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/*
* 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 <linux/platform_device.h>
#include <linux/via-core.h>
#include <linux/via-gpio.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];
const 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 = via_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);
via_write_reg(VIASR, gpio->vg_port_index, 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];
via_write_reg_mask(VIASR, gpio->vg_port_index, 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 = via_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)
{
via_write_reg_mask(VIASR, gpio->vg_port_index, 0x02, 0x02);
}
static void viafb_gpio_disable(struct viafb_gpio *gpio)
{
via_write_reg_mask(VIASR, gpio->vg_port_index, 0, 0x02);
}
/*
* 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);
/*
* Platform device stuff.
*/
static __devinit int viafb_gpio_probe(struct platform_device *platdev)
{
struct viafb_dev *vdev = platdev->dev.platform_data;
struct via_port_cfg *port_cfg = vdev->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;
}
static int viafb_gpio_remove(struct platform_device *platdev)
{
unsigned long flags;
int ret = 0, i;
/*
* 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");
return ret;
}
}
/*
* Disable the ports.
*/
spin_lock_irqsave(&gpio_config.vdev->reg_lock, flags);
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;
spin_unlock_irqrestore(&gpio_config.vdev->reg_lock, flags);
return ret;
}
static struct platform_driver via_gpio_driver = {
.driver = {
.name = "viafb-gpio",
},
.probe = viafb_gpio_probe,
.remove = viafb_gpio_remove,
};
int viafb_gpio_init(void)
{
return platform_driver_register(&via_gpio_driver);
}
void viafb_gpio_exit(void)
{
platform_driver_unregister(&via_gpio_driver);
}
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