write protect: extract checking write protect

The write-protect state can be checked on 2 pins GPIO_WP or GPIO_WP_L.
The CONFIG_WP_ACTIVE_HIGH config is used to distinguish these two cases.
Move the checking the config and pin state to a separate header file.

For Zephyr, start using the gpio_get_level function that takes into
account the GPIO_ACTIVE_LOW flag. Also, use 'gpio-wp' alias to the WP
pin instead of the legacy enum-name property and 'int-wp' alias to the
WP GPIO interrupt.

BUG=b:211779766
TEST=zmake testall & make sure WP works
BRANCH=main

Signed-off-by: Dawid Niedzwiecki <dn@semihalf.com>
Change-Id: I70bfbcd5e539fcc8cd157f2feae1a6c8e25083a4
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3447404
Reviewed-by: Andrew McRae <amcrae@google.com>
Reviewed-by: Keith Short <keithshort@chromium.org>
Commit-Queue: Keith Short <keithshort@chromium.org>

1 files changed, 43 insertions, 0 deletions

diff --git a/zephyr/shim/include/zephyr_write_protect.h b/zephyr/shim/include/zephyr_write_protect.h
new file mode 100644
index 0000000000..3d82b2ec93
--- /dev/null
+++ b/zephyr/shim/include/zephyr_write_protect.h
@@ -0,0 +1,43 @@
+/* Copyright 2022 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_ZEPHYR_WRITE_PROTECT_H
+#define __CROS_EC_ZEPHYR_WRITE_PROTECT_H
+
+#include "gpio/gpio_int.h"
+#include "gpio_signal.h"
+#include <drivers/gpio.h>
+
+/**
+ * Check the WP state. The function depends on the alias 'gpio_wp'. It is used
+ * to replace the enum-name.
+ *
+ * @return true if the WP is active, false otherwise.
+ */
+static inline int write_protect_is_asserted(void)
+{
+#ifdef CONFIG_WP_ALWAYS
+	return true;
+#else
+	return gpio_pin_get_dt(GPIO_DT_FROM_ALIAS(gpio_wp));
+#endif
+}
+
+/**
+ * Enable interrupt for WP pin. The interrupt itself has to be defined in a node
+ * with compatible = "cros-ec,gpio-interrupts" and pointed by the alias int_wp.
+ *
+ * @return 0 if success
+ */
+static inline int write_protect_enable_interrupt(void)
+{
+#if DT_NODE_EXISTS(DT_ALIAS(int_wp))
+	return gpio_enable_dt_interrupt(GPIO_INT_FROM_NODE(DT_ALIAS(int_wp)));
+#else
+	return -1;
+#endif
+}
+
+#endif /* __CROS_EC_ZEPHYR_WRITE_PROTECT_H */