/*
   * omap-ocp2scp.c - transform ocp interface protocol to scp protocol
   *
   * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * Author: Kishon Vijay Abraham I <kishon@ti.com>
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   */

  #include <linux/io.h>

  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/err.h>
  #include <linux/pm_runtime.h>
  #include <linux/of.h>
  #include <linux/of_platform.h>

  #define OCP2SCP_TIMING 0x18
  #define SYNC2_MASK 0xf

  static int ocp2scp_remove_devices(struct device *dev, void *c)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  
  	platform_device_unregister(pdev);
  
  	return 0;
  }

  static int omap_ocp2scp_probe(struct platform_device *pdev)

  {

  	int ret;

  	u32 reg;
  	void __iomem *regs;
  	struct resource *res;

  	struct device_node *np = pdev->dev.of_node;

  
  	if (np) {
  		ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
  		if (ret) {

  			dev_err(&pdev->dev,
  			    "failed to add resources for ocp2scp child
  ");

  			goto err0;
  		}
  	}

  	pm_runtime_enable(&pdev->dev);

  	/*
  	 * As per AM572x TRM: http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf
  	 * under section 26.3.2.2, table 26-26 OCP2SCP TIMING Caution;
  	 * As per OMAP4430 TRM: http://www.ti.com/lit/ug/swpu231ap/swpu231ap.pdf
  	 * under section 23.12.6.2.2 , Table 23-1213 OCP2SCP TIMING Caution;
  	 * As per OMAP4460 TRM: http://www.ti.com/lit/ug/swpu235ab/swpu235ab.pdf
  	 * under section 23.12.6.2.2, Table 23-1213 OCP2SCP TIMING Caution;
  	 * As per OMAP543x TRM http://www.ti.com/lit/pdf/swpu249
  	 * under section 27.3.2.2, Table 27-27 OCP2SCP TIMING Caution;
  	 *
  	 * Read path of OCP2SCP is not working properly due to low reset value
  	 * of SYNC2 parameter in OCP2SCP. Suggested reset value is 0x6 or more.
  	 */
  	if (!of_device_is_compatible(np, "ti,am437x-ocp2scp")) {
  		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  		regs = devm_ioremap_resource(&pdev->dev, res);
  		if (IS_ERR(regs))
  			goto err0;
  
  		pm_runtime_get_sync(&pdev->dev);
  		reg = readl_relaxed(regs + OCP2SCP_TIMING);
  		reg &= ~(SYNC2_MASK);
  		reg |= 0x6;
  		writel_relaxed(reg, regs + OCP2SCP_TIMING);
  		pm_runtime_put_sync(&pdev->dev);
  	}

  
  	return 0;
  
  err0:
  	device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
  
  	return ret;
  }

  static int omap_ocp2scp_remove(struct platform_device *pdev)

  {
  	pm_runtime_disable(&pdev->dev);
  	device_for_each_child(&pdev->dev, NULL, ocp2scp_remove_devices);
  
  	return 0;
  }
  
  #ifdef CONFIG_OF
  static const struct of_device_id omap_ocp2scp_id_table[] = {
  	{ .compatible = "ti,omap-ocp2scp" },

  	{ .compatible = "ti,am437x-ocp2scp" },

  	{}
  };

  MODULE_DEVICE_TABLE(of, omap_ocp2scp_id_table);

  #endif
  
  static struct platform_driver omap_ocp2scp_driver = {
  	.probe		= omap_ocp2scp_probe,

  	.remove		= omap_ocp2scp_remove,

  	.driver		= {
  		.name	= "omap-ocp2scp",

  		.of_match_table = of_match_ptr(omap_ocp2scp_id_table),
  	},
  };
  
  module_platform_driver(omap_ocp2scp_driver);

  MODULE_ALIAS("platform:omap-ocp2scp");

  MODULE_AUTHOR("Texas Instruments Inc.");
  MODULE_DESCRIPTION("OMAP OCP2SCP driver");
  MODULE_LICENSE("GPL v2");