/*
   * Marvell Armada 370/XP thermal sensor driver
   *
   * Copyright (C) 2013 Marvell
   *
   * 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/device.h>
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <linux/of.h>
  #include <linux/module.h>
  #include <linux/delay.h>
  #include <linux/platform_device.h>
  #include <linux/of_device.h>
  #include <linux/thermal.h>
  
  #define THERMAL_VALID_OFFSET		9
  #define THERMAL_VALID_MASK		0x1
  #define THERMAL_TEMP_OFFSET		10
  #define THERMAL_TEMP_MASK		0x1ff
  
  /* Thermal Manager Control and Status Register */
  #define PMU_TDC0_SW_RST_MASK		(0x1 << 1)
  #define PMU_TM_DISABLE_OFFS		0
  #define PMU_TM_DISABLE_MASK		(0x1 << PMU_TM_DISABLE_OFFS)
  #define PMU_TDC0_REF_CAL_CNT_OFFS	11
  #define PMU_TDC0_REF_CAL_CNT_MASK	(0x1ff << PMU_TDC0_REF_CAL_CNT_OFFS)
  #define PMU_TDC0_OTF_CAL_MASK		(0x1 << 30)
  #define PMU_TDC0_START_CAL_MASK		(0x1 << 25)
  
  struct armada_thermal_ops;
  
  /* Marvell EBU Thermal Sensor Dev Structure */
  struct armada_thermal_priv {
  	void __iomem *sensor;
  	void __iomem *control;
  	struct armada_thermal_ops *ops;
  };
  
  struct armada_thermal_ops {
  	/* Initialize the sensor */
  	void (*init_sensor)(struct armada_thermal_priv *);
  
  	/* Test for a valid sensor value (optional) */
  	bool (*is_valid)(struct armada_thermal_priv *);
  };
  
  static void armadaxp_init_sensor(struct armada_thermal_priv *priv)
  {
  	unsigned long reg;
  
  	reg = readl_relaxed(priv->control);
  	reg |= PMU_TDC0_OTF_CAL_MASK;
  	writel(reg, priv->control);
  
  	/* Reference calibration value */
  	reg &= ~PMU_TDC0_REF_CAL_CNT_MASK;
  	reg |= (0xf1 << PMU_TDC0_REF_CAL_CNT_OFFS);
  	writel(reg, priv->control);
  
  	/* Reset the sensor */
  	reg = readl_relaxed(priv->control);
  	writel((reg | PMU_TDC0_SW_RST_MASK), priv->control);
  
  	writel(reg, priv->control);
  
  	/* Enable the sensor */
  	reg = readl_relaxed(priv->sensor);
  	reg &= ~PMU_TM_DISABLE_MASK;
  	writel(reg, priv->sensor);
  }
  
  static void armada370_init_sensor(struct armada_thermal_priv *priv)
  {
  	unsigned long reg;
  
  	reg = readl_relaxed(priv->control);
  	reg |= PMU_TDC0_OTF_CAL_MASK;
  	writel(reg, priv->control);
  
  	/* Reference calibration value */
  	reg &= ~PMU_TDC0_REF_CAL_CNT_MASK;
  	reg |= (0xf1 << PMU_TDC0_REF_CAL_CNT_OFFS);
  	writel(reg, priv->control);
  
  	reg &= ~PMU_TDC0_START_CAL_MASK;
  	writel(reg, priv->control);
  
  	mdelay(10);
  }
  
  static bool armada_is_valid(struct armada_thermal_priv *priv)
  {
  	unsigned long reg = readl_relaxed(priv->sensor);
  
  	return (reg >> THERMAL_VALID_OFFSET) & THERMAL_VALID_MASK;
  }
  
  static int armada_get_temp(struct thermal_zone_device *thermal,
  			  unsigned long *temp)
  {
  	struct armada_thermal_priv *priv = thermal->devdata;
  	unsigned long reg;
  
  	/* Valid check */
  	if (priv->ops->is_valid && !priv->ops->is_valid(priv)) {
  		dev_err(&thermal->device,
  			"Temperature sensor reading not valid
  ");
  		return -EIO;
  	}
  
  	reg = readl_relaxed(priv->sensor);
  	reg = (reg >> THERMAL_TEMP_OFFSET) & THERMAL_TEMP_MASK;
  	*temp = (3153000000UL - (10000000UL*reg)) / 13825;
  	return 0;
  }
  
  static struct thermal_zone_device_ops ops = {
  	.get_temp = armada_get_temp,
  };
  
  static const struct armada_thermal_ops armadaxp_ops = {
  	.init_sensor = armadaxp_init_sensor,
  };
  
  static const struct armada_thermal_ops armada370_ops = {
  	.is_valid = armada_is_valid,
  	.init_sensor = armada370_init_sensor,
  };
  
  static const struct of_device_id armada_thermal_id_table[] = {
  	{
  		.compatible = "marvell,armadaxp-thermal",
  		.data       = &armadaxp_ops,
  	},
  	{
  		.compatible = "marvell,armada370-thermal",
  		.data       = &armada370_ops,
  	},
  	{
  		/* sentinel */
  	},
  };
  MODULE_DEVICE_TABLE(of, armada_thermal_id_table);
  
  static int armada_thermal_probe(struct platform_device *pdev)
  {
  	struct thermal_zone_device *thermal;
  	const struct of_device_id *match;
  	struct armada_thermal_priv *priv;
  	struct resource *res;
  
  	match = of_match_device(armada_thermal_id_table, &pdev->dev);
  	if (!match)
  		return -ENODEV;
  
  	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
  	if (!priv)
  		return -ENOMEM;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	priv->sensor = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(priv->sensor))
  		return PTR_ERR(priv->sensor);
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
  	priv->control = devm_ioremap_resource(&pdev->dev, res);
  	if (IS_ERR(priv->control))
  		return PTR_ERR(priv->control);
  
  	priv->ops = (struct armada_thermal_ops *)match->data;
  	priv->ops->init_sensor(priv);
  
  	thermal = thermal_zone_device_register("armada_thermal", 0, 0,
  					       priv, &ops, NULL, 0, 0);
  	if (IS_ERR(thermal)) {
  		dev_err(&pdev->dev,
  			"Failed to register thermal zone device
  ");
  		return PTR_ERR(thermal);
  	}
  
  	platform_set_drvdata(pdev, thermal);
  
  	return 0;
  }
  
  static int armada_thermal_exit(struct platform_device *pdev)
  {
  	struct thermal_zone_device *armada_thermal =
  		platform_get_drvdata(pdev);
  
  	thermal_zone_device_unregister(armada_thermal);
  
  	return 0;
  }
  
  static struct platform_driver armada_thermal_driver = {
  	.probe = armada_thermal_probe,
  	.remove = armada_thermal_exit,
  	.driver = {
  		.name = "armada_thermal",
  		.owner = THIS_MODULE,
  		.of_match_table = armada_thermal_id_table,
  	},
  };
  
  module_platform_driver(armada_thermal_driver);
  
  MODULE_AUTHOR("Ezequiel Garcia <ezequiel.garcia@free-electrons.com>");
  MODULE_DESCRIPTION("Armada 370/XP thermal driver");
  MODULE_LICENSE("GPL v2");