Cr50: Add DIO_PULL_UP and DIO_PULL_DOWN flags

In board/*/gpio.inc, we can specify pullups and pulldowns on pads
connected to GPIOs, like so:

  GPIO(SOME_BUTTON, PIN(0,0), GPIO_INPUT | GPIO_PULL_UP)

This adds flags to do the same thing for pads that connect to
internal periperals:

  PINMUX(FUNC(UART0_RX), A1, DIO_PULL_UP)

BUG=chrome-os-partner:51410
BRANCH=none
TEST=make buildall; manual test on Cr50

I added these flags to the gpio.inc file and tested the result:

  PINMUX(FUNC(I2C0_SCL),        B0, DIO_INPUT | DIO_PULL_UP)
  PINMUX(FUNC(I2C0_SDA),        B1, DIO_INPUT | DIO_PULL_DOWN)

The "pinmux" console command showed that the new flags took effect:

Before:

  400600a0: DIOB0    0  IN
  400600a8: DIOB1    0  IN

After:

  400600a0: DIOB0    0  IN PU
  400600a8: DIOB1    0  IN PD

Change-Id: I1d212331431ef67b2f1bcece8729d092b9ad5ba8
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/339254
Reviewed-by: Dominic Rizzo <domrizzo@google.com>

2 files changed, 32 insertions, 8 deletions

diff --git a/chip/g/gpio.c b/chip/g/gpio.c
index 64c441bcbd..b03d951258 100644
--- a/chip/g/gpio.c
+++ b/chip/g/gpio.c
@@ -188,16 +188,37 @@ static int connect_dio_to_gpio(struct pinmux const *p)
 static void connect_pinmux(struct pinmux const *p)
 {
 	uint32_t bitmask;
+	int is_input;
+
+	if (p->flags & DIO_ENABLE_DIRECT_INPUT) {
+		/* We don't have to setup any muxes for directly connected
+		 * pads. The only ones that we are likely to ever care about
+		 * are tied to the SPS and SPI peripherals, and they're all
+		 * inouts, so we can just enable the digital input for them
+		 * regardless. */
+		is_input = 1;
+	} else {
+		/* Pads that must be muxed to specific GPIOs or peripherals may
+		 * or may not be inputs. We'll check those individually. */
+		if (p->flags & DIO_TO_PERIPHERAL)
+			is_input = connect_dio_to_peripheral(p);
+		else
+			is_input = connect_dio_to_gpio(p);
+	}
 
-	/* Connect the pinmux DIO to the right thing */
-	if ((p->flags & DIO_ENABLE_DIRECT_INPUT) ||
-	    ((p->flags & DIO_TO_PERIPHERAL) ?
-	     connect_dio_to_peripheral(p) :
-	     connect_dio_to_gpio(p)))
-		/* and maybe enable the pin as an input */
+	/* Configure the DIO pad controls */
+	if (is_input)
 		REG_WRITE_MLV(DIO_CTL_REG(p->dio.offset),
 			      DIO_CTL_IE_MASK,
 			      DIO_CTL_IE_LSB, 1);
+	if (p->flags & DIO_PULL_UP)
+		REG_WRITE_MLV(DIO_CTL_REG(p->dio.offset),
+			      DIO_CTL_PU_MASK,
+			      DIO_CTL_PU_LSB, 1);
+	if (p->flags & DIO_PULL_DOWN)
+		REG_WRITE_MLV(DIO_CTL_REG(p->dio.offset),
+			      DIO_CTL_PD_MASK,
+			      DIO_CTL_PD_LSB, 1);
 
 	/* Enable any wake pins needed to exit low-power modes */
 	if ((p->flags & DIO_WAKE_EN0) &&
diff --git a/chip/g/registers.h b/chip/g/registers.h
index 5ecd12fa34..8ce2e90d7b 100644
--- a/chip/g/registers.h
+++ b/chip/g/registers.h
@@ -181,14 +181,17 @@ static inline int x_uart_addr(int ch, int offset)
 #define DIO_ENABLE_DIRECT_INPUT 0x0004
 #define DIO_TO_PERIPHERAL       0x0008
 /* Bits to indicate pinmux wake-from-sleep controls */
-#define DIO_WAKE_EN0            0x0040
-#define DIO_WAKE_EDGE0          0x0020
 #define DIO_WAKE_INV0           0x0010
+#define DIO_WAKE_EDGE0          0x0020
+#define DIO_WAKE_EN0            0x0040
 /* Use these combinations in gpio.inc for clarity */
 #define DIO_WAKE_HIGH           (DIO_WAKE_EN0)
 #define DIO_WAKE_LOW            (DIO_WAKE_EN0 | DIO_WAKE_INV0)
 #define DIO_WAKE_RISING         (DIO_WAKE_EN0 | DIO_WAKE_EDG0)
 #define DIO_WAKE_FALLING        (DIO_WAKE_EN0 | DIO_WAKE_EDG0 | DIO_WAKE_INV0)
+/* Flags for pullup/pulldowns */
+#define DIO_PULL_UP             0x0080
+#define DIO_PULL_DOWN           0x0100
 
 /* Generate the MUX selector register address for the DIO */
 #define DIO_SEL_REG(offset) REG32(GC_PINMUX_BASE_ADDR + offset)