text: /*
   * Access to GPOs on TWL6040 chip
   *
   * Copyright (C) 2012 Texas Instruments, Inc.
   *
   * Authors:
   *	Sergio Aguirre <saaguirre@ti.com>
   *	Peter Ujfalusi <peter.ujfalusi@ti.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/kthread.h>
  #include <linux/irq.h>
  #include <linux/gpio.h>
  #include <linux/platform_device.h>
  #include <linux/of.h>
  
  #include <linux/mfd/twl6040.h>
  
  static struct gpio_chip twl6040gpo_chip;
  
  static int twl6040gpo_get(struct gpio_chip *chip, unsigned offset)
  {
  	struct twl6040 *twl6040 = dev_get_drvdata(chip->parent->parent);
  	int ret = 0;
  
  	ret = twl6040_reg_read(twl6040, TWL6040_REG_GPOCTL);
  	if (ret < 0)
  		return ret;
  
  	return (ret >> offset) & 1;
  }
  
  static int twl6040gpo_direction_out(struct gpio_chip *chip, unsigned offset,
  				    int value)
  {
  	/* This only drives GPOs, and can't change direction */
  	return 0;
  }
  
  static void twl6040gpo_set(struct gpio_chip *chip, unsigned offset, int value)
  {
  	struct twl6040 *twl6040 = dev_get_drvdata(chip->parent->parent);
  	int ret;
  	u8 gpoctl;
  
  	ret = twl6040_reg_read(twl6040, TWL6040_REG_GPOCTL);
  	if (ret < 0)
  		return;
  
  	if (value)
  		gpoctl = ret | (1 << offset);
  	else
  		gpoctl = ret & ~(1 << offset);
  
  	twl6040_reg_write(twl6040, TWL6040_REG_GPOCTL, gpoctl);
  }
  
  static struct gpio_chip twl6040gpo_chip = {
  	.label			= "twl6040",
  	.owner			= THIS_MODULE,
  	.get			= twl6040gpo_get,
  	.direction_output	= twl6040gpo_direction_out,
  	.set			= twl6040gpo_set,
  	.can_sleep		= true,
  };
  
  /*----------------------------------------------------------------------*/
  
  static int gpo_twl6040_probe(struct platform_device *pdev)
  {
  	struct device *twl6040_core_dev = pdev->dev.parent;
  	struct twl6040 *twl6040 = dev_get_drvdata(twl6040_core_dev);
  	int ret;
  
  	twl6040gpo_chip.base = -1;
  
  	if (twl6040_get_revid(twl6040) < TWL6041_REV_ES2_0)
  		twl6040gpo_chip.ngpio = 3; /* twl6040 have 3 GPO */
  	else
  		twl6040gpo_chip.ngpio = 1; /* twl6041 have 1 GPO */
  
  	twl6040gpo_chip.parent = &pdev->dev;
  #ifdef CONFIG_OF_GPIO
  	twl6040gpo_chip.of_node = twl6040_core_dev->of_node;
  #endif
  
  	ret = devm_gpiochip_add_data(&pdev->dev, &twl6040gpo_chip, NULL);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "could not register gpiochip, %d\n", ret);
  		twl6040gpo_chip.ngpio = 0;
  	}
  
  	return ret;
  }
  
  /* Note:  this hardware lives inside an I2C-based multi-function device. */
  MODULE_ALIAS("platform:twl6040-gpo");
  
  static struct platform_driver gpo_twl6040_driver = {
  	.driver = {
  		.name	= "twl6040-gpo",
  	},
  	.probe		= gpo_twl6040_probe,
  };
  
  module_platform_driver(gpo_twl6040_driver);
  
  MODULE_AUTHOR("Texas Instruments, Inc.");
  MODULE_DESCRIPTION("GPO interface for TWL6040");
  MODULE_LICENSE("GPL");
  