1 /*
2 * Core driver for STw4810/STw4811
3 *
4 * Copyright (C) 2013 ST-Ericsson SA
5 * Written on behalf of Linaro for ST-Ericsson
6 *
7 * Author: Linus Walleij <linus.walleij@linaro.org>
8 *
9 * License terms: GNU General Public License (GPL) version 2
10 */
11
12 #include <linux/err.h>
13 #include <linux/i2c.h>
14 #include <linux/init.h>
15 #include <linux/mfd/core.h>
16 #include <linux/mfd/stw481x.h>
17 #include <linux/module.h>
18 #include <linux/regmap.h>
19 #include <linux/spinlock.h>
20 #include <linux/slab.h>
21
22 /*
23 * This driver can only access the non-USB portions of STw4811, the register
24 * range 0x00-0x10 dealing with USB is bound to the two special I2C pins used
25 * for USB control.
26 */
27
28 /* Registers inside the power control address space */
29 #define STW_PC_VCORE_SEL 0x05U
30 #define STW_PC_VAUX_SEL 0x06U
31 #define STW_PC_VPLL_SEL 0x07U
32
33 /**
34 * stw481x_get_pctl_reg() - get a power control register
35 * @stw481x: handle to the stw481x chip
36 * @reg: power control register to fetch
37 *
38 * The power control registers is a set of one-time-programmable registers
39 * in its own register space, accessed by writing addess bits to these
40 * two registers: bits 7,6,5 of PCTL_REG_LO corresponds to the 3 LSBs of
41 * the address and bits 8,9 of PCTL_REG_HI corresponds to the 2 MSBs of
42 * the address, forming an address space of 5 bits, i.e. 32 registers
43 * 0x00 ... 0x1f can be obtained.
44 */
stw481x_get_pctl_reg(struct stw481x * stw481x,u8 reg)45 static int stw481x_get_pctl_reg(struct stw481x *stw481x, u8 reg)
46 {
47 u8 msb = (reg >> 3) & 0x03;
48 u8 lsb = (reg << 5) & 0xe0;
49 unsigned int val;
50 u8 vrfy;
51 int ret;
52
53 ret = regmap_write(stw481x->map, STW_PCTL_REG_HI, msb);
54 if (ret)
55 return ret;
56 ret = regmap_write(stw481x->map, STW_PCTL_REG_LO, lsb);
57 if (ret)
58 return ret;
59 ret = regmap_read(stw481x->map, STW_PCTL_REG_HI, &val);
60 if (ret)
61 return ret;
62 vrfy = (val & 0x03) << 3;
63 ret = regmap_read(stw481x->map, STW_PCTL_REG_LO, &val);
64 if (ret)
65 return ret;
66 vrfy |= ((val >> 5) & 0x07);
67 if (vrfy != reg)
68 return -EIO;
69 return (val >> 1) & 0x0f;
70 }
71
stw481x_startup(struct stw481x * stw481x)72 static int stw481x_startup(struct stw481x *stw481x)
73 {
74 /* Voltages multiplied by 100 */
75 u8 vcore_val[] = { 100, 105, 110, 115, 120, 122, 124, 126, 128,
76 130, 132, 134, 136, 138, 140, 145 };
77 u8 vpll_val[] = { 105, 120, 130, 180 };
78 u8 vaux_val[] = { 15, 18, 25, 28 };
79 u8 vcore;
80 u8 vcore_slp;
81 u8 vpll;
82 u8 vaux;
83 bool vaux_en;
84 bool it_warn;
85 int ret;
86 unsigned int val;
87
88 ret = regmap_read(stw481x->map, STW_CONF1, &val);
89 if (ret)
90 return ret;
91 vaux_en = !!(val & STW_CONF1_PDN_VAUX);
92 it_warn = !!(val & STW_CONF1_IT_WARN);
93
94 dev_info(&stw481x->client->dev, "voltages %s\n",
95 (val & STW_CONF1_V_MONITORING) ? "OK" : "LOW");
96 dev_info(&stw481x->client->dev, "MMC level shifter %s\n",
97 (val & STW_CONF1_MMC_LS_STATUS) ? "high impedance" : "ON");
98 dev_info(&stw481x->client->dev, "VMMC: %s\n",
99 (val & STW_CONF1_PDN_VMMC) ? "ON" : "disabled");
100
101 dev_info(&stw481x->client->dev, "STw481x power control registers:\n");
102
103 ret = stw481x_get_pctl_reg(stw481x, STW_PC_VCORE_SEL);
104 if (ret < 0)
105 return ret;
106 vcore = ret & 0x0f;
107
108 ret = stw481x_get_pctl_reg(stw481x, STW_PC_VAUX_SEL);
109 if (ret < 0)
110 return ret;
111 vaux = (ret >> 2) & 3;
112 vpll = (ret >> 4) & 1; /* Save bit 4 */
113
114 ret = stw481x_get_pctl_reg(stw481x, STW_PC_VPLL_SEL);
115 if (ret < 0)
116 return ret;
117 vpll |= (ret >> 1) & 2;
118
119 dev_info(&stw481x->client->dev, "VCORE: %u.%uV %s\n",
120 vcore_val[vcore] / 100, vcore_val[vcore] % 100,
121 (ret & 4) ? "ON" : "OFF");
122
123 dev_info(&stw481x->client->dev, "VPLL: %u.%uV %s\n",
124 vpll_val[vpll] / 100, vpll_val[vpll] % 100,
125 (ret & 0x10) ? "ON" : "OFF");
126
127 dev_info(&stw481x->client->dev, "VAUX: %u.%uV %s\n",
128 vaux_val[vaux] / 10, vaux_val[vaux] % 10,
129 vaux_en ? "ON" : "OFF");
130
131 ret = regmap_read(stw481x->map, STW_CONF2, &val);
132 if (ret)
133 return ret;
134
135 dev_info(&stw481x->client->dev, "TWARN: %s threshold, %s\n",
136 it_warn ? "below" : "above",
137 (val & STW_CONF2_MASK_TWARN) ?
138 "enabled" : "mask through VDDOK");
139 dev_info(&stw481x->client->dev, "VMMC: %s\n",
140 (val & STW_CONF2_VMMC_EXT) ? "internal" : "external");
141 dev_info(&stw481x->client->dev, "IT WAKE UP: %s\n",
142 (val & STW_CONF2_MASK_IT_WAKE_UP) ? "enabled" : "masked");
143 dev_info(&stw481x->client->dev, "GPO1: %s\n",
144 (val & STW_CONF2_GPO1) ? "low" : "high impedance");
145 dev_info(&stw481x->client->dev, "GPO2: %s\n",
146 (val & STW_CONF2_GPO2) ? "low" : "high impedance");
147
148 ret = regmap_read(stw481x->map, STW_VCORE_SLEEP, &val);
149 if (ret)
150 return ret;
151 vcore_slp = val & 0x0f;
152 dev_info(&stw481x->client->dev, "VCORE SLEEP: %u.%uV\n",
153 vcore_val[vcore_slp] / 100, vcore_val[vcore_slp] % 100);
154
155 return 0;
156 }
157
158 /*
159 * MFD cells - we have one cell which is selected operation
160 * mode, and we always have a GPIO cell.
161 */
162 static struct mfd_cell stw481x_cells[] = {
163 {
164 .of_compatible = "st,stw481x-vmmc",
165 .name = "stw481x-vmmc-regulator",
166 .id = -1,
167 },
168 };
169
170 static const struct regmap_config stw481x_regmap_config = {
171 .reg_bits = 8,
172 .val_bits = 8,
173 };
174
stw481x_probe(struct i2c_client * client,const struct i2c_device_id * id)175 static int stw481x_probe(struct i2c_client *client,
176 const struct i2c_device_id *id)
177 {
178 struct stw481x *stw481x;
179 int ret;
180 int i;
181
182 stw481x = devm_kzalloc(&client->dev, sizeof(*stw481x), GFP_KERNEL);
183 if (!stw481x)
184 return -ENOMEM;
185
186 i2c_set_clientdata(client, stw481x);
187 stw481x->client = client;
188 stw481x->map = devm_regmap_init_i2c(client, &stw481x_regmap_config);
189 if (IS_ERR(stw481x->map)) {
190 ret = PTR_ERR(stw481x->map);
191 dev_err(&client->dev, "Failed to allocate register map: %d\n",
192 ret);
193 return ret;
194 }
195
196 ret = stw481x_startup(stw481x);
197 if (ret) {
198 dev_err(&client->dev, "chip initialization failed\n");
199 return ret;
200 }
201
202 /* Set up and register the platform devices. */
203 for (i = 0; i < ARRAY_SIZE(stw481x_cells); i++) {
204 /* One state holder for all drivers, this is simple */
205 stw481x_cells[i].platform_data = stw481x;
206 stw481x_cells[i].pdata_size = sizeof(*stw481x);
207 }
208
209 ret = mfd_add_devices(&client->dev, 0, stw481x_cells,
210 ARRAY_SIZE(stw481x_cells), NULL, 0, NULL);
211 if (ret)
212 return ret;
213
214 dev_info(&client->dev, "initialized STw481x device\n");
215
216 return ret;
217 }
218
stw481x_remove(struct i2c_client * client)219 static int stw481x_remove(struct i2c_client *client)
220 {
221 mfd_remove_devices(&client->dev);
222 return 0;
223 }
224
225 /*
226 * This ID table is completely unused, as this is a pure
227 * device-tree probed driver, but it has to be here due to
228 * the structure of the I2C core.
229 */
230 static const struct i2c_device_id stw481x_id[] = {
231 { "stw481x", 0 },
232 { },
233 };
234 MODULE_DEVICE_TABLE(i2c, stw481x_id);
235
236 static const struct of_device_id stw481x_match[] = {
237 { .compatible = "st,stw4810", },
238 { .compatible = "st,stw4811", },
239 { },
240 };
241 MODULE_DEVICE_TABLE(of, stw481x_match);
242
243 static struct i2c_driver stw481x_driver = {
244 .driver = {
245 .name = "stw481x",
246 .of_match_table = stw481x_match,
247 },
248 .probe = stw481x_probe,
249 .remove = stw481x_remove,
250 .id_table = stw481x_id,
251 };
252
253 module_i2c_driver(stw481x_driver);
254
255 MODULE_AUTHOR("Linus Walleij");
256 MODULE_DESCRIPTION("STw481x PMIC driver");
257 MODULE_LICENSE("GPL v2");
258