1 /*
2 * ZTE's zx2967 family thermal sensor driver
3 *
4 * Copyright (C) 2017 ZTE Ltd.
5 *
6 * Author: Baoyou Xie <baoyou.xie@linaro.org>
7 *
8 * License terms: GNU General Public License (GPL) version 2
9 */
10
11 #include <linux/clk.h>
12 #include <linux/device.h>
13 #include <linux/err.h>
14 #include <linux/iopoll.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 #include <linux/thermal.h>
18
19 /* Power Mode: 0->low 1->high */
20 #define ZX2967_THERMAL_POWER_MODE 0
21 #define ZX2967_POWER_MODE_LOW 0
22 #define ZX2967_POWER_MODE_HIGH 1
23
24 /* DCF Control Register */
25 #define ZX2967_THERMAL_DCF 0x4
26 #define ZX2967_DCF_EN BIT(1)
27 #define ZX2967_DCF_FREEZE BIT(0)
28
29 /* Selection Register */
30 #define ZX2967_THERMAL_SEL 0x8
31
32 /* Control Register */
33 #define ZX2967_THERMAL_CTRL 0x10
34
35 #define ZX2967_THERMAL_READY BIT(12)
36 #define ZX2967_THERMAL_TEMP_MASK GENMASK(11, 0)
37 #define ZX2967_THERMAL_ID_MASK 0x18
38 #define ZX2967_THERMAL_ID 0x10
39
40 #define ZX2967_GET_TEMP_TIMEOUT_US (100 * 1024)
41
42 /**
43 * struct zx2967_thermal_priv - zx2967 thermal sensor private structure
44 * @tzd: struct thermal_zone_device where the sensor is registered
45 * @lock: prevents read sensor in parallel
46 * @clk_topcrm: topcrm clk structure
47 * @clk_apb: apb clk structure
48 * @regs: pointer to base address of the thermal sensor
49 */
50
51 struct zx2967_thermal_priv {
52 struct thermal_zone_device *tzd;
53 struct mutex lock;
54 struct clk *clk_topcrm;
55 struct clk *clk_apb;
56 void __iomem *regs;
57 struct device *dev;
58 };
59
zx2967_thermal_get_temp(void * data,int * temp)60 static int zx2967_thermal_get_temp(void *data, int *temp)
61 {
62 void __iomem *regs;
63 struct zx2967_thermal_priv *priv = data;
64 u32 val;
65 int ret;
66
67 if (!priv->tzd)
68 return -EAGAIN;
69
70 regs = priv->regs;
71 mutex_lock(&priv->lock);
72 writel_relaxed(ZX2967_POWER_MODE_LOW,
73 regs + ZX2967_THERMAL_POWER_MODE);
74 writel_relaxed(ZX2967_DCF_EN, regs + ZX2967_THERMAL_DCF);
75
76 val = readl_relaxed(regs + ZX2967_THERMAL_SEL);
77 val &= ~ZX2967_THERMAL_ID_MASK;
78 val |= ZX2967_THERMAL_ID;
79 writel_relaxed(val, regs + ZX2967_THERMAL_SEL);
80
81 /*
82 * Must wait for a while, surely it's a bit odd.
83 * otherwise temperature value we got has a few deviation, even if
84 * the THERMAL_READY bit is set.
85 */
86 usleep_range(100, 300);
87 ret = readx_poll_timeout(readl, regs + ZX2967_THERMAL_CTRL,
88 val, val & ZX2967_THERMAL_READY, 300,
89 ZX2967_GET_TEMP_TIMEOUT_US);
90 if (ret) {
91 dev_err(priv->dev, "Thermal sensor data timeout\n");
92 goto unlock;
93 }
94
95 writel_relaxed(ZX2967_DCF_FREEZE | ZX2967_DCF_EN,
96 regs + ZX2967_THERMAL_DCF);
97 val = readl_relaxed(regs + ZX2967_THERMAL_CTRL)
98 & ZX2967_THERMAL_TEMP_MASK;
99 writel_relaxed(ZX2967_POWER_MODE_HIGH,
100 regs + ZX2967_THERMAL_POWER_MODE);
101
102 /*
103 * Calculate temperature
104 * In dts, slope is multiplied by 1000.
105 */
106 *temp = DIV_ROUND_CLOSEST(((s32)val + priv->tzd->tzp->offset) * 1000,
107 priv->tzd->tzp->slope);
108
109 unlock:
110 mutex_unlock(&priv->lock);
111 return ret;
112 }
113
114 static const struct thermal_zone_of_device_ops zx2967_of_thermal_ops = {
115 .get_temp = zx2967_thermal_get_temp,
116 };
117
zx2967_thermal_probe(struct platform_device * pdev)118 static int zx2967_thermal_probe(struct platform_device *pdev)
119 {
120 struct zx2967_thermal_priv *priv;
121 struct resource *res;
122 int ret;
123
124 priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
125 if (!priv)
126 return -ENOMEM;
127
128 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
129 priv->regs = devm_ioremap_resource(&pdev->dev, res);
130 if (IS_ERR(priv->regs))
131 return PTR_ERR(priv->regs);
132
133 priv->clk_topcrm = devm_clk_get(&pdev->dev, "topcrm");
134 if (IS_ERR(priv->clk_topcrm)) {
135 ret = PTR_ERR(priv->clk_topcrm);
136 dev_err(&pdev->dev, "failed to get topcrm clock: %d\n", ret);
137 return ret;
138 }
139
140 ret = clk_prepare_enable(priv->clk_topcrm);
141 if (ret) {
142 dev_err(&pdev->dev, "failed to enable topcrm clock: %d\n",
143 ret);
144 return ret;
145 }
146
147 priv->clk_apb = devm_clk_get(&pdev->dev, "apb");
148 if (IS_ERR(priv->clk_apb)) {
149 ret = PTR_ERR(priv->clk_apb);
150 dev_err(&pdev->dev, "failed to get apb clock: %d\n", ret);
151 goto disable_clk_topcrm;
152 }
153
154 ret = clk_prepare_enable(priv->clk_apb);
155 if (ret) {
156 dev_err(&pdev->dev, "failed to enable apb clock: %d\n",
157 ret);
158 goto disable_clk_topcrm;
159 }
160
161 mutex_init(&priv->lock);
162 priv->tzd = thermal_zone_of_sensor_register(&pdev->dev,
163 0, priv, &zx2967_of_thermal_ops);
164
165 if (IS_ERR(priv->tzd)) {
166 ret = PTR_ERR(priv->tzd);
167 dev_err(&pdev->dev, "failed to register sensor: %d\n", ret);
168 goto disable_clk_all;
169 }
170
171 if (priv->tzd->tzp->slope == 0) {
172 thermal_zone_of_sensor_unregister(&pdev->dev, priv->tzd);
173 dev_err(&pdev->dev, "coefficients of sensor is invalid\n");
174 ret = -EINVAL;
175 goto disable_clk_all;
176 }
177
178 priv->dev = &pdev->dev;
179 platform_set_drvdata(pdev, priv);
180
181 return 0;
182
183 disable_clk_all:
184 clk_disable_unprepare(priv->clk_apb);
185 disable_clk_topcrm:
186 clk_disable_unprepare(priv->clk_topcrm);
187 return ret;
188 }
189
zx2967_thermal_exit(struct platform_device * pdev)190 static int zx2967_thermal_exit(struct platform_device *pdev)
191 {
192 struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
193
194 thermal_zone_of_sensor_unregister(&pdev->dev, priv->tzd);
195 clk_disable_unprepare(priv->clk_topcrm);
196 clk_disable_unprepare(priv->clk_apb);
197
198 return 0;
199 }
200
201 static const struct of_device_id zx2967_thermal_id_table[] = {
202 { .compatible = "zte,zx296718-thermal" },
203 {}
204 };
205 MODULE_DEVICE_TABLE(of, zx2967_thermal_id_table);
206
207 #ifdef CONFIG_PM_SLEEP
zx2967_thermal_suspend(struct device * dev)208 static int zx2967_thermal_suspend(struct device *dev)
209 {
210 struct platform_device *pdev = to_platform_device(dev);
211 struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
212
213 if (priv && priv->clk_topcrm)
214 clk_disable_unprepare(priv->clk_topcrm);
215
216 if (priv && priv->clk_apb)
217 clk_disable_unprepare(priv->clk_apb);
218
219 return 0;
220 }
221
zx2967_thermal_resume(struct device * dev)222 static int zx2967_thermal_resume(struct device *dev)
223 {
224 struct platform_device *pdev = to_platform_device(dev);
225 struct zx2967_thermal_priv *priv = platform_get_drvdata(pdev);
226 int error;
227
228 error = clk_prepare_enable(priv->clk_topcrm);
229 if (error)
230 return error;
231
232 error = clk_prepare_enable(priv->clk_apb);
233 if (error) {
234 clk_disable_unprepare(priv->clk_topcrm);
235 return error;
236 }
237
238 return 0;
239 }
240 #endif
241
242 static SIMPLE_DEV_PM_OPS(zx2967_thermal_pm_ops,
243 zx2967_thermal_suspend, zx2967_thermal_resume);
244
245 static struct platform_driver zx2967_thermal_driver = {
246 .probe = zx2967_thermal_probe,
247 .remove = zx2967_thermal_exit,
248 .driver = {
249 .name = "zx2967_thermal",
250 .of_match_table = zx2967_thermal_id_table,
251 .pm = &zx2967_thermal_pm_ops,
252 },
253 };
254 module_platform_driver(zx2967_thermal_driver);
255
256 MODULE_AUTHOR("Baoyou Xie <baoyou.xie@linaro.org>");
257 MODULE_DESCRIPTION("ZTE zx2967 thermal driver");
258 MODULE_LICENSE("GPL v2");
259
