sunxi: gpio: Add support for gpio pins on the AXP209 pmic

Some boards use GPIO-s on the pmic, one example of this is the A13-OLinuXino
board, which uses gpio0 of the axp209 for the lcd-power signal.

This commit adds support for gpio pins on the AXP209 pmic, the sunxi_gpio.c
changes are universal, adding gpio support for the other AXP pmics (when
necessary) should be a matter of adding the necessary axp_gpio_foo functions
to their resp. drivers, and add "#define AXP_GPIO" to their header file.

Note this commit only adds support for the non device-model version of the
gpio code, patches for adding support to the device-model version are very
welcome.

The string representation for these gpio-s is AXP0-#, the 0 in the AXP0 prefix
is there in case we need to support gpio-s on more then 1 pmic in the future.
At least A80 boards have 2 pmics, and we may end up needing to support gpio-s
on both.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

1 files changed, 72 insertions, 0 deletions

diff --git a/drivers/power/axp209.c b/drivers/power/axp209.c
index 9798e5b..3b1a6a7 100644
--- a/drivers/power/axp209.c
+++ b/drivers/power/axp209.c
@@ -18,6 +18,11 @@ enum axp209_reg {
 	AXP209_LDO3_VOLTAGE = 0x29,
 	AXP209_IRQ_STATUS5 = 0x4c,
 	AXP209_SHUTDOWN = 0x32,
+	AXP209_GPIO0_CTRL = 0x90,
+	AXP209_GPIO1_CTRL = 0x92,
+	AXP209_GPIO2_CTRL = 0x93,
+	AXP209_GPIO_STATE = 0x94,
+	AXP209_GPIO3_CTRL = 0x95,
 };
 
 #define AXP209_POWER_STATUS_ON_BY_DC	(1 << 0)
@@ -27,6 +32,15 @@ enum axp209_reg {
 
 #define AXP209_POWEROFF			(1 << 7)
 
+#define AXP209_GPIO_OUTPUT_LOW		0x00 /* Drive pin low */
+#define AXP209_GPIO_OUTPUT_HIGH		0x01 /* Drive pin high */
+#define AXP209_GPIO_INPUT		0x02 /* Float pin */
+
+/* GPIO3 is different from the others */
+#define AXP209_GPIO3_OUTPUT_LOW		0x00 /* Drive pin low, Output mode */
+#define AXP209_GPIO3_OUTPUT_HIGH	0x02 /* Float pin, Output mode */
+#define AXP209_GPIO3_INPUT		0x06 /* Float pin, Input mode */
+
 static int axp209_write(enum axp209_reg reg, u8 val)
 {
 	return i2c_write(0x34, reg, 1, &val, 1);
@@ -165,3 +179,61 @@ int axp209_power_button(void)
 
 	return v & AXP209_IRQ5_PEK_DOWN;
 }
+
+static u8 axp209_get_gpio_ctrl_reg(unsigned int pin)
+{
+	switch (pin) {
+	case 0: return AXP209_GPIO0_CTRL;
+	case 1: return AXP209_GPIO1_CTRL;
+	case 2: return AXP209_GPIO2_CTRL;
+	case 3: return AXP209_GPIO3_CTRL;
+	}
+	return 0;
+}
+
+int axp_gpio_direction_input(unsigned int pin)
+{
+	u8 reg = axp209_get_gpio_ctrl_reg(pin);
+	/* GPIO3 is "special" */
+	u8 val = (pin == 3) ? AXP209_GPIO3_INPUT : AXP209_GPIO_INPUT;
+
+	return axp209_write(reg, val);
+}
+
+int axp_gpio_direction_output(unsigned int pin, unsigned int val)
+{
+	u8 reg = axp209_get_gpio_ctrl_reg(pin);
+
+	if (val) {
+		val = (pin == 3) ? AXP209_GPIO3_OUTPUT_HIGH :
+				   AXP209_GPIO_OUTPUT_HIGH;
+	} else {
+		val = (pin == 3) ? AXP209_GPIO3_OUTPUT_LOW :
+				   AXP209_GPIO_OUTPUT_LOW;
+	}
+
+	return axp209_write(reg, val);
+}
+
+int axp_gpio_get_value(unsigned int pin)
+{
+	u8 val, mask;
+	int rc;
+
+	if (pin == 3) {
+		rc = axp209_read(AXP209_GPIO3_CTRL, &val);
+		mask = 1;
+	} else {
+		rc = axp209_read(AXP209_GPIO_STATE, &val);
+		mask = 1 << (pin + 4);
+	}
+	if (rc)
+		return rc;
+
+	return (val & mask) ? 1 : 0;
+}
+
+int axp_gpio_set_value(unsigned int pin, unsigned int val)
+{
+	return axp_gpio_direction_output(pin, val);
+}