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#define OTPTSUTRIM_EN_MASK	BIT(31)
 36#define OTPTSUTRIM_MASK		GENMASK(11, 0)
 37
 38/* Sensor Mode Register(TSU_SM) */
 39#define TSU_SM_EN_TS		BIT(0)
 40#define TSU_SM_ADC_EN_TS	BIT(1)
 41#define TSU_SM_NORMAL_MODE	(TSU_SM_EN_TS | TSU_SM_ADC_EN_TS)
 42
 43/* TSU_ST bits */
 44#define TSU_ST_START		BIT(0)
 45
 46#define TSU_SS_CONV_RUNNING	BIT(0)
 47
 48#define TS_CODE_AVE_SCALE(x)	((x) * 1000000)
 49#define MCELSIUS(temp)		((temp) * MILLIDEGREE_PER_DEGREE)
 50#define TS_CODE_CAP_TIMES	8	/* Total number of ADC data samples */
 51
 52#define RZG2L_THERMAL_GRAN	500	/* milli Celsius */
 53#define RZG2L_TSU_SS_TIMEOUT_US	1000
 54
 55#define CURVATURE_CORRECTION_CONST	13
 56
 57struct rzg2l_thermal_priv {
 58	struct device *dev;
 59	void __iomem *base;
 60	struct thermal_zone_device *zone;
 61	struct reset_control *rstc;
 62	u32 calib0, calib1;
 63};
 64
 65static inline u32 rzg2l_thermal_read(struct rzg2l_thermal_priv *priv, u32 reg)
 66{
 67	return ioread32(priv->base + reg);
 68}
 69
 70static inline void rzg2l_thermal_write(struct rzg2l_thermal_priv *priv, u32 reg,
 71				       u32 data)
 72{
 73	iowrite32(data, priv->base + reg);
 74}
 75
 76static int rzg2l_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
 77{
 78	struct rzg2l_thermal_priv *priv = tz->devdata;
 79	u32 result = 0, dsensor, ts_code_ave;
 80	int val, i;
 81
 82	for (i = 0; i < TS_CODE_CAP_TIMES ; i++) {
 83		/*
 84		 * TSU repeats measurement at 20 microseconds intervals and
 85		 * automatically updates the results of measurement. As per
 86		 * the HW manual for measuring temperature we need to read 8
 87		 * values consecutively and then take the average.
 88		 * ts_code_ave = (ts_code[0] + ⋯ + ts_code[7]) / 8
 89		 */
 90		result += rzg2l_thermal_read(priv, TSU_SAD) & CTEMP_MASK;
 91		usleep_range(20, 30);
 92	}
 93
 94	ts_code_ave = result / TS_CODE_CAP_TIMES;
 95
 96	/*
 97	 * Calculate actual sensor value by applying curvature correction formula
 98	 * dsensor = ts_code_ave / (1 + ts_code_ave * 0.000013). Here we are doing
 99	 * integer calculation by scaling all the values by 1000000.
100	 */
101	dsensor = TS_CODE_AVE_SCALE(ts_code_ave) /
102		(TS_CODE_AVE_SCALE(1) + (ts_code_ave * CURVATURE_CORRECTION_CONST));
103
104	/*
105	 * The temperature Tj is calculated by the formula
106	 * Tj = (dsensor − calib1) * 165/ (calib0 − calib1) − 40
107	 * where calib0 and calib1 are the calibration values.
108	 */
109	val = ((dsensor - priv->calib1) * (MCELSIUS(165) /
110		(priv->calib0 - priv->calib1))) - MCELSIUS(40);
111
112	*temp = roundup(val, RZG2L_THERMAL_GRAN);
113
114	return 0;
115}
116
117static const struct thermal_zone_device_ops rzg2l_tz_of_ops = {
118	.get_temp = rzg2l_thermal_get_temp,
119};
120
121static int rzg2l_thermal_init(struct rzg2l_thermal_priv *priv)
122{
123	u32 reg_val;
124
125	rzg2l_thermal_write(priv, TSU_SM, TSU_SM_NORMAL_MODE);
126	rzg2l_thermal_write(priv, TSU_ST, 0);
127
128	/*
129	 * Before setting the START bit, TSU should be in normal operating
130	 * mode. As per the HW manual, it will take 60 µs to place the TSU
131	 * into normal operating mode.
132	 */
133	usleep_range(60, 80);
134
135	reg_val = rzg2l_thermal_read(priv, TSU_ST);
136	reg_val |= TSU_ST_START;
137	rzg2l_thermal_write(priv, TSU_ST, reg_val);
138
139	return readl_poll_timeout(priv->base + TSU_SS, reg_val,
140				  reg_val == TSU_SS_CONV_RUNNING, 50,
141				  RZG2L_TSU_SS_TIMEOUT_US);
142}
143
144static void rzg2l_thermal_reset_assert_pm_disable_put(struct platform_device *pdev)
145{
146	struct rzg2l_thermal_priv *priv = dev_get_drvdata(&pdev->dev);
147
148	pm_runtime_put(&pdev->dev);
149	pm_runtime_disable(&pdev->dev);
150	reset_control_assert(priv->rstc);
151}
152
153static int rzg2l_thermal_remove(struct platform_device *pdev)
154{
155	struct rzg2l_thermal_priv *priv = dev_get_drvdata(&pdev->dev);
156
157	thermal_remove_hwmon_sysfs(priv->zone);
158	rzg2l_thermal_reset_assert_pm_disable_put(pdev);
159
160	return 0;
161}
162
163static int rzg2l_thermal_probe(struct platform_device *pdev)
164{
165	struct thermal_zone_device *zone;
166	struct rzg2l_thermal_priv *priv;
167	struct device *dev = &pdev->dev;
168	int ret;
169
170	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
171	if (!priv)
172		return -ENOMEM;
173
174	priv->base = devm_platform_ioremap_resource(pdev, 0);
175	if (IS_ERR(priv->base))
176		return PTR_ERR(priv->base);
177
178	priv->dev = dev;
179	priv->rstc = devm_reset_control_get_exclusive(dev, NULL);
180	if (IS_ERR(priv->rstc))
181		return dev_err_probe(dev, PTR_ERR(priv->rstc),
182				     "failed to get cpg reset");
183
184	ret = reset_control_deassert(priv->rstc);
185	if (ret)
186		return dev_err_probe(dev, ret, "failed to deassert");
187
188	pm_runtime_enable(dev);
189	pm_runtime_get_sync(dev);
190
191	priv->calib0 = rzg2l_thermal_read(priv, OTPTSUTRIM_REG(0));
192	if (priv->calib0 & OTPTSUTRIM_EN_MASK)
193		priv->calib0 &= OTPTSUTRIM_MASK;
194	else
195		priv->calib0 = SW_CALIB0_VAL;
196
197	priv->calib1 = rzg2l_thermal_read(priv, OTPTSUTRIM_REG(1));
198	if (priv->calib1 & OTPTSUTRIM_EN_MASK)
199		priv->calib1 &= OTPTSUTRIM_MASK;
200	else
201		priv->calib1 = SW_CALIB1_VAL;
202
203	platform_set_drvdata(pdev, priv);
204	ret = rzg2l_thermal_init(priv);
205	if (ret) {
206		dev_err(dev, "Failed to start TSU");
207		goto err;
208	}
209
210	zone = devm_thermal_of_zone_register(dev, 0, priv,
211					     &rzg2l_tz_of_ops);
212	if (IS_ERR(zone)) {
213		dev_err(dev, "Can't register thermal zone");
214		ret = PTR_ERR(zone);
215		goto err;
216	}
217
218	priv->zone = zone;
219	priv->zone->tzp->no_hwmon = false;
220	ret = thermal_add_hwmon_sysfs(priv->zone);
221	if (ret)
222		goto err;
223
224	dev_dbg(dev, "TSU probed with %s calibration values",
225		rzg2l_thermal_read(priv, OTPTSUTRIM_REG(0)) ?  "hw" : "sw");
226
227	return 0;
228
229err:
230	rzg2l_thermal_reset_assert_pm_disable_put(pdev);
231	return ret;
232}
233
234static const struct of_device_id rzg2l_thermal_dt_ids[] = {
235	{ .compatible = "renesas,rzg2l-tsu", },
236	{ /* sentinel */ }
237};
238MODULE_DEVICE_TABLE(of, rzg2l_thermal_dt_ids);
239
240static struct platform_driver rzg2l_thermal_driver = {
241	.driver = {
242		.name = "rzg2l_thermal",
243		.of_match_table = rzg2l_thermal_dt_ids,
244	},
245	.probe = rzg2l_thermal_probe,
246	.remove = rzg2l_thermal_remove,
247};
248module_platform_driver(rzg2l_thermal_driver);
249
250MODULE_DESCRIPTION("Renesas RZ/G2L TSU Thermal Sensor Driver");
251MODULE_AUTHOR("Biju Das <biju.das.jz@bp.renesas.com>");
252MODULE_LICENSE("GPL v2");