/*
   * Driver for the enhanced rotary controller on pxa930 and pxa935
   *
   * 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/interrupt.h>
  #include <linux/input.h>
  #include <linux/platform_device.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  
  #include <linux/platform_data/keyboard-pxa930_rotary.h>
  
  #define SBCR	(0x04)
  #define ERCR	(0x0c)
  
  #define SBCR_ERSB	(1 << 5)
  
  struct pxa930_rotary {
  	struct input_dev	*input_dev;
  	void __iomem		*mmio_base;
  	int			last_ercr;
  
  	struct pxa930_rotary_platform_data *pdata;
  };
  
  static void clear_sbcr(struct pxa930_rotary *r)
  {
  	uint32_t sbcr = __raw_readl(r->mmio_base + SBCR);
  
  	__raw_writel(sbcr | SBCR_ERSB, r->mmio_base + SBCR);
  	__raw_writel(sbcr & ~SBCR_ERSB, r->mmio_base + SBCR);
  }
  
  static irqreturn_t rotary_irq(int irq, void *dev_id)
  {
  	struct pxa930_rotary *r = dev_id;
  	struct pxa930_rotary_platform_data *pdata = r->pdata;
  	int ercr, delta, key;
  
  	ercr = __raw_readl(r->mmio_base + ERCR) & 0xf;
  	clear_sbcr(r);
  
  	delta = ercr - r->last_ercr;
  	if (delta == 0)
  		return IRQ_HANDLED;
  
  	r->last_ercr = ercr;
  
  	if (pdata->up_key && pdata->down_key) {
  		key = (delta > 0) ? pdata->up_key : pdata->down_key;
  		input_report_key(r->input_dev, key, 1);
  		input_sync(r->input_dev);
  		input_report_key(r->input_dev, key, 0);
  	} else
  		input_report_rel(r->input_dev, pdata->rel_code, delta);
  
  	input_sync(r->input_dev);
  
  	return IRQ_HANDLED;
  }
  
  static int pxa930_rotary_open(struct input_dev *dev)
  {
  	struct pxa930_rotary *r = input_get_drvdata(dev);
  
  	clear_sbcr(r);
  
  	return 0;
  }
  
  static void pxa930_rotary_close(struct input_dev *dev)
  {
  	struct pxa930_rotary *r = input_get_drvdata(dev);
  
  	clear_sbcr(r);
  }
  
  static int pxa930_rotary_probe(struct platform_device *pdev)
  {
  	struct pxa930_rotary_platform_data *pdata =
  			dev_get_platdata(&pdev->dev);
  	struct pxa930_rotary *r;
  	struct input_dev *input_dev;
  	struct resource *res;
  	int irq;
  	int err;
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0) {
  		dev_err(&pdev->dev, "no irq for rotary controller
  ");
  		return -ENXIO;
  	}
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!res) {
  		dev_err(&pdev->dev, "no I/O memory defined
  ");
  		return -ENXIO;
  	}
  
  	if (!pdata) {
  		dev_err(&pdev->dev, "no platform data defined
  ");
  		return -EINVAL;
  	}
  
  	r = kzalloc(sizeof(struct pxa930_rotary), GFP_KERNEL);
  	if (!r)
  		return -ENOMEM;
  
  	r->mmio_base = ioremap_nocache(res->start, resource_size(res));
  	if (r->mmio_base == NULL) {
  		dev_err(&pdev->dev, "failed to remap IO memory
  ");
  		err = -ENXIO;
  		goto failed_free;
  	}
  
  	r->pdata = pdata;
  	platform_set_drvdata(pdev, r);
  
  	/* allocate and register the input device */
  	input_dev = input_allocate_device();
  	if (!input_dev) {
  		dev_err(&pdev->dev, "failed to allocate input device
  ");
  		err = -ENOMEM;
  		goto failed_free_io;
  	}
  
  	input_dev->name = pdev->name;
  	input_dev->id.bustype = BUS_HOST;
  	input_dev->open = pxa930_rotary_open;
  	input_dev->close = pxa930_rotary_close;
  	input_dev->dev.parent = &pdev->dev;
  
  	if (pdata->up_key && pdata->down_key) {
  		__set_bit(pdata->up_key, input_dev->keybit);
  		__set_bit(pdata->down_key, input_dev->keybit);
  		__set_bit(EV_KEY, input_dev->evbit);
  	} else {
  		__set_bit(pdata->rel_code, input_dev->relbit);
  		__set_bit(EV_REL, input_dev->evbit);
  	}
  
  	r->input_dev = input_dev;
  	input_set_drvdata(input_dev, r);
  
  	err = request_irq(irq, rotary_irq, 0,
  			"enhanced rotary", r);
  	if (err) {
  		dev_err(&pdev->dev, "failed to request IRQ
  ");
  		goto failed_free_input;
  	}
  
  	err = input_register_device(input_dev);
  	if (err) {
  		dev_err(&pdev->dev, "failed to register input device
  ");
  		goto failed_free_irq;
  	}
  
  	return 0;
  
  failed_free_irq:
  	free_irq(irq, r);
  failed_free_input:
  	input_free_device(input_dev);
  failed_free_io:
  	iounmap(r->mmio_base);
  failed_free:
  	kfree(r);
  	return err;
  }
  
  static int pxa930_rotary_remove(struct platform_device *pdev)
  {
  	struct pxa930_rotary *r = platform_get_drvdata(pdev);
  
  	free_irq(platform_get_irq(pdev, 0), r);
  	input_unregister_device(r->input_dev);
  	iounmap(r->mmio_base);
  	kfree(r);
  
  	return 0;
  }
  
  static struct platform_driver pxa930_rotary_driver = {
  	.driver		= {
  		.name	= "pxa930-rotary",
  	},
  	.probe		= pxa930_rotary_probe,
  	.remove		= pxa930_rotary_remove,
  };
  module_platform_driver(pxa930_rotary_driver);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("Driver for PXA93x Enhanced Rotary Controller");
  MODULE_AUTHOR("Yao Yong <yaoyong@marvell.com>");