1/*
  2 * SPEAr thermal driver.
  3 *
  4 * Copyright (C) 2011-2012 ST Microelectronics
  5 * Author: Vincenzo Frascino <vincenzo.frascino@st.com>
  6 *
  7 * This software is licensed under the terms of the GNU General Public
  8 * License version 2, as published by the Free Software Foundation, and
  9 * may be copied, distributed, and modified under those terms.
 10 *
 11 * This program is distributed in the hope that it will be useful,
 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 14 * GNU General Public License for more details.
 15 *
 16 */
 17
 18#include <linux/clk.h>
 19#include <linux/device.h>
 20#include <linux/err.h>
 21#include <linux/io.h>
 22#include <linux/kernel.h>
 23#include <linux/of.h>
 24#include <linux/module.h>
 25#include <linux/platform_device.h>
 26#include <linux/thermal.h>
 27
 28#define MD_FACTOR	1000
 29
 30/* SPEAr Thermal Sensor Dev Structure */
 31struct spear_thermal_dev {
 32	/* pointer to base address of the thermal sensor */
 33	void __iomem *thermal_base;
 34	/* clk structure */
 35	struct clk *clk;
 36	/* pointer to thermal flags */
 37	unsigned int flags;
 38};
 39
 40static inline int thermal_get_temp(struct thermal_zone_device *thermal,
 41				unsigned long *temp)
 42{
 43	struct spear_thermal_dev *stdev = thermal->devdata;
 44
 45	/*
 46	 * Data are ready to be read after 628 usec from POWERDOWN signal
 47	 * (PDN) = 1
 48	 */
 49	*temp = (readl_relaxed(stdev->thermal_base) & 0x7F) * MD_FACTOR;
 50	return 0;
 51}
 52
 53static struct thermal_zone_device_ops ops = {
 54	.get_temp = thermal_get_temp,
 55};
 56
 57#ifdef CONFIG_PM
 58static int spear_thermal_suspend(struct device *dev)
 59{
 60	struct platform_device *pdev = to_platform_device(dev);
 61	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
 62	struct spear_thermal_dev *stdev = spear_thermal->devdata;
 63	unsigned int actual_mask = 0;
 64
 65	/* Disable SPEAr Thermal Sensor */
 66	actual_mask = readl_relaxed(stdev->thermal_base);
 67	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
 68
 69	clk_disable(stdev->clk);
 70	dev_info(dev, "Suspended.\n");
 71
 72	return 0;
 73}
 74
 75static int spear_thermal_resume(struct device *dev)
 76{
 77	struct platform_device *pdev = to_platform_device(dev);
 78	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
 79	struct spear_thermal_dev *stdev = spear_thermal->devdata;
 80	unsigned int actual_mask = 0;
 81	int ret = 0;
 82
 83	ret = clk_enable(stdev->clk);
 84	if (ret) {
 85		dev_err(&pdev->dev, "Can't enable clock\n");
 86		return ret;
 87	}
 88
 89	/* Enable SPEAr Thermal Sensor */
 90	actual_mask = readl_relaxed(stdev->thermal_base);
 91	writel_relaxed(actual_mask | stdev->flags, stdev->thermal_base);
 92
 93	dev_info(dev, "Resumed.\n");
 94
 95	return 0;
 96}
 97#endif
 98
 99static SIMPLE_DEV_PM_OPS(spear_thermal_pm_ops, spear_thermal_suspend,
100		spear_thermal_resume);
101
102static int spear_thermal_probe(struct platform_device *pdev)
103{
104	struct thermal_zone_device *spear_thermal = NULL;
105	struct spear_thermal_dev *stdev;
106	struct device_node *np = pdev->dev.of_node;
107	struct resource *res;
108	int ret = 0, val;
109
110	if (!np || !of_property_read_u32(np, "st,thermal-flags", &val)) {
111		dev_err(&pdev->dev, "Failed: DT Pdata not passed\n");
112		return -EINVAL;
113	}
114
115	stdev = devm_kzalloc(&pdev->dev, sizeof(*stdev), GFP_KERNEL);
116	if (!stdev) {
117		dev_err(&pdev->dev, "kzalloc fail\n");
118		return -ENOMEM;
119	}
120
121	/* Enable thermal sensor */
122	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
123	stdev->thermal_base = devm_ioremap_resource(&pdev->dev, res);
124	if (IS_ERR(stdev->thermal_base))
125		return PTR_ERR(stdev->thermal_base);
126
127	stdev->clk = devm_clk_get(&pdev->dev, NULL);
128	if (IS_ERR(stdev->clk)) {
129		dev_err(&pdev->dev, "Can't get clock\n");
130		return PTR_ERR(stdev->clk);
131	}
132
133	ret = clk_enable(stdev->clk);
134	if (ret) {
135		dev_err(&pdev->dev, "Can't enable clock\n");
136		return ret;
137	}
138
139	stdev->flags = val;
140	writel_relaxed(stdev->flags, stdev->thermal_base);
141
142	spear_thermal = thermal_zone_device_register("spear_thermal", 0, 0,
143				stdev, &ops, NULL, 0, 0);
144	if (IS_ERR(spear_thermal)) {
145		dev_err(&pdev->dev, "thermal zone device is NULL\n");
146		ret = PTR_ERR(spear_thermal);
147		goto disable_clk;
148	}
149
150	platform_set_drvdata(pdev, spear_thermal);
151
152	dev_info(&spear_thermal->device, "Thermal Sensor Loaded at: 0x%p.\n",
153			stdev->thermal_base);
154
155	return 0;
156
157disable_clk:
158	clk_disable(stdev->clk);
159
160	return ret;
161}
162
163static int spear_thermal_exit(struct platform_device *pdev)
164{
165	unsigned int actual_mask = 0;
166	struct thermal_zone_device *spear_thermal = platform_get_drvdata(pdev);
167	struct spear_thermal_dev *stdev = spear_thermal->devdata;
168
169	thermal_zone_device_unregister(spear_thermal);
170
171	/* Disable SPEAr Thermal Sensor */
172	actual_mask = readl_relaxed(stdev->thermal_base);
173	writel_relaxed(actual_mask & ~stdev->flags, stdev->thermal_base);
174
175	clk_disable(stdev->clk);
176
177	return 0;
178}
179
180static const struct of_device_id spear_thermal_id_table[] = {
181	{ .compatible = "st,thermal-spear1340" },
182	{}
183};
184MODULE_DEVICE_TABLE(of, spear_thermal_id_table);
185
186static struct platform_driver spear_thermal_driver = {
187	.probe = spear_thermal_probe,
188	.remove = spear_thermal_exit,
189	.driver = {
190		.name = "spear_thermal",
191		.owner = THIS_MODULE,
192		.pm = &spear_thermal_pm_ops,
193		.of_match_table = spear_thermal_id_table,
194	},
195};
196
197module_platform_driver(spear_thermal_driver);
198
199MODULE_AUTHOR("Vincenzo Frascino <vincenzo.frascino@st.com>");
200MODULE_DESCRIPTION("SPEAr thermal driver");
201MODULE_LICENSE("GPL");