308 lines
7.1 KiB
C
Executable file
308 lines
7.1 KiB
C
Executable file
/*
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* Support for viafb GPIO ports.
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*
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* Copyright 2009 Jonathan Corbet <corbet@lwn.net>
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* Distributable under version 2 of the GNU General Public License.
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*/
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#include <linux/spinlock.h>
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#include <linux/gpio/driver.h>
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#include <linux/platform_device.h>
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#include <linux/via-core.h>
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#include <linux/via-gpio.h>
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#include <linux/export.h>
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/*
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* The ports we know about. Note that the port-25 gpios are not
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* mentioned in the datasheet.
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*/
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struct viafb_gpio {
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char *vg_name; /* Data sheet name */
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u16 vg_io_port;
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u8 vg_port_index;
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int vg_mask_shift;
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};
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static struct viafb_gpio viafb_all_gpios[] = {
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{
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.vg_name = "VGPIO0", /* Guess - not in datasheet */
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.vg_io_port = VIASR,
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.vg_port_index = 0x25,
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.vg_mask_shift = 1
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},
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{
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.vg_name = "VGPIO1",
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.vg_io_port = VIASR,
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.vg_port_index = 0x25,
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.vg_mask_shift = 0
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},
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{
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.vg_name = "VGPIO2", /* aka DISPCLKI0 */
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.vg_io_port = VIASR,
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.vg_port_index = 0x2c,
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.vg_mask_shift = 1
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},
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{
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.vg_name = "VGPIO3", /* aka DISPCLKO0 */
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.vg_io_port = VIASR,
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.vg_port_index = 0x2c,
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.vg_mask_shift = 0
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},
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{
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.vg_name = "VGPIO4", /* DISPCLKI1 */
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.vg_io_port = VIASR,
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.vg_port_index = 0x3d,
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.vg_mask_shift = 1
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},
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{
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.vg_name = "VGPIO5", /* DISPCLKO1 */
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.vg_io_port = VIASR,
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.vg_port_index = 0x3d,
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.vg_mask_shift = 0
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},
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};
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#define VIAFB_NUM_GPIOS ARRAY_SIZE(viafb_all_gpios)
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/*
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* This structure controls the active GPIOs, which may be a subset
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* of those which are known.
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*/
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struct viafb_gpio_cfg {
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struct gpio_chip gpio_chip;
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struct viafb_dev *vdev;
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struct viafb_gpio *active_gpios[VIAFB_NUM_GPIOS];
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const char *gpio_names[VIAFB_NUM_GPIOS];
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};
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/*
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* GPIO access functions
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*/
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static void via_gpio_set(struct gpio_chip *chip, unsigned int nr,
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int value)
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{
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struct viafb_gpio_cfg *cfg = gpiochip_get_data(chip);
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u8 reg;
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struct viafb_gpio *gpio;
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unsigned long flags;
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spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
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gpio = cfg->active_gpios[nr];
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reg = via_read_reg(VIASR, gpio->vg_port_index);
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reg |= 0x40 << gpio->vg_mask_shift; /* output enable */
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if (value)
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reg |= 0x10 << gpio->vg_mask_shift;
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else
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reg &= ~(0x10 << gpio->vg_mask_shift);
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via_write_reg(VIASR, gpio->vg_port_index, reg);
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spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
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}
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static int via_gpio_dir_out(struct gpio_chip *chip, unsigned int nr,
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int value)
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{
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via_gpio_set(chip, nr, value);
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return 0;
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}
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/*
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* Set the input direction. I'm not sure this is right; we should
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* be able to do input without disabling output.
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*/
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static int via_gpio_dir_input(struct gpio_chip *chip, unsigned int nr)
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{
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struct viafb_gpio_cfg *cfg = gpiochip_get_data(chip);
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struct viafb_gpio *gpio;
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unsigned long flags;
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spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
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gpio = cfg->active_gpios[nr];
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via_write_reg_mask(VIASR, gpio->vg_port_index, 0,
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0x40 << gpio->vg_mask_shift);
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spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
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return 0;
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}
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static int via_gpio_get(struct gpio_chip *chip, unsigned int nr)
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{
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struct viafb_gpio_cfg *cfg = gpiochip_get_data(chip);
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u8 reg;
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struct viafb_gpio *gpio;
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unsigned long flags;
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spin_lock_irqsave(&cfg->vdev->reg_lock, flags);
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gpio = cfg->active_gpios[nr];
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reg = via_read_reg(VIASR, gpio->vg_port_index);
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spin_unlock_irqrestore(&cfg->vdev->reg_lock, flags);
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return !!(reg & (0x04 << gpio->vg_mask_shift));
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}
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static struct viafb_gpio_cfg viafb_gpio_config = {
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.gpio_chip = {
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.label = "VIAFB onboard GPIO",
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.owner = THIS_MODULE,
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.direction_output = via_gpio_dir_out,
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.set = via_gpio_set,
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.direction_input = via_gpio_dir_input,
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.get = via_gpio_get,
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.base = -1,
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.ngpio = 0,
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.can_sleep = 0
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}
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};
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/*
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* Manage the software enable bit.
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*/
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static void viafb_gpio_enable(struct viafb_gpio *gpio)
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{
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via_write_reg_mask(VIASR, gpio->vg_port_index, 0x02, 0x02);
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}
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static void viafb_gpio_disable(struct viafb_gpio *gpio)
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{
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via_write_reg_mask(VIASR, gpio->vg_port_index, 0, 0x02);
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}
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#ifdef CONFIG_PM
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static int viafb_gpio_suspend(void *private)
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{
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return 0;
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}
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static int viafb_gpio_resume(void *private)
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{
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int i;
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for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i += 2)
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viafb_gpio_enable(viafb_gpio_config.active_gpios[i]);
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return 0;
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}
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static struct viafb_pm_hooks viafb_gpio_pm_hooks = {
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.suspend = viafb_gpio_suspend,
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.resume = viafb_gpio_resume
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};
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#endif /* CONFIG_PM */
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/*
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* Look up a specific gpio and return the number it was assigned.
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*/
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int viafb_gpio_lookup(const char *name)
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{
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int i;
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for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i++)
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if (!strcmp(name, viafb_gpio_config.active_gpios[i]->vg_name))
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return viafb_gpio_config.gpio_chip.base + i;
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return -1;
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}
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EXPORT_SYMBOL_GPL(viafb_gpio_lookup);
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/*
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* Platform device stuff.
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*/
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static int viafb_gpio_probe(struct platform_device *platdev)
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{
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struct viafb_dev *vdev = platdev->dev.platform_data;
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struct via_port_cfg *port_cfg = vdev->port_cfg;
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int i, ngpio = 0, ret;
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struct viafb_gpio *gpio;
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unsigned long flags;
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/*
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* Set up entries for all GPIOs which have been configured to
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* operate as such (as opposed to as i2c ports).
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*/
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for (i = 0; i < VIAFB_NUM_PORTS; i++) {
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if (port_cfg[i].mode != VIA_MODE_GPIO)
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continue;
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for (gpio = viafb_all_gpios;
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gpio < viafb_all_gpios + VIAFB_NUM_GPIOS; gpio++)
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if (gpio->vg_port_index == port_cfg[i].ioport_index) {
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viafb_gpio_config.active_gpios[ngpio] = gpio;
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viafb_gpio_config.gpio_names[ngpio] =
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gpio->vg_name;
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ngpio++;
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}
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}
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viafb_gpio_config.gpio_chip.ngpio = ngpio;
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viafb_gpio_config.gpio_chip.names = viafb_gpio_config.gpio_names;
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viafb_gpio_config.vdev = vdev;
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if (ngpio == 0) {
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printk(KERN_INFO "viafb: no GPIOs configured\n");
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return 0;
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}
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/*
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* Enable the ports. They come in pairs, with a single
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* enable bit for both.
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*/
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spin_lock_irqsave(&viafb_gpio_config.vdev->reg_lock, flags);
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for (i = 0; i < ngpio; i += 2)
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viafb_gpio_enable(viafb_gpio_config.active_gpios[i]);
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spin_unlock_irqrestore(&viafb_gpio_config.vdev->reg_lock, flags);
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/*
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* Get registered.
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*/
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viafb_gpio_config.gpio_chip.base = -1; /* Dynamic */
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ret = gpiochip_add_data(&viafb_gpio_config.gpio_chip,
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&viafb_gpio_config);
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if (ret) {
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printk(KERN_ERR "viafb: failed to add gpios (%d)\n", ret);
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viafb_gpio_config.gpio_chip.ngpio = 0;
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}
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#ifdef CONFIG_PM
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viafb_pm_register(&viafb_gpio_pm_hooks);
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#endif
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return ret;
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}
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static int viafb_gpio_remove(struct platform_device *platdev)
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{
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unsigned long flags;
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int i;
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#ifdef CONFIG_PM
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viafb_pm_unregister(&viafb_gpio_pm_hooks);
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#endif
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/*
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* Get unregistered.
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*/
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if (viafb_gpio_config.gpio_chip.ngpio > 0) {
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gpiochip_remove(&viafb_gpio_config.gpio_chip);
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}
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/*
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* Disable the ports.
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*/
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spin_lock_irqsave(&viafb_gpio_config.vdev->reg_lock, flags);
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for (i = 0; i < viafb_gpio_config.gpio_chip.ngpio; i += 2)
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viafb_gpio_disable(viafb_gpio_config.active_gpios[i]);
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viafb_gpio_config.gpio_chip.ngpio = 0;
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spin_unlock_irqrestore(&viafb_gpio_config.vdev->reg_lock, flags);
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return 0;
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}
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static struct platform_driver via_gpio_driver = {
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.driver = {
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.name = "viafb-gpio",
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},
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.probe = viafb_gpio_probe,
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.remove = viafb_gpio_remove,
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};
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int viafb_gpio_init(void)
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{
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return platform_driver_register(&via_gpio_driver);
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}
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void viafb_gpio_exit(void)
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{
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platform_driver_unregister(&via_gpio_driver);
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}
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