text: /*
   * Copyright 2013 Red Hat Inc.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
   * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
   * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
   * OTHER DEALINGS IN THE SOFTWARE.
   *
   * Authors: Ben Skeggs
   */
  #include <subdev/volt.h>
  #include <subdev/bios.h>
  #include <subdev/bios/gpio.h>
  #include <subdev/gpio.h>
  
  static const u8 tags[] = {
  	DCB_GPIO_VID0, DCB_GPIO_VID1, DCB_GPIO_VID2, DCB_GPIO_VID3,
  	DCB_GPIO_VID4, DCB_GPIO_VID5, DCB_GPIO_VID6, DCB_GPIO_VID7,
  };
  
  int
  nvkm_voltgpio_get(struct nvkm_volt *volt)
  {
  	struct nvkm_gpio *gpio = nvkm_gpio(volt);
  	u8 vid = 0;
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(tags); i++) {
  		if (volt->vid_mask & (1 << i)) {
  			int ret = gpio->get(gpio, 0, tags[i], 0xff);
  			if (ret < 0)
  				return ret;
  			vid |= ret << i;
  		}
  	}
  
  	return vid;
  }
  
  int
  nvkm_voltgpio_set(struct nvkm_volt *volt, u8 vid)
  {
  	struct nvkm_gpio *gpio = nvkm_gpio(volt);
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(tags); i++, vid >>= 1) {
  		if (volt->vid_mask & (1 << i)) {
  			int ret = gpio->set(gpio, 0, tags[i], 0xff, vid & 1);
  			if (ret < 0)
  				return ret;
  		}
  	}
  
  	return 0;
  }
  
  int
  nvkm_voltgpio_init(struct nvkm_volt *volt)
  {
  	struct nvkm_gpio *gpio = nvkm_gpio(volt);
  	struct dcb_gpio_func func;
  	int i;
  
  	/* check we have gpio function info for each vid bit.  on some
  	 * boards (ie. nvs295) the vid mask has more bits than there
  	 * are valid gpio functions... from traces, nvidia appear to
  	 * just touch the existing ones, so let's mask off the invalid
  	 * bits and continue with life
  	 */
  	for (i = 0; i < ARRAY_SIZE(tags); i++) {
  		if (volt->vid_mask & (1 << i)) {
  			int ret = gpio->find(gpio, 0, tags[i], 0xff, &func);
  			if (ret) {
  				if (ret != -ENOENT)
  					return ret;
  				nv_debug(volt, "VID bit %d has no GPIO\n", i);
  				volt->vid_mask &= ~(1 << i);
  			}
  		}
  	}
  
  	return 0;
  }
  