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564e73d2 WS |
1 | /* |
2 | * R-Car Gen3 THS thermal sensor driver | |
3 | * Based on rcar_thermal.c and work from Hien Dang and Khiem Nguyen. | |
4 | * | |
5 | * Copyright (C) 2016 Renesas Electronics Corporation. | |
6 | * Copyright (C) 2016 Sang Engineering | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; version 2 of the License. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, but | |
13 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * General Public License for more details. | |
16 | * | |
17 | */ | |
18 | #include <linux/delay.h> | |
19 | #include <linux/err.h> | |
20 | #include <linux/interrupt.h> | |
21 | #include <linux/io.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/mutex.h> | |
24 | #include <linux/of_device.h> | |
25 | #include <linux/platform_device.h> | |
26 | #include <linux/pm_runtime.h> | |
27 | #include <linux/thermal.h> | |
28 | ||
29 | /* Register offsets */ | |
30 | #define REG_GEN3_IRQSTR 0x04 | |
31 | #define REG_GEN3_IRQMSK 0x08 | |
32 | #define REG_GEN3_IRQCTL 0x0C | |
33 | #define REG_GEN3_IRQEN 0x10 | |
34 | #define REG_GEN3_IRQTEMP1 0x14 | |
35 | #define REG_GEN3_IRQTEMP2 0x18 | |
36 | #define REG_GEN3_IRQTEMP3 0x1C | |
37 | #define REG_GEN3_CTSR 0x20 | |
38 | #define REG_GEN3_THCTR 0x20 | |
39 | #define REG_GEN3_TEMP 0x28 | |
40 | #define REG_GEN3_THCODE1 0x50 | |
41 | #define REG_GEN3_THCODE2 0x54 | |
42 | #define REG_GEN3_THCODE3 0x58 | |
43 | ||
44 | /* CTSR bits */ | |
45 | #define CTSR_PONM BIT(8) | |
46 | #define CTSR_AOUT BIT(7) | |
47 | #define CTSR_THBGR BIT(5) | |
48 | #define CTSR_VMEN BIT(4) | |
49 | #define CTSR_VMST BIT(1) | |
50 | #define CTSR_THSST BIT(0) | |
51 | ||
52 | /* THCTR bits */ | |
53 | #define THCTR_PONM BIT(6) | |
54 | #define THCTR_THSST BIT(0) | |
55 | ||
56 | #define CTEMP_MASK 0xFFF | |
57 | ||
58 | #define MCELSIUS(temp) ((temp) * 1000) | |
59 | #define GEN3_FUSE_MASK 0xFFF | |
60 | ||
61 | #define TSC_MAX_NUM 3 | |
62 | ||
63 | /* Structure for thermal temperature calculation */ | |
64 | struct equation_coefs { | |
65 | int a1; | |
66 | int b1; | |
67 | int a2; | |
68 | int b2; | |
69 | }; | |
70 | ||
71 | struct rcar_gen3_thermal_tsc { | |
72 | void __iomem *base; | |
73 | struct thermal_zone_device *zone; | |
74 | struct equation_coefs coef; | |
75 | struct mutex lock; | |
76 | }; | |
77 | ||
78 | struct rcar_gen3_thermal_priv { | |
79 | struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM]; | |
80 | }; | |
81 | ||
82 | struct rcar_gen3_thermal_data { | |
83 | void (*thermal_init)(struct rcar_gen3_thermal_tsc *tsc); | |
84 | }; | |
85 | ||
86 | static inline u32 rcar_gen3_thermal_read(struct rcar_gen3_thermal_tsc *tsc, | |
87 | u32 reg) | |
88 | { | |
89 | return ioread32(tsc->base + reg); | |
90 | } | |
91 | ||
92 | static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc, | |
93 | u32 reg, u32 data) | |
94 | { | |
95 | iowrite32(data, tsc->base + reg); | |
96 | } | |
97 | ||
98 | /* | |
99 | * Linear approximation for temperature | |
100 | * | |
101 | * [reg] = [temp] * a + b => [temp] = ([reg] - b) / a | |
102 | * | |
103 | * The constants a and b are calculated using two triplets of int values PTAT | |
104 | * and THCODE. PTAT and THCODE can either be read from hardware or use hard | |
105 | * coded values from driver. The formula to calculate a and b are taken from | |
106 | * BSP and sparsely documented and understood. | |
107 | * | |
108 | * Examining the linear formula and the formula used to calculate constants a | |
109 | * and b while knowing that the span for PTAT and THCODE values are between | |
110 | * 0x000 and 0xfff the largest integer possible is 0xfff * 0xfff == 0xffe001. | |
111 | * Integer also needs to be signed so that leaves 7 bits for binary | |
112 | * fixed point scaling. | |
113 | */ | |
114 | ||
115 | #define FIXPT_SHIFT 7 | |
116 | #define FIXPT_INT(_x) ((_x) << FIXPT_SHIFT) | |
117 | #define FIXPT_DIV(_a, _b) DIV_ROUND_CLOSEST(((_a) << FIXPT_SHIFT), (_b)) | |
118 | #define FIXPT_TO_MCELSIUS(_x) ((_x) * 1000 >> FIXPT_SHIFT) | |
119 | ||
120 | #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */ | |
121 | ||
122 | /* no idea where these constants come from */ | |
123 | #define TJ_1 96 | |
124 | #define TJ_3 -41 | |
125 | ||
126 | static void rcar_gen3_thermal_calc_coefs(struct equation_coefs *coef, | |
127 | int *ptat, int *thcode) | |
128 | { | |
129 | int tj_2; | |
130 | ||
131 | /* TODO: Find documentation and document constant calculation formula */ | |
132 | ||
133 | /* | |
134 | * Division is not scaled in BSP and if scaled it might overflow | |
135 | * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled | |
136 | */ | |
137 | tj_2 = (FIXPT_INT((ptat[1] - ptat[2]) * 137) | |
138 | / (ptat[0] - ptat[2])) - FIXPT_INT(41); | |
139 | ||
140 | coef->a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]), | |
141 | tj_2 - FIXPT_INT(TJ_3)); | |
142 | coef->b1 = FIXPT_INT(thcode[2]) - coef->a1 * TJ_3; | |
143 | ||
144 | coef->a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), | |
145 | tj_2 - FIXPT_INT(TJ_1)); | |
146 | coef->b2 = FIXPT_INT(thcode[0]) - coef->a2 * TJ_1; | |
147 | } | |
148 | ||
149 | static int rcar_gen3_thermal_round(int temp) | |
150 | { | |
151 | int result, round_offs; | |
152 | ||
153 | round_offs = temp >= 0 ? RCAR3_THERMAL_GRAN / 2 : | |
154 | -RCAR3_THERMAL_GRAN / 2; | |
155 | result = (temp + round_offs) / RCAR3_THERMAL_GRAN; | |
156 | return result * RCAR3_THERMAL_GRAN; | |
157 | } | |
158 | ||
159 | static int rcar_gen3_thermal_get_temp(void *devdata, int *temp) | |
160 | { | |
161 | struct rcar_gen3_thermal_tsc *tsc = devdata; | |
162 | int mcelsius, val1, val2; | |
163 | u32 reg; | |
164 | ||
165 | /* Read register and convert to mili Celsius */ | |
166 | mutex_lock(&tsc->lock); | |
167 | ||
168 | reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK; | |
169 | ||
170 | val1 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b1, tsc->coef.a1); | |
171 | val2 = FIXPT_DIV(FIXPT_INT(reg) - tsc->coef.b2, tsc->coef.a2); | |
172 | mcelsius = FIXPT_TO_MCELSIUS((val1 + val2) / 2); | |
173 | ||
174 | mutex_unlock(&tsc->lock); | |
175 | ||
176 | /* Make sure we are inside specifications */ | |
177 | if ((mcelsius < MCELSIUS(-40)) || (mcelsius > MCELSIUS(125))) | |
178 | return -EIO; | |
179 | ||
180 | /* Round value to device granularity setting */ | |
181 | *temp = rcar_gen3_thermal_round(mcelsius); | |
182 | ||
183 | return 0; | |
184 | } | |
185 | ||
186 | static struct thermal_zone_of_device_ops rcar_gen3_tz_of_ops = { | |
187 | .get_temp = rcar_gen3_thermal_get_temp, | |
188 | }; | |
189 | ||
190 | static void r8a7795_thermal_init(struct rcar_gen3_thermal_tsc *tsc) | |
191 | { | |
192 | rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_THBGR); | |
193 | rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, 0x0); | |
194 | ||
195 | usleep_range(1000, 2000); | |
196 | ||
197 | rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, CTSR_PONM); | |
198 | rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F); | |
199 | rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, | |
200 | CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN); | |
201 | ||
202 | usleep_range(100, 200); | |
203 | ||
204 | rcar_gen3_thermal_write(tsc, REG_GEN3_CTSR, | |
205 | CTSR_PONM | CTSR_AOUT | CTSR_THBGR | CTSR_VMEN | | |
206 | CTSR_VMST | CTSR_THSST); | |
207 | ||
208 | usleep_range(1000, 2000); | |
209 | } | |
210 | ||
211 | static void r8a7796_thermal_init(struct rcar_gen3_thermal_tsc *tsc) | |
212 | { | |
213 | u32 reg_val; | |
214 | ||
215 | reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR); | |
216 | reg_val &= ~THCTR_PONM; | |
217 | rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val); | |
218 | ||
219 | usleep_range(1000, 2000); | |
220 | ||
221 | rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0x3F); | |
222 | reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR); | |
223 | reg_val |= THCTR_THSST; | |
224 | rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val); | |
225 | } | |
226 | ||
227 | static const struct rcar_gen3_thermal_data r8a7795_data = { | |
228 | .thermal_init = r8a7795_thermal_init, | |
229 | }; | |
230 | ||
231 | static const struct rcar_gen3_thermal_data r8a7796_data = { | |
232 | .thermal_init = r8a7796_thermal_init, | |
233 | }; | |
234 | ||
235 | static const struct of_device_id rcar_gen3_thermal_dt_ids[] = { | |
236 | { .compatible = "renesas,r8a7795-thermal", .data = &r8a7795_data}, | |
237 | { .compatible = "renesas,r8a7796-thermal", .data = &r8a7796_data}, | |
238 | {}, | |
239 | }; | |
240 | MODULE_DEVICE_TABLE(of, rcar_gen3_thermal_dt_ids); | |
241 | ||
242 | static int rcar_gen3_thermal_remove(struct platform_device *pdev) | |
243 | { | |
244 | struct device *dev = &pdev->dev; | |
245 | ||
246 | pm_runtime_put(dev); | |
247 | pm_runtime_disable(dev); | |
248 | ||
249 | return 0; | |
250 | } | |
251 | ||
252 | static int rcar_gen3_thermal_probe(struct platform_device *pdev) | |
253 | { | |
254 | struct rcar_gen3_thermal_priv *priv; | |
255 | struct device *dev = &pdev->dev; | |
256 | struct resource *res; | |
257 | struct thermal_zone_device *zone; | |
258 | int ret, i; | |
259 | const struct rcar_gen3_thermal_data *match_data = | |
260 | of_device_get_match_data(dev); | |
261 | ||
262 | /* default values if FUSEs are missing */ | |
263 | /* TODO: Read values from hardware on supported platforms */ | |
264 | int ptat[3] = { 2351, 1509, 435 }; | |
265 | int thcode[TSC_MAX_NUM][3] = { | |
266 | { 3248, 2800, 2221 }, | |
267 | { 3245, 2795, 2216 }, | |
268 | { 3250, 2805, 2237 }, | |
269 | }; | |
270 | ||
271 | priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); | |
272 | if (!priv) | |
273 | return -ENOMEM; | |
274 | ||
275 | platform_set_drvdata(pdev, priv); | |
276 | ||
277 | pm_runtime_enable(dev); | |
278 | pm_runtime_get_sync(dev); | |
279 | ||
280 | for (i = 0; i < TSC_MAX_NUM; i++) { | |
281 | struct rcar_gen3_thermal_tsc *tsc; | |
282 | ||
283 | tsc = devm_kzalloc(dev, sizeof(*tsc), GFP_KERNEL); | |
284 | if (!tsc) { | |
285 | ret = -ENOMEM; | |
286 | goto error_unregister; | |
287 | } | |
288 | ||
289 | res = platform_get_resource(pdev, IORESOURCE_MEM, i); | |
290 | if (!res) | |
291 | break; | |
292 | ||
293 | tsc->base = devm_ioremap_resource(dev, res); | |
294 | if (IS_ERR(tsc->base)) { | |
295 | ret = PTR_ERR(tsc->base); | |
296 | goto error_unregister; | |
297 | } | |
298 | ||
299 | priv->tscs[i] = tsc; | |
300 | mutex_init(&tsc->lock); | |
301 | ||
302 | match_data->thermal_init(tsc); | |
303 | rcar_gen3_thermal_calc_coefs(&tsc->coef, ptat, thcode[i]); | |
304 | ||
305 | zone = devm_thermal_zone_of_sensor_register(dev, i, tsc, | |
306 | &rcar_gen3_tz_of_ops); | |
307 | if (IS_ERR(zone)) { | |
308 | dev_err(dev, "Can't register thermal zone\n"); | |
309 | ret = PTR_ERR(zone); | |
310 | goto error_unregister; | |
311 | } | |
312 | tsc->zone = zone; | |
313 | } | |
314 | ||
315 | return 0; | |
316 | ||
317 | error_unregister: | |
318 | rcar_gen3_thermal_remove(pdev); | |
319 | ||
320 | return ret; | |
321 | } | |
322 | ||
323 | static struct platform_driver rcar_gen3_thermal_driver = { | |
324 | .driver = { | |
325 | .name = "rcar_gen3_thermal", | |
326 | .of_match_table = rcar_gen3_thermal_dt_ids, | |
327 | }, | |
328 | .probe = rcar_gen3_thermal_probe, | |
329 | .remove = rcar_gen3_thermal_remove, | |
330 | }; | |
331 | module_platform_driver(rcar_gen3_thermal_driver); | |
332 | ||
333 | MODULE_LICENSE("GPL v2"); | |
334 | MODULE_DESCRIPTION("R-Car Gen3 THS thermal sensor driver"); | |
335 | MODULE_AUTHOR("Wolfram Sang <wsa+renesas@sang-engineering.com>"); |