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 */
45static 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
72static 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 */
162static struct mfd_cell stw481x_cells[] = {
163	{
164		.of_compatible = "st,stw481x-vmmc",
165		.name = "stw481x-vmmc-regulator",
166		.id = -1,
167	},
168};
169
170static const struct regmap_config stw481x_regmap_config = {
171	.reg_bits = 8,
172	.val_bits = 8,
173};
174
175static 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
219static 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 */
230static const struct i2c_device_id stw481x_id[] = {
231	{ "stw481x", 0 },
232	{ },
233};
234MODULE_DEVICE_TABLE(i2c, stw481x_id);
235
236static const struct of_device_id stw481x_match[] = {
237	{ .compatible = "st,stw4810", },
238	{ .compatible = "st,stw4811", },
239	{ },
240};
241MODULE_DEVICE_TABLE(of, stw481x_match);
242
243static 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
253module_i2c_driver(stw481x_driver);
254
255MODULE_AUTHOR("Linus Walleij");
256MODULE_DESCRIPTION("STw481x PMIC driver");
257MODULE_LICENSE("GPL v2");
258