1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Renesas RZ/G2L TSU Thermal Sensor Driver
4  *
5  * Copyright (C) 2021 Renesas Electronics Corporation
6  */
7 #include <linux/delay.h>
8 #include <linux/err.h>
9 #include <linux/io.h>
10 #include <linux/iopoll.h>
11 #include <linux/math.h>
12 #include <linux/module.h>
13 #include <linux/of_device.h>
14 #include <linux/platform_device.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/reset.h>
17 #include <linux/thermal.h>
18 #include <linux/units.h>
19 
20 #include "thermal_hwmon.h"
21 
22 #define CTEMP_MASK	0xFFF
23 
24 /* default calibration values, if FUSE values are missing */
25 #define SW_CALIB0_VAL	3148
26 #define SW_CALIB1_VAL	503
27 
28 /* Register offsets */
29 #define TSU_SM		0x00
30 #define TSU_ST		0x04
31 #define TSU_SAD		0x0C
32 #define TSU_SS		0x10
33 
34 #define OTPTSUTRIM_REG(n)	(0x18 + ((n) * 0x4))
35 
36 /* Sensor Mode Register(TSU_SM) */
37 #define TSU_SM_EN_TS		BIT(0)
38 #define TSU_SM_ADC_EN_TS	BIT(1)
39 #define TSU_SM_NORMAL_MODE	(TSU_SM_EN_TS | TSU_SM_ADC_EN_TS)
40 
41 /* TSU_ST bits */
42 #define TSU_ST_START		BIT(0)
43 
44 #define TSU_SS_CONV_RUNNING	BIT(0)
45 
46 #define TS_CODE_AVE_SCALE(x)	((x) * 1000000)
47 #define MCELSIUS(temp)		((temp) * MILLIDEGREE_PER_DEGREE)
48 #define TS_CODE_CAP_TIMES	8	/* Capture  times */
49 
50 #define RZG2L_THERMAL_GRAN	500	/* milli Celsius */
51 #define RZG2L_TSU_SS_TIMEOUT_US	1000
52 
53 #define CURVATURE_CORRECTION_CONST	13
54 
55 struct rzg2l_thermal_priv {
56 	struct device *dev;
57 	void __iomem *base;
58 	struct thermal_zone_device *zone;
59 	struct reset_control *rstc;
60 	u32 calib0, calib1;
61 };
62 
63 static inline u32 rzg2l_thermal_read(struct rzg2l_thermal_priv *priv, u32 reg)
64 {
65 	return ioread32(priv->base + reg);
66 }
67 
68 static inline void rzg2l_thermal_write(struct rzg2l_thermal_priv *priv, u32 reg,
69 				       u32 data)
70 {
71 	iowrite32(data, priv->base + reg);
72 }
73 
74 static int rzg2l_thermal_get_temp(void *devdata, int *temp)
75 {
76 	struct rzg2l_thermal_priv *priv = devdata;
77 	u32 result = 0, dsensor, ts_code_ave;
78 	int val, i;
79 
80 	for (i = 0; i < TS_CODE_CAP_TIMES ; i++) {
81 		/* TSU repeats measurement at 20 microseconds intervals and
82 		 * automatically updates the results of measurement. As per
83 		 * the HW manual for measuring temperature we need to read 8
84 		 * values consecutively and then take the average.
85 		 * ts_code_ave = (ts_code[0] + ⋯ + ts_code[7]) / 8
86 		 */
87 		result += rzg2l_thermal_read(priv, TSU_SAD) & CTEMP_MASK;
88 		usleep_range(20, 30);
89 	}
90 
91 	ts_code_ave = result / TS_CODE_CAP_TIMES;
92 
93 	/* Calculate actual sensor value by applying curvature correction formula
94 	 * dsensor = ts_code_ave / (1 + ts_code_ave * 0.000013). Here we are doing
95 	 * integer calculation by scaling all the values by 1000000.
96 	 */
97 	dsensor = TS_CODE_AVE_SCALE(ts_code_ave) /
98 		(TS_CODE_AVE_SCALE(1) + (ts_code_ave * CURVATURE_CORRECTION_CONST));
99 
100 	/* The temperature Tj is calculated by the formula
101 	 * Tj = (dsensor − calib1) * 165/ (calib0 − calib1) − 40
102 	 * where calib0 and calib1 are the caliberation values.
103 	 */
104 	val = ((dsensor - priv->calib1) * (MCELSIUS(165) /
105 		(priv->calib0 - priv->calib1))) - MCELSIUS(40);
106 
107 	*temp = roundup(val, RZG2L_THERMAL_GRAN);
108 
109 	return 0;
110 }
111 
112 static const struct thermal_zone_of_device_ops rzg2l_tz_of_ops = {
113 	.get_temp = rzg2l_thermal_get_temp,
114 };
115 
116 static int rzg2l_thermal_init(struct rzg2l_thermal_priv *priv)
117 {
118 	u32 reg_val;
119 
120 	rzg2l_thermal_write(priv, TSU_SM, TSU_SM_NORMAL_MODE);
121 	rzg2l_thermal_write(priv, TSU_ST, 0);
122 
123 	/* Before setting the START bit, TSU should be in normal operating
124 	 * mode. As per the HW manual, it will take 60 µs to place the TSU
125 	 * into normal operating mode.
126 	 */
127 	usleep_range(60, 80);
128 
129 	reg_val = rzg2l_thermal_read(priv, TSU_ST);
130 	reg_val |= TSU_ST_START;
131 	rzg2l_thermal_write(priv, TSU_ST, reg_val);
132 
133 	return readl_poll_timeout(priv->base + TSU_SS, reg_val,
134 				  reg_val == TSU_SS_CONV_RUNNING, 50,
135 				  RZG2L_TSU_SS_TIMEOUT_US);
136 }
137 
138 static void rzg2l_thermal_reset_assert_pm_disable_put(struct platform_device *pdev)
139 {
140 	struct rzg2l_thermal_priv *priv = dev_get_drvdata(&pdev->dev);
141 
142 	pm_runtime_put(&pdev->dev);
143 	pm_runtime_disable(&pdev->dev);
144 	reset_control_assert(priv->rstc);
145 }
146 
147 static int rzg2l_thermal_remove(struct platform_device *pdev)
148 {
149 	struct rzg2l_thermal_priv *priv = dev_get_drvdata(&pdev->dev);
150 
151 	thermal_remove_hwmon_sysfs(priv->zone);
152 	rzg2l_thermal_reset_assert_pm_disable_put(pdev);
153 
154 	return 0;
155 }
156 
157 static int rzg2l_thermal_probe(struct platform_device *pdev)
158 {
159 	struct thermal_zone_device *zone;
160 	struct rzg2l_thermal_priv *priv;
161 	struct device *dev = &pdev->dev;
162 	int ret;
163 
164 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
165 	if (!priv)
166 		return -ENOMEM;
167 
168 	priv->base = devm_platform_ioremap_resource(pdev, 0);
169 	if (IS_ERR(priv->base))
170 		return PTR_ERR(priv->base);
171 
172 	priv->dev = dev;
173 	priv->rstc = devm_reset_control_get_exclusive(dev, NULL);
174 	if (IS_ERR(priv->rstc))
175 		return dev_err_probe(dev, PTR_ERR(priv->rstc),
176 				     "failed to get cpg reset");
177 
178 	ret = reset_control_deassert(priv->rstc);
179 	if (ret)
180 		return dev_err_probe(dev, ret, "failed to deassert");
181 
182 	pm_runtime_enable(dev);
183 	pm_runtime_get_sync(dev);
184 
185 	priv->calib0 = rzg2l_thermal_read(priv, OTPTSUTRIM_REG(0));
186 	if (!priv->calib0)
187 		priv->calib0 = SW_CALIB0_VAL;
188 
189 	priv->calib1 = rzg2l_thermal_read(priv, OTPTSUTRIM_REG(1));
190 	if (!priv->calib1)
191 		priv->calib1 = SW_CALIB1_VAL;
192 
193 	platform_set_drvdata(pdev, priv);
194 	ret = rzg2l_thermal_init(priv);
195 	if (ret) {
196 		dev_err(dev, "Failed to start TSU");
197 		goto err;
198 	}
199 
200 	zone = devm_thermal_zone_of_sensor_register(dev, 0, priv,
201 						    &rzg2l_tz_of_ops);
202 	if (IS_ERR(zone)) {
203 		dev_err(dev, "Can't register thermal zone");
204 		ret = PTR_ERR(zone);
205 		goto err;
206 	}
207 
208 	priv->zone = zone;
209 	priv->zone->tzp->no_hwmon = false;
210 	ret = thermal_add_hwmon_sysfs(priv->zone);
211 	if (ret)
212 		goto err;
213 
214 	dev_dbg(dev, "TSU probed with %s caliberation values",
215 		rzg2l_thermal_read(priv, OTPTSUTRIM_REG(0)) ?  "hw" : "sw");
216 
217 	return 0;
218 
219 err:
220 	rzg2l_thermal_reset_assert_pm_disable_put(pdev);
221 	return ret;
222 }
223 
224 static const struct of_device_id rzg2l_thermal_dt_ids[] = {
225 	{ .compatible = "renesas,rzg2l-tsu", },
226 	{ /* sentinel */ }
227 };
228 MODULE_DEVICE_TABLE(of, rzg2l_thermal_dt_ids);
229 
230 static struct platform_driver rzg2l_thermal_driver = {
231 	.driver = {
232 		.name = "rzg2l_thermal",
233 		.of_match_table = rzg2l_thermal_dt_ids,
234 	},
235 	.probe = rzg2l_thermal_probe,
236 	.remove = rzg2l_thermal_remove,
237 };
238 module_platform_driver(rzg2l_thermal_driver);
239 
240 MODULE_DESCRIPTION("Renesas RZ/G2L TSU Thermal Sensor Driver");
241 MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
242 MODULE_LICENSE("GPL v2");
243