1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Copyright (c) 2022 Collabora Ltd.
4 // Author: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
5 //
6 // Based on mt6323-regulator.c,
7 //     Copyright (c) 2016 MediaTek Inc.
8 //
9 
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/platform_device.h>
13 #include <linux/regmap.h>
14 #include <linux/mfd/mt6397/core.h>
15 #include <linux/mfd/mt6331/registers.h>
16 #include <linux/regulator/driver.h>
17 #include <linux/regulator/machine.h>
18 #include <linux/regulator/mt6331-regulator.h>
19 #include <linux/regulator/of_regulator.h>
20 
21 #define MT6331_LDO_MODE_NORMAL	0
22 #define MT6331_LDO_MODE_LP	1
23 
24 /*
25  * MT6331 regulators information
26  *
27  * @desc: standard fields of regulator description.
28  * @qi: Mask for query enable signal status of regulators
29  * @vselon_reg: Register sections for hardware control mode of bucks
30  * @vselctrl_reg: Register for controlling the buck control mode.
31  * @vselctrl_mask: Mask for query buck's voltage control mode.
32  * @status_reg: Register for regulator enable status where qi unavailable
33  * @status_mask: Mask for querying regulator enable status
34  */
35 struct mt6331_regulator_info {
36 	struct regulator_desc desc;
37 	u32 qi;
38 	u32 vselon_reg;
39 	u32 vselctrl_reg;
40 	u32 vselctrl_mask;
41 	u32 modeset_reg;
42 	u32 modeset_mask;
43 	u32 status_reg;
44 	u32 status_mask;
45 };
46 
47 #define MT6331_BUCK(match, vreg, min, max, step, volt_ranges, enreg,	\
48 		vosel, vosel_mask, voselon, vosel_ctrl)			\
49 [MT6331_ID_##vreg] = {							\
50 	.desc = {							\
51 		.name = #vreg,						\
52 		.of_match = of_match_ptr(match),			\
53 		.ops = &mt6331_volt_range_ops,				\
54 		.type = REGULATOR_VOLTAGE,				\
55 		.id = MT6331_ID_##vreg,					\
56 		.owner = THIS_MODULE,					\
57 		.n_voltages = (max - min)/step + 1,			\
58 		.linear_ranges = volt_ranges,				\
59 		.n_linear_ranges = ARRAY_SIZE(volt_ranges),		\
60 		.vsel_reg = vosel,					\
61 		.vsel_mask = vosel_mask,				\
62 		.enable_reg = enreg,					\
63 		.enable_mask = BIT(0),					\
64 	},								\
65 	.qi = BIT(13),							\
66 	.vselon_reg = voselon,						\
67 	.vselctrl_reg = vosel_ctrl,					\
68 	.vselctrl_mask = BIT(1),					\
69 	.status_mask = 0,						\
70 }
71 
72 #define MT6331_LDO_AO(match, vreg, ldo_volt_table, vosel, vosel_mask)	\
73 [MT6331_ID_##vreg] = {							\
74 	.desc = {							\
75 		.name = #vreg,						\
76 		.of_match = of_match_ptr(match),			\
77 		.ops = &mt6331_volt_table_ao_ops,			\
78 		.type = REGULATOR_VOLTAGE,				\
79 		.id = MT6331_ID_##vreg,					\
80 		.owner = THIS_MODULE,					\
81 		.n_voltages = ARRAY_SIZE(ldo_volt_table),		\
82 		.volt_table = ldo_volt_table,				\
83 		.vsel_reg = vosel,					\
84 		.vsel_mask = vosel_mask,				\
85 	},								\
86 }
87 
88 #define MT6331_LDO_S(match, vreg, ldo_volt_table, enreg, enbit, vosel,	\
89 		     vosel_mask, _modeset_reg, _modeset_mask,		\
90 		     _status_reg, _status_mask)				\
91 [MT6331_ID_##vreg] = {							\
92 	.desc = {							\
93 		.name = #vreg,						\
94 		.of_match = of_match_ptr(match),			\
95 		.ops = &mt6331_volt_table_no_qi_ops,			\
96 		.type = REGULATOR_VOLTAGE,				\
97 		.id = MT6331_ID_##vreg,					\
98 		.owner = THIS_MODULE,					\
99 		.n_voltages = ARRAY_SIZE(ldo_volt_table),		\
100 		.volt_table = ldo_volt_table,				\
101 		.vsel_reg = vosel,					\
102 		.vsel_mask = vosel_mask,				\
103 		.enable_reg = enreg,					\
104 		.enable_mask = BIT(enbit),				\
105 	},								\
106 	.modeset_reg = _modeset_reg,					\
107 	.modeset_mask = _modeset_mask,					\
108 	.status_reg = _status_reg,					\
109 	.status_mask = _status_mask,					\
110 }
111 
112 #define MT6331_LDO(match, vreg, ldo_volt_table, enreg, enbit, vosel,	\
113 		   vosel_mask, _modeset_reg, _modeset_mask)		\
114 [MT6331_ID_##vreg] = {							\
115 	.desc = {							\
116 		.name = #vreg,						\
117 		.of_match = of_match_ptr(match),			\
118 		.ops = (_modeset_reg ?					\
119 			&mt6331_volt_table_ops :			\
120 			&mt6331_volt_table_no_ms_ops),			\
121 		.type = REGULATOR_VOLTAGE,				\
122 		.id = MT6331_ID_##vreg,					\
123 		.owner = THIS_MODULE,					\
124 		.n_voltages = ARRAY_SIZE(ldo_volt_table),		\
125 		.volt_table = ldo_volt_table,				\
126 		.vsel_reg = vosel,					\
127 		.vsel_mask = vosel_mask,				\
128 		.enable_reg = enreg,					\
129 		.enable_mask = BIT(enbit),				\
130 	},								\
131 	.qi = BIT(15),							\
132 	.modeset_reg = _modeset_reg,					\
133 	.modeset_mask = _modeset_mask,					\
134 }
135 
136 #define MT6331_REG_FIXED(match, vreg, enreg, enbit, qibit, volt,	\
137 			 _modeset_reg, _modeset_mask)			\
138 [MT6331_ID_##vreg] = {							\
139 	.desc = {							\
140 		.name = #vreg,						\
141 		.of_match = of_match_ptr(match),			\
142 		.ops = (_modeset_reg ?					\
143 			&mt6331_volt_fixed_ops :			\
144 			&mt6331_volt_fixed_no_ms_ops),			\
145 		.type = REGULATOR_VOLTAGE,				\
146 		.id = MT6331_ID_##vreg,					\
147 		.owner = THIS_MODULE,					\
148 		.n_voltages = 1,					\
149 		.enable_reg = enreg,					\
150 		.enable_mask = BIT(enbit),				\
151 		.min_uV = volt,						\
152 	},								\
153 	.qi = BIT(qibit),						\
154 	.modeset_reg = _modeset_reg,					\
155 	.modeset_mask = _modeset_mask,					\
156 }
157 
158 static const struct linear_range buck_volt_range[] = {
159 	REGULATOR_LINEAR_RANGE(700000, 0, 0x7f, 6250),
160 };
161 
162 static const unsigned int ldo_volt_table1[] = {
163 	2800000, 3000000, 0, 3200000
164 };
165 
166 static const unsigned int ldo_volt_table2[] = {
167 	1500000, 1800000, 2500000, 2800000,
168 };
169 
170 static const unsigned int ldo_volt_table3[] = {
171 	1200000, 1300000, 1500000, 1800000, 2000000, 2800000, 3000000, 3300000,
172 };
173 
174 static const unsigned int ldo_volt_table4[] = {
175 	0, 0, 1700000, 1800000, 1860000, 2760000, 3000000, 3100000,
176 };
177 
178 static const unsigned int ldo_volt_table5[] = {
179 	1800000, 3300000, 1800000, 3300000,
180 };
181 
182 static const unsigned int ldo_volt_table6[] = {
183 	3000000, 3300000,
184 };
185 
186 static const unsigned int ldo_volt_table7[] = {
187 	1200000, 1600000, 1700000, 1800000, 1900000, 2000000, 2100000, 2200000,
188 };
189 
190 static const unsigned int ldo_volt_table8[] = {
191 	900000, 1000000, 1100000, 1220000, 1300000, 1500000, 1500000, 1500000,
192 };
193 
194 static const unsigned int ldo_volt_table9[] = {
195 	1000000, 1050000, 1100000, 1150000, 1200000, 1250000, 1300000, 1300000,
196 };
197 
198 static const unsigned int ldo_volt_table10[] = {
199 	1200000, 1300000, 1500000, 1800000,
200 };
201 
202 static const unsigned int ldo_volt_table11[] = {
203 	1200000, 1300000, 1400000, 1500000, 1600000, 1700000, 1800000, 1800000,
204 };
205 
206 static int mt6331_get_status(struct regulator_dev *rdev)
207 {
208 	struct mt6331_regulator_info *info = rdev_get_drvdata(rdev);
209 	u32 regval;
210 	int ret;
211 
212 	ret = regmap_read(rdev->regmap, info->desc.enable_reg, &regval);
213 	if (ret != 0) {
214 		dev_err(&rdev->dev, "Failed to get enable reg: %d\n", ret);
215 		return ret;
216 	}
217 
218 	return (regval & info->qi) ? REGULATOR_STATUS_ON : REGULATOR_STATUS_OFF;
219 }
220 
221 static int mt6331_ldo_set_mode(struct regulator_dev *rdev, unsigned int mode)
222 {
223 	struct mt6331_regulator_info *info = rdev_get_drvdata(rdev);
224 	int val;
225 
226 	switch (mode) {
227 	case REGULATOR_MODE_STANDBY:
228 		val = MT6331_LDO_MODE_LP;
229 		break;
230 	case REGULATOR_MODE_NORMAL:
231 		val = MT6331_LDO_MODE_NORMAL;
232 		break;
233 	default:
234 		return -EINVAL;
235 	}
236 
237 	val <<= ffs(info->modeset_mask) - 1;
238 
239 	return regmap_update_bits(rdev->regmap, info->modeset_reg,
240 				  info->modeset_mask, val);
241 }
242 
243 static unsigned int mt6331_ldo_get_mode(struct regulator_dev *rdev)
244 {
245 	struct mt6331_regulator_info *info = rdev_get_drvdata(rdev);
246 	unsigned int val;
247 	int ret;
248 
249 	ret = regmap_read(rdev->regmap, info->modeset_reg, &val);
250 	if (ret < 0)
251 		return ret;
252 
253 	val &= info->modeset_mask;
254 	val >>= ffs(info->modeset_mask) - 1;
255 
256 	return (val & BIT(0)) ? REGULATOR_MODE_STANDBY : REGULATOR_MODE_NORMAL;
257 }
258 
259 static const struct regulator_ops mt6331_volt_range_ops = {
260 	.list_voltage = regulator_list_voltage_linear_range,
261 	.map_voltage = regulator_map_voltage_linear_range,
262 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
263 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
264 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
265 	.enable = regulator_enable_regmap,
266 	.disable = regulator_disable_regmap,
267 	.is_enabled = regulator_is_enabled_regmap,
268 	.get_status = mt6331_get_status,
269 };
270 
271 static const struct regulator_ops mt6331_volt_table_no_ms_ops = {
272 	.list_voltage = regulator_list_voltage_table,
273 	.map_voltage = regulator_map_voltage_iterate,
274 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
275 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
276 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
277 	.enable = regulator_enable_regmap,
278 	.disable = regulator_disable_regmap,
279 	.is_enabled = regulator_is_enabled_regmap,
280 	.get_status = mt6331_get_status,
281 };
282 
283 static const struct regulator_ops mt6331_volt_table_no_qi_ops = {
284 	.list_voltage = regulator_list_voltage_table,
285 	.map_voltage = regulator_map_voltage_iterate,
286 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
287 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
288 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
289 	.enable = regulator_enable_regmap,
290 	.disable = regulator_disable_regmap,
291 	.is_enabled = regulator_is_enabled_regmap,
292 	.set_mode = mt6331_ldo_set_mode,
293 	.get_mode = mt6331_ldo_get_mode,
294 };
295 
296 static const struct regulator_ops mt6331_volt_table_ops = {
297 	.list_voltage = regulator_list_voltage_table,
298 	.map_voltage = regulator_map_voltage_iterate,
299 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
300 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
301 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
302 	.enable = regulator_enable_regmap,
303 	.disable = regulator_disable_regmap,
304 	.is_enabled = regulator_is_enabled_regmap,
305 	.get_status = mt6331_get_status,
306 	.set_mode = mt6331_ldo_set_mode,
307 	.get_mode = mt6331_ldo_get_mode,
308 };
309 
310 static const struct regulator_ops mt6331_volt_table_ao_ops = {
311 	.list_voltage = regulator_list_voltage_table,
312 	.map_voltage = regulator_map_voltage_iterate,
313 	.set_voltage_sel = regulator_set_voltage_sel_regmap,
314 	.get_voltage_sel = regulator_get_voltage_sel_regmap,
315 	.set_voltage_time_sel = regulator_set_voltage_time_sel,
316 };
317 
318 static const struct regulator_ops mt6331_volt_fixed_no_ms_ops = {
319 	.list_voltage = regulator_list_voltage_linear,
320 	.enable = regulator_enable_regmap,
321 	.disable = regulator_disable_regmap,
322 	.is_enabled = regulator_is_enabled_regmap,
323 	.get_status = mt6331_get_status,
324 };
325 
326 static const struct regulator_ops mt6331_volt_fixed_ops = {
327 	.list_voltage = regulator_list_voltage_linear,
328 	.enable = regulator_enable_regmap,
329 	.disable = regulator_disable_regmap,
330 	.is_enabled = regulator_is_enabled_regmap,
331 	.get_status = mt6331_get_status,
332 	.set_mode = mt6331_ldo_set_mode,
333 	.get_mode = mt6331_ldo_get_mode,
334 };
335 
336 /* The array is indexed by id(MT6331_ID_XXX) */
337 static struct mt6331_regulator_info mt6331_regulators[] = {
338 	MT6331_BUCK("buck-vdvfs11", VDVFS11, 700000, 1493750, 6250,
339 		    buck_volt_range, MT6331_VDVFS11_CON9,
340 		    MT6331_VDVFS11_CON11, GENMASK(6, 0),
341 		    MT6331_VDVFS11_CON12, MT6331_VDVFS11_CON7),
342 	MT6331_BUCK("buck-vdvfs12", VDVFS12, 700000, 1493750, 6250,
343 		    buck_volt_range, MT6331_VDVFS12_CON9,
344 		    MT6331_VDVFS12_CON11, GENMASK(6, 0),
345 		    MT6331_VDVFS12_CON12, MT6331_VDVFS12_CON7),
346 	MT6331_BUCK("buck-vdvfs13", VDVFS13, 700000, 1493750, 6250,
347 		    buck_volt_range, MT6331_VDVFS13_CON9,
348 		    MT6331_VDVFS13_CON11, GENMASK(6, 0),
349 		    MT6331_VDVFS13_CON12, MT6331_VDVFS13_CON7),
350 	MT6331_BUCK("buck-vdvfs14", VDVFS14, 700000, 1493750, 6250,
351 		    buck_volt_range, MT6331_VDVFS14_CON9,
352 		    MT6331_VDVFS14_CON11, GENMASK(6, 0),
353 		    MT6331_VDVFS14_CON12, MT6331_VDVFS14_CON7),
354 	MT6331_BUCK("buck-vcore2", VCORE2, 700000, 1493750, 6250,
355 		    buck_volt_range, MT6331_VCORE2_CON9,
356 		    MT6331_VCORE2_CON11, GENMASK(6, 0),
357 		    MT6331_VCORE2_CON12, MT6331_VCORE2_CON7),
358 	MT6331_REG_FIXED("buck-vio18", VIO18, MT6331_VIO18_CON9, 0, 13, 1800000, 0, 0),
359 	MT6331_REG_FIXED("ldo-vrtc", VRTC, MT6331_DIGLDO_CON11, 8, 15, 2800000, 0, 0),
360 	MT6331_REG_FIXED("ldo-vtcxo1", VTCXO1, MT6331_ANALDO_CON1, 10, 15, 2800000,
361 			 MT6331_ANALDO_CON1, GENMASK(1, 0)),
362 	MT6331_REG_FIXED("ldo-vtcxo2", VTCXO2, MT6331_ANALDO_CON2, 10, 15, 2800000,
363 			 MT6331_ANALDO_CON2, GENMASK(1, 0)),
364 	MT6331_REG_FIXED("ldo-vsram", VSRAM_DVFS1, MT6331_SYSLDO_CON4, 10, 15, 1012500,
365 			 MT6331_SYSLDO_CON4, GENMASK(1, 0)),
366 	MT6331_REG_FIXED("ldo-vio28", VIO28, MT6331_DIGLDO_CON1, 10, 15, 2800000,
367 			 MT6331_DIGLDO_CON1, GENMASK(1, 0)),
368 	MT6331_LDO("ldo-avdd32aud", AVDD32_AUD, ldo_volt_table1, MT6331_ANALDO_CON3, 10,
369 		   MT6331_ANALDO_CON10, GENMASK(6, 5), MT6331_ANALDO_CON3, GENMASK(1, 0)),
370 	MT6331_LDO("ldo-vauxa32", VAUXA32, ldo_volt_table1, MT6331_ANALDO_CON4, 10,
371 		   MT6331_ANALDO_CON6, GENMASK(6, 5), MT6331_ANALDO_CON4, GENMASK(1, 0)),
372 	MT6331_LDO("ldo-vemc33", VEMC33, ldo_volt_table6, MT6331_DIGLDO_CON5, 10,
373 		   MT6331_DIGLDO_CON17, BIT(6), MT6331_DIGLDO_CON5, GENMASK(1, 0)),
374 	MT6331_LDO("ldo-vibr", VIBR, ldo_volt_table3, MT6331_DIGLDO_CON12, 10,
375 		   MT6331_DIGLDO_CON20, GENMASK(6, 4), MT6331_DIGLDO_CON12, GENMASK(1, 0)),
376 	MT6331_LDO("ldo-vmc", VMC, ldo_volt_table5, MT6331_DIGLDO_CON3, 10,
377 		   MT6331_DIGLDO_CON15, GENMASK(5, 4), MT6331_DIGLDO_CON3, GENMASK(1, 0)),
378 	MT6331_LDO("ldo-vmch", VMCH, ldo_volt_table6, MT6331_DIGLDO_CON4, 10,
379 		   MT6331_DIGLDO_CON16, BIT(6), MT6331_DIGLDO_CON4, GENMASK(1, 0)),
380 	MT6331_LDO("ldo-vmipi", VMIPI, ldo_volt_table3, MT6331_SYSLDO_CON5, 10,
381 		   MT6331_SYSLDO_CON13, GENMASK(5, 3), MT6331_SYSLDO_CON5, GENMASK(1, 0)),
382 	MT6331_LDO("ldo-vsim1", VSIM1, ldo_volt_table4, MT6331_DIGLDO_CON8, 10,
383 		   MT6331_DIGLDO_CON21, GENMASK(6, 4), MT6331_DIGLDO_CON8, GENMASK(1, 0)),
384 	MT6331_LDO("ldo-vsim2", VSIM2, ldo_volt_table4, MT6331_DIGLDO_CON9, 10,
385 		   MT6331_DIGLDO_CON22, GENMASK(6, 4), MT6331_DIGLDO_CON9, GENMASK(1, 0)),
386 	MT6331_LDO("ldo-vusb10", VUSB10, ldo_volt_table9, MT6331_SYSLDO_CON2, 10,
387 		   MT6331_SYSLDO_CON10, GENMASK(5, 3), MT6331_SYSLDO_CON2, GENMASK(1, 0)),
388 	MT6331_LDO("ldo-vcama", VCAMA, ldo_volt_table2, MT6331_ANALDO_CON5, 15,
389 		   MT6331_ANALDO_CON9, GENMASK(5, 4), 0, 0),
390 	MT6331_LDO_S("ldo-vcamaf", VCAM_AF, ldo_volt_table3, MT6331_DIGLDO_CON2, 10,
391 		     MT6331_DIGLDO_CON14, GENMASK(6, 4), MT6331_DIGLDO_CON2, GENMASK(1, 0),
392 		     MT6331_EN_STATUS1, BIT(0)),
393 	MT6331_LDO_S("ldo-vcamd", VCAMD, ldo_volt_table8, MT6331_SYSLDO_CON1, 15,
394 		     MT6331_SYSLDO_CON9, GENMASK(6, 4), MT6331_SYSLDO_CON1, GENMASK(1, 0),
395 		     MT6331_EN_STATUS1, BIT(11)),
396 	MT6331_LDO_S("ldo-vcamio", VCAM_IO,  ldo_volt_table10, MT6331_SYSLDO_CON3, 10,
397 		     MT6331_SYSLDO_CON11, GENMASK(4, 3), MT6331_SYSLDO_CON3, GENMASK(1, 0),
398 		     MT6331_EN_STATUS1, BIT(13)),
399 	MT6331_LDO_S("ldo-vgp1", VGP1, ldo_volt_table3, MT6331_DIGLDO_CON6, 10,
400 		     MT6331_DIGLDO_CON19, GENMASK(6, 4), MT6331_DIGLDO_CON6, GENMASK(1, 0),
401 		     MT6331_EN_STATUS1, BIT(4)),
402 	MT6331_LDO_S("ldo-vgp2", VGP2, ldo_volt_table10, MT6331_SYSLDO_CON6, 10,
403 		     MT6331_SYSLDO_CON14, GENMASK(4, 3), MT6331_SYSLDO_CON6, GENMASK(1, 0),
404 		     MT6331_EN_STATUS1, BIT(15)),
405 	MT6331_LDO_S("ldo-vgp3", VGP3, ldo_volt_table10, MT6331_SYSLDO_CON7, 10,
406 		     MT6331_SYSLDO_CON15, GENMASK(4, 3), MT6331_SYSLDO_CON7, GENMASK(1, 0),
407 		     MT6331_EN_STATUS2, BIT(0)),
408 	MT6331_LDO_S("ldo-vgp4", VGP4, ldo_volt_table7, MT6331_DIGLDO_CON7, 10,
409 		     MT6331_DIGLDO_CON18, GENMASK(6, 4), MT6331_DIGLDO_CON7, GENMASK(1, 0),
410 		     MT6331_EN_STATUS1, BIT(5)),
411 	MT6331_LDO_AO("ldo-vdig18", VDIG18, ldo_volt_table11,
412 		      MT6331_DIGLDO_CON28, GENMASK(14, 12)),
413 };
414 
415 static int mt6331_set_buck_vosel_reg(struct platform_device *pdev)
416 {
417 	struct mt6397_chip *mt6331 = dev_get_drvdata(pdev->dev.parent);
418 	int i;
419 	u32 regval;
420 
421 	for (i = 0; i < MT6331_ID_VREG_MAX; i++) {
422 		if (mt6331_regulators[i].vselctrl_reg) {
423 			if (regmap_read(mt6331->regmap,
424 				mt6331_regulators[i].vselctrl_reg,
425 				&regval) < 0) {
426 				dev_err(&pdev->dev,
427 					"Failed to read buck ctrl\n");
428 				return -EIO;
429 			}
430 
431 			if (regval & mt6331_regulators[i].vselctrl_mask) {
432 				mt6331_regulators[i].desc.vsel_reg =
433 				mt6331_regulators[i].vselon_reg;
434 			}
435 		}
436 	}
437 
438 	return 0;
439 }
440 
441 static int mt6331_regulator_probe(struct platform_device *pdev)
442 {
443 	struct mt6397_chip *mt6331 = dev_get_drvdata(pdev->dev.parent);
444 	struct regulator_config config = {};
445 	struct regulator_dev *rdev;
446 	int i;
447 	u32 reg_value;
448 
449 	/* Query buck controller to select activated voltage register part */
450 	if (mt6331_set_buck_vosel_reg(pdev))
451 		return -EIO;
452 
453 	/* Read PMIC chip revision to update constraints and voltage table */
454 	if (regmap_read(mt6331->regmap, MT6331_HWCID, &reg_value) < 0) {
455 		dev_err(&pdev->dev, "Failed to read Chip ID\n");
456 		return -EIO;
457 	}
458 	reg_value &= GENMASK(7, 0);
459 
460 	dev_info(&pdev->dev, "Chip ID = 0x%x\n", reg_value);
461 
462 	/*
463 	 * ChipID 0x10 is "MT6331 E1", has a different voltage table and
464 	 * it's currently not supported in this driver. Upon detection of
465 	 * this ID, refuse to register the regulators, as we will wrongly
466 	 * interpret the VSEL for this revision, potentially overvolting
467 	 * some device.
468 	 */
469 	if (reg_value == 0x10) {
470 		dev_err(&pdev->dev, "Chip version not supported. Bailing out.\n");
471 		return -EINVAL;
472 	}
473 
474 	for (i = 0; i < MT6331_ID_VREG_MAX; i++) {
475 		config.dev = &pdev->dev;
476 		config.driver_data = &mt6331_regulators[i];
477 		config.regmap = mt6331->regmap;
478 		rdev = devm_regulator_register(&pdev->dev,
479 				&mt6331_regulators[i].desc, &config);
480 		if (IS_ERR(rdev)) {
481 			dev_err(&pdev->dev, "failed to register %s\n",
482 				mt6331_regulators[i].desc.name);
483 			return PTR_ERR(rdev);
484 		}
485 	}
486 	return 0;
487 }
488 
489 static const struct platform_device_id mt6331_platform_ids[] = {
490 	{"mt6331-regulator", 0},
491 	{ /* sentinel */ },
492 };
493 MODULE_DEVICE_TABLE(platform, mt6331_platform_ids);
494 
495 static struct platform_driver mt6331_regulator_driver = {
496 	.driver = {
497 		.name = "mt6331-regulator",
498 	},
499 	.probe = mt6331_regulator_probe,
500 	.id_table = mt6331_platform_ids,
501 };
502 
503 module_platform_driver(mt6331_regulator_driver);
504 
505 MODULE_AUTHOR("AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>");
506 MODULE_DESCRIPTION("Regulator Driver for MediaTek MT6331 PMIC");
507 MODULE_LICENSE("GPL");
508