/*
   * SPEAr Keyboard Driver
   * Based on omap-keypad driver
   *
   * Copyright (C) 2010 ST Microelectronics
   * Rajeev Kumar <rajeevkumar.linux@gmail.com>
   *
   * This file is licensed under the terms of the GNU General Public
   * License version 2. This program is licensed "as is" without any
   * warranty of any kind, whether express or implied.
   */
  
  #include <linux/clk.h>
  #include <linux/errno.h>
  #include <linux/interrupt.h>
  #include <linux/input.h>
  #include <linux/io.h>
  #include <linux/irq.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/of.h>
  #include <linux/platform_device.h>
  #include <linux/pm_wakeup.h>
  #include <linux/slab.h>
  #include <linux/types.h>
  #include <linux/platform_data/keyboard-spear.h>
  
  /* Keyboard Registers */
  #define MODE_CTL_REG	0x00
  #define STATUS_REG	0x0C
  #define DATA_REG	0x10
  #define INTR_MASK	0x54
  
  /* Register Values */
  #define NUM_ROWS	16
  #define NUM_COLS	16
  #define MODE_CTL_PCLK_FREQ_SHIFT	9
  #define MODE_CTL_PCLK_FREQ_MSK		0x7F
  
  #define MODE_CTL_KEYBOARD	(0x2 << 0)
  #define MODE_CTL_SCAN_RATE_10	(0x0 << 2)
  #define MODE_CTL_SCAN_RATE_20	(0x1 << 2)
  #define MODE_CTL_SCAN_RATE_40	(0x2 << 2)
  #define MODE_CTL_SCAN_RATE_80	(0x3 << 2)
  #define MODE_CTL_KEYNUM_SHIFT	6
  #define MODE_CTL_START_SCAN	(0x1 << 8)
  
  #define STATUS_DATA_AVAIL	(0x1 << 1)
  
  #define DATA_ROW_MASK		0xF0
  #define DATA_COLUMN_MASK	0x0F
  
  #define ROW_SHIFT		4
  
  struct spear_kbd {
  	struct input_dev *input;
  	void __iomem *io_base;
  	struct clk *clk;
  	unsigned int irq;
  	unsigned int mode;
  	unsigned int suspended_rate;
  	unsigned short last_key;
  	unsigned short keycodes[NUM_ROWS * NUM_COLS];
  	bool rep;
  	bool irq_wake_enabled;
  	u32 mode_ctl_reg;
  };
  
  static irqreturn_t spear_kbd_interrupt(int irq, void *dev_id)
  {
  	struct spear_kbd *kbd = dev_id;
  	struct input_dev *input = kbd->input;
  	unsigned int key;
  	u32 sts, val;
  
  	sts = readl_relaxed(kbd->io_base + STATUS_REG);
  	if (!(sts & STATUS_DATA_AVAIL))
  		return IRQ_NONE;
  
  	if (kbd->last_key != KEY_RESERVED) {
  		input_report_key(input, kbd->last_key, 0);
  		kbd->last_key = KEY_RESERVED;
  	}
  
  	/* following reads active (row, col) pair */
  	val = readl_relaxed(kbd->io_base + DATA_REG) &
  		(DATA_ROW_MASK | DATA_COLUMN_MASK);
  	key = kbd->keycodes[val];
  
  	input_event(input, EV_MSC, MSC_SCAN, val);
  	input_report_key(input, key, 1);
  	input_sync(input);
  
  	kbd->last_key = key;
  
  	/* clear interrupt */
  	writel_relaxed(0, kbd->io_base + STATUS_REG);
  
  	return IRQ_HANDLED;
  }
  
  static int spear_kbd_open(struct input_dev *dev)
  {
  	struct spear_kbd *kbd = input_get_drvdata(dev);
  	int error;
  	u32 val;
  
  	kbd->last_key = KEY_RESERVED;
  
  	error = clk_enable(kbd->clk);
  	if (error)
  		return error;
  
  	/* keyboard rate to be programmed is input clock (in MHz) - 1 */
  	val = clk_get_rate(kbd->clk) / 1000000 - 1;
  	val = (val & MODE_CTL_PCLK_FREQ_MSK) << MODE_CTL_PCLK_FREQ_SHIFT;
  
  	/* program keyboard */
  	val = MODE_CTL_SCAN_RATE_80 | MODE_CTL_KEYBOARD | val |
  		(kbd->mode << MODE_CTL_KEYNUM_SHIFT);
  	writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
  	writel_relaxed(1, kbd->io_base + STATUS_REG);
  
  	/* start key scan */
  	val = readl_relaxed(kbd->io_base + MODE_CTL_REG);
  	val |= MODE_CTL_START_SCAN;
  	writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
  
  	return 0;
  }
  
  static void spear_kbd_close(struct input_dev *dev)
  {
  	struct spear_kbd *kbd = input_get_drvdata(dev);
  	u32 val;
  
  	/* stop key scan */
  	val = readl_relaxed(kbd->io_base + MODE_CTL_REG);
  	val &= ~MODE_CTL_START_SCAN;
  	writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
  
  	clk_disable(kbd->clk);
  
  	kbd->last_key = KEY_RESERVED;
  }
  
  #ifdef CONFIG_OF
  static int spear_kbd_parse_dt(struct platform_device *pdev,
                                          struct spear_kbd *kbd)
  {
  	struct device_node *np = pdev->dev.of_node;
  	int error;
  	u32 val, suspended_rate;
  
  	if (!np) {
  		dev_err(&pdev->dev, "Missing DT data
  ");
  		return -EINVAL;
  	}
  
  	if (of_property_read_bool(np, "autorepeat"))
  		kbd->rep = true;
  
  	if (of_property_read_u32(np, "suspended_rate", &suspended_rate))
  		kbd->suspended_rate = suspended_rate;
  
  	error = of_property_read_u32(np, "st,mode", &val);
  	if (error) {
  		dev_err(&pdev->dev, "DT: Invalid or missing mode
  ");
  		return error;
  	}
  
  	kbd->mode = val;
  	return 0;
  }
  #else
  static inline int spear_kbd_parse_dt(struct platform_device *pdev,
  				     struct spear_kbd *kbd)
  {
  	return -ENOSYS;
  }
  #endif
  
  static int spear_kbd_probe(struct platform_device *pdev)
  {
  	struct kbd_platform_data *pdata = dev_get_platdata(&pdev->dev);
  	const struct matrix_keymap_data *keymap = pdata ? pdata->keymap : NULL;
  	struct spear_kbd *kbd;
  	struct input_dev *input_dev;
  	struct resource *res;
  	int irq;
  	int error;
  
  	irq = platform_get_irq(pdev, 0);
  	if (irq < 0) {
  		dev_err(&pdev->dev, "not able to get irq for the device
  ");
  		return irq;
  	}
  
  	kbd = devm_kzalloc(&pdev->dev, sizeof(*kbd), GFP_KERNEL);
  	if (!kbd) {
  		dev_err(&pdev->dev, "not enough memory for driver data
  ");
  		return -ENOMEM;
  	}
  
  	input_dev = devm_input_allocate_device(&pdev->dev);
  	if (!input_dev) {
  		dev_err(&pdev->dev, "unable to allocate input device
  ");
  		return -ENOMEM;
  	}
  
  	kbd->input = input_dev;
  	kbd->irq = irq;
  
  	if (!pdata) {
  		error = spear_kbd_parse_dt(pdev, kbd);
  		if (error)
  			return error;
  	} else {
  		kbd->mode = pdata->mode;
  		kbd->rep = pdata->rep;
  		kbd->suspended_rate = pdata->suspended_rate;
  	}
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	kbd->io_base = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(kbd->io_base))
  		return PTR_ERR(kbd->io_base);
  
  	kbd->clk = devm_clk_get(&pdev->dev, NULL);
  	if (IS_ERR(kbd->clk))
  		return PTR_ERR(kbd->clk);
  
  	input_dev->name = "Spear Keyboard";
  	input_dev->phys = "keyboard/input0";
  	input_dev->id.bustype = BUS_HOST;
  	input_dev->id.vendor = 0x0001;
  	input_dev->id.product = 0x0001;
  	input_dev->id.version = 0x0100;
  	input_dev->open = spear_kbd_open;
  	input_dev->close = spear_kbd_close;
  
  	error = matrix_keypad_build_keymap(keymap, NULL, NUM_ROWS, NUM_COLS,
  					   kbd->keycodes, input_dev);
  	if (error) {
  		dev_err(&pdev->dev, "Failed to build keymap
  ");
  		return error;
  	}
  
  	if (kbd->rep)
  		__set_bit(EV_REP, input_dev->evbit);
  	input_set_capability(input_dev, EV_MSC, MSC_SCAN);
  
  	input_set_drvdata(input_dev, kbd);
  
  	error = devm_request_irq(&pdev->dev, irq, spear_kbd_interrupt, 0,
  			"keyboard", kbd);
  	if (error) {
  		dev_err(&pdev->dev, "request_irq failed
  ");
  		return error;
  	}
  
  	error = clk_prepare(kbd->clk);
  	if (error)
  		return error;
  
  	error = input_register_device(input_dev);
  	if (error) {
  		dev_err(&pdev->dev, "Unable to register keyboard device
  ");
  		clk_unprepare(kbd->clk);
  		return error;
  	}
  
  	device_init_wakeup(&pdev->dev, 1);
  	platform_set_drvdata(pdev, kbd);
  
  	return 0;
  }
  
  static int spear_kbd_remove(struct platform_device *pdev)
  {
  	struct spear_kbd *kbd = platform_get_drvdata(pdev);
  
  	input_unregister_device(kbd->input);
  	clk_unprepare(kbd->clk);
  
  	device_init_wakeup(&pdev->dev, 0);
  
  	return 0;
  }
  
  #ifdef CONFIG_PM
  static int spear_kbd_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct spear_kbd *kbd = platform_get_drvdata(pdev);
  	struct input_dev *input_dev = kbd->input;
  	unsigned int rate = 0, mode_ctl_reg, val;
  
  	mutex_lock(&input_dev->mutex);
  
  	/* explicitly enable clock as we may program device */
  	clk_enable(kbd->clk);
  
  	mode_ctl_reg = readl_relaxed(kbd->io_base + MODE_CTL_REG);
  
  	if (device_may_wakeup(&pdev->dev)) {
  		if (!enable_irq_wake(kbd->irq))
  			kbd->irq_wake_enabled = true;
  
  		/*
  		 * reprogram the keyboard operating frequency as on some
  		 * platform it may change during system suspended
  		 */
  		if (kbd->suspended_rate)
  			rate = kbd->suspended_rate / 1000000 - 1;
  		else
  			rate = clk_get_rate(kbd->clk) / 1000000 - 1;
  
  		val = mode_ctl_reg &
  			~(MODE_CTL_PCLK_FREQ_MSK << MODE_CTL_PCLK_FREQ_SHIFT);
  		val |= (rate & MODE_CTL_PCLK_FREQ_MSK)
  			<< MODE_CTL_PCLK_FREQ_SHIFT;
  		writel_relaxed(val, kbd->io_base + MODE_CTL_REG);
  
  	} else {
  		if (input_dev->users) {
  			writel_relaxed(mode_ctl_reg & ~MODE_CTL_START_SCAN,
  					kbd->io_base + MODE_CTL_REG);
  			clk_disable(kbd->clk);
  		}
  	}
  
  	/* store current configuration */
  	if (input_dev->users)
  		kbd->mode_ctl_reg = mode_ctl_reg;
  
  	/* restore previous clk state */
  	clk_disable(kbd->clk);
  
  	mutex_unlock(&input_dev->mutex);
  
  	return 0;
  }
  
  static int spear_kbd_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct spear_kbd *kbd = platform_get_drvdata(pdev);
  	struct input_dev *input_dev = kbd->input;
  
  	mutex_lock(&input_dev->mutex);
  
  	if (device_may_wakeup(&pdev->dev)) {
  		if (kbd->irq_wake_enabled) {
  			kbd->irq_wake_enabled = false;
  			disable_irq_wake(kbd->irq);
  		}
  	} else {
  		if (input_dev->users)
  			clk_enable(kbd->clk);
  	}
  
  	/* restore current configuration */
  	if (input_dev->users)
  		writel_relaxed(kbd->mode_ctl_reg, kbd->io_base + MODE_CTL_REG);
  
  	mutex_unlock(&input_dev->mutex);
  
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(spear_kbd_pm_ops, spear_kbd_suspend, spear_kbd_resume);
  
  #ifdef CONFIG_OF
  static const struct of_device_id spear_kbd_id_table[] = {
  	{ .compatible = "st,spear300-kbd" },
  	{}
  };
  MODULE_DEVICE_TABLE(of, spear_kbd_id_table);
  #endif
  
  static struct platform_driver spear_kbd_driver = {
  	.probe		= spear_kbd_probe,
  	.remove		= spear_kbd_remove,
  	.driver		= {
  		.name	= "keyboard",
  		.pm	= &spear_kbd_pm_ops,
  		.of_match_table = of_match_ptr(spear_kbd_id_table),
  	},
  };
  module_platform_driver(spear_kbd_driver);
  
  MODULE_AUTHOR("Rajeev Kumar");
  MODULE_DESCRIPTION("SPEAr Keyboard Driver");
  MODULE_LICENSE("GPL");