Root/drivers/regulator/max8952.c

1/*
2 * max8952.c - Voltage and current regulation for the Maxim 8952
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 * MyungJoo Ham <myungjoo.ham@samsung.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 */
21
22#include <linux/module.h>
23#include <linux/init.h>
24#include <linux/i2c.h>
25#include <linux/err.h>
26#include <linux/platform_device.h>
27#include <linux/regulator/driver.h>
28#include <linux/regulator/max8952.h>
29#include <linux/gpio.h>
30#include <linux/io.h>
31#include <linux/slab.h>
32
33/* Registers */
34enum {
35    MAX8952_REG_MODE0,
36    MAX8952_REG_MODE1,
37    MAX8952_REG_MODE2,
38    MAX8952_REG_MODE3,
39    MAX8952_REG_CONTROL,
40    MAX8952_REG_SYNC,
41    MAX8952_REG_RAMP,
42    MAX8952_REG_CHIP_ID1,
43    MAX8952_REG_CHIP_ID2,
44};
45
46struct max8952_data {
47    struct i2c_client *client;
48    struct device *dev;
49    struct max8952_platform_data *pdata;
50    struct regulator_dev *rdev;
51
52    bool vid0;
53    bool vid1;
54};
55
56static int max8952_read_reg(struct max8952_data *max8952, u8 reg)
57{
58    int ret = i2c_smbus_read_byte_data(max8952->client, reg);
59    if (ret > 0)
60        ret &= 0xff;
61
62    return ret;
63}
64
65static int max8952_write_reg(struct max8952_data *max8952,
66        u8 reg, u8 value)
67{
68    return i2c_smbus_write_byte_data(max8952->client, reg, value);
69}
70
71static int max8952_list_voltage(struct regulator_dev *rdev,
72        unsigned int selector)
73{
74    struct max8952_data *max8952 = rdev_get_drvdata(rdev);
75
76    if (rdev_get_id(rdev) != 0)
77        return -EINVAL;
78
79    return (max8952->pdata->dvs_mode[selector] * 10 + 770) * 1000;
80}
81
82static int max8952_get_voltage_sel(struct regulator_dev *rdev)
83{
84    struct max8952_data *max8952 = rdev_get_drvdata(rdev);
85    u8 vid = 0;
86
87    if (max8952->vid0)
88        vid += 1;
89    if (max8952->vid1)
90        vid += 2;
91
92    return vid;
93}
94
95static int max8952_set_voltage_sel(struct regulator_dev *rdev,
96                   unsigned selector)
97{
98    struct max8952_data *max8952 = rdev_get_drvdata(rdev);
99
100    if (!gpio_is_valid(max8952->pdata->gpio_vid0) ||
101            !gpio_is_valid(max8952->pdata->gpio_vid1)) {
102        /* DVS not supported */
103        return -EPERM;
104    }
105
106    max8952->vid0 = selector & 0x1;
107    max8952->vid1 = (selector >> 1) & 0x1;
108    gpio_set_value(max8952->pdata->gpio_vid0, max8952->vid0);
109    gpio_set_value(max8952->pdata->gpio_vid1, max8952->vid1);
110
111    return 0;
112}
113
114static struct regulator_ops max8952_ops = {
115    .list_voltage = max8952_list_voltage,
116    .get_voltage_sel = max8952_get_voltage_sel,
117    .set_voltage_sel = max8952_set_voltage_sel,
118};
119
120static const struct regulator_desc regulator = {
121    .name = "MAX8952_VOUT",
122    .id = 0,
123    .n_voltages = MAX8952_NUM_DVS_MODE,
124    .ops = &max8952_ops,
125    .type = REGULATOR_VOLTAGE,
126    .owner = THIS_MODULE,
127};
128
129static int __devinit max8952_pmic_probe(struct i2c_client *client,
130        const struct i2c_device_id *i2c_id)
131{
132    struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
133    struct max8952_platform_data *pdata = client->dev.platform_data;
134    struct regulator_config config = { };
135    struct max8952_data *max8952;
136
137    int ret = 0, err = 0;
138
139    if (!pdata) {
140        dev_err(&client->dev, "Require the platform data\n");
141        return -EINVAL;
142    }
143
144    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
145        return -EIO;
146
147    max8952 = devm_kzalloc(&client->dev, sizeof(struct max8952_data),
148                   GFP_KERNEL);
149    if (!max8952)
150        return -ENOMEM;
151
152    max8952->client = client;
153    max8952->dev = &client->dev;
154    max8952->pdata = pdata;
155
156    config.dev = max8952->dev;
157    config.init_data = &pdata->reg_data;
158    config.driver_data = max8952;
159
160    config.ena_gpio = pdata->gpio_en;
161    if (pdata->reg_data.constraints.boot_on)
162        config.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
163
164    max8952->rdev = regulator_register(&regulator, &config);
165
166    if (IS_ERR(max8952->rdev)) {
167        ret = PTR_ERR(max8952->rdev);
168        dev_err(max8952->dev, "regulator init failed (%d)\n", ret);
169        return ret;
170    }
171
172    max8952->vid0 = pdata->default_mode & 0x1;
173    max8952->vid1 = (pdata->default_mode >> 1) & 0x1;
174
175    if (gpio_is_valid(pdata->gpio_vid0) &&
176            gpio_is_valid(pdata->gpio_vid1)) {
177        if (!gpio_request(pdata->gpio_vid0, "MAX8952 VID0"))
178            gpio_direction_output(pdata->gpio_vid0,
179                    (pdata->default_mode) & 0x1);
180        else
181            err = 1;
182
183        if (!gpio_request(pdata->gpio_vid1, "MAX8952 VID1"))
184            gpio_direction_output(pdata->gpio_vid1,
185                (pdata->default_mode >> 1) & 0x1);
186        else {
187            if (!err)
188                gpio_free(pdata->gpio_vid0);
189            err = 2;
190        }
191
192    } else
193        err = 3;
194
195    if (err) {
196        dev_warn(max8952->dev, "VID0/1 gpio invalid: "
197                "DVS not available.\n");
198        max8952->vid0 = 0;
199        max8952->vid1 = 0;
200        /* Mark invalid */
201        pdata->gpio_vid0 = -1;
202        pdata->gpio_vid1 = -1;
203
204        /* Disable Pulldown of EN only */
205        max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x60);
206
207        dev_err(max8952->dev, "DVS modes disabled because VID0 and VID1"
208                " do not have proper controls.\n");
209    } else {
210        /*
211         * Disable Pulldown on EN, VID0, VID1 to reduce
212         * leakage current of MAX8952 assuming that MAX8952
213         * is turned on (EN==1). Note that without having VID0/1
214         * properly connected, turning pulldown off can be
215         * problematic. Thus, turn this off only when they are
216         * controllable by GPIO.
217         */
218        max8952_write_reg(max8952, MAX8952_REG_CONTROL, 0x0);
219    }
220
221    max8952_write_reg(max8952, MAX8952_REG_MODE0,
222            (max8952_read_reg(max8952,
223                      MAX8952_REG_MODE0) & 0xC0) |
224            (pdata->dvs_mode[0] & 0x3F));
225    max8952_write_reg(max8952, MAX8952_REG_MODE1,
226            (max8952_read_reg(max8952,
227                      MAX8952_REG_MODE1) & 0xC0) |
228            (pdata->dvs_mode[1] & 0x3F));
229    max8952_write_reg(max8952, MAX8952_REG_MODE2,
230            (max8952_read_reg(max8952,
231                      MAX8952_REG_MODE2) & 0xC0) |
232            (pdata->dvs_mode[2] & 0x3F));
233    max8952_write_reg(max8952, MAX8952_REG_MODE3,
234            (max8952_read_reg(max8952,
235                      MAX8952_REG_MODE3) & 0xC0) |
236            (pdata->dvs_mode[3] & 0x3F));
237
238    max8952_write_reg(max8952, MAX8952_REG_SYNC,
239            (max8952_read_reg(max8952, MAX8952_REG_SYNC) & 0x3F) |
240            ((pdata->sync_freq & 0x3) << 6));
241    max8952_write_reg(max8952, MAX8952_REG_RAMP,
242            (max8952_read_reg(max8952, MAX8952_REG_RAMP) & 0x1F) |
243            ((pdata->ramp_speed & 0x7) << 5));
244
245    i2c_set_clientdata(client, max8952);
246
247    return 0;
248}
249
250static int __devexit max8952_pmic_remove(struct i2c_client *client)
251{
252    struct max8952_data *max8952 = i2c_get_clientdata(client);
253    struct max8952_platform_data *pdata = max8952->pdata;
254    struct regulator_dev *rdev = max8952->rdev;
255
256    regulator_unregister(rdev);
257
258    gpio_free(pdata->gpio_vid0);
259    gpio_free(pdata->gpio_vid1);
260    return 0;
261}
262
263static const struct i2c_device_id max8952_ids[] = {
264    { "max8952", 0 },
265    { },
266};
267MODULE_DEVICE_TABLE(i2c, max8952_ids);
268
269static struct i2c_driver max8952_pmic_driver = {
270    .probe = max8952_pmic_probe,
271    .remove = __devexit_p(max8952_pmic_remove),
272    .driver = {
273        .name = "max8952",
274    },
275    .id_table = max8952_ids,
276};
277
278static int __init max8952_pmic_init(void)
279{
280    return i2c_add_driver(&max8952_pmic_driver);
281}
282subsys_initcall(max8952_pmic_init);
283
284static void __exit max8952_pmic_exit(void)
285{
286    i2c_del_driver(&max8952_pmic_driver);
287}
288module_exit(max8952_pmic_exit);
289
290MODULE_DESCRIPTION("MAXIM 8952 voltage regulator driver");
291MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
292MODULE_LICENSE("GPL");
293

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