1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Core driver for STw4810/STw4811
4  *
5  * Copyright (C) 2013 ST-Ericsson SA
6  * Written on behalf of Linaro for ST-Ericsson
7  *
8  * Author: Linus Walleij <linus.walleij@linaro.org>
9  */
10 
11 #include <linux/err.h>
12 #include <linux/i2c.h>
13 #include <linux/init.h>
14 #include <linux/mfd/core.h>
15 #include <linux/mfd/stw481x.h>
16 #include <linux/module.h>
17 #include <linux/regmap.h>
18 #include <linux/spinlock.h>
19 #include <linux/slab.h>
20 
21 /*
22  * This driver can only access the non-USB portions of STw4811, the register
23  * range 0x00-0x10 dealing with USB is bound to the two special I2C pins used
24  * for USB control.
25  */
26 
27 /* Registers inside the power control address space */
28 #define STW_PC_VCORE_SEL	0x05U
29 #define STW_PC_VAUX_SEL		0x06U
30 #define STW_PC_VPLL_SEL		0x07U
31 
32 /**
33  * stw481x_get_pctl_reg() - get a power control register
34  * @stw481x: handle to the stw481x chip
35  * @reg: power control register to fetch
36  *
37  * The power control registers is a set of one-time-programmable registers
38  * in its own register space, accessed by writing addess bits to these
39  * two registers: bits 7,6,5 of PCTL_REG_LO corresponds to the 3 LSBs of
40  * the address and bits 8,9 of PCTL_REG_HI corresponds to the 2 MSBs of
41  * the address, forming an address space of 5 bits, i.e. 32 registers
42  * 0x00 ... 0x1f can be obtained.
43  */
stw481x_get_pctl_reg(struct stw481x * stw481x,u8 reg)44 static int stw481x_get_pctl_reg(struct stw481x *stw481x, u8 reg)
45 {
46 	u8 msb = (reg >> 3) & 0x03;
47 	u8 lsb = (reg << 5) & 0xe0;
48 	unsigned int val;
49 	u8 vrfy;
50 	int ret;
51 
52 	ret = regmap_write(stw481x->map, STW_PCTL_REG_HI, msb);
53 	if (ret)
54 		return ret;
55 	ret = regmap_write(stw481x->map, STW_PCTL_REG_LO, lsb);
56 	if (ret)
57 		return ret;
58 	ret = regmap_read(stw481x->map, STW_PCTL_REG_HI, &val);
59 	if (ret)
60 		return ret;
61 	vrfy = (val & 0x03) << 3;
62 	ret = regmap_read(stw481x->map, STW_PCTL_REG_LO, &val);
63 	if (ret)
64 		return ret;
65 	vrfy |= ((val >> 5) & 0x07);
66 	if (vrfy != reg)
67 		return -EIO;
68 	return (val >> 1) & 0x0f;
69 }
70 
stw481x_startup(struct stw481x * stw481x)71 static int stw481x_startup(struct stw481x *stw481x)
72 {
73 	/* Voltages multiplied by 100 */
74 	static const u8 vcore_val[] = {
75 		100, 105, 110, 115, 120, 122, 124, 126, 128,
76 		130, 132, 134, 136, 138, 140, 145
77 	};
78 	static const u8 vpll_val[] = { 105, 120, 130, 180 };
79 	static const u8 vaux_val[] = { 15, 18, 25, 28 };
80 	u8 vcore;
81 	u8 vcore_slp;
82 	u8 vpll;
83 	u8 vaux;
84 	bool vaux_en;
85 	bool it_warn;
86 	int ret;
87 	unsigned int val;
88 
89 	ret = regmap_read(stw481x->map, STW_CONF1, &val);
90 	if (ret)
91 		return ret;
92 	vaux_en = !!(val & STW_CONF1_PDN_VAUX);
93 	it_warn = !!(val & STW_CONF1_IT_WARN);
94 
95 	dev_info(&stw481x->client->dev, "voltages %s\n",
96 		(val & STW_CONF1_V_MONITORING) ? "OK" : "LOW");
97 	dev_info(&stw481x->client->dev, "MMC level shifter %s\n",
98 		(val & STW_CONF1_MMC_LS_STATUS) ? "high impedance" : "ON");
99 	dev_info(&stw481x->client->dev, "VMMC: %s\n",
100 		(val & STW_CONF1_PDN_VMMC) ? "ON" : "disabled");
101 
102 	dev_info(&stw481x->client->dev, "STw481x power control registers:\n");
103 
104 	ret = stw481x_get_pctl_reg(stw481x, STW_PC_VCORE_SEL);
105 	if (ret < 0)
106 		return ret;
107 	vcore = ret & 0x0f;
108 
109 	ret = stw481x_get_pctl_reg(stw481x, STW_PC_VAUX_SEL);
110 	if (ret < 0)
111 		return ret;
112 	vaux = (ret >> 2) & 3;
113 	vpll = (ret >> 4) & 1; /* Save bit 4 */
114 
115 	ret = stw481x_get_pctl_reg(stw481x, STW_PC_VPLL_SEL);
116 	if (ret < 0)
117 		return ret;
118 	vpll |= (ret >> 1) & 2;
119 
120 	dev_info(&stw481x->client->dev, "VCORE: %u.%uV %s\n",
121 		vcore_val[vcore] / 100, vcore_val[vcore] % 100,
122 		(ret & 4) ? "ON" : "OFF");
123 
124 	dev_info(&stw481x->client->dev, "VPLL:  %u.%uV %s\n",
125 		vpll_val[vpll] / 100, vpll_val[vpll] % 100,
126 		(ret & 0x10) ? "ON" : "OFF");
127 
128 	dev_info(&stw481x->client->dev, "VAUX:  %u.%uV %s\n",
129 		vaux_val[vaux] / 10, vaux_val[vaux] % 10,
130 		vaux_en ? "ON" : "OFF");
131 
132 	ret = regmap_read(stw481x->map, STW_CONF2, &val);
133 	if (ret)
134 		return ret;
135 
136 	dev_info(&stw481x->client->dev, "TWARN: %s threshold, %s\n",
137 		it_warn ? "below" : "above",
138 		(val & STW_CONF2_MASK_TWARN) ?
139 		 "enabled" : "mask through VDDOK");
140 	dev_info(&stw481x->client->dev, "VMMC: %s\n",
141 		(val & STW_CONF2_VMMC_EXT) ? "internal" : "external");
142 	dev_info(&stw481x->client->dev, "IT WAKE UP: %s\n",
143 		(val & STW_CONF2_MASK_IT_WAKE_UP) ? "enabled" : "masked");
144 	dev_info(&stw481x->client->dev, "GPO1: %s\n",
145 		(val & STW_CONF2_GPO1) ? "low" : "high impedance");
146 	dev_info(&stw481x->client->dev, "GPO2: %s\n",
147 		(val & STW_CONF2_GPO2) ? "low" : "high impedance");
148 
149 	ret = regmap_read(stw481x->map, STW_VCORE_SLEEP, &val);
150 	if (ret)
151 		return ret;
152 	vcore_slp = val & 0x0f;
153 	dev_info(&stw481x->client->dev, "VCORE SLEEP: %u.%uV\n",
154 		vcore_val[vcore_slp] / 100, vcore_val[vcore_slp] % 100);
155 
156 	return 0;
157 }
158 
159 /*
160  * MFD cells - we have one cell which is selected operation
161  * mode, and we always have a GPIO cell.
162  */
163 static struct mfd_cell stw481x_cells[] = {
164 	{
165 		.of_compatible = "st,stw481x-vmmc",
166 		.name = "stw481x-vmmc-regulator",
167 		.id = -1,
168 	},
169 };
170 
171 static const struct regmap_config stw481x_regmap_config = {
172 	.reg_bits = 8,
173 	.val_bits = 8,
174 };
175 
stw481x_probe(struct i2c_client * client)176 static int stw481x_probe(struct i2c_client *client)
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 = devm_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 
219 /*
220  * This ID table is completely unused, as this is a pure
221  * device-tree probed driver, but it has to be here due to
222  * the structure of the I2C core.
223  */
224 static const struct i2c_device_id stw481x_id[] = {
225 	{ "stw481x", 0 },
226 	{ },
227 };
228 MODULE_DEVICE_TABLE(i2c, stw481x_id);
229 
230 static const struct of_device_id stw481x_match[] = {
231 	{ .compatible = "st,stw4810", },
232 	{ .compatible = "st,stw4811", },
233 	{ },
234 };
235 MODULE_DEVICE_TABLE(of, stw481x_match);
236 
237 static struct i2c_driver stw481x_driver = {
238 	.driver = {
239 		.name	= "stw481x",
240 		.of_match_table = stw481x_match,
241 	},
242 	.probe_new	= stw481x_probe,
243 	.id_table	= stw481x_id,
244 };
245 
246 module_i2c_driver(stw481x_driver);
247 
248 MODULE_AUTHOR("Linus Walleij");
249 MODULE_DESCRIPTION("STw481x PMIC driver");
250 MODULE_LICENSE("GPL v2");
251