[PATCH v4 07/16] gpio: sandbox: Use a separate flag for the value

[Simon Glass]

At present with the sandbox GPIO driver it is not possible to change the
value of GPIOD_IS_OUT_ACTIVE unless the GPIO is an output. This makes it
hard to test changing the flags since we need to be aware of the internal
workings of the driver.

The feature is designed to aid testing.

Split this feature out into a separate sandbox-specific flag, so that the
flags can change unimpeded. This will make it easier to allow updating the
flags in a future patch.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

(no changes since v3)

Changes in v3:
- Start at BIT(31) for sandbox-specific flags
- Add a comment to sandbox_gpio_set_flags() about clearing GPIOD_EXT_HIGH

 arch/sandbox/include/asm/gpio.h |  5 ++++
 drivers/gpio/sandbox.c          | 47 +++++++++++++++++----------------
 2 files changed, 29 insertions(+), 23 deletions(-)

diff --git a/arch/sandbox/include/asm/gpio.h b/arch/sandbox/include/asm/gpio.h
index 20d78296551..74d7a4cd959 100644
--- a/arch/sandbox/include/asm/gpio.h
+++ b/arch/sandbox/include/asm/gpio.h
@@ -23,6 +23,11 @@
  */
 #include <asm-generic/gpio.h>
 
+/* Our own private GPIO flags, which musn't conflict with GPIOD_... */
+#define GPIOD_EXT_HIGH		BIT(31)	/* external source is high (else low) */
+
+#define GPIOD_SANDBOX_MASK	BIT(31)
+
 /**
  * Return the simulated value of a GPIO (used only in sandbox test code)
  *
diff --git a/drivers/gpio/sandbox.c b/drivers/gpio/sandbox.c
index 6f2eed50bf1..4d73b954b26 100644
--- a/drivers/gpio/sandbox.c
+++ b/drivers/gpio/sandbox.c
@@ -59,12 +59,12 @@ static int get_gpio_flag(struct udevice *dev, unsigned int offset, ulong flag)
 static int set_gpio_flag(struct udevice *dev, unsigned int offset, ulong flag,
 			 int value)
 {
-	ulong *gpio = get_gpio_flags(dev, offset);
+	struct gpio_state *state = get_gpio_state(dev, offset);
 
 	if (value)
-		*gpio |= flag;
+		state->flags |= flag;
 	else
-		*gpio &= ~flag;
+		state->flags &= ~flag;
 
 	return 0;
 }
@@ -75,14 +75,19 @@ static int set_gpio_flag(struct udevice *dev, unsigned int offset, ulong flag,
 
 int sandbox_gpio_get_value(struct udevice *dev, unsigned offset)
 {
+	struct gpio_state *state = get_gpio_state(dev, offset);
+
 	if (get_gpio_flag(dev, offset, GPIOD_IS_OUT))
 		debug("sandbox_gpio: get_value on output gpio %u\n", offset);
-	return get_gpio_flag(dev, offset, GPIOD_IS_OUT_ACTIVE);
+
+	return state->flags & GPIOD_EXT_HIGH ? true : false;
 }
 
 int sandbox_gpio_set_value(struct udevice *dev, unsigned offset, int value)
 {
-	return set_gpio_flag(dev, offset, GPIOD_IS_OUT_ACTIVE, value);
+	set_gpio_flag(dev, offset, GPIOD_IS_OUT_ACTIVE | GPIOD_EXT_HIGH, value);
+
+	return 0;
 }
 
 int sandbox_gpio_get_direction(struct udevice *dev, unsigned offset)
@@ -93,19 +98,29 @@ int sandbox_gpio_get_direction(struct udevice *dev, unsigned offset)
 int sandbox_gpio_set_direction(struct udevice *dev, unsigned offset, int output)
 {
 	set_gpio_flag(dev, offset, GPIOD_IS_OUT, output);
-	set_gpio_flag(dev, offset, GPIOD_IS_IN, !(output));
+	set_gpio_flag(dev, offset, GPIOD_IS_IN, !output);
 
 	return 0;
 }
 
 ulong sandbox_gpio_get_flags(struct udevice *dev, uint offset)
 {
-	return *get_gpio_flags(dev, offset);
+	ulong flags = *get_gpio_flags(dev, offset);
+
+	return flags & ~GPIOD_SANDBOX_MASK;
 }
 
 int sandbox_gpio_set_flags(struct udevice *dev, uint offset, ulong flags)
 {
-	*get_gpio_flags(dev, offset) = flags;
+	struct gpio_state *state = get_gpio_state(dev, offset);
+
+	/*
+	 * We don't need to clear GPIOD_EXT_HIGH here to make the tests pass,
+	 * but this is handled in a future patch.
+	 */
+	if (flags & GPIOD_IS_OUT_ACTIVE)
+		flags |= GPIOD_EXT_HIGH;
+	state->flags = (state->flags & GPIOD_SANDBOX_MASK) | flags;
 
 	return 0;
 }
@@ -189,23 +204,9 @@ static int sb_gpio_xlate(struct udevice *dev, struct gpio_desc *desc,
 static int sb_gpio_set_flags(struct udevice *dev, unsigned int offset,
 			     ulong flags)
 {
-	ulong *newf;
-
 	debug("%s: offset:%u, flags = %lx\n", __func__, offset, flags);
 
-	newf = get_gpio_flags(dev, offset);
-
-	/*
-	 * For testing purposes keep the output value when switching to input.
-	 * This allows us to manipulate the input value via the gpio command.
-	 */
-	if (flags & GPIOD_IS_IN)
-		*newf = (flags & ~GPIOD_IS_OUT_ACTIVE) |
-			(*newf & GPIOD_IS_OUT_ACTIVE);
-	else
-		*newf = flags;
-
-	return 0;
+	return sandbox_gpio_set_flags(dev, offset, flags);
 }
 
 static int sb_gpio_get_flags(struct udevice *dev, uint offset, ulong *flagsp)
-- 
2.30.0.478.g8a0d178c01-goog