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![Mika Westerberg](/assets/img/avatar_default.png)
Currently we already have two pin configuration related callbacks available for GPIO chips .set_single_ended() and .set_debounce(). In future we expect to have even more, which does not scale well if we need to add yet another callback to the GPIO chip structure for each possible configuration parameter. Better solution is to reuse what we already have available in the generic pinconf. To support this, we introduce a new .set_config() callback for GPIO chips. The callback takes a single packed pin configuration value as parameter. This can then be extended easily beyond what is currently supported by just adding new types to the generic pinconf enum. If the GPIO driver is backed up by a pinctrl driver the GPIO driver can just assign gpiochip_generic_config() (introduced in this patch) to .set_config and that will take care configuration requests are directed to the pinctrl driver. We then convert the existing drivers over .set_config() and finally remove the .set_single_ended() and .set_debounce() callbacks. Suggested-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
301 lines
7.8 KiB
C
301 lines
7.8 KiB
C
/*
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* Linux GPIOlib driver for the VIA VX855 integrated southbridge GPIO
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*
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* Copyright (C) 2009 VIA Technologies, Inc.
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* Copyright (C) 2010 One Laptop per Child
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* Author: Harald Welte <HaraldWelte@viatech.com>
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/gpio.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/platform_device.h>
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#include <linux/pci.h>
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#include <linux/io.h>
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#define MODULE_NAME "vx855_gpio"
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/* The VX855 south bridge has the following GPIO pins:
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* GPI 0...13 General Purpose Input
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* GPO 0...12 General Purpose Output
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* GPIO 0...14 General Purpose I/O (Open-Drain)
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*/
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#define NR_VX855_GPI 14
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#define NR_VX855_GPO 13
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#define NR_VX855_GPIO 15
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#define NR_VX855_GPInO (NR_VX855_GPI + NR_VX855_GPO)
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#define NR_VX855_GP (NR_VX855_GPI + NR_VX855_GPO + NR_VX855_GPIO)
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struct vx855_gpio {
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struct gpio_chip gpio;
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spinlock_t lock;
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u32 io_gpi;
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u32 io_gpo;
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};
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/* resolve a GPIx into the corresponding bit position */
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static inline u_int32_t gpi_i_bit(int i)
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{
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if (i < 10)
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return 1 << i;
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else
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return 1 << (i + 14);
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}
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static inline u_int32_t gpo_o_bit(int i)
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{
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if (i < 11)
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return 1 << i;
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else
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return 1 << (i + 14);
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}
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static inline u_int32_t gpio_i_bit(int i)
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{
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if (i < 14)
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return 1 << (i + 10);
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else
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return 1 << (i + 14);
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}
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static inline u_int32_t gpio_o_bit(int i)
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{
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if (i < 14)
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return 1 << (i + 11);
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else
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return 1 << (i + 13);
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}
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/* Mapping betwee numeric GPIO ID and the actual GPIO hardware numbering:
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* 0..13 GPI 0..13
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* 14..26 GPO 0..12
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* 27..41 GPIO 0..14
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*/
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static int vx855gpio_direction_input(struct gpio_chip *gpio,
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unsigned int nr)
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{
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struct vx855_gpio *vg = gpiochip_get_data(gpio);
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unsigned long flags;
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u_int32_t reg_out;
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/* Real GPI bits are always in input direction */
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if (nr < NR_VX855_GPI)
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return 0;
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/* Real GPO bits cannot be put in output direction */
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if (nr < NR_VX855_GPInO)
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return -EINVAL;
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/* Open Drain GPIO have to be set to one */
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spin_lock_irqsave(&vg->lock, flags);
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reg_out = inl(vg->io_gpo);
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reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
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outl(reg_out, vg->io_gpo);
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spin_unlock_irqrestore(&vg->lock, flags);
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return 0;
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}
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static int vx855gpio_get(struct gpio_chip *gpio, unsigned int nr)
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{
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struct vx855_gpio *vg = gpiochip_get_data(gpio);
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u_int32_t reg_in;
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int ret = 0;
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if (nr < NR_VX855_GPI) {
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reg_in = inl(vg->io_gpi);
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if (reg_in & gpi_i_bit(nr))
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ret = 1;
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} else if (nr < NR_VX855_GPInO) {
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/* GPO don't have an input bit, we need to read it
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* back from the output register */
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reg_in = inl(vg->io_gpo);
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if (reg_in & gpo_o_bit(nr - NR_VX855_GPI))
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ret = 1;
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} else {
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reg_in = inl(vg->io_gpi);
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if (reg_in & gpio_i_bit(nr - NR_VX855_GPInO))
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ret = 1;
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}
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return ret;
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}
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static void vx855gpio_set(struct gpio_chip *gpio, unsigned int nr,
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int val)
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{
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struct vx855_gpio *vg = gpiochip_get_data(gpio);
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unsigned long flags;
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u_int32_t reg_out;
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/* True GPI cannot be switched to output mode */
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if (nr < NR_VX855_GPI)
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return;
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spin_lock_irqsave(&vg->lock, flags);
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reg_out = inl(vg->io_gpo);
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if (nr < NR_VX855_GPInO) {
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if (val)
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reg_out |= gpo_o_bit(nr - NR_VX855_GPI);
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else
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reg_out &= ~gpo_o_bit(nr - NR_VX855_GPI);
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} else {
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if (val)
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reg_out |= gpio_o_bit(nr - NR_VX855_GPInO);
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else
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reg_out &= ~gpio_o_bit(nr - NR_VX855_GPInO);
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}
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outl(reg_out, vg->io_gpo);
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spin_unlock_irqrestore(&vg->lock, flags);
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}
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static int vx855gpio_direction_output(struct gpio_chip *gpio,
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unsigned int nr, int val)
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{
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/* True GPI cannot be switched to output mode */
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if (nr < NR_VX855_GPI)
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return -EINVAL;
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/* True GPO don't need to be switched to output mode,
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* and GPIO are open-drain, i.e. also need no switching,
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* so all we do is set the level */
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vx855gpio_set(gpio, nr, val);
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return 0;
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}
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static int vx855gpio_set_config(struct gpio_chip *gpio, unsigned int nr,
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unsigned long config)
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{
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enum pin_config_param param = pinconf_to_config_param(config);
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/* The GPI cannot be single-ended */
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if (nr < NR_VX855_GPI)
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return -EINVAL;
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/* The GPO's are push-pull */
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if (nr < NR_VX855_GPInO) {
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if (param != PIN_CONFIG_DRIVE_PUSH_PULL)
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return -ENOTSUPP;
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return 0;
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}
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/* The GPIO's are open drain */
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if (param != PIN_CONFIG_DRIVE_OPEN_DRAIN)
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return -ENOTSUPP;
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return 0;
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}
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static const char *vx855gpio_names[NR_VX855_GP] = {
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"VX855_GPI0", "VX855_GPI1", "VX855_GPI2", "VX855_GPI3", "VX855_GPI4",
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"VX855_GPI5", "VX855_GPI6", "VX855_GPI7", "VX855_GPI8", "VX855_GPI9",
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"VX855_GPI10", "VX855_GPI11", "VX855_GPI12", "VX855_GPI13",
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"VX855_GPO0", "VX855_GPO1", "VX855_GPO2", "VX855_GPO3", "VX855_GPO4",
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"VX855_GPO5", "VX855_GPO6", "VX855_GPO7", "VX855_GPO8", "VX855_GPO9",
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"VX855_GPO10", "VX855_GPO11", "VX855_GPO12",
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"VX855_GPIO0", "VX855_GPIO1", "VX855_GPIO2", "VX855_GPIO3",
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"VX855_GPIO4", "VX855_GPIO5", "VX855_GPIO6", "VX855_GPIO7",
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"VX855_GPIO8", "VX855_GPIO9", "VX855_GPIO10", "VX855_GPIO11",
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"VX855_GPIO12", "VX855_GPIO13", "VX855_GPIO14"
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};
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static void vx855gpio_gpio_setup(struct vx855_gpio *vg)
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{
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struct gpio_chip *c = &vg->gpio;
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c->label = "VX855 South Bridge";
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c->owner = THIS_MODULE;
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c->direction_input = vx855gpio_direction_input;
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c->direction_output = vx855gpio_direction_output;
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c->get = vx855gpio_get;
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c->set = vx855gpio_set;
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c->set_config = vx855gpio_set_config,
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c->dbg_show = NULL;
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c->base = 0;
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c->ngpio = NR_VX855_GP;
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c->can_sleep = false;
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c->names = vx855gpio_names;
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}
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/* This platform device is ordinarily registered by the vx855 mfd driver */
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static int vx855gpio_probe(struct platform_device *pdev)
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{
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struct resource *res_gpi;
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struct resource *res_gpo;
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struct vx855_gpio *vg;
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res_gpi = platform_get_resource(pdev, IORESOURCE_IO, 0);
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res_gpo = platform_get_resource(pdev, IORESOURCE_IO, 1);
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if (!res_gpi || !res_gpo)
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return -EBUSY;
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vg = devm_kzalloc(&pdev->dev, sizeof(*vg), GFP_KERNEL);
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if (!vg)
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return -ENOMEM;
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platform_set_drvdata(pdev, vg);
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dev_info(&pdev->dev, "found VX855 GPIO controller\n");
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vg->io_gpi = res_gpi->start;
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vg->io_gpo = res_gpo->start;
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spin_lock_init(&vg->lock);
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/*
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* A single byte is used to control various GPIO ports on the VX855,
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* and in the case of the OLPC XO-1.5, some of those ports are used
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* for switches that are interpreted and exposed through ACPI. ACPI
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* will have reserved the region, so our own reservation will not
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* succeed. Ignore and continue.
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*/
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if (!devm_request_region(&pdev->dev, res_gpi->start,
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resource_size(res_gpi), MODULE_NAME "_gpi"))
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dev_warn(&pdev->dev,
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"GPI I/O resource busy, probably claimed by ACPI\n");
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if (!devm_request_region(&pdev->dev, res_gpo->start,
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resource_size(res_gpo), MODULE_NAME "_gpo"))
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dev_warn(&pdev->dev,
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"GPO I/O resource busy, probably claimed by ACPI\n");
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vx855gpio_gpio_setup(vg);
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return devm_gpiochip_add_data(&pdev->dev, &vg->gpio, vg);
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}
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static struct platform_driver vx855gpio_driver = {
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.driver = {
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.name = MODULE_NAME,
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},
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.probe = vx855gpio_probe,
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};
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module_platform_driver(vx855gpio_driver);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Harald Welte <HaraldWelte@viatech.com>");
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MODULE_DESCRIPTION("GPIO driver for the VIA VX855 chipset");
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MODULE_ALIAS("platform:vx855_gpio");
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