viafb: add a driver for GPIO lines
This is a simple gpiolib driver giving access to the GPIO lines in the
VIA framebuffer system. A simple mechanism exists for switching lines
between GPIO and I2C, but it's only compile-time for now.
Cc: ScottFang@viatech.com.cn
Cc: JosephChan@via.com.tw
Cc: Harald Welte <laforge@gnumonks.org>
Acked-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/drivers/video/via/via-gpio.c b/drivers/video/via/via-gpio.c
new file mode 100644
index 0000000..e119d21
--- /dev/null
+++ b/drivers/video/via/via-gpio.c
@@ -0,0 +1,268 @@
+/*
+ * Support for viafb GPIO ports.
+ *
+ * Copyright 2009 Jonathan Corbet <corbet@lwn.net>
+ * Distributable under version 2 of the GNU General Public License.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/gpio.h>
+#include "via-core.h"
+#include "via-gpio.h"
+#include "global.h"
+
+/*
+ * The ports we know about. Note that the port-25 gpios are not
+ * mentioned in the datasheet.
+ */
+
+struct viafb_gpio {
+ char *vg_name; /* Data sheet name */
+ u16 vg_io_port;
+ u8 vg_port_index;
+ int vg_mask_shift;
+};
+
+static struct viafb_gpio viafb_all_gpios[] = {
+ {
+ .vg_name = "VGPIO0", /* Guess - not in datasheet */
+ .vg_io_port = VIASR,
+ .vg_port_index = 0x25,
+ .vg_mask_shift = 1
+ },
+ {
+ .vg_name = "VGPIO1",
+ .vg_io_port = VIASR,
+ .vg_port_index = 0x25,
+ .vg_mask_shift = 0
+ },
+ {
+ .vg_name = "VGPIO2", /* aka DISPCLKI0 */
+ .vg_io_port = VIASR,
+ .vg_port_index = 0x2c,
+ .vg_mask_shift = 1
+ },
+ {
+ .vg_name = "VGPIO3", /* aka DISPCLKO0 */
+ .vg_io_port = VIASR,
+ .vg_port_index = 0x2c,
+ .vg_mask_shift = 0
+ },
+ {
+ .vg_name = "VGPIO4", /* DISPCLKI1 */
+ .vg_io_port = VIASR,
+ .vg_port_index = 0x3d,
+ .vg_mask_shift = 1
+ },
+ {
+ .vg_name = "VGPIO5", /* DISPCLKO1 */
+ .vg_io_port = VIASR,
+ .vg_port_index = 0x3d,
+ .vg_mask_shift = 0
+ },
+};
+
+#define VIAFB_NUM_GPIOS ARRAY_SIZE(viafb_all_gpios)
+
+/*
+ * This structure controls the active GPIOs, which may be a subset
+ * of those which are known.
+ */
+
+struct viafb_gpio_cfg {
+ struct gpio_chip gpio_chip;
+ struct viafb_dev *vdev;
+ struct viafb_gpio *active_gpios[VIAFB_NUM_GPIOS];
+ char *gpio_names[VIAFB_NUM_GPIOS];
+};
+
+/*
+ * GPIO access functions
+ */
+static void via_gpio_set(struct gpio_chip *chip, unsigned int nr,
+ int value)
+{
+ struct viafb_gpio_cfg *cfg = container_of(chip,
+ struct viafb_gpio_cfg,
+ gpio_chip);
+ u8 reg;
+ struct viafb_gpio *gpio;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
+ gpio = cfg->active_gpios[nr];
+ reg = viafb_read_reg(VIASR, gpio->vg_port_index);
+ reg |= 0x40 << gpio->vg_mask_shift; /* output enable */
+ if (value)
+ reg |= 0x10 << gpio->vg_mask_shift;
+ else
+ reg &= ~(0x10 << gpio->vg_mask_shift);
+ viafb_write_reg(gpio->vg_port_index, VIASR, reg);
+ spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
+}
+
+static int via_gpio_dir_out(struct gpio_chip *chip, unsigned int nr,
+ int value)
+{
+ via_gpio_set(chip, nr, value);
+ return 0;
+}
+
+/*
+ * Set the input direction. I'm not sure this is right; we should
+ * be able to do input without disabling output.
+ */
+static int via_gpio_dir_input(struct gpio_chip *chip, unsigned int nr)
+{
+ struct viafb_gpio_cfg *cfg = container_of(chip,
+ struct viafb_gpio_cfg,
+ gpio_chip);
+ struct viafb_gpio *gpio;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
+ gpio = cfg->active_gpios[nr];
+ viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0,
+ 0x40 << gpio->vg_mask_shift);
+ spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
+ return 0;
+}
+
+static int via_gpio_get(struct gpio_chip *chip, unsigned int nr)
+{
+ struct viafb_gpio_cfg *cfg = container_of(chip,
+ struct viafb_gpio_cfg,
+ gpio_chip);
+ u8 reg;
+ struct viafb_gpio *gpio;
+ unsigned long flags;
+
+ spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
+ gpio = cfg->active_gpios[nr];
+ reg = viafb_read_reg(VIASR, gpio->vg_port_index);
+ spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
+ return reg & (0x04 << gpio->vg_mask_shift);
+}
+
+
+static struct viafb_gpio_cfg gpio_config = {
+ .gpio_chip = {
+ .label = "VIAFB onboard GPIO",
+ .owner = THIS_MODULE,
+ .direction_output = via_gpio_dir_out,
+ .set = via_gpio_set,
+ .direction_input = via_gpio_dir_input,
+ .get = via_gpio_get,
+ .base = -1,
+ .ngpio = 0,
+ .can_sleep = 0
+ }
+};
+
+/*
+ * Manage the software enable bit.
+ */
+static void viafb_gpio_enable(struct viafb_gpio *gpio)
+{
+ viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0x02, 0x02);
+}
+
+static void viafb_gpio_disable(struct viafb_gpio *gpio)
+{
+ viafb_write_reg_mask(gpio->vg_port_index, VIASR, 0, 0x02);
+}
+
+
+
+
+int viafb_create_gpios(struct viafb_dev *vdev,
+ const struct via_port_cfg *port_cfg)
+{
+ int i, ngpio = 0, ret;
+ struct viafb_gpio *gpio;
+ unsigned long flags;
+
+ /*
+ * Set up entries for all GPIOs which have been configured to
+ * operate as such (as opposed to as i2c ports).
+ */
+ for (i = 0; i < VIAFB_NUM_PORTS; i++) {
+ if (port_cfg[i].mode != VIA_MODE_GPIO)
+ continue;
+ for (gpio = viafb_all_gpios;
+ gpio < viafb_all_gpios + VIAFB_NUM_GPIOS; gpio++)
+ if (gpio->vg_port_index == port_cfg[i].ioport_index) {
+ gpio_config.active_gpios[ngpio] = gpio;
+ gpio_config.gpio_names[ngpio] = gpio->vg_name;
+ ngpio++;
+ }
+ }
+ gpio_config.gpio_chip.ngpio = ngpio;
+ gpio_config.gpio_chip.names = gpio_config.gpio_names;
+ gpio_config.vdev = vdev;
+ if (ngpio == 0) {
+ printk(KERN_INFO "viafb: no GPIOs configured\n");
+ return 0;
+ }
+ /*
+ * Enable the ports. They come in pairs, with a single
+ * enable bit for both.
+ */
+ spin_lock_irqsave(&gpio_config.vdev->reg_lock, flags);
+ for (i = 0; i < ngpio; i += 2)
+ viafb_gpio_enable(gpio_config.active_gpios[i]);
+ spin_unlock_irqrestore(&gpio_config.vdev->reg_lock, flags);
+ /*
+ * Get registered.
+ */
+ gpio_config.gpio_chip.base = -1; /* Dynamic */
+ ret = gpiochip_add(&gpio_config.gpio_chip);
+ if (ret) {
+ printk(KERN_ERR "viafb: failed to add gpios (%d)\n", ret);
+ gpio_config.gpio_chip.ngpio = 0;
+ }
+ return ret;
+/* Port enable ? */
+}
+
+
+int viafb_destroy_gpios(void)
+{
+ unsigned long flags;
+ int ret = 0, i;
+
+ spin_lock_irqsave(&gpio_config.vdev->reg_lock, flags);
+ /*
+ * Get unregistered.
+ */
+ if (gpio_config.gpio_chip.ngpio > 0) {
+ ret = gpiochip_remove(&gpio_config.gpio_chip);
+ if (ret) { /* Somebody still using it? */
+ printk(KERN_ERR "Viafb: GPIO remove failed\n");
+ goto out;
+ }
+ }
+ /*
+ * Disable the ports.
+ */
+ for (i = 0; i < gpio_config.gpio_chip.ngpio; i += 2)
+ viafb_gpio_disable(gpio_config.active_gpios[i]);
+ gpio_config.gpio_chip.ngpio = 0;
+out:
+ spin_unlock_irqrestore(&gpio_config.vdev->reg_lock, flags);
+ return ret;
+}
+
+/*
+ * Look up a specific gpio and return the number it was assigned.
+ */
+int viafb_gpio_lookup(const char *name)
+{
+ int i;
+
+ for (i = 0; i < gpio_config.gpio_chip.ngpio; i++)
+ if (!strcmp(name, gpio_config.active_gpios[i]->vg_name))
+ return gpio_config.gpio_chip.base + i;
+ return -1;
+}
+EXPORT_SYMBOL_GPL(viafb_gpio_lookup);