/*
   * Rotary counter driver for Analog Devices Blackfin Processors
   *
   * Copyright 2008-2009 Analog Devices Inc.
   * Licensed under the GPL-2 or later.
   */
  
  #include <linux/module.h>
  #include <linux/interrupt.h>
  #include <linux/io.h>
  #include <linux/irq.h>
  #include <linux/pm.h>
  #include <linux/platform_device.h>
  #include <linux/input.h>
  #include <linux/slab.h>
  #include <linux/platform_data/bfin_rotary.h>
  
  #include <asm/portmux.h>
  
  #define CNT_CONFIG_OFF		0	/* CNT Config Offset */
  #define CNT_IMASK_OFF		4	/* CNT Interrupt Mask Offset */
  #define CNT_STATUS_OFF		8	/* CNT Status Offset */
  #define CNT_COMMAND_OFF		12	/* CNT Command Offset */
  #define CNT_DEBOUNCE_OFF	16	/* CNT Debounce Offset */
  #define CNT_COUNTER_OFF		20	/* CNT Counter Offset */
  #define CNT_MAX_OFF		24	/* CNT Maximum Count Offset */
  #define CNT_MIN_OFF		28	/* CNT Minimum Count Offset */
  
  struct bfin_rot {
  	struct input_dev *input;
  	void __iomem *base;
  	int irq;
  	unsigned int up_key;
  	unsigned int down_key;
  	unsigned int button_key;
  	unsigned int rel_code;
  
  	unsigned short mode;
  	unsigned short debounce;
  
  	unsigned short cnt_config;
  	unsigned short cnt_imask;
  	unsigned short cnt_debounce;
  };
  
  static void report_key_event(struct input_dev *input, int keycode)
  {
  	/* simulate a press-n-release */
  	input_report_key(input, keycode, 1);
  	input_sync(input);
  	input_report_key(input, keycode, 0);
  	input_sync(input);
  }
  
  static void report_rotary_event(struct bfin_rot *rotary, int delta)
  {
  	struct input_dev *input = rotary->input;
  
  	if (rotary->up_key) {
  		report_key_event(input,
  				 delta > 0 ? rotary->up_key : rotary->down_key);
  	} else {
  		input_report_rel(input, rotary->rel_code, delta);
  		input_sync(input);
  	}
  }
  
  static irqreturn_t bfin_rotary_isr(int irq, void *dev_id)
  {
  	struct bfin_rot *rotary = dev_id;
  	int delta;
  
  	switch (readw(rotary->base + CNT_STATUS_OFF)) {
  
  	case ICII:
  		break;
  
  	case UCII:
  	case DCII:
  		delta = readl(rotary->base + CNT_COUNTER_OFF);
  		if (delta)
  			report_rotary_event(rotary, delta);
  		break;
  
  	case CZMII:
  		report_key_event(rotary->input, rotary->button_key);
  		break;
  
  	default:
  		break;
  	}
  
  	writew(W1LCNT_ZERO, rotary->base + CNT_COMMAND_OFF); /* Clear COUNTER */
  	writew(-1, rotary->base + CNT_STATUS_OFF); /* Clear STATUS */
  
  	return IRQ_HANDLED;
  }
  
  static int bfin_rotary_open(struct input_dev *input)
  {
  	struct bfin_rot *rotary = input_get_drvdata(input);
  	unsigned short val;
  
  	if (rotary->mode & ROT_DEBE)
  		writew(rotary->debounce & DPRESCALE,
  			rotary->base + CNT_DEBOUNCE_OFF);
  
  	writew(rotary->mode & ~CNTE, rotary->base + CNT_CONFIG_OFF);
  
  	val = UCIE | DCIE;
  	if (rotary->button_key)
  		val |= CZMIE;
  	writew(val, rotary->base + CNT_IMASK_OFF);
  
  	writew(rotary->mode | CNTE, rotary->base + CNT_CONFIG_OFF);
  
  	return 0;
  }
  
  static void bfin_rotary_close(struct input_dev *input)
  {
  	struct bfin_rot *rotary = input_get_drvdata(input);
  
  	writew(0, rotary->base + CNT_CONFIG_OFF);
  	writew(0, rotary->base + CNT_IMASK_OFF);
  }
  
  static void bfin_rotary_free_action(void *data)
  {
  	peripheral_free_list(data);
  }
  
  static int bfin_rotary_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	const struct bfin_rotary_platform_data *pdata = dev_get_platdata(dev);
  	struct bfin_rot *rotary;
  	struct resource *res;
  	struct input_dev *input;
  	int error;
  
  	/* Basic validation */
  	if ((pdata->rotary_up_key && !pdata->rotary_down_key) ||
  	    (!pdata->rotary_up_key && pdata->rotary_down_key)) {
  		return -EINVAL;
  	}
  
  	if (pdata->pin_list) {
  		error = peripheral_request_list(pdata->pin_list,
  						dev_name(&pdev->dev));
  		if (error) {
  			dev_err(dev, "requesting peripherals failed: %d
  ",
  				error);
  			return error;
  		}
  
  		error = devm_add_action(dev, bfin_rotary_free_action,
  					pdata->pin_list);
  		if (error) {
  			dev_err(dev, "setting cleanup action failed: %d
  ",
  				error);
  			peripheral_free_list(pdata->pin_list);
  			return error;
  		}
  	}
  
  	rotary = devm_kzalloc(dev, sizeof(struct bfin_rot), GFP_KERNEL);
  	if (!rotary)
  		return -ENOMEM;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	rotary->base = devm_ioremap_resource(dev, res);
  	if (IS_ERR(rotary->base))
  		return PTR_ERR(rotary->base);
  
  	input = devm_input_allocate_device(dev);
  	if (!input)
  		return -ENOMEM;
  
  	rotary->input = input;
  
  	rotary->up_key = pdata->rotary_up_key;
  	rotary->down_key = pdata->rotary_down_key;
  	rotary->button_key = pdata->rotary_button_key;
  	rotary->rel_code = pdata->rotary_rel_code;
  
  	rotary->mode = pdata->mode;
  	rotary->debounce = pdata->debounce;
  
  	input->name = pdev->name;
  	input->phys = "bfin-rotary/input0";
  	input->dev.parent = &pdev->dev;
  
  	input_set_drvdata(input, rotary);
  
  	input->id.bustype = BUS_HOST;
  	input->id.vendor = 0x0001;
  	input->id.product = 0x0001;
  	input->id.version = 0x0100;
  
  	input->open = bfin_rotary_open;
  	input->close = bfin_rotary_close;
  
  	if (rotary->up_key) {
  		__set_bit(EV_KEY, input->evbit);
  		__set_bit(rotary->up_key, input->keybit);
  		__set_bit(rotary->down_key, input->keybit);
  	} else {
  		__set_bit(EV_REL, input->evbit);
  		__set_bit(rotary->rel_code, input->relbit);
  	}
  
  	if (rotary->button_key) {
  		__set_bit(EV_KEY, input->evbit);
  		__set_bit(rotary->button_key, input->keybit);
  	}
  
  	/* Quiesce the device before requesting irq */
  	bfin_rotary_close(input);
  
  	rotary->irq = platform_get_irq(pdev, 0);
  	if (rotary->irq < 0) {
  		dev_err(dev, "No rotary IRQ specified
  ");
  		return -ENOENT;
  	}
  
  	error = devm_request_irq(dev, rotary->irq, bfin_rotary_isr,
  				 0, dev_name(dev), rotary);
  	if (error) {
  		dev_err(dev, "unable to claim irq %d; error %d
  ",
  			rotary->irq, error);
  		return error;
  	}
  
  	error = input_register_device(input);
  	if (error) {
  		dev_err(dev, "unable to register input device (%d)
  ", error);
  		return error;
  	}
  
  	platform_set_drvdata(pdev, rotary);
  	device_init_wakeup(&pdev->dev, 1);
  
  	return 0;
  }
  
  static int __maybe_unused bfin_rotary_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct bfin_rot *rotary = platform_get_drvdata(pdev);
  
  	rotary->cnt_config = readw(rotary->base + CNT_CONFIG_OFF);
  	rotary->cnt_imask = readw(rotary->base + CNT_IMASK_OFF);
  	rotary->cnt_debounce = readw(rotary->base + CNT_DEBOUNCE_OFF);
  
  	if (device_may_wakeup(&pdev->dev))
  		enable_irq_wake(rotary->irq);
  
  	return 0;
  }
  
  static int __maybe_unused bfin_rotary_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct bfin_rot *rotary = platform_get_drvdata(pdev);
  
  	writew(rotary->cnt_debounce, rotary->base + CNT_DEBOUNCE_OFF);
  	writew(rotary->cnt_imask, rotary->base + CNT_IMASK_OFF);
  	writew(rotary->cnt_config & ~CNTE, rotary->base + CNT_CONFIG_OFF);
  
  	if (device_may_wakeup(&pdev->dev))
  		disable_irq_wake(rotary->irq);
  
  	if (rotary->cnt_config & CNTE)
  		writew(rotary->cnt_config, rotary->base + CNT_CONFIG_OFF);
  
  	return 0;
  }
  
  static SIMPLE_DEV_PM_OPS(bfin_rotary_pm_ops,
  			 bfin_rotary_suspend, bfin_rotary_resume);
  
  static struct platform_driver bfin_rotary_device_driver = {
  	.probe		= bfin_rotary_probe,
  	.driver		= {
  		.name	= "bfin-rotary",
  		.pm	= &bfin_rotary_pm_ops,
  	},
  };
  module_platform_driver(bfin_rotary_device_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
  MODULE_DESCRIPTION("Rotary Counter driver for Blackfin Processors");
  MODULE_ALIAS("platform:bfin-rotary");