC_TIMER "${PLATFORM_EC}/common/timer.c")
+zephyr_sources_ifdef(CONFIG_SHELL "${PLATFORM_EC}/common/gpio_commands.c")
diff --git a/zephyr/shim/include/board.h b/zephyr/shim/include/board.h
index 01f9344a8a..62bb1b23e2 100644
--- a/zephyr/shim/include/board.h
+++ b/zephyr/shim/include/board.h
@@ -6,6 +6,13 @@
 #ifndef __BOARD_H
 #define __BOARD_H
 
-/* Intentionally empty. */
+#include <devicetree.h>
+
+/* Included shimed version of gpio signal. */
+#include <gpio_signal.h>
+/* Include board specific gpio mapping/aliases if named_pgios node exists */
+#if DT_NODE_EXISTS(DT_PATH(named_gpios))
+#include <gpio_map.h>
+#endif
 
 #endif  /* __BOARD_H */
diff --git a/zephyr/shim/include/gpio_signal.h b/zephyr/shim/include/gpio_signal.h
new file mode 100644
index 0000000000..698ef126bb
--- /dev/null
+++ b/zephyr/shim/include/gpio_signal.h
@@ -0,0 +1,29 @@
+/* Copyright 2020 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef __CROS_EC_GPIO_SIGNAL_H
+#define __CROS_EC_GPIO_SIGNAL_H
+
+#include <devicetree.h>
+
+#define GPIO_SIGNAL(id) _CONCAT(GPIO_, id)
+#define GPIO_SIGNAL_WITH_COMMA(id) GPIO_SIGNAL(id),
+enum gpio_signal {
+#if DT_NODE_EXISTS(DT_PATH(named_gpios))
+	DT_FOREACH_CHILD(DT_PATH(named_gpios), GPIO_SIGNAL_WITH_COMMA)
+#endif
+	GPIO_COUNT
+};
+#undef GPIO_SIGNAL_WITH_COMMA
+
+/** @brief Converts a node identifier under named gpios to enum
+ *
+ * Converts the specified node identifier name, which should be nested under
+ * the named_gpios node, into the correct enum gpio_signal that can be used
+ * with platform/ec gpio API
+ */
+#define NAMED_GPIO(name) GPIO_SIGNAL(DT_PATH(named_gpios, name))
+
+#endif  /* __CROS_EC_GPIO_SIGNAL_H */
diff --git a/zephyr/shim/src/CMakeLists.txt b/zephyr/shim/src/CMakeLists.txt
index f87b114949..b56557deb9 100644
--- a/zephyr/shim/src/CMakeLists.txt
+++ b/zephyr/shim/src/CMakeLists.txt
@@ -4,4 +4,5 @@
 
 zephyr_sources(console.c)
 zephyr_sources(util.c)
+zephyr_sources(gpio.c)
 zephyr_sources_ifdef(CONFIG_PLATFORM_EC_TIMER hwtimer.c)
diff --git a/zephyr/shim/src/gpio.c b/zephyr/shim/src/gpio.c
new file mode 100644
index 0000000000..96d982052c
--- /dev/null
+++ b/zephyr/shim/src/gpio.c
@@ -0,0 +1,130 @@
+/* Copyright 2020 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <device.h>
+#include <gpio.h>
+#include <init.h>
+#include <kernel.h>
+#include <logging/log.h>
+
+LOG_MODULE_REGISTER(gpio_shim, LOG_LEVEL_ERR);
+
+/*
+ * Static information about each GPIO that is configured in the named_gpios
+ * device tree node.
+ */
+struct gpio_config {
+	const char *name;	 /* GPIO net name */
+	const char *dev_name;	 /* Set at build time for lookup */
+	gpio_pin_t pin;		 /* Bit number of pin within device */
+	gpio_flags_t init_flags; /* From build time */
+};
+
+#define GPIO_CONFIG(id)                                      \
+	{                                                    \
+		.name = DT_LABEL(id),                        \
+		.dev_name = DT_LABEL(DT_PHANDLE(id, gpios)), \
+		.pin = DT_GPIO_PIN(id, gpios),               \
+		.init_flags = DT_GPIO_FLAGS(id, gpios),      \
+	},
+static const struct gpio_config configs[] = {
+#if DT_NODE_EXISTS(DT_PATH(named_gpios))
+	DT_FOREACH_CHILD(DT_PATH(named_gpios), GPIO_CONFIG)
+#endif
+};
+
+/* Runtime information for each GPIO that is configured in named_gpios */
+struct gpio_data {
+	const struct device *dev; /* Set during in init function */
+};
+
+#define GPIO_DATA(id) { },
+static struct gpio_data data[] = {
+#if DT_NODE_EXISTS(DT_PATH(named_gpios))
+	DT_FOREACH_CHILD(DT_PATH(named_gpios), GPIO_DATA)
+#endif
+};
+
+
+int gpio_is_implemented(enum gpio_signal signal)
+{
+	/* All GPIOs listed in Device Tree are consider implemented */
+	return 1;
+}
+
+int gpio_get_level(enum gpio_signal signal)
+{
+	const int l = gpio_pin_get_raw(data[signal].dev, configs[signal].pin);
+
+	if (l < 0) {
+		LOG_ERR("Cannot read %s (%d)", configs[signal].name, l);
+		return 0;
+	}
+	return l;
+}
+
+const char *gpio_get_name(enum gpio_signal signal)
+{
+	return configs[signal].name;
+}
+
+void gpio_set_level(enum gpio_signal signal, int value)
+{
+	int rv;
+
+	if (value != 0) {
+		rv = gpio_port_set_bits_raw(data[signal].dev,
+					    BIT(configs[signal].pin));
+	} else {
+		rv = gpio_port_clear_bits_raw(data[signal].dev,
+					      BIT(configs[signal].pin));
+	}
+
+	if (rv < 0) {
+		LOG_ERR("Cannot write %s (%d)", configs[signal].name, rv);
+	}
+}
+
+static int convert_from_zephyr_flags(const gpio_flags_t zephyr)
+{
+	int ec_flags = 0;
+
+	/*
+	 * Convert from Zephyr flags to EC flags. Note that a few flags have
+	 * the same value in both builds environments (e.g. GPIO_OUTPUT)
+	 */
+	if (zephyr | GPIO_OUTPUT) {
+		ec_flags |= GPIO_OUTPUT;
+	}
+
+	return ec_flags;
+}
+
+int gpio_get_default_flags(enum gpio_signal signal)
+{
+	return convert_from_zephyr_flags(configs[signal].init_flags);
+}
+
+static int init_gpios(const struct device *unused)
+{
+	ARG_UNUSED(unused);
+
+	for (size_t i = 0; i < ARRAY_SIZE(configs); ++i) {
+		data[i].dev = device_get_binding(configs[i].dev_name);
+
+		if (data[i].dev == NULL) {
+			LOG_ERR("Not found (%s)", configs[i].name);
+		}
+
+		const int rv = gpio_pin_configure(data[i].dev, configs[i].pin,
+						  configs[i].init_flags);
+
+		if (rv < 0) {
+			LOG_ERR("Config failed %s (%d)", configs[i].name, rv);
+		}
+	}
+	return 0;
+}
+SYS_INIT(init_gpios, PRE_KERNEL_1, 50);
diff --git a/zephyr/shim/src/util.c b/zephyr/shim/src/util.c
index 998a0db01d..6cd6e0dc68 100644
--- a/zephyr/shim/src/util.c
+++ b/zephyr/shim/src/util.c
@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <stdlib.h>
+#include <ctype.h>
 
 /* Int and Long are same size, just forward to existing Long implementation */
 int strtoi(const char *nptr, char **endptr, int base)
@@ -12,3 +13,15 @@ int strtoi(const char *nptr, char **endptr, int base)
 	return strtol(nptr, endptr, base);
 }
 BUILD_ASSERT(sizeof(int) == sizeof(long));
+
+int strcasecmp(const char *s1, const char *s2)
+{
+	int diff;
+
+	do {
+		diff = tolower(*s1) - tolower(*s2);
+		if (diff)
+			return diff;
+	} while (*(s1++) && *(s2++));
+	return 0;
+}