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>

5 files changed, 296 insertions, 1 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 6e16244f3ed1..22c1662de964 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -1511,6 +1511,7 @@ config FB_VIA
        select FB_CFB_IMAGEBLIT
        select I2C_ALGOBIT
        select I2C
+       select GPIOLIB
        help
           This is the frame buffer device driver for Graphics chips of VIA
           UniChrome (Pro) Family (CLE266,PM800/CN400,P4M800CE/P4M800Pro/
@@ -1520,6 +1521,7 @@ config FB_VIA
 
           To compile this driver as a module, choose M here: the
           module will be called viafb.
+
 config FB_NEOMAGIC
         tristate "NeoMagic display support"
         depends on FB && PCI
diff --git a/drivers/video/via/Makefile b/drivers/video/via/Makefile
index aec3f8b24a96..8c42a42c3dbb 100644
--- a/drivers/video/via/Makefile
+++ b/drivers/video/via/Makefile
@@ -4,4 +4,7 @@
 
 obj-$(CONFIG_FB_VIA) += viafb.o
 
-viafb-y :=viafbdev.o hw.o via_i2c.o dvi.o lcd.o ioctl.o accel.o via_utility.o vt1636.o global.o tblDPASetting.o viamode.o tbl1636.o via-core.o
+viafb-y :=viafbdev.o hw.o via_i2c.o dvi.o lcd.o ioctl.o accel.o \
+        via_utility.o vt1636.o global.o tblDPASetting.o viamode.o tbl1636.o \
+        via-core.o via-gpio.o
+
diff --git a/drivers/video/via/via-core.c b/drivers/video/via/via-core.c
index b77cd5c2fc96..806237e8b4a4 100644
--- a/drivers/video/via/via-core.c
+++ b/drivers/video/via/via-core.c
@@ -9,6 +9,7 @@
  */
 #include "via-core.h"
 #include "via_i2c.h"
+#include "via-gpio.h"
 #include "global.h"
 
 #include <linux/module.h>
@@ -221,6 +222,11 @@ static int __devinit via_pci_probe(struct pci_dev *pdev,
         ret = via_fb_pci_probe(&global_dev);
         if (ret)
                 goto out_i2c;
+        /*
+         * Create the GPIOs.  We continue whether or not this succeeds;
+         * the framebuffer might be useful even without GPIO ports.
+         */
+        ret = viafb_create_gpios(&global_dev, adap_configs);
         return 0;
 
 out_i2c:
@@ -234,6 +240,7 @@ out_disable:
 
 static void __devexit via_pci_remove(struct pci_dev *pdev)
 {
+        viafb_destroy_gpios();
         viafb_delete_i2c_busses();
         via_fb_pci_remove(pdev);
         via_pci_teardown_mmio(&global_dev);
diff --git a/drivers/video/via/via-gpio.c b/drivers/video/via/via-gpio.c
new file mode 100644
index 000000000000..e119d2103730
--- /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);
diff --git a/drivers/video/via/via-gpio.h b/drivers/video/via/via-gpio.h
new file mode 100644
index 000000000000..7b53f966eb4b
--- /dev/null
+++ b/drivers/video/via/via-gpio.h
@@ -0,0 +1,15 @@
+/*
+ * Support for viafb GPIO ports.
+ *
+ * Copyright 2009 Jonathan Corbet <corbet@lwn.net>
+ * Distributable under version 2 of the GNU General Public License.
+ */
+
+#ifndef __VIA_GPIO_H__
+#define __VIA_GPIO_H__
+
+extern int viafb_create_gpios(struct viafb_dev *vdev,
+                const struct via_port_cfg *port_cfg);
+extern int viafb_destroy_gpios(void);
+extern int viafb_gpio_lookup(const char *name);
+#endif