Move looking at write protect GPIO to button/switches module

Since that already monitors the WP signal for reporting it as a
switch.  And if we have that code in two places and the WP signal
polarity changes, we'll inevitably forget to change it in the other
place...

BUG=chrome-os-partner:11150
TEST=manual

flashinfo -> WP pin asserted
remove WP screw
flashinfo -> WP pin deasserted

Change-Id: I6091c8bb470c357e02ede8a5b184b2a76b70dc60
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/27720

3 files changed, 22 insertions, 9 deletions

diff --git a/chip/lm4/power_button.c b/chip/lm4/power_button.c
index 55bc92e041..93dd42e944 100644
--- a/chip/lm4/power_button.c
+++ b/chip/lm4/power_button.c
@@ -345,6 +345,11 @@ int power_lid_open_debounced(void)
 	return debounced_lid_open;
 }
 
+int write_protect_asserted(void)
+{
+	return gpio_get_level(GPIO_WRITE_PROTECT);
+}
+
 /*****************************************************************************/
 /* Task / state machine */
 
diff --git a/common/flash_common.c b/common/flash_common.c
index c9fb74aebf..5ee966e06a 100644
--- a/common/flash_common.c
+++ b/common/flash_common.c
@@ -8,8 +8,8 @@
 #include "config.h"
 #include "console.h"
 #include "flash.h"
-#include "gpio.h"
 #include "host_command.h"
+#include "power_button.h"
 #include "registers.h"
 #include "shared_mem.h"
 #include "system.h"
@@ -40,19 +40,22 @@ int stuck_locked;  /* Is physical flash stuck protected? */
 
 static struct persist_state pstate; /* RAM copy of pstate data */
 
-
 /* Return non-zero if the write protect pin is asserted */
 static int wp_pin_asserted(void)
 {
-#ifdef CHIP_stm32
+#ifdef BOARD_link
+	return write_protect_asserted();
+#elif defined(CHIP_stm32)
 	/* TODO (vpalatin) : write protect scheme for stm32 */
-	return 1; /* Always enable write protect until we have WP pin.
-		   * For developer to unlock WP, please use stm32mon -u and
-		   * immediately re-program the pstate sector (so that
-		   * apply_pstate() has no chance to run).
-		   */
+	/*
+	 * Always enable write protect until we have WP pin.  For developer to
+	 * unlock WP, please use stm32mon -u and immediately re-program the
+	 * pstate sector (so that apply_pstate() has no chance to run).
+	 */
+	return 1;
 #else
-	return gpio_get_level(GPIO_WRITE_PROTECT);
+	/* Other boards don't have a WP pin */
+	return 0;
 #endif
 }
 
diff --git a/include/power_button.h b/include/power_button.h
index 7e99690185..bc80bfb54c 100644
--- a/include/power_button.h
+++ b/include/power_button.h
@@ -29,4 +29,9 @@ int power_ac_present(void);
  */
 int power_lid_open_debounced(void);
 
+/**
+ * Return non-zero if write protect signal is asserted.
+ */
+int write_protect_asserted(void);
+
 #endif  /* __CROS_EC_POWER_BUTTON_H */