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