xref: /openbmc/linux/arch/arm/mach-omap2/voltage.c (revision 6aeb51c1)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * OMAP3/OMAP4 Voltage Management Routines
4  *
5  * Author: Thara Gopinath	<thara@ti.com>
6  *
7  * Copyright (C) 2007 Texas Instruments, Inc.
8  * Rajendra Nayak <rnayak@ti.com>
9  * Lesly A M <x0080970@ti.com>
10  *
11  * Copyright (C) 2008, 2011 Nokia Corporation
12  * Kalle Jokiniemi
13  * Paul Walmsley
14  *
15  * Copyright (C) 2010 Texas Instruments, Inc.
16  * Thara Gopinath <thara@ti.com>
17  */
18 
19 #include <linux/delay.h>
20 #include <linux/io.h>
21 #include <linux/err.h>
22 #include <linux/export.h>
23 #include <linux/debugfs.h>
24 #include <linux/slab.h>
25 #include <linux/clk.h>
26 
27 #include "common.h"
28 
29 #include "prm-regbits-34xx.h"
30 #include "prm-regbits-44xx.h"
31 #include "prm44xx.h"
32 #include "prcm44xx.h"
33 #include "prminst44xx.h"
34 #include "control.h"
35 
36 #include "voltage.h"
37 #include "powerdomain.h"
38 
39 #include "vc.h"
40 #include "vp.h"
41 
42 static LIST_HEAD(voltdm_list);
43 
44 /* Public functions */
45 /**
46  * voltdm_get_voltage() - Gets the current non-auto-compensated voltage
47  * @voltdm:	pointer to the voltdm for which current voltage info is needed
48  *
49  * API to get the current non-auto-compensated voltage for a voltage domain.
50  * Returns 0 in case of error else returns the current voltage.
51  */
voltdm_get_voltage(struct voltagedomain * voltdm)52 unsigned long voltdm_get_voltage(struct voltagedomain *voltdm)
53 {
54 	if (!voltdm || IS_ERR(voltdm)) {
55 		pr_warn("%s: VDD specified does not exist!\n", __func__);
56 		return 0;
57 	}
58 
59 	return voltdm->nominal_volt;
60 }
61 
62 /**
63  * voltdm_scale() - API to scale voltage of a particular voltage domain.
64  * @voltdm: pointer to the voltage domain which is to be scaled.
65  * @target_volt: The target voltage of the voltage domain
66  *
67  * This API should be called by the kernel to do the voltage scaling
68  * for a particular voltage domain during DVFS.
69  */
voltdm_scale(struct voltagedomain * voltdm,unsigned long target_volt)70 static int voltdm_scale(struct voltagedomain *voltdm,
71 		 unsigned long target_volt)
72 {
73 	int ret, i;
74 	unsigned long volt = 0;
75 
76 	if (!voltdm || IS_ERR(voltdm)) {
77 		pr_warn("%s: VDD specified does not exist!\n", __func__);
78 		return -EINVAL;
79 	}
80 
81 	if (!voltdm->scale) {
82 		pr_err("%s: No voltage scale API registered for vdd_%s\n",
83 			__func__, voltdm->name);
84 		return -ENODATA;
85 	}
86 
87 	if (!voltdm->volt_data) {
88 		pr_err("%s: No voltage data defined for vdd_%s\n",
89 			__func__, voltdm->name);
90 		return -ENODATA;
91 	}
92 
93 	/* Adjust voltage to the exact voltage from the OPP table */
94 	for (i = 0; voltdm->volt_data[i].volt_nominal != 0; i++) {
95 		if (voltdm->volt_data[i].volt_nominal >= target_volt) {
96 			volt = voltdm->volt_data[i].volt_nominal;
97 			break;
98 		}
99 	}
100 
101 	if (!volt) {
102 		pr_warn("%s: not scaling. OPP voltage for %lu, not found.\n",
103 			__func__, target_volt);
104 		return -EINVAL;
105 	}
106 
107 	ret = voltdm->scale(voltdm, volt);
108 	if (!ret)
109 		voltdm->nominal_volt = volt;
110 
111 	return ret;
112 }
113 
114 /**
115  * voltdm_reset() - Resets the voltage of a particular voltage domain
116  *		    to that of the current OPP.
117  * @voltdm: pointer to the voltage domain whose voltage is to be reset.
118  *
119  * This API finds out the correct voltage the voltage domain is supposed
120  * to be at and resets the voltage to that level. Should be used especially
121  * while disabling any voltage compensation modules.
122  */
voltdm_reset(struct voltagedomain * voltdm)123 void voltdm_reset(struct voltagedomain *voltdm)
124 {
125 	unsigned long target_volt;
126 
127 	if (!voltdm || IS_ERR(voltdm)) {
128 		pr_warn("%s: VDD specified does not exist!\n", __func__);
129 		return;
130 	}
131 
132 	target_volt = voltdm_get_voltage(voltdm);
133 	if (!target_volt) {
134 		pr_err("%s: unable to find current voltage for vdd_%s\n",
135 			__func__, voltdm->name);
136 		return;
137 	}
138 
139 	voltdm_scale(voltdm, target_volt);
140 }
141 
142 /**
143  * omap_voltage_get_volttable() - API to get the voltage table associated with a
144  *				particular voltage domain.
145  * @voltdm:	pointer to the VDD for which the voltage table is required
146  * @volt_data:	the voltage table for the particular vdd which is to be
147  *		populated by this API
148  *
149  * This API populates the voltage table associated with a VDD into the
150  * passed parameter pointer. Returns the count of distinct voltages
151  * supported by this vdd.
152  *
153  */
omap_voltage_get_volttable(struct voltagedomain * voltdm,struct omap_volt_data ** volt_data)154 void omap_voltage_get_volttable(struct voltagedomain *voltdm,
155 				struct omap_volt_data **volt_data)
156 {
157 	if (!voltdm || IS_ERR(voltdm)) {
158 		pr_warn("%s: VDD specified does not exist!\n", __func__);
159 		return;
160 	}
161 
162 	*volt_data = voltdm->volt_data;
163 }
164 
165 /**
166  * omap_voltage_get_voltdata() - API to get the voltage table entry for a
167  *				particular voltage
168  * @voltdm:	pointer to the VDD whose voltage table has to be searched
169  * @volt:	the voltage to be searched in the voltage table
170  *
171  * This API searches through the voltage table for the required voltage
172  * domain and tries to find a matching entry for the passed voltage volt.
173  * If a matching entry is found volt_data is populated with that entry.
174  * This API searches only through the non-compensated voltages int the
175  * voltage table.
176  * Returns pointer to the voltage table entry corresponding to volt on
177  * success. Returns -ENODATA if no voltage table exisits for the passed voltage
178  * domain or if there is no matching entry.
179  */
omap_voltage_get_voltdata(struct voltagedomain * voltdm,unsigned long volt)180 struct omap_volt_data *omap_voltage_get_voltdata(struct voltagedomain *voltdm,
181 						 unsigned long volt)
182 {
183 	int i;
184 
185 	if (!voltdm || IS_ERR(voltdm)) {
186 		pr_warn("%s: VDD specified does not exist!\n", __func__);
187 		return ERR_PTR(-EINVAL);
188 	}
189 
190 	if (!voltdm->volt_data) {
191 		pr_warn("%s: voltage table does not exist for vdd_%s\n",
192 			__func__, voltdm->name);
193 		return ERR_PTR(-ENODATA);
194 	}
195 
196 	for (i = 0; voltdm->volt_data[i].volt_nominal != 0; i++) {
197 		if (voltdm->volt_data[i].volt_nominal == volt)
198 			return &voltdm->volt_data[i];
199 	}
200 
201 	pr_notice("%s: Unable to match the current voltage with the voltage table for vdd_%s\n",
202 		  __func__, voltdm->name);
203 
204 	return ERR_PTR(-ENODATA);
205 }
206 
207 /**
208  * omap_voltage_register_pmic() - API to register PMIC specific data
209  * @voltdm:	pointer to the VDD for which the PMIC specific data is
210  *		to be registered
211  * @pmic:	the structure containing pmic info
212  *
213  * This API is to be called by the SOC/PMIC file to specify the
214  * pmic specific info as present in omap_voltdm_pmic structure.
215  */
omap_voltage_register_pmic(struct voltagedomain * voltdm,struct omap_voltdm_pmic * pmic)216 int omap_voltage_register_pmic(struct voltagedomain *voltdm,
217 			       struct omap_voltdm_pmic *pmic)
218 {
219 	if (!voltdm || IS_ERR(voltdm)) {
220 		pr_warn("%s: VDD specified does not exist!\n", __func__);
221 		return -EINVAL;
222 	}
223 
224 	voltdm->pmic = pmic;
225 
226 	return 0;
227 }
228 
229 /**
230  * omap_voltage_late_init() - Init the various voltage parameters
231  *
232  * This API is to be called in the later stages of the
233  * system boot to init the voltage controller and
234  * voltage processors.
235  */
omap_voltage_late_init(void)236 int __init omap_voltage_late_init(void)
237 {
238 	struct voltagedomain *voltdm;
239 
240 	if (list_empty(&voltdm_list)) {
241 		pr_err("%s: Voltage driver support not added\n",
242 			__func__);
243 		return -EINVAL;
244 	}
245 
246 	list_for_each_entry(voltdm, &voltdm_list, node) {
247 		struct clk *sys_ck;
248 
249 		if (!voltdm->scalable)
250 			continue;
251 
252 		sys_ck = clk_get(NULL, voltdm->sys_clk.name);
253 		if (IS_ERR(sys_ck)) {
254 			pr_warn("%s: Could not get sys clk.\n", __func__);
255 			return -EINVAL;
256 		}
257 		voltdm->sys_clk.rate = clk_get_rate(sys_ck);
258 		WARN_ON(!voltdm->sys_clk.rate);
259 		clk_put(sys_ck);
260 
261 		if (voltdm->vc) {
262 			voltdm->scale = omap_vc_bypass_scale;
263 			omap_vc_init_channel(voltdm);
264 		}
265 
266 		if (voltdm->vp) {
267 			voltdm->scale = omap_vp_forceupdate_scale;
268 			omap_vp_init(voltdm);
269 		}
270 	}
271 
272 	return 0;
273 }
274 
_voltdm_lookup(const char * name)275 static struct voltagedomain *_voltdm_lookup(const char *name)
276 {
277 	struct voltagedomain *voltdm, *temp_voltdm;
278 
279 	voltdm = NULL;
280 
281 	list_for_each_entry(temp_voltdm, &voltdm_list, node) {
282 		if (!strcmp(name, temp_voltdm->name)) {
283 			voltdm = temp_voltdm;
284 			break;
285 		}
286 	}
287 
288 	return voltdm;
289 }
290 
_voltdm_register(struct voltagedomain * voltdm)291 static int _voltdm_register(struct voltagedomain *voltdm)
292 {
293 	if (!voltdm || !voltdm->name)
294 		return -EINVAL;
295 
296 	list_add(&voltdm->node, &voltdm_list);
297 
298 	pr_debug("voltagedomain: registered %s\n", voltdm->name);
299 
300 	return 0;
301 }
302 
303 /**
304  * voltdm_lookup - look up a voltagedomain by name, return a pointer
305  * @name: name of voltagedomain
306  *
307  * Find a registered voltagedomain by its name @name.  Returns a pointer
308  * to the struct voltagedomain if found, or NULL otherwise.
309  */
voltdm_lookup(const char * name)310 struct voltagedomain *voltdm_lookup(const char *name)
311 {
312 	struct voltagedomain *voltdm ;
313 
314 	if (!name)
315 		return NULL;
316 
317 	voltdm = _voltdm_lookup(name);
318 
319 	return voltdm;
320 }
321 
322 /**
323  * voltdm_init - set up the voltagedomain layer
324  * @voltdm_list: array of struct voltagedomain pointers to register
325  *
326  * Loop through the array of voltagedomains @voltdm_list, registering all
327  * that are available on the current CPU. If voltdm_list is supplied
328  * and not null, all of the referenced voltagedomains will be
329  * registered.  No return value.
330  */
voltdm_init(struct voltagedomain ** voltdms)331 void voltdm_init(struct voltagedomain **voltdms)
332 {
333 	struct voltagedomain **v;
334 
335 	if (voltdms) {
336 		for (v = voltdms; *v; v++)
337 			_voltdm_register(*v);
338 	}
339 }
340