Clean up configuring GPIO alternate functions

GPIO alternate functions used to be configured throughout the code,
which made it hard to tell which ones you needed to configure yourself
in board.c.  It also sometimes (chip/lm4/i2c.c) led to GPIOs being
configured as alternate functions even if they weren't used on a given
board.

With this change, every board has a table in board.c which lists ALL
GPIOs which have alternate functions.  This is now the only place
where alternate functions are configured.  Each module then calls
gpio_init_module() to set up its GPIOs.

This also fixes a bug where gpio_set_flags() ignored most of the flags
passed to it (only direction and level were actually used).

On stm32f, gpio_set_alternate() does not exist, and pins are
configured via direct register writes from board.c.  Rather than
attempt to change that in the same CL, I've stubbed out
gpio_set_alternate() for stm32f, and will fix the register writes in a
follow-up CL.

BUG=chrome-os-partner:21618
BRANCH=peppy (fixes I2C1 being initialized even though those pins are used
       for other things)
TEST=boot link, falco, pit, spring

Change-Id: I40f47025d8f767e0723c6b40c80413af9ba8deba
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/64400

1 files changed, 77 insertions, 20 deletions

diff --git a/include/gpio.h b/include/gpio.h
index 9517cf40ee..eee7711ee3 100644
--- a/include/gpio.h
+++ b/include/gpio.h
@@ -10,20 +10,24 @@
 
 #include "common.h"
 
-/* Flag definitions for gpio_info. */
-#define GPIO_INPUT       0x0000  /* Input */
-#define GPIO_OUTPUT      0x0001  /* Output */
-#define GPIO_OPEN_DRAIN  0x0002  /* Output type is open-drain */
-#define GPIO_PULL_UP     0x0004  /* Enable on-chip pullup */
-#define GPIO_PULL_DOWN   0x0008  /* Enable on-chip pulldown */
-#define GPIO_LOW         0x0010  /* If GPIO_OUTPUT, set level low */
-#define GPIO_HIGH        0x0020  /* If GPIO_OUTPUT, set level high */
-#define GPIO_INT_RISING  0x0040  /* Interrupt on rising edge */
-#define GPIO_INT_FALLING 0x0080  /* Interrupt on falling edge */
-#define GPIO_INT_BOTH    0x0100  /* Interrupt on both edges */
-#define GPIO_INT_LOW     0x0200  /* Interrupt on low level */
-#define GPIO_INT_HIGH    0x0400  /* Interrupt on high level */
-#define GPIO_DEFAULT     0x0800  /* Don't set up on boot */
+/* Flag definitions for gpio_info and gpio_alt_func */
+/* The following are valid for both gpio_info and gpio_alt_func: */
+#define GPIO_OPEN_DRAIN  (1 << 0)  /* Output type is open-drain */
+#define GPIO_PULL_UP     (1 << 1)  /* Enable on-chip pullup */
+#define GPIO_PULL_DOWN   (1 << 2)  /* Enable on-chip pulldown */
+/* The following are valid for gpio_alt_func only */
+#define GPIO_ANALOG      (1 << 3)  /* Set pin to analog-mode */
+/* The following are valid for gpio_info only */
+#define GPIO_INPUT       0         /* Input */
+#define GPIO_OUTPUT      (1 << 4)  /* Output */
+#define GPIO_LOW         (1 << 5)  /* If GPIO_OUTPUT, set level low */
+#define GPIO_HIGH        (1 << 6)  /* If GPIO_OUTPUT, set level high */
+#define GPIO_INT_RISING  (1 << 7)  /* Interrupt on rising edge */
+#define GPIO_INT_FALLING (1 << 8)  /* Interrupt on falling edge */
+#define GPIO_INT_BOTH    (1 << 9)  /* Interrupt on both edges */
+#define GPIO_INT_LOW     (1 << 10) /* Interrupt on low level */
+#define GPIO_INT_HIGH    (1 << 11) /* Interrupt on high level */
+#define GPIO_DEFAULT     (1 << 12) /* Don't set up on boot */
 
 /* Common flag combinations */
 #define GPIO_OUT_LOW     (GPIO_OUTPUT | GPIO_LOW)
@@ -37,11 +41,18 @@
 
 /* GPIO signal definition structure, for use by board.c */
 struct gpio_info {
+	/* Signal name */
 	const char *name;
-	int port;         /* Port (LM4_GPIO_*) */
-	int mask;         /* Bitmask on that port (0x01 - 0x80; 0x00 =
-			   * signal not implemented) */
-	uint32_t flags;   /* Flags (GPIO_*) */
+
+	/* Port base address */
+	uint32_t port;
+
+	/* Bitmask on that port (1 << N; 0 = signal not implemented) */
+	int mask;
+
+	/* Flags (GPIO_*; see above) */
+	uint32_t flags;
+
 	/*
 	 * Interrupt handler.  If non-NULL, and the signal's interrupt is
 	 * enabled, this will be called in the context of the GPIO interrupt
@@ -60,6 +71,27 @@ extern const struct gpio_info gpio_list[];
 #define GPIO_SIGNAL_NOT_IMPLEMENTED(name) {name, GPIO_A, 0, 0, NULL}
 #endif
 
+/* GPIO alternate function structure, for use by board.c */
+struct gpio_alt_func {
+	/* Port base address */
+	uint32_t port;
+
+	/* Bitmask on that port (multiple bits allowed) */
+	uint32_t mask;
+
+	/* Alternate function number */
+	int8_t func;
+
+	/* Module ID (as uint8_t, since enum would be 32-bit) */
+	uint8_t module_id;
+
+	/* Flags (GPIO_*; see above). */
+	uint16_t flags;
+};
+
+extern const struct gpio_alt_func gpio_alt_funcs[];
+extern const int gpio_alt_funcs_count;
+
 /**
  * Pre-initialize GPIOs.
  *
@@ -68,6 +100,14 @@ extern const struct gpio_info gpio_list[];
 void gpio_pre_init(void);
 
 /**
+ * Configure GPIO pin functions for a module.
+ *
+ * @param id		Module ID to initialize
+ * @param enable	Enable alternate functions if 1; high-Z pins if 0.
+ */
+void gpio_config_module(enum module_id id, int enable);
+
+/**
  * Get the current value of a signal.
  *
  * @param signal	Signal to get
@@ -123,11 +163,28 @@ void gpio_set_level(enum gpio_signal signal, int value);
 int gpio_enable_interrupt(enum gpio_signal signal);
 
 /**
+ * Set flags for GPIO(s) by port and mask.
+ *
+ * Use gpio_set_flags() to set flags for an individual GPIO by id.
+ *
+ * Note that modules should usually declare their GPIO alternate functions in
+ * gpio_alt_funcs[] and call gpio_init_module() instead of calling this
+ * directly.
+ *
+ * @param port		GPIO port to set (GPIO_*)
+ * @param mask		Bitmask of pins on that port to affect
+ * @param flags		Flags (GPIO_*; see above)
+ */
+void gpio_set_flags_by_mask(uint32_t port, uint32_t mask, uint32_t flags);
+
+/**
  * Set alternate function for GPIO(s).
  *
- * This is intended for use by other modules' configure_gpio() functions.
+ * Note that modules should usually declare their GPIO alternate functions in
+ * gpio_alt_funcs[] and call gpio_init_module() instead of calling this
+ * directly.
  *
- * @param port		GPIO port to set (LM4_GPIO_*)
+ * @param port		GPIO port to set (GPIO_*)
  * @param mask		Bitmask of pins on that port to affect
  * @param func		Alternate function; if <0, configures the specified
  *			GPIOs for normal GPIO operation.