xref: /openbmc/linux/drivers/opp/ti-opp-supply.c (revision dc6a81c3)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2016-2017 Texas Instruments Incorporated - http://www.ti.com/
4  *	Nishanth Menon <nm@ti.com>
5  *	Dave Gerlach <d-gerlach@ti.com>
6  *
7  * TI OPP supply driver that provides override into the regulator control
8  * for generic opp core to handle devices with ABB regulator and/or
9  * SmartReflex Class0.
10  */
11 #include <linux/clk.h>
12 #include <linux/cpufreq.h>
13 #include <linux/device.h>
14 #include <linux/io.h>
15 #include <linux/module.h>
16 #include <linux/notifier.h>
17 #include <linux/of_device.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/pm_opp.h>
21 #include <linux/regulator/consumer.h>
22 #include <linux/slab.h>
23 
24 /**
25  * struct ti_opp_supply_optimum_voltage_table - optimized voltage table
26  * @reference_uv:	reference voltage (usually Nominal voltage)
27  * @optimized_uv:	Optimized voltage from efuse
28  */
29 struct ti_opp_supply_optimum_voltage_table {
30 	unsigned int reference_uv;
31 	unsigned int optimized_uv;
32 };
33 
34 /**
35  * struct ti_opp_supply_data - OMAP specific opp supply data
36  * @vdd_table:	Optimized voltage mapping table
37  * @num_vdd_table: number of entries in vdd_table
38  * @vdd_absolute_max_voltage_uv: absolute maximum voltage in UV for the supply
39  */
40 struct ti_opp_supply_data {
41 	struct ti_opp_supply_optimum_voltage_table *vdd_table;
42 	u32 num_vdd_table;
43 	u32 vdd_absolute_max_voltage_uv;
44 };
45 
46 static struct ti_opp_supply_data opp_data;
47 
48 /**
49  * struct ti_opp_supply_of_data - device tree match data
50  * @flags:	specific type of opp supply
51  * @efuse_voltage_mask: mask required for efuse register representing voltage
52  * @efuse_voltage_uv: Are the efuse entries in micro-volts? if not, assume
53  *		milli-volts.
54  */
55 struct ti_opp_supply_of_data {
56 #define OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE	BIT(1)
57 #define OPPDM_HAS_NO_ABB			BIT(2)
58 	const u8 flags;
59 	const u32 efuse_voltage_mask;
60 	const bool efuse_voltage_uv;
61 };
62 
63 /**
64  * _store_optimized_voltages() - store optimized voltages
65  * @dev:	ti opp supply device for which we need to store info
66  * @data:	data specific to the device
67  *
68  * Picks up efuse based optimized voltages for VDD unique per device and
69  * stores it in internal data structure for use during transition requests.
70  *
71  * Return: If successful, 0, else appropriate error value.
72  */
73 static int _store_optimized_voltages(struct device *dev,
74 				     struct ti_opp_supply_data *data)
75 {
76 	void __iomem *base;
77 	struct property *prop;
78 	struct resource *res;
79 	const __be32 *val;
80 	int proplen, i;
81 	int ret = 0;
82 	struct ti_opp_supply_optimum_voltage_table *table;
83 	const struct ti_opp_supply_of_data *of_data = dev_get_drvdata(dev);
84 
85 	/* pick up Efuse based voltages */
86 	res = platform_get_resource(to_platform_device(dev), IORESOURCE_MEM, 0);
87 	if (!res) {
88 		dev_err(dev, "Unable to get IO resource\n");
89 		ret = -ENODEV;
90 		goto out_map;
91 	}
92 
93 	base = ioremap(res->start, resource_size(res));
94 	if (!base) {
95 		dev_err(dev, "Unable to map Efuse registers\n");
96 		ret = -ENOMEM;
97 		goto out_map;
98 	}
99 
100 	/* Fetch efuse-settings. */
101 	prop = of_find_property(dev->of_node, "ti,efuse-settings", NULL);
102 	if (!prop) {
103 		dev_err(dev, "No 'ti,efuse-settings' property found\n");
104 		ret = -EINVAL;
105 		goto out;
106 	}
107 
108 	proplen = prop->length / sizeof(int);
109 	data->num_vdd_table = proplen / 2;
110 	/* Verify for corrupted OPP entries in dt */
111 	if (data->num_vdd_table * 2 * sizeof(int) != prop->length) {
112 		dev_err(dev, "Invalid 'ti,efuse-settings'\n");
113 		ret = -EINVAL;
114 		goto out;
115 	}
116 
117 	ret = of_property_read_u32(dev->of_node, "ti,absolute-max-voltage-uv",
118 				   &data->vdd_absolute_max_voltage_uv);
119 	if (ret) {
120 		dev_err(dev, "ti,absolute-max-voltage-uv is missing\n");
121 		ret = -EINVAL;
122 		goto out;
123 	}
124 
125 	table = kcalloc(data->num_vdd_table, sizeof(*data->vdd_table),
126 			GFP_KERNEL);
127 	if (!table) {
128 		ret = -ENOMEM;
129 		goto out;
130 	}
131 	data->vdd_table = table;
132 
133 	val = prop->value;
134 	for (i = 0; i < data->num_vdd_table; i++, table++) {
135 		u32 efuse_offset;
136 		u32 tmp;
137 
138 		table->reference_uv = be32_to_cpup(val++);
139 		efuse_offset = be32_to_cpup(val++);
140 
141 		tmp = readl(base + efuse_offset);
142 		tmp &= of_data->efuse_voltage_mask;
143 		tmp >>= __ffs(of_data->efuse_voltage_mask);
144 
145 		table->optimized_uv = of_data->efuse_voltage_uv ? tmp :
146 					tmp * 1000;
147 
148 		dev_dbg(dev, "[%d] efuse=0x%08x volt_table=%d vset=%d\n",
149 			i, efuse_offset, table->reference_uv,
150 			table->optimized_uv);
151 
152 		/*
153 		 * Some older samples might not have optimized efuse
154 		 * Use reference voltage for those - just add debug message
155 		 * for them.
156 		 */
157 		if (!table->optimized_uv) {
158 			dev_dbg(dev, "[%d] efuse=0x%08x volt_table=%d:vset0\n",
159 				i, efuse_offset, table->reference_uv);
160 			table->optimized_uv = table->reference_uv;
161 		}
162 	}
163 out:
164 	iounmap(base);
165 out_map:
166 	return ret;
167 }
168 
169 /**
170  * _free_optimized_voltages() - free resources for optvoltages
171  * @dev:	device for which we need to free info
172  * @data:	data specific to the device
173  */
174 static void _free_optimized_voltages(struct device *dev,
175 				     struct ti_opp_supply_data *data)
176 {
177 	kfree(data->vdd_table);
178 	data->vdd_table = NULL;
179 	data->num_vdd_table = 0;
180 }
181 
182 /**
183  * _get_optimal_vdd_voltage() - Finds optimal voltage for the supply
184  * @dev:	device for which we need to find info
185  * @data:	data specific to the device
186  * @reference_uv:	reference voltage (OPP voltage) for which we need value
187  *
188  * Return: if a match is found, return optimized voltage, else return
189  * reference_uv, also return reference_uv if no optimization is needed.
190  */
191 static int _get_optimal_vdd_voltage(struct device *dev,
192 				    struct ti_opp_supply_data *data,
193 				    int reference_uv)
194 {
195 	int i;
196 	struct ti_opp_supply_optimum_voltage_table *table;
197 
198 	if (!data->num_vdd_table)
199 		return reference_uv;
200 
201 	table = data->vdd_table;
202 	if (!table)
203 		return -EINVAL;
204 
205 	/* Find a exact match - this list is usually very small */
206 	for (i = 0; i < data->num_vdd_table; i++, table++)
207 		if (table->reference_uv == reference_uv)
208 			return table->optimized_uv;
209 
210 	/* IF things are screwed up, we'd make a mess on console.. ratelimit */
211 	dev_err_ratelimited(dev, "%s: Failed optimized voltage match for %d\n",
212 			    __func__, reference_uv);
213 	return reference_uv;
214 }
215 
216 static int _opp_set_voltage(struct device *dev,
217 			    struct dev_pm_opp_supply *supply,
218 			    int new_target_uv, struct regulator *reg,
219 			    char *reg_name)
220 {
221 	int ret;
222 	unsigned long vdd_uv, uv_max;
223 
224 	if (new_target_uv)
225 		vdd_uv = new_target_uv;
226 	else
227 		vdd_uv = supply->u_volt;
228 
229 	/*
230 	 * If we do have an absolute max voltage specified, then we should
231 	 * use that voltage instead to allow for cases where the voltage rails
232 	 * are ganged (example if we set the max for an opp as 1.12v, and
233 	 * the absolute max is 1.5v, for another rail to get 1.25v, it cannot
234 	 * be achieved if the regulator is constrainted to max of 1.12v, even
235 	 * if it can function at 1.25v
236 	 */
237 	if (opp_data.vdd_absolute_max_voltage_uv)
238 		uv_max = opp_data.vdd_absolute_max_voltage_uv;
239 	else
240 		uv_max = supply->u_volt_max;
241 
242 	if (vdd_uv > uv_max ||
243 	    vdd_uv < supply->u_volt_min ||
244 	    supply->u_volt_min > uv_max) {
245 		dev_warn(dev,
246 			 "Invalid range voltages [Min:%lu target:%lu Max:%lu]\n",
247 			 supply->u_volt_min, vdd_uv, uv_max);
248 		return -EINVAL;
249 	}
250 
251 	dev_dbg(dev, "%s scaling to %luuV[min %luuV max %luuV]\n", reg_name,
252 		vdd_uv, supply->u_volt_min,
253 		uv_max);
254 
255 	ret = regulator_set_voltage_triplet(reg,
256 					    supply->u_volt_min,
257 					    vdd_uv,
258 					    uv_max);
259 	if (ret) {
260 		dev_err(dev, "%s failed for %luuV[min %luuV max %luuV]\n",
261 			reg_name, vdd_uv, supply->u_volt_min,
262 			uv_max);
263 		return ret;
264 	}
265 
266 	return 0;
267 }
268 
269 /**
270  * ti_opp_supply_set_opp() - do the opp supply transition
271  * @data:	information on regulators and new and old opps provided by
272  *		opp core to use in transition
273  *
274  * Return: If successful, 0, else appropriate error value.
275  */
276 static int ti_opp_supply_set_opp(struct dev_pm_set_opp_data *data)
277 {
278 	struct dev_pm_opp_supply *old_supply_vdd = &data->old_opp.supplies[0];
279 	struct dev_pm_opp_supply *old_supply_vbb = &data->old_opp.supplies[1];
280 	struct dev_pm_opp_supply *new_supply_vdd = &data->new_opp.supplies[0];
281 	struct dev_pm_opp_supply *new_supply_vbb = &data->new_opp.supplies[1];
282 	struct device *dev = data->dev;
283 	unsigned long old_freq = data->old_opp.rate, freq = data->new_opp.rate;
284 	struct clk *clk = data->clk;
285 	struct regulator *vdd_reg = data->regulators[0];
286 	struct regulator *vbb_reg = data->regulators[1];
287 	int vdd_uv;
288 	int ret;
289 
290 	vdd_uv = _get_optimal_vdd_voltage(dev, &opp_data,
291 					  new_supply_vdd->u_volt);
292 
293 	if (new_supply_vdd->u_volt_min < vdd_uv)
294 		new_supply_vdd->u_volt_min = vdd_uv;
295 
296 	/* Scaling up? Scale voltage before frequency */
297 	if (freq > old_freq) {
298 		ret = _opp_set_voltage(dev, new_supply_vdd, vdd_uv, vdd_reg,
299 				       "vdd");
300 		if (ret)
301 			goto restore_voltage;
302 
303 		ret = _opp_set_voltage(dev, new_supply_vbb, 0, vbb_reg, "vbb");
304 		if (ret)
305 			goto restore_voltage;
306 	}
307 
308 	/* Change frequency */
309 	dev_dbg(dev, "%s: switching OPP: %lu Hz --> %lu Hz\n",
310 		__func__, old_freq, freq);
311 
312 	ret = clk_set_rate(clk, freq);
313 	if (ret) {
314 		dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
315 			ret);
316 		goto restore_voltage;
317 	}
318 
319 	/* Scaling down? Scale voltage after frequency */
320 	if (freq < old_freq) {
321 		ret = _opp_set_voltage(dev, new_supply_vbb, 0, vbb_reg, "vbb");
322 		if (ret)
323 			goto restore_freq;
324 
325 		ret = _opp_set_voltage(dev, new_supply_vdd, vdd_uv, vdd_reg,
326 				       "vdd");
327 		if (ret)
328 			goto restore_freq;
329 	}
330 
331 	return 0;
332 
333 restore_freq:
334 	ret = clk_set_rate(clk, old_freq);
335 	if (ret)
336 		dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
337 			__func__, old_freq);
338 restore_voltage:
339 	/* This shouldn't harm even if the voltages weren't updated earlier */
340 	if (old_supply_vdd->u_volt) {
341 		ret = _opp_set_voltage(dev, old_supply_vbb, 0, vbb_reg, "vbb");
342 		if (ret)
343 			return ret;
344 
345 		ret = _opp_set_voltage(dev, old_supply_vdd, 0, vdd_reg,
346 				       "vdd");
347 		if (ret)
348 			return ret;
349 	}
350 
351 	return ret;
352 }
353 
354 static const struct ti_opp_supply_of_data omap_generic_of_data = {
355 };
356 
357 static const struct ti_opp_supply_of_data omap_omap5_of_data = {
358 	.flags = OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE,
359 	.efuse_voltage_mask = 0xFFF,
360 	.efuse_voltage_uv = false,
361 };
362 
363 static const struct ti_opp_supply_of_data omap_omap5core_of_data = {
364 	.flags = OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE | OPPDM_HAS_NO_ABB,
365 	.efuse_voltage_mask = 0xFFF,
366 	.efuse_voltage_uv = false,
367 };
368 
369 static const struct of_device_id ti_opp_supply_of_match[] = {
370 	{.compatible = "ti,omap-opp-supply", .data = &omap_generic_of_data},
371 	{.compatible = "ti,omap5-opp-supply", .data = &omap_omap5_of_data},
372 	{.compatible = "ti,omap5-core-opp-supply",
373 	 .data = &omap_omap5core_of_data},
374 	{},
375 };
376 MODULE_DEVICE_TABLE(of, ti_opp_supply_of_match);
377 
378 static int ti_opp_supply_probe(struct platform_device *pdev)
379 {
380 	struct device *dev = &pdev->dev;
381 	struct device *cpu_dev = get_cpu_device(0);
382 	const struct of_device_id *match;
383 	const struct ti_opp_supply_of_data *of_data;
384 	int ret = 0;
385 
386 	match = of_match_device(ti_opp_supply_of_match, dev);
387 	if (!match) {
388 		/* We do not expect this to happen */
389 		dev_err(dev, "%s: Unable to match device\n", __func__);
390 		return -ENODEV;
391 	}
392 	if (!match->data) {
393 		/* Again, unlikely.. but mistakes do happen */
394 		dev_err(dev, "%s: Bad data in match\n", __func__);
395 		return -EINVAL;
396 	}
397 	of_data = match->data;
398 
399 	dev_set_drvdata(dev, (void *)of_data);
400 
401 	/* If we need optimized voltage */
402 	if (of_data->flags & OPPDM_EFUSE_CLASS0_OPTIMIZED_VOLTAGE) {
403 		ret = _store_optimized_voltages(dev, &opp_data);
404 		if (ret)
405 			return ret;
406 	}
407 
408 	ret = PTR_ERR_OR_ZERO(dev_pm_opp_register_set_opp_helper(cpu_dev,
409 								 ti_opp_supply_set_opp));
410 	if (ret)
411 		_free_optimized_voltages(dev, &opp_data);
412 
413 	return ret;
414 }
415 
416 static struct platform_driver ti_opp_supply_driver = {
417 	.probe = ti_opp_supply_probe,
418 	.driver = {
419 		   .name = "ti_opp_supply",
420 		   .of_match_table = of_match_ptr(ti_opp_supply_of_match),
421 		   },
422 };
423 module_platform_driver(ti_opp_supply_driver);
424 
425 MODULE_DESCRIPTION("Texas Instruments OMAP OPP Supply driver");
426 MODULE_AUTHOR("Texas Instruments Inc.");
427 MODULE_LICENSE("GPL v2");
428