media: solo6x10: export hardware GPIO pins 8:31 to gpiolib interface

24 GPIO pins from 32 available on solo6x10 chips are exported
to gpiolib. First 8 GPIOs are reserved for internal use on capture card
boards, GPIOs in range 8:15 are configured as outputs to control relays,
remaining 16:31 are configured as inputs to read sensor states.
Now with this patch userspace DVR software can switch relays and read
sensor states when GPIO extension cards are attached to Softlogic solo6x10
based video capture cards.

Signed-off-by: Anton Sviridenko <anton@corp.bluecherry.net>
Signed-off-by: Ismael Luceno <ismael@iodev.co.uk>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/pci/solo6x10/solo6x10-gpio.c

@@ -57,6 +57,9 @@ static void solo_gpio_mode(struct solo_dev *solo_dev,
 			ret |= 1 << port;
 	}
 
+	/* Enable GPIO[31:16] */
+	ret |= 0xffff0000;
+
 	solo_reg_write(solo_dev, SOLO_GPIO_CONFIG_1, ret);
 }
 
@@ -90,16 +93,110 @@ static void solo_gpio_config(struct solo_dev *solo_dev)
 
 	/* Initially set relay status to 0 */
 	solo_gpio_clear(solo_dev, 0xff00);
+
+	/* Set input pins direction */
+	solo_gpio_mode(solo_dev, 0xffff0000, 0);
+}
+
+#ifdef CONFIG_GPIOLIB
+/* Pins 0-7 are not exported, because it seems from code above they are
+ * used for internal purposes. So offset 0 corresponds to pin 8, therefore
+ * offsets 0-7 are relay GPIOs, 8-23 - input GPIOs.
+ */
+static int solo_gpiochip_get_direction(struct gpio_chip *chip,
+				       unsigned int offset)
+{
+	int ret, mode;
+	struct solo_dev *solo_dev = gpiochip_get_data(chip);
+
+	if (offset < 8) {
+		ret = solo_reg_read(solo_dev, SOLO_GPIO_CONFIG_0);
+		mode = 3 & (ret >> ((offset + 8) * 2));
+	} else {
+		ret = solo_reg_read(solo_dev, SOLO_GPIO_CONFIG_1);
+		mode =  1 & (ret >> (offset - 8));
+	}
+
+	if (!mode)
+		return 1;
+	else if (mode == 1)
+		return 0;
+
+	return -1;
 }
 
+static int solo_gpiochip_direction_input(struct gpio_chip *chip,
+					 unsigned int offset)
+{
+	return -1;
+}
+
+static int solo_gpiochip_direction_output(struct gpio_chip *chip,
+					  unsigned int offset, int value)
+{
+	return -1;
+}
+
+static int solo_gpiochip_get(struct gpio_chip *chip,
+						unsigned int offset)
+{
+	int ret;
+	struct solo_dev *solo_dev = gpiochip_get_data(chip);
+
+	ret = solo_reg_read(solo_dev, SOLO_GPIO_DATA_IN);
+
+	return 1 & (ret >> (offset + 8));
+}
+
+static void solo_gpiochip_set(struct gpio_chip *chip,
+						unsigned int offset, int value)
+{
+	struct solo_dev *solo_dev = gpiochip_get_data(chip);
+
+	if (value)
+		solo_gpio_set(solo_dev, 1 << (offset + 8));
+	else
+		solo_gpio_clear(solo_dev, 1 << (offset + 8));
+}
+#endif
+
 int solo_gpio_init(struct solo_dev *solo_dev)
 {
+	int ret;
+
 	solo_gpio_config(solo_dev);
+#ifdef CONFIG_GPIOLIB
+	solo_dev->gpio_dev.label = SOLO6X10_NAME"_gpio";
+	solo_dev->gpio_dev.parent = &solo_dev->pdev->dev;
+	solo_dev->gpio_dev.owner = THIS_MODULE;
+	solo_dev->gpio_dev.base = -1;
+	solo_dev->gpio_dev.ngpio = 24;
+	solo_dev->gpio_dev.can_sleep = 0;
+
+	solo_dev->gpio_dev.get_direction = solo_gpiochip_get_direction;
+	solo_dev->gpio_dev.direction_input = solo_gpiochip_direction_input;
+	solo_dev->gpio_dev.direction_output = solo_gpiochip_direction_output;
+	solo_dev->gpio_dev.get = solo_gpiochip_get;
+	solo_dev->gpio_dev.set = solo_gpiochip_set;
+
+	ret = gpiochip_add_data(&solo_dev->gpio_dev, solo_dev);
+
+	if (ret) {
+		solo_dev->gpio_dev.label = NULL;
+		return -1;
+	}
+#endif
 	return 0;
 }
 
 void solo_gpio_exit(struct solo_dev *solo_dev)
 {
+#ifdef CONFIG_GPIOLIB
+	if (solo_dev->gpio_dev.label) {
+		gpiochip_remove(&solo_dev->gpio_dev);
+		solo_dev->gpio_dev.label = NULL;
+	}
+#endif
 	solo_gpio_clear(solo_dev, 0x30);
 	solo_gpio_config(solo_dev);
 }

drivers/media/pci/solo6x10/solo6x10.h

@@ -31,6 +31,7 @@
 #include <linux/atomic.h>
 #include <linux/slab.h>
 #include <linux/videodev2.h>
+#include <linux/gpio/driver.h>
 
 #include <media/v4l2-dev.h>
 #include <media/v4l2-device.h>
@@ -199,6 +200,10 @@ struct solo_dev {
 	u32			irq_mask;
 	u32			motion_mask;
 	struct v4l2_device	v4l2_dev;
+#ifdef CONFIG_GPIOLIB
+	/* GPIO */
+	struct gpio_chip	gpio_dev;
+#endif
 
 	/* tw28xx accounting */
 	u8			tw2865, tw2864, tw2815;