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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2021 Emil Renner Berthing <kernel@esmil.dk>
4 * Copyright (C) 2021 Samin Guo <samin.guo@starfivetech.com>
5 */
6
7#include <linux/bits.h>
8#include <linux/clk.h>
9#include <linux/delay.h>
10#include <linux/hwmon.h>
11#include <linux/io.h>
12#include <linux/module.h>
13#include <linux/mutex.h>
14#include <linux/of.h>
15#include <linux/platform_device.h>
16#include <linux/reset.h>
17
18/*
19 * TempSensor reset. The RSTN can be de-asserted once the analog core has
20 * powered up. Trst(min 100ns)
21 * 0:reset 1:de-assert
22 */
23#define SFCTEMP_RSTN BIT(0)
24
25/*
26 * TempSensor analog core power down. The analog core will be powered up
27 * Tpu(min 50us) after PD is de-asserted. RSTN should be held low until the
28 * analog core is powered up.
29 * 0:power up 1:power down
30 */
31#define SFCTEMP_PD BIT(1)
32
33/*
34 * TempSensor start conversion enable.
35 * 0:disable 1:enable
36 */
37#define SFCTEMP_RUN BIT(2)
38
39/*
40 * TempSensor conversion value output.
41 * Temp(C)=DOUT*Y/4094 - K
42 */
43#define SFCTEMP_DOUT_POS 16
44#define SFCTEMP_DOUT_MSK GENMASK(27, 16)
45
46/* DOUT to Celcius conversion constants */
47#define SFCTEMP_Y1000 237500L
48#define SFCTEMP_Z 4094L
49#define SFCTEMP_K1000 81100L
50
51struct sfctemp {
52 /* serialize access to hardware register and enabled below */
53 struct mutex lock;
54 void __iomem *regs;
55 struct clk *clk_sense;
56 struct clk *clk_bus;
57 struct reset_control *rst_sense;
58 struct reset_control *rst_bus;
59 bool enabled;
60};
61
62static void sfctemp_power_up(struct sfctemp *sfctemp)
63{
64 /* make sure we're powered down first */
65 writel(SFCTEMP_PD, sfctemp->regs);
66 udelay(1);
67
68 writel(0, sfctemp->regs);
69 /* wait t_pu(50us) + t_rst(100ns) */
70 usleep_range(60, 200);
71
72 /* de-assert reset */
73 writel(SFCTEMP_RSTN, sfctemp->regs);
74 udelay(1); /* wait t_su(500ps) */
75}
76
77static void sfctemp_power_down(struct sfctemp *sfctemp)
78{
79 writel(SFCTEMP_PD, sfctemp->regs);
80}
81
82static void sfctemp_run(struct sfctemp *sfctemp)
83{
84 writel(SFCTEMP_RSTN | SFCTEMP_RUN, sfctemp->regs);
85 udelay(1);
86}
87
88static void sfctemp_stop(struct sfctemp *sfctemp)
89{
90 writel(SFCTEMP_RSTN, sfctemp->regs);
91}
92
93static int sfctemp_enable(struct sfctemp *sfctemp)
94{
95 int ret = 0;
96
97 mutex_lock(&sfctemp->lock);
98 if (sfctemp->enabled)
99 goto done;
100
101 ret = clk_prepare_enable(sfctemp->clk_bus);
102 if (ret)
103 goto err;
104 ret = reset_control_deassert(sfctemp->rst_bus);
105 if (ret)
106 goto err_disable_bus;
107
108 ret = clk_prepare_enable(sfctemp->clk_sense);
109 if (ret)
110 goto err_assert_bus;
111 ret = reset_control_deassert(sfctemp->rst_sense);
112 if (ret)
113 goto err_disable_sense;
114
115 sfctemp_power_up(sfctemp);
116 sfctemp_run(sfctemp);
117 sfctemp->enabled = true;
118done:
119 mutex_unlock(&sfctemp->lock);
120 return ret;
121
122err_disable_sense:
123 clk_disable_unprepare(sfctemp->clk_sense);
124err_assert_bus:
125 reset_control_assert(sfctemp->rst_bus);
126err_disable_bus:
127 clk_disable_unprepare(sfctemp->clk_bus);
128err:
129 mutex_unlock(&sfctemp->lock);
130 return ret;
131}
132
133static int sfctemp_disable(struct sfctemp *sfctemp)
134{
135 mutex_lock(&sfctemp->lock);
136 if (!sfctemp->enabled)
137 goto done;
138
139 sfctemp_stop(sfctemp);
140 sfctemp_power_down(sfctemp);
141 reset_control_assert(sfctemp->rst_sense);
142 clk_disable_unprepare(sfctemp->clk_sense);
143 reset_control_assert(sfctemp->rst_bus);
144 clk_disable_unprepare(sfctemp->clk_bus);
145 sfctemp->enabled = false;
146done:
147 mutex_unlock(&sfctemp->lock);
148 return 0;
149}
150
151static void sfctemp_disable_action(void *data)
152{
153 sfctemp_disable(data);
154}
155
156static int sfctemp_convert(struct sfctemp *sfctemp, long *val)
157{
158 int ret;
159
160 mutex_lock(&sfctemp->lock);
161 if (!sfctemp->enabled) {
162 ret = -ENODATA;
163 goto out;
164 }
165
166 /* calculate temperature in milli Celcius */
167 *val = (long)((readl(sfctemp->regs) & SFCTEMP_DOUT_MSK) >> SFCTEMP_DOUT_POS)
168 * SFCTEMP_Y1000 / SFCTEMP_Z - SFCTEMP_K1000;
169
170 ret = 0;
171out:
172 mutex_unlock(&sfctemp->lock);
173 return ret;
174}
175
176static umode_t sfctemp_is_visible(const void *data, enum hwmon_sensor_types type,
177 u32 attr, int channel)
178{
179 switch (type) {
180 case hwmon_temp:
181 switch (attr) {
182 case hwmon_temp_enable:
183 return 0644;
184 case hwmon_temp_input:
185 return 0444;
186 default:
187 return 0;
188 }
189 default:
190 return 0;
191 }
192}
193
194static int sfctemp_read(struct device *dev, enum hwmon_sensor_types type,
195 u32 attr, int channel, long *val)
196{
197 struct sfctemp *sfctemp = dev_get_drvdata(dev);
198
199 switch (type) {
200 case hwmon_temp:
201 switch (attr) {
202 case hwmon_temp_enable:
203 *val = sfctemp->enabled;
204 return 0;
205 case hwmon_temp_input:
206 return sfctemp_convert(sfctemp, val);
207 default:
208 return -EINVAL;
209 }
210 default:
211 return -EINVAL;
212 }
213}
214
215static int sfctemp_write(struct device *dev, enum hwmon_sensor_types type,
216 u32 attr, int channel, long val)
217{
218 struct sfctemp *sfctemp = dev_get_drvdata(dev);
219
220 switch (type) {
221 case hwmon_temp:
222 switch (attr) {
223 case hwmon_temp_enable:
224 if (val == 0)
225 return sfctemp_disable(sfctemp);
226 if (val == 1)
227 return sfctemp_enable(sfctemp);
228 return -EINVAL;
229 default:
230 return -EINVAL;
231 }
232 default:
233 return -EINVAL;
234 }
235}
236
237static const struct hwmon_channel_info *sfctemp_info[] = {
238 HWMON_CHANNEL_INFO(chip, HWMON_C_REGISTER_TZ),
239 HWMON_CHANNEL_INFO(temp, HWMON_T_ENABLE | HWMON_T_INPUT),
240 NULL
241};
242
243static const struct hwmon_ops sfctemp_hwmon_ops = {
244 .is_visible = sfctemp_is_visible,
245 .read = sfctemp_read,
246 .write = sfctemp_write,
247};
248
249static const struct hwmon_chip_info sfctemp_chip_info = {
250 .ops = &sfctemp_hwmon_ops,
251 .info = sfctemp_info,
252};
253
254static int sfctemp_probe(struct platform_device *pdev)
255{
256 struct device *dev = &pdev->dev;
257 struct device *hwmon_dev;
258 struct sfctemp *sfctemp;
259 int ret;
260
261 sfctemp = devm_kzalloc(dev, sizeof(*sfctemp), GFP_KERNEL);
262 if (!sfctemp)
263 return -ENOMEM;
264
265 dev_set_drvdata(dev, sfctemp);
266 mutex_init(&sfctemp->lock);
267
268 sfctemp->regs = devm_platform_ioremap_resource(pdev, 0);
269 if (IS_ERR(sfctemp->regs))
270 return PTR_ERR(sfctemp->regs);
271
272 sfctemp->clk_sense = devm_clk_get(dev, "sense");
273 if (IS_ERR(sfctemp->clk_sense))
274 return dev_err_probe(dev, PTR_ERR(sfctemp->clk_sense),
275 "error getting sense clock\n");
276
277 sfctemp->clk_bus = devm_clk_get(dev, "bus");
278 if (IS_ERR(sfctemp->clk_bus))
279 return dev_err_probe(dev, PTR_ERR(sfctemp->clk_bus),
280 "error getting bus clock\n");
281
282 sfctemp->rst_sense = devm_reset_control_get_exclusive(dev, "sense");
283 if (IS_ERR(sfctemp->rst_sense))
284 return dev_err_probe(dev, PTR_ERR(sfctemp->rst_sense),
285 "error getting sense reset\n");
286
287 sfctemp->rst_bus = devm_reset_control_get_exclusive(dev, "bus");
288 if (IS_ERR(sfctemp->rst_bus))
289 return dev_err_probe(dev, PTR_ERR(sfctemp->rst_bus),
290 "error getting busreset\n");
291
292 ret = reset_control_assert(sfctemp->rst_sense);
293 if (ret)
294 return dev_err_probe(dev, ret, "error asserting sense reset\n");
295
296 ret = reset_control_assert(sfctemp->rst_bus);
297 if (ret)
298 return dev_err_probe(dev, ret, "error asserting bus reset\n");
299
300 ret = devm_add_action(dev, sfctemp_disable_action, sfctemp);
301 if (ret)
302 return ret;
303
304 ret = sfctemp_enable(sfctemp);
305 if (ret)
306 return dev_err_probe(dev, ret, "error enabling temperature sensor\n");
307
308 hwmon_dev = devm_hwmon_device_register_with_info(dev, "sfctemp", sfctemp,
309 &sfctemp_chip_info, NULL);
310 return PTR_ERR_OR_ZERO(hwmon_dev);
311}
312
313static const struct of_device_id sfctemp_of_match[] = {
314 { .compatible = "starfive,jh7100-temp" },
315 { .compatible = "starfive,jh7110-temp" },
316 { /* sentinel */ }
317};
318MODULE_DEVICE_TABLE(of, sfctemp_of_match);
319
320static struct platform_driver sfctemp_driver = {
321 .probe = sfctemp_probe,
322 .driver = {
323 .name = "sfctemp",
324 .of_match_table = sfctemp_of_match,
325 },
326};
327module_platform_driver(sfctemp_driver);
328
329MODULE_AUTHOR("Emil Renner Berthing");
330MODULE_DESCRIPTION("StarFive JH71x0 temperature sensor driver");
331MODULE_LICENSE("GPL");