/*
   * Driver for Intel MSIC
   *
   * Copyright (C) 2011, Intel Corporation
   * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
   *
   * 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/err.h>
  #include <linux/gpio.h>
  #include <linux/io.h>
  #include <linux/module.h>
  #include <linux/mfd/core.h>
  #include <linux/mfd/intel_msic.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  
  #include <asm/intel_scu_ipc.h>
  
  #define MSIC_VENDOR(id)		((id >> 6) & 3)
  #define MSIC_VERSION(id)	(id & 0x3f)
  #define MSIC_MAJOR(id)		('A' + ((id >> 3) & 7))
  #define MSIC_MINOR(id)		(id & 7)
  
  /*
   * MSIC interrupt tree is readable from SRAM at INTEL_MSIC_IRQ_PHYS_BASE.
   * Since IRQ block starts from address 0x002 we need to substract that from
   * the actual IRQ status register address.
   */
  #define MSIC_IRQ_STATUS(x)	(INTEL_MSIC_IRQ_PHYS_BASE + ((x) - 2))
  #define MSIC_IRQ_STATUS_ACCDET	MSIC_IRQ_STATUS(INTEL_MSIC_ACCDET)
  
  /*
   * The SCU hardware has limitation of 16 bytes per read/write buffer on
   * Medfield.
   */
  #define SCU_IPC_RWBUF_LIMIT	16
  
  /**
   * struct intel_msic - an MSIC MFD instance
   * @pdev: pointer to the platform device
   * @vendor: vendor ID
   * @version: chip version
   * @irq_base: base address of the mapped MSIC SRAM interrupt tree
   */
  struct intel_msic {
  	struct platform_device		*pdev;
  	unsigned			vendor;
  	unsigned			version;
  	void __iomem			*irq_base;
  };
  
  static struct resource msic_touch_resources[] = {
  	{
  		.flags		= IORESOURCE_IRQ,
  	},
  };
  
  static struct resource msic_adc_resources[] = {
  	{
  		.flags		= IORESOURCE_IRQ,
  	},
  };
  
  static struct resource msic_battery_resources[] = {
  	{
  		.flags		= IORESOURCE_IRQ,
  	},
  };
  
  static struct resource msic_gpio_resources[] = {
  	{
  		.flags		= IORESOURCE_IRQ,
  	},
  };
  
  static struct resource msic_audio_resources[] = {
  	{
  		.name		= "IRQ",
  		.flags		= IORESOURCE_IRQ,
  	},
  	/*
  	 * We will pass IRQ_BASE to the driver now but this can be removed
  	 * when/if the driver starts to use intel_msic_irq_read().
  	 */
  	{
  		.name		= "IRQ_BASE",
  		.flags		= IORESOURCE_MEM,
  		.start		= MSIC_IRQ_STATUS_ACCDET,
  		.end		= MSIC_IRQ_STATUS_ACCDET,
  	},
  };
  
  static struct resource msic_hdmi_resources[] = {
  	{
  		.flags		= IORESOURCE_IRQ,
  	},
  };
  
  static struct resource msic_thermal_resources[] = {
  	{
  		.flags		= IORESOURCE_IRQ,
  	},
  };
  
  static struct resource msic_power_btn_resources[] = {
  	{
  		.flags		= IORESOURCE_IRQ,
  	},
  };
  
  static struct resource msic_ocd_resources[] = {
  	{
  		.flags		= IORESOURCE_IRQ,
  	},
  };
  
  /*
   * Devices that are part of the MSIC and are available via firmware
   * populated SFI DEVS table.
   */
  static struct mfd_cell msic_devs[] = {
  	[INTEL_MSIC_BLOCK_TOUCH]	= {
  		.name			= "msic_touch",
  		.num_resources		= ARRAY_SIZE(msic_touch_resources),
  		.resources		= msic_touch_resources,
  	},
  	[INTEL_MSIC_BLOCK_ADC]		= {
  		.name			= "msic_adc",
  		.num_resources		= ARRAY_SIZE(msic_adc_resources),
  		.resources		= msic_adc_resources,
  	},
  	[INTEL_MSIC_BLOCK_BATTERY]	= {
  		.name			= "msic_battery",
  		.num_resources		= ARRAY_SIZE(msic_battery_resources),
  		.resources		= msic_battery_resources,
  	},
  	[INTEL_MSIC_BLOCK_GPIO]		= {
  		.name			= "msic_gpio",
  		.num_resources		= ARRAY_SIZE(msic_gpio_resources),
  		.resources		= msic_gpio_resources,
  	},
  	[INTEL_MSIC_BLOCK_AUDIO]	= {
  		.name			= "msic_audio",
  		.num_resources		= ARRAY_SIZE(msic_audio_resources),
  		.resources		= msic_audio_resources,
  	},
  	[INTEL_MSIC_BLOCK_HDMI]		= {
  		.name			= "msic_hdmi",
  		.num_resources		= ARRAY_SIZE(msic_hdmi_resources),
  		.resources		= msic_hdmi_resources,
  	},
  	[INTEL_MSIC_BLOCK_THERMAL]	= {
  		.name			= "msic_thermal",
  		.num_resources		= ARRAY_SIZE(msic_thermal_resources),
  		.resources		= msic_thermal_resources,
  	},
  	[INTEL_MSIC_BLOCK_POWER_BTN]	= {
  		.name			= "msic_power_btn",
  		.num_resources		= ARRAY_SIZE(msic_power_btn_resources),
  		.resources		= msic_power_btn_resources,
  	},
  	[INTEL_MSIC_BLOCK_OCD]		= {
  		.name			= "msic_ocd",
  		.num_resources		= ARRAY_SIZE(msic_ocd_resources),
  		.resources		= msic_ocd_resources,
  	},
  };
  
  /*
   * Other MSIC related devices which are not directly available via SFI DEVS
   * table. These can be pseudo devices, regulators etc. which are needed for
   * different purposes.
   *
   * These devices appear only after the MSIC driver itself is initialized so
   * we can guarantee that the SCU IPC interface is ready.
   */
  static const struct mfd_cell msic_other_devs[] = {
  	/* Audio codec in the MSIC */
  	{
  		.id			= -1,
  		.name			= "sn95031",
  	},
  };
  
  /**
   * intel_msic_reg_read - read a single MSIC register
   * @reg: register to read
   * @val: register value is placed here
   *
   * Read a single register from MSIC. Returns %0 on success and negative
   * errno in case of failure.
   *
   * Function may sleep.
   */
  int intel_msic_reg_read(unsigned short reg, u8 *val)
  {
  	return intel_scu_ipc_ioread8(reg, val);
  }
  EXPORT_SYMBOL_GPL(intel_msic_reg_read);
  
  /**
   * intel_msic_reg_write - write a single MSIC register
   * @reg: register to write
   * @val: value to write to that register
   *
   * Write a single MSIC register. Returns 0 on success and negative
   * errno in case of failure.
   *
   * Function may sleep.
   */
  int intel_msic_reg_write(unsigned short reg, u8 val)
  {
  	return intel_scu_ipc_iowrite8(reg, val);
  }
  EXPORT_SYMBOL_GPL(intel_msic_reg_write);
  
  /**
   * intel_msic_reg_update - update a single MSIC register
   * @reg: register to update
   * @val: value to write to the register
   * @mask: specifies which of the bits are updated (%0 = don't update,
   *        %1 = update)
   *
   * Perform an update to a register @reg. @mask is used to specify which
   * bits are updated. Returns %0 in case of success and negative errno in
   * case of failure.
   *
   * Function may sleep.
   */
  int intel_msic_reg_update(unsigned short reg, u8 val, u8 mask)
  {
  	return intel_scu_ipc_update_register(reg, val, mask);
  }
  EXPORT_SYMBOL_GPL(intel_msic_reg_update);
  
  /**
   * intel_msic_bulk_read - read an array of registers
   * @reg: array of register addresses to read
   * @buf: array where the read values are placed
   * @count: number of registers to read
   *
   * Function reads @count registers from the MSIC using addresses passed in
   * @reg. Read values are placed in @buf. Reads are performed atomically
   * wrt. MSIC.
   *
   * Returns %0 in case of success and negative errno in case of failure.
   *
   * Function may sleep.
   */
  int intel_msic_bulk_read(unsigned short *reg, u8 *buf, size_t count)
  {
  	if (WARN_ON(count > SCU_IPC_RWBUF_LIMIT))
  		return -EINVAL;
  
  	return intel_scu_ipc_readv(reg, buf, count);
  }
  EXPORT_SYMBOL_GPL(intel_msic_bulk_read);
  
  /**
   * intel_msic_bulk_write - write an array of values to the MSIC registers
   * @reg: array of registers to write
   * @buf: values to write to each register
   * @count: number of registers to write
   *
   * Function writes @count registers in @buf to MSIC. Writes are performed
   * atomically wrt MSIC. Returns %0 in case of success and negative errno in
   * case of failure.
   *
   * Function may sleep.
   */
  int intel_msic_bulk_write(unsigned short *reg, u8 *buf, size_t count)
  {
  	if (WARN_ON(count > SCU_IPC_RWBUF_LIMIT))
  		return -EINVAL;
  
  	return intel_scu_ipc_writev(reg, buf, count);
  }
  EXPORT_SYMBOL_GPL(intel_msic_bulk_write);
  
  /**
   * intel_msic_irq_read - read a register from an MSIC interrupt tree
   * @msic: MSIC instance
   * @reg: interrupt register (between %INTEL_MSIC_IRQLVL1 and
   *	 %INTEL_MSIC_RESETIRQ2)
   * @val: value of the register is placed here
   *
   * This function can be used by an MSIC subdevice interrupt handler to read
   * a register value from the MSIC interrupt tree. In this way subdevice
   * drivers don't have to map in the interrupt tree themselves but can just
   * call this function instead.
   *
   * Function doesn't sleep and is callable from interrupt context.
   *
   * Returns %-EINVAL if @reg is outside of the allowed register region.
   */
  int intel_msic_irq_read(struct intel_msic *msic, unsigned short reg, u8 *val)
  {
  	if (WARN_ON(reg < INTEL_MSIC_IRQLVL1 || reg > INTEL_MSIC_RESETIRQ2))
  		return -EINVAL;
  
  	*val = readb(msic->irq_base + (reg - INTEL_MSIC_IRQLVL1));
  	return 0;
  }
  EXPORT_SYMBOL_GPL(intel_msic_irq_read);
  
  static int intel_msic_init_devices(struct intel_msic *msic)
  {
  	struct platform_device *pdev = msic->pdev;
  	struct intel_msic_platform_data *pdata = dev_get_platdata(&pdev->dev);
  	int ret, i;
  
  	if (pdata->gpio) {
  		struct mfd_cell *cell = &msic_devs[INTEL_MSIC_BLOCK_GPIO];
  
  		cell->platform_data = pdata->gpio;
  		cell->pdata_size = sizeof(*pdata->gpio);
  	}
  
  	if (pdata->ocd) {
  		unsigned gpio = pdata->ocd->gpio;
  
  		ret = devm_gpio_request_one(&pdev->dev, gpio,
  					GPIOF_IN, "ocd_gpio");
  		if (ret) {
  			dev_err(&pdev->dev, "failed to register OCD GPIO
  ");
  			return ret;
  		}
  
  		ret = gpio_to_irq(gpio);
  		if (ret < 0) {
  			dev_err(&pdev->dev, "no IRQ number for OCD GPIO
  ");
  			return ret;
  		}
  
  		/* Update the IRQ number for the OCD */
  		pdata->irq[INTEL_MSIC_BLOCK_OCD] = ret;
  	}
  
  	for (i = 0; i < ARRAY_SIZE(msic_devs); i++) {
  		if (!pdata->irq[i])
  			continue;
  
  		ret = mfd_add_devices(&pdev->dev, -1, &msic_devs[i], 1, NULL,
  				      pdata->irq[i], NULL);
  		if (ret)
  			goto fail;
  	}
  
  	ret = mfd_add_devices(&pdev->dev, 0, msic_other_devs,
  			      ARRAY_SIZE(msic_other_devs), NULL, 0, NULL);
  	if (ret)
  		goto fail;
  
  	return 0;
  
  fail:
  	mfd_remove_devices(&pdev->dev);
  
  	return ret;
  }
  
  static void intel_msic_remove_devices(struct intel_msic *msic)
  {
  	struct platform_device *pdev = msic->pdev;
  
  	mfd_remove_devices(&pdev->dev);
  }
  
  static int intel_msic_probe(struct platform_device *pdev)
  {
  	struct intel_msic_platform_data *pdata = dev_get_platdata(&pdev->dev);
  	struct intel_msic *msic;
  	struct resource *res;
  	u8 id0, id1;
  	int ret;
  
  	if (!pdata) {
  		dev_err(&pdev->dev, "no platform data passed
  ");
  		return -EINVAL;
  	}
  
  	/* First validate that we have an MSIC in place */
  	ret = intel_scu_ipc_ioread8(INTEL_MSIC_ID0, &id0);
  	if (ret) {
  		dev_err(&pdev->dev, "failed to identify the MSIC chip (ID0)
  ");
  		return -ENXIO;
  	}
  
  	ret = intel_scu_ipc_ioread8(INTEL_MSIC_ID1, &id1);
  	if (ret) {
  		dev_err(&pdev->dev, "failed to identify the MSIC chip (ID1)
  ");
  		return -ENXIO;
  	}
  
  	if (MSIC_VENDOR(id0) != MSIC_VENDOR(id1)) {
  		dev_err(&pdev->dev, "invalid vendor ID: %x, %x
  ", id0, id1);
  		return -ENXIO;
  	}
  
  	msic = devm_kzalloc(&pdev->dev, sizeof(*msic), GFP_KERNEL);
  	if (!msic)
  		return -ENOMEM;
  
  	msic->vendor = MSIC_VENDOR(id0);
  	msic->version = MSIC_VERSION(id0);
  	msic->pdev = pdev;
  
  	/*
  	 * Map in the MSIC interrupt tree area in SRAM. This is exposed to
  	 * the clients via intel_msic_irq_read().
  	 */
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	msic->irq_base = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(msic->irq_base))
  		return PTR_ERR(msic->irq_base);
  
  	platform_set_drvdata(pdev, msic);
  
  	ret = intel_msic_init_devices(msic);
  	if (ret) {
  		dev_err(&pdev->dev, "failed to initialize MSIC devices
  ");
  		return ret;
  	}
  
  	dev_info(&pdev->dev, "Intel MSIC version %c%d (vendor %#x)
  ",
  		 MSIC_MAJOR(msic->version), MSIC_MINOR(msic->version),
  		 msic->vendor);
  
  	return 0;
  }
  
  static int intel_msic_remove(struct platform_device *pdev)
  {
  	struct intel_msic *msic = platform_get_drvdata(pdev);
  
  	intel_msic_remove_devices(msic);
  
  	return 0;
  }
  
  static struct platform_driver intel_msic_driver = {
  	.probe		= intel_msic_probe,
  	.remove		= intel_msic_remove,
  	.driver		= {
  		.name	= "intel_msic",
  		.owner	= THIS_MODULE,
  	},
  };
  
  module_platform_driver(intel_msic_driver);
  
  MODULE_DESCRIPTION("Driver for Intel MSIC");
  MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
  MODULE_LICENSE("GPL");