/*
   *  i2c_pca_platform.c
   *
   *  Platform driver for the PCA9564 I2C controller.
   *
   *  Copyright (C) 2008 Pengutronix
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License version 2 as
   *  published by the Free Software Foundation.
  
   */
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/delay.h>
  #include <linux/jiffies.h>
  #include <linux/errno.h>
  #include <linux/i2c.h>
  #include <linux/interrupt.h>
  #include <linux/platform_device.h>
  #include <linux/i2c-algo-pca.h>
  #include <linux/i2c-pca-platform.h>
  #include <linux/gpio.h>
  #include <linux/io.h>
  
  #include <asm/irq.h>
  
  struct i2c_pca_pf_data {
  	void __iomem			*reg_base;
  	int				irq;	/* if 0, use polling */
  	int				gpio;
  	wait_queue_head_t		wait;
  	struct i2c_adapter		adap;
  	struct i2c_algo_pca_data	algo_data;
  	unsigned long			io_base;
  	unsigned long			io_size;
  };
  
  /* Read/Write functions for different register alignments */
  
  static int i2c_pca_pf_readbyte8(void *pd, int reg)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  	return ioread8(i2c->reg_base + reg);
  }
  
  static int i2c_pca_pf_readbyte16(void *pd, int reg)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  	return ioread8(i2c->reg_base + reg * 2);
  }
  
  static int i2c_pca_pf_readbyte32(void *pd, int reg)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  	return ioread8(i2c->reg_base + reg * 4);
  }
  
  static void i2c_pca_pf_writebyte8(void *pd, int reg, int val)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  	iowrite8(val, i2c->reg_base + reg);
  }
  
  static void i2c_pca_pf_writebyte16(void *pd, int reg, int val)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  	iowrite8(val, i2c->reg_base + reg * 2);
  }
  
  static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  	iowrite8(val, i2c->reg_base + reg * 4);
  }
  
  
  static int i2c_pca_pf_waitforcompletion(void *pd)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  	unsigned long timeout;
  	long ret;
  
  	if (i2c->irq) {
  		ret = wait_event_timeout(i2c->wait,
  			i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  			& I2C_PCA_CON_SI, i2c->adap.timeout);
  	} else {
  		/* Do polling */
  		timeout = jiffies + i2c->adap.timeout;
  		do {
  			ret = time_before(jiffies, timeout);
  			if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
  					& I2C_PCA_CON_SI)
  				break;
  			udelay(100);
  		} while (ret);
  	}
  
  	return ret > 0;
  }
  
  static void i2c_pca_pf_dummyreset(void *pd)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  	printk(KERN_WARNING "%s: No reset-pin found. Chip may get stuck!
  ",
  		i2c->adap.name);
  }
  
  static void i2c_pca_pf_resetchip(void *pd)
  {
  	struct i2c_pca_pf_data *i2c = pd;
  
  	gpio_set_value(i2c->gpio, 0);
  	ndelay(100);
  	gpio_set_value(i2c->gpio, 1);
  }
  
  static irqreturn_t i2c_pca_pf_handler(int this_irq, void *dev_id)
  {
  	struct i2c_pca_pf_data *i2c = dev_id;
  
  	if ((i2c->algo_data.read_byte(i2c, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
  		return IRQ_NONE;
  
  	wake_up(&i2c->wait);
  
  	return IRQ_HANDLED;
  }
  
  
  static int i2c_pca_pf_probe(struct platform_device *pdev)
  {
  	struct i2c_pca_pf_data *i2c;
  	struct resource *res;
  	struct i2c_pca9564_pf_platform_data *platform_data =
  				dev_get_platdata(&pdev->dev);
  	int ret = 0;
  	int irq;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	irq = platform_get_irq(pdev, 0);
  	/* If irq is 0, we do polling. */
  
  	if (res == NULL) {
  		ret = -ENODEV;
  		goto e_print;
  	}
  
  	if (!request_mem_region(res->start, resource_size(res), res->name)) {
  		ret = -ENOMEM;
  		goto e_print;
  	}
  
  	i2c = kzalloc(sizeof(struct i2c_pca_pf_data), GFP_KERNEL);
  	if (!i2c) {
  		ret = -ENOMEM;
  		goto e_alloc;
  	}
  
  	init_waitqueue_head(&i2c->wait);
  
  	i2c->reg_base = ioremap(res->start, resource_size(res));
  	if (!i2c->reg_base) {
  		ret = -ENOMEM;
  		goto e_remap;
  	}
  	i2c->io_base = res->start;
  	i2c->io_size = resource_size(res);
  	i2c->irq = irq;
  
  	i2c->adap.nr = pdev->id;
  	i2c->adap.owner = THIS_MODULE;
  	snprintf(i2c->adap.name, sizeof(i2c->adap.name),
  		 "PCA9564/PCA9665 at 0x%08lx",
  		 (unsigned long) res->start);
  	i2c->adap.algo_data = &i2c->algo_data;
  	i2c->adap.dev.parent = &pdev->dev;
  
  	if (platform_data) {
  		i2c->adap.timeout = platform_data->timeout;
  		i2c->algo_data.i2c_clock = platform_data->i2c_clock_speed;
  		i2c->gpio = platform_data->gpio;
  	} else {
  		i2c->adap.timeout = HZ;
  		i2c->algo_data.i2c_clock = 59000;
  		i2c->gpio = -1;
  	}
  
  	i2c->algo_data.data = i2c;
  	i2c->algo_data.wait_for_completion = i2c_pca_pf_waitforcompletion;
  	i2c->algo_data.reset_chip = i2c_pca_pf_dummyreset;
  
  	switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
  	case IORESOURCE_MEM_32BIT:
  		i2c->algo_data.write_byte = i2c_pca_pf_writebyte32;
  		i2c->algo_data.read_byte = i2c_pca_pf_readbyte32;
  		break;
  	case IORESOURCE_MEM_16BIT:
  		i2c->algo_data.write_byte = i2c_pca_pf_writebyte16;
  		i2c->algo_data.read_byte = i2c_pca_pf_readbyte16;
  		break;
  	case IORESOURCE_MEM_8BIT:
  	default:
  		i2c->algo_data.write_byte = i2c_pca_pf_writebyte8;
  		i2c->algo_data.read_byte = i2c_pca_pf_readbyte8;
  		break;
  	}
  
  	/* Use gpio_is_valid() when in mainline */
  	if (i2c->gpio > -1) {
  		ret = gpio_request(i2c->gpio, i2c->adap.name);
  		if (ret == 0) {
  			gpio_direction_output(i2c->gpio, 1);
  			i2c->algo_data.reset_chip = i2c_pca_pf_resetchip;
  		} else {
  			printk(KERN_WARNING "%s: Registering gpio failed!
  ",
  				i2c->adap.name);
  			i2c->gpio = ret;
  		}
  	}
  
  	if (irq) {
  		ret = request_irq(irq, i2c_pca_pf_handler,
  			IRQF_TRIGGER_FALLING, pdev->name, i2c);
  		if (ret)
  			goto e_reqirq;
  	}
  
  	if (i2c_pca_add_numbered_bus(&i2c->adap) < 0) {
  		ret = -ENODEV;
  		goto e_adapt;
  	}
  
  	platform_set_drvdata(pdev, i2c);
  
  	printk(KERN_INFO "%s registered.
  ", i2c->adap.name);
  
  	return 0;
  
  e_adapt:
  	if (irq)
  		free_irq(irq, i2c);
  e_reqirq:
  	if (i2c->gpio > -1)
  		gpio_free(i2c->gpio);
  
  	iounmap(i2c->reg_base);
  e_remap:
  	kfree(i2c);
  e_alloc:
  	release_mem_region(res->start, resource_size(res));
  e_print:
  	printk(KERN_ERR "Registering PCA9564/PCA9665 FAILED! (%d)
  ", ret);
  	return ret;
  }
  
  static int i2c_pca_pf_remove(struct platform_device *pdev)
  {
  	struct i2c_pca_pf_data *i2c = platform_get_drvdata(pdev);
  
  	i2c_del_adapter(&i2c->adap);
  
  	if (i2c->irq)
  		free_irq(i2c->irq, i2c);
  
  	if (i2c->gpio > -1)
  		gpio_free(i2c->gpio);
  
  	iounmap(i2c->reg_base);
  	release_mem_region(i2c->io_base, i2c->io_size);
  	kfree(i2c);
  
  	return 0;
  }
  
  static struct platform_driver i2c_pca_pf_driver = {
  	.probe = i2c_pca_pf_probe,
  	.remove = i2c_pca_pf_remove,
  	.driver = {
  		.name = "i2c-pca-platform",
  	},
  };
  
  module_platform_driver(i2c_pca_pf_driver);
  
  MODULE_AUTHOR("Wolfram Sang <kernel@pengutronix.de>");
  MODULE_DESCRIPTION("I2C-PCA9564/PCA9665 platform driver");
  MODULE_LICENSE("GPL");