diff options
Diffstat (limited to 'drivers/video/via/via-gpio.c')
| -rw-r--r-- | drivers/video/via/via-gpio.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/drivers/video/via/via-gpio.c b/drivers/video/via/via-gpio.c new file mode 100644 index 000000000000..595516aea691 --- /dev/null +++ b/drivers/video/via/via-gpio.c @@ -0,0 +1,285 @@ +/* + * 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]; + 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); +} |