/*
   * TI Palma series PMIC's GPIO driver.
   *
   * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
   *
   * Author: Laxman Dewangan <ldewangan@nvidia.com>
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
   */
  
  #include <linux/gpio.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/mfd/palmas.h>
  #include <linux/of.h>
  #include <linux/of_device.h>
  #include <linux/platform_device.h>
  
  struct palmas_gpio {
  	struct gpio_chip gpio_chip;
  	struct palmas *palmas;
  };
  
  struct palmas_device_data {
  	int ngpio;
  };
  
  static inline struct palmas_gpio *to_palmas_gpio(struct gpio_chip *chip)
  {
  	return container_of(chip, struct palmas_gpio, gpio_chip);
  }
  
  static int palmas_gpio_get(struct gpio_chip *gc, unsigned offset)
  {
  	struct palmas_gpio *pg = to_palmas_gpio(gc);
  	struct palmas *palmas = pg->palmas;
  	unsigned int val;
  	int ret;
  	unsigned int reg;
  	int gpio16 = (offset/8);
  
  	offset %= 8;
  	reg = (gpio16) ? PALMAS_GPIO_DATA_DIR2 : PALMAS_GPIO_DATA_DIR;
  
  	ret = palmas_read(palmas, PALMAS_GPIO_BASE, reg, &val);
  	if (ret < 0) {
  		dev_err(gc->dev, "Reg 0x%02x read failed, %d
  ", reg, ret);
  		return ret;
  	}
  
  	if (val & BIT(offset))
  		reg = (gpio16) ? PALMAS_GPIO_DATA_OUT2 : PALMAS_GPIO_DATA_OUT;
  	else
  		reg = (gpio16) ? PALMAS_GPIO_DATA_IN2 : PALMAS_GPIO_DATA_IN;
  
  	ret = palmas_read(palmas, PALMAS_GPIO_BASE, reg, &val);
  	if (ret < 0) {
  		dev_err(gc->dev, "Reg 0x%02x read failed, %d
  ", reg, ret);
  		return ret;
  	}
  	return !!(val & BIT(offset));
  }
  
  static void palmas_gpio_set(struct gpio_chip *gc, unsigned offset,
  			int value)
  {
  	struct palmas_gpio *pg = to_palmas_gpio(gc);
  	struct palmas *palmas = pg->palmas;
  	int ret;
  	unsigned int reg;
  	int gpio16 = (offset/8);
  
  	offset %= 8;
  	if (gpio16)
  		reg = (value) ?
  			PALMAS_GPIO_SET_DATA_OUT2 : PALMAS_GPIO_CLEAR_DATA_OUT2;
  	else
  		reg = (value) ?
  			PALMAS_GPIO_SET_DATA_OUT : PALMAS_GPIO_CLEAR_DATA_OUT;
  
  	ret = palmas_write(palmas, PALMAS_GPIO_BASE, reg, BIT(offset));
  	if (ret < 0)
  		dev_err(gc->dev, "Reg 0x%02x write failed, %d
  ", reg, ret);
  }
  
  static int palmas_gpio_output(struct gpio_chip *gc, unsigned offset,
  				int value)
  {
  	struct palmas_gpio *pg = to_palmas_gpio(gc);
  	struct palmas *palmas = pg->palmas;
  	int ret;
  	unsigned int reg;
  	int gpio16 = (offset/8);
  
  	offset %= 8;
  	reg = (gpio16) ? PALMAS_GPIO_DATA_DIR2 : PALMAS_GPIO_DATA_DIR;
  
  	/* Set the initial value */
  	palmas_gpio_set(gc, offset, value);
  
  	ret = palmas_update_bits(palmas, PALMAS_GPIO_BASE, reg,
  				BIT(offset), BIT(offset));
  	if (ret < 0)
  		dev_err(gc->dev, "Reg 0x%02x update failed, %d
  ", reg, ret);
  	return ret;
  }
  
  static int palmas_gpio_input(struct gpio_chip *gc, unsigned offset)
  {
  	struct palmas_gpio *pg = to_palmas_gpio(gc);
  	struct palmas *palmas = pg->palmas;
  	int ret;
  	unsigned int reg;
  	int gpio16 = (offset/8);
  
  	offset %= 8;
  	reg = (gpio16) ? PALMAS_GPIO_DATA_DIR2 : PALMAS_GPIO_DATA_DIR;
  
  	ret = palmas_update_bits(palmas, PALMAS_GPIO_BASE, reg, BIT(offset), 0);
  	if (ret < 0)
  		dev_err(gc->dev, "Reg 0x%02x update failed, %d
  ", reg, ret);
  	return ret;
  }
  
  static int palmas_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
  {
  	struct palmas_gpio *pg = to_palmas_gpio(gc);
  	struct palmas *palmas = pg->palmas;
  
  	return palmas_irq_get_virq(palmas, PALMAS_GPIO_0_IRQ + offset);
  }
  
  static const struct palmas_device_data palmas_dev_data = {
  	.ngpio = 8,
  };
  
  static const struct palmas_device_data tps80036_dev_data = {
  	.ngpio = 16,
  };
  
  static struct of_device_id of_palmas_gpio_match[] = {
  	{ .compatible = "ti,palmas-gpio", .data = &palmas_dev_data,},
  	{ .compatible = "ti,tps65913-gpio", .data = &palmas_dev_data,},
  	{ .compatible = "ti,tps65914-gpio", .data = &palmas_dev_data,},
  	{ .compatible = "ti,tps80036-gpio", .data = &tps80036_dev_data,},
  	{ },
  };
  MODULE_DEVICE_TABLE(of, of_palmas_gpio_match);
  
  static int palmas_gpio_probe(struct platform_device *pdev)
  {
  	struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
  	struct palmas_platform_data *palmas_pdata;
  	struct palmas_gpio *palmas_gpio;
  	int ret;
  	const struct of_device_id *match;
  	const struct palmas_device_data *dev_data;
  
  	match = of_match_device(of_palmas_gpio_match, &pdev->dev);
  	dev_data = match->data;
  	if (!dev_data)
  		dev_data = &palmas_dev_data;
  
  	palmas_gpio = devm_kzalloc(&pdev->dev,
  				sizeof(*palmas_gpio), GFP_KERNEL);
  	if (!palmas_gpio) {
  		dev_err(&pdev->dev, "Could not allocate palmas_gpio
  ");
  		return -ENOMEM;
  	}
  
  	palmas_gpio->palmas = palmas;
  	palmas_gpio->gpio_chip.owner = THIS_MODULE;
  	palmas_gpio->gpio_chip.label = dev_name(&pdev->dev);
  	palmas_gpio->gpio_chip.ngpio = dev_data->ngpio;
  	palmas_gpio->gpio_chip.can_sleep = true;
  	palmas_gpio->gpio_chip.direction_input = palmas_gpio_input;
  	palmas_gpio->gpio_chip.direction_output = palmas_gpio_output;
  	palmas_gpio->gpio_chip.to_irq = palmas_gpio_to_irq;
  	palmas_gpio->gpio_chip.set	= palmas_gpio_set;
  	palmas_gpio->gpio_chip.get	= palmas_gpio_get;
  	palmas_gpio->gpio_chip.dev = &pdev->dev;
  #ifdef CONFIG_OF_GPIO
  	palmas_gpio->gpio_chip.of_node = pdev->dev.of_node;
  #endif
  	palmas_pdata = dev_get_platdata(palmas->dev);
  	if (palmas_pdata && palmas_pdata->gpio_base)
  		palmas_gpio->gpio_chip.base = palmas_pdata->gpio_base;
  	else
  		palmas_gpio->gpio_chip.base = -1;
  
  	ret = gpiochip_add(&palmas_gpio->gpio_chip);
  	if (ret < 0) {
  		dev_err(&pdev->dev, "Could not register gpiochip, %d
  ", ret);
  		return ret;
  	}
  
  	platform_set_drvdata(pdev, palmas_gpio);
  	return ret;
  }
  
  static int palmas_gpio_remove(struct platform_device *pdev)
  {
  	struct palmas_gpio *palmas_gpio = platform_get_drvdata(pdev);
  
  	return gpiochip_remove(&palmas_gpio->gpio_chip);
  }
  
  static struct platform_driver palmas_gpio_driver = {
  	.driver.name	= "palmas-gpio",
  	.driver.owner	= THIS_MODULE,
  	.driver.of_match_table = of_palmas_gpio_match,
  	.probe		= palmas_gpio_probe,
  	.remove		= palmas_gpio_remove,
  };
  
  static int __init palmas_gpio_init(void)
  {
  	return platform_driver_register(&palmas_gpio_driver);
  }
  subsys_initcall(palmas_gpio_init);
  
  static void __exit palmas_gpio_exit(void)
  {
  	platform_driver_unregister(&palmas_gpio_driver);
  }
  module_exit(palmas_gpio_exit);
  
  MODULE_ALIAS("platform:palmas-gpio");
  MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
  MODULE_DESCRIPTION("GPIO driver for TI Palmas series PMICs");
  MODULE_LICENSE("GPL v2");