Generalize revision number calculation function

Some platforms use tertiary interpretation of GPIO input state to
increase number of distinct values represented by a limited number of
GPIOs. The three states are

- external pull down (interpreted as 0)
- external pull up (1)
- not connected (2)

This has been required by Nvidia devices so far, but Exynos and
Ipq8086 platforms need this too.

This patch moves the function reading the tertiary state into the
library and exposes the necessary GPIO API functions in a new include
file. The functions are still supposed to be provided by platform
specific modules.

The function interpreting the GPIO states has been modified to allow
to interpret the state either as a true tertiary number or as a set
two bit fields.

Since linker garbage collection is not happening when building x86
targets, a new configuration option is being added to include the new
module only when needed.

BUG=chrome-os-partner:30489
TEST=verified that nyan_big still reports proper revision ID.

Change-Id: Ib55122c359629b58288c1022da83e6c63dc2264d
Original-Change-Id: I243c9f43c82bd4a41de2154bbdbd07df0a241046
Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/209673
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
(cherry picked from commit c79ef1c545d073eaad69e6c8c629f9656b8c2f3e)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>
Reviewed-on: http://review.coreboot.org/8717
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

2 files changed, 17 insertions, 74 deletions

diff --git a/src/soc/nvidia/tegra/gpio.c b/src/soc/nvidia/tegra/gpio.c
index b10cded12d..17b90aa1d9 100644
--- a/src/soc/nvidia/tegra/gpio.c
+++ b/src/soc/nvidia/tegra/gpio.c
@@ -23,6 +23,7 @@
 #include <stddef.h>
 #include <stdint.h>
 #include <delay.h>
+#include <gpiolib.h>
 
 #include "gpio.h"
 #include "pinmux.h"
@@ -175,58 +176,6 @@ int gpio_get_in_value(gpio_t gpio)
 	return (port & (1 << bit)) != 0;
 }
 
-int gpio_get_in_tristate_values(gpio_t gpio[], int num_gpio, int value[])
-{
-	/*
-	 * GPIOs which are tied to stronger external pull up or pull down
-	 * will stay there regardless of the internal pull up or pull
-	 * down setting.
-	 *
-	 * GPIOs which are floating will go to whatever level they're
-	 * internally pulled to.
-	 */
-
-	int temp;
-	int index;
-
-	/* Enable internal pull up */
-	for (index = 0; index < num_gpio; ++index)
-		gpio_input_pullup(gpio[index]);
-
-	/* Wait until signals become stable */
-	udelay(10);
-
-	/* Get gpio values at internal pull up */
-	for (index = 0; index < num_gpio; ++index)
-		value[index] = gpio_get_in_value(gpio[index]);
-
-	/* Enable internal pull down */
-	for (index = 0; index < num_gpio; ++index)
-		gpio_input_pulldown(gpio[index]);
-
-	/* Wait until signals become stable */
-	udelay(10);
-
-	/*
-	 * Get gpio values at internal pull down.
-	 * Compare with gpio pull up value and then
-	 * determine a gpio final value/state:
-	 *  0: pull down
-	 *  1: pull up
-	 *  2: floating
-	 */
-	for (index = 0; index < num_gpio; ++index) {
-		temp = gpio_get_in_value(gpio[index]);
-		value[index] = ((value[index] ^ temp) << 1) | temp;
-	}
-
-	/* Disable pull up / pull down to conserve power */
-	for (index = 0; index < num_gpio; ++index)
-		gpio_input(gpio[index]);
-
-	return 0;
-}
-
 int gpio_get_int_status(gpio_t gpio)
 {
 	int bit = gpio % GPIO_GPIOS_PER_PORT;
@@ -279,3 +228,18 @@ void gpio_set_int_clear(gpio_t gpio)
 			offsetof(struct gpio_bank, int_clear),
 			1 << bit, 1 << bit);
 }
+
+void gpio_input_pulldown(gpio_t gpio)
+{
+	__gpio_input(gpio, PINMUX_PULL_DOWN);
+}
+
+void gpio_input_pullup(gpio_t gpio)
+{
+	__gpio_input(gpio, PINMUX_PULL_UP);
+}
+
+void gpio_input(gpio_t gpio)
+{
+	__gpio_input(gpio, PINMUX_PULL_NONE);
+}
diff --git a/src/soc/nvidia/tegra/gpio.h b/src/soc/nvidia/tegra/gpio.h
index 5f6833af79..43f898958e 100644
--- a/src/soc/nvidia/tegra/gpio.h
+++ b/src/soc/nvidia/tegra/gpio.h
@@ -21,12 +21,10 @@
 #define __SOC_NVIDIA_TEGRA_GPIO_H__
 
 #include <stdint.h>
+#include <gpiolib.h>
 
 #include "pinmux.h"
 
-/* Wrapper type for GPIOs. Always use GPIO() macro to generate. */
-typedef u32 gpio_t;
-
 #define GPIO_PINMUX_SHIFT 16
 #define GPIO(name) ((gpio_t)(GPIO_##name##_INDEX | \
 			     (PINMUX_GPIO_##name << GPIO_PINMUX_SHIFT)))
@@ -46,21 +44,6 @@ static inline void gpio_output_open_drain(gpio_t gpio, int value)
 	__gpio_output(gpio, value, PINMUX_OPEN_DRAIN);
 }
 
-static inline void gpio_input(gpio_t gpio)
-{
-	__gpio_input(gpio, PINMUX_PULL_NONE);
-}
-
-static inline void gpio_input_pulldown(gpio_t gpio)
-{
-	__gpio_input(gpio, PINMUX_PULL_DOWN);
-}
-
-static inline void gpio_input_pullup(gpio_t gpio)
-{
-	__gpio_input(gpio, PINMUX_PULL_UP);
-}
-
 /* Functions to modify specific GPIO control values. */
 
 enum gpio_mode {
@@ -77,12 +60,8 @@ int gpio_get_lock(gpio_t gpio);
 void gpio_set_out_enable(gpio_t gpio, int enable);
 int gpio_get_out_enable(gpio_t gpio);
 
-void gpio_set_out_value(gpio_t gpio, int value);
 int gpio_get_out_value(gpio_t gpio);
 
-int gpio_get_in_value(gpio_t gpio);
-int gpio_get_in_tristate_values(gpio_t gpio[], int num_gpio, int value[]);
-
 int gpio_get_int_status(gpio_t gpio);
 
 void gpio_set_int_enable(gpio_t gpio, int enable);