/*
   * SPEAr thermal driver.
   *
   * Copyright (C) 2011-2012 ST Microelectronics
   * Author: Vincenzo Frascino <vincenzo.frascino@st.com>
   *
   * This software is licensed under the terms of the GNU General Public
   * License version 2, as published by the Free Software Foundation, and
   * may be copied, distributed, and modified under those terms.
   *
   * 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/clk.h>
  #include <linux/device.h>
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <linux/of.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/thermal.h>
  
  #define MD_FACTOR	1000
  
  /* SPEAr Thermal Sensor Dev Structure */
  struct spear_thermal_dev {
  	/* pointer to base address of the thermal sensor */
  	void __iomem *thermal_base;
  	/* clk structure */
  	struct clk *clk;
  	/* pointer to thermal flags */
  	unsigned int flags;
  };
  
  static inline int thermal_get_temp(struct thermal_zone_device *thermal,
  				unsigned long *temp)
  {
  	struct spear_thermal_dev *stdev = thermal->devdata;
  
  	/*
  	 * Data are ready to be read after 628 usec from POWERDOWN signal
  	 * (PDN) = 1
  	 */
  	*temp = (readl_relaxed(stdev->thermal_base) & 0x7F) * MD_FACTOR;
  	return 0;
  }
  
  static struct thermal_zone_device_ops ops = {
  	.get_temp = thermal_get_temp,
  };
  
  #ifdef CONFIG_PM
  static int spear_thermal_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
  	struct spear_thermal_dev *stdev = spear_thermal->devdata;
  	unsigned int actual_mask = 0;
  
  	/* Disable SPEAr Thermal Sensor */
  	actual_mask = readl_relaxed(stdev->thermal_base);
  	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
  
  	clk_disable(stdev->clk);
  	dev_info(dev, "Suspended.
  ");
  
  	return 0;
  }
  
  static int spear_thermal_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
  	struct spear_thermal_dev *stdev = spear_thermal->devdata;
  	unsigned int actual_mask = 0;
  	int ret = 0;
  
  	ret = clk_enable(stdev->clk);
  	if (ret) {
  		dev_err(&pdev->dev, "Can't enable clock
  ");
  		return ret;
  	}
  
  	/* Enable SPEAr Thermal Sensor */
  	actual_mask = readl_relaxed(stdev->thermal_base);
  	writel_relaxed(actual_mask | stdev->flags, stdev->thermal_base);
  
  	dev_info(dev, "Resumed.
  ");
  
  	return 0;
  }
  #endif
  
  static SIMPLE_DEV_PM_OPS(spear_thermal_pm_ops, spear_thermal_suspend,
  		spear_thermal_resume);
  
  static int spear_thermal_probe(struct platform_device *pdev)
  {
  	struct thermal_zone_device *spear_thermal = NULL;
  	struct spear_thermal_dev *stdev;
  	struct device_node *np = pdev->dev.of_node;
  	struct resource *res;
  	int ret = 0, val;
  
  	if (!np || !of_property_read_u32(np, "st,thermal-flags", &val)) {
  		dev_err(&pdev->dev, "Failed: DT Pdata not passed
  ");
  		return -EINVAL;
  	}
  
  	stdev = devm_kzalloc(&pdev->dev, sizeof(*stdev), GFP_KERNEL);
  	if (!stdev) {
  		dev_err(&pdev->dev, "kzalloc fail
  ");
  		return -ENOMEM;
  	}
  
  	/* Enable thermal sensor */
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	stdev->thermal_base = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(stdev->thermal_base))
  		return PTR_ERR(stdev->thermal_base);
  
  	stdev->clk = devm_clk_get(&pdev->dev, NULL);
  	if (IS_ERR(stdev->clk)) {
  		dev_err(&pdev->dev, "Can't get clock
  ");
  		return PTR_ERR(stdev->clk);
  	}
  
  	ret = clk_enable(stdev->clk);
  	if (ret) {
  		dev_err(&pdev->dev, "Can't enable clock
  ");
  		return ret;
  	}
  
  	stdev->flags = val;
  	writel_relaxed(stdev->flags, stdev->thermal_base);
  
  	spear_thermal = thermal_zone_device_register("spear_thermal", 0, 0,
  				stdev, &ops, NULL, 0, 0);
  	if (IS_ERR(spear_thermal)) {
  		dev_err(&pdev->dev, "thermal zone device is NULL
  ");
  		ret = PTR_ERR(spear_thermal);
  		goto disable_clk;
  	}
  
  	platform_set_drvdata(pdev, spear_thermal);
  
  	dev_info(&spear_thermal->device, "Thermal Sensor Loaded at: 0x%p.
  ",
  			stdev->thermal_base);
  
  	return 0;
  
  disable_clk:
  	clk_disable(stdev->clk);
  
  	return ret;
  }
  
  static int spear_thermal_exit(struct platform_device *pdev)
  {
  	unsigned int actual_mask = 0;
  	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
  	struct spear_thermal_dev *stdev = spear_thermal->devdata;
  
  	thermal_zone_device_unregister(spear_thermal);
  
  	/* Disable SPEAr Thermal Sensor */
  	actual_mask = readl_relaxed(stdev->thermal_base);
  	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
  
  	clk_disable(stdev->clk);
  
  	return 0;
  }
  
  static const struct of_device_id spear_thermal_id_table[] = {
  	{ .compatible = "st,thermal-spear1340" },
  	{}
  };
  MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
  
  static struct platform_driver spear_thermal_driver = {
  	.probe = spear_thermal_probe,
  	.remove = spear_thermal_exit,
  	.driver = {
  		.name = "spear_thermal",
  		.owner = THIS_MODULE,
  		.pm = &spear_thermal_pm_ops,
  		.of_match_table = spear_thermal_id_table,
  	},
  };
  
  module_platform_driver(spear_thermal_driver);
  
  MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
  MODULE_DESCRIPTION("SPEAr thermal driver");
  MODULE_LICENSE("GPL");