1 /*
2 * Copyright (c) 2016 MediaTek Inc.
3 * Author: Zhiyong Tao <zhiyong.tao@mediatek.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15 #include <linux/clk.h>
16 #include <linux/delay.h>
17 #include <linux/err.h>
18 #include <linux/kernel.h>
19 #include <linux/module.h>
20 #include <linux/of.h>
21 #include <linux/of_device.h>
22 #include <linux/platform_device.h>
23 #include <linux/iopoll.h>
24 #include <linux/io.h>
25 #include <linux/iio/iio.h>
26
27 /* Register definitions */
28 #define MT6577_AUXADC_CON0 0x00
29 #define MT6577_AUXADC_CON1 0x04
30 #define MT6577_AUXADC_CON2 0x10
31 #define MT6577_AUXADC_STA BIT(0)
32
33 #define MT6577_AUXADC_DAT0 0x14
34 #define MT6577_AUXADC_RDY0 BIT(12)
35
36 #define MT6577_AUXADC_MISC 0x94
37 #define MT6577_AUXADC_PDN_EN BIT(14)
38
39 #define MT6577_AUXADC_DAT_MASK 0xfff
40 #define MT6577_AUXADC_SLEEP_US 1000
41 #define MT6577_AUXADC_TIMEOUT_US 10000
42 #define MT6577_AUXADC_POWER_READY_MS 1
43 #define MT6577_AUXADC_SAMPLE_READY_US 25
44
45 struct mt6577_auxadc_device {
46 void __iomem *reg_base;
47 struct clk *adc_clk;
48 struct mutex lock;
49 };
50
51 #define MT6577_AUXADC_CHANNEL(idx) { \
52 .type = IIO_VOLTAGE, \
53 .indexed = 1, \
54 .channel = (idx), \
55 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
56 }
57
58 static const struct iio_chan_spec mt6577_auxadc_iio_channels[] = {
59 MT6577_AUXADC_CHANNEL(0),
60 MT6577_AUXADC_CHANNEL(1),
61 MT6577_AUXADC_CHANNEL(2),
62 MT6577_AUXADC_CHANNEL(3),
63 MT6577_AUXADC_CHANNEL(4),
64 MT6577_AUXADC_CHANNEL(5),
65 MT6577_AUXADC_CHANNEL(6),
66 MT6577_AUXADC_CHANNEL(7),
67 MT6577_AUXADC_CHANNEL(8),
68 MT6577_AUXADC_CHANNEL(9),
69 MT6577_AUXADC_CHANNEL(10),
70 MT6577_AUXADC_CHANNEL(11),
71 MT6577_AUXADC_CHANNEL(12),
72 MT6577_AUXADC_CHANNEL(13),
73 MT6577_AUXADC_CHANNEL(14),
74 MT6577_AUXADC_CHANNEL(15),
75 };
76
mt6577_auxadc_mod_reg(void __iomem * reg,u32 or_mask,u32 and_mask)77 static inline void mt6577_auxadc_mod_reg(void __iomem *reg,
78 u32 or_mask, u32 and_mask)
79 {
80 u32 val;
81
82 val = readl(reg);
83 val |= or_mask;
84 val &= ~and_mask;
85 writel(val, reg);
86 }
87
mt6577_auxadc_read(struct iio_dev * indio_dev,struct iio_chan_spec const * chan)88 static int mt6577_auxadc_read(struct iio_dev *indio_dev,
89 struct iio_chan_spec const *chan)
90 {
91 u32 val;
92 void __iomem *reg_channel;
93 int ret;
94 struct mt6577_auxadc_device *adc_dev = iio_priv(indio_dev);
95
96 reg_channel = adc_dev->reg_base + MT6577_AUXADC_DAT0 +
97 chan->channel * 0x04;
98
99 mutex_lock(&adc_dev->lock);
100
101 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_CON1,
102 0, 1 << chan->channel);
103
104 /* read channel and make sure old ready bit == 0 */
105 ret = readl_poll_timeout(reg_channel, val,
106 ((val & MT6577_AUXADC_RDY0) == 0),
107 MT6577_AUXADC_SLEEP_US,
108 MT6577_AUXADC_TIMEOUT_US);
109 if (ret < 0) {
110 dev_err(indio_dev->dev.parent,
111 "wait for channel[%d] ready bit clear time out\n",
112 chan->channel);
113 goto err_timeout;
114 }
115
116 /* set bit to trigger sample */
117 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_CON1,
118 1 << chan->channel, 0);
119
120 /* we must delay here for hardware sample channel data */
121 udelay(MT6577_AUXADC_SAMPLE_READY_US);
122
123 /* check MTK_AUXADC_CON2 if auxadc is idle */
124 ret = readl_poll_timeout(adc_dev->reg_base + MT6577_AUXADC_CON2, val,
125 ((val & MT6577_AUXADC_STA) == 0),
126 MT6577_AUXADC_SLEEP_US,
127 MT6577_AUXADC_TIMEOUT_US);
128 if (ret < 0) {
129 dev_err(indio_dev->dev.parent,
130 "wait for auxadc idle time out\n");
131 goto err_timeout;
132 }
133
134 /* read channel and make sure ready bit == 1 */
135 ret = readl_poll_timeout(reg_channel, val,
136 ((val & MT6577_AUXADC_RDY0) != 0),
137 MT6577_AUXADC_SLEEP_US,
138 MT6577_AUXADC_TIMEOUT_US);
139 if (ret < 0) {
140 dev_err(indio_dev->dev.parent,
141 "wait for channel[%d] data ready time out\n",
142 chan->channel);
143 goto err_timeout;
144 }
145
146 /* read data */
147 val = readl(reg_channel) & MT6577_AUXADC_DAT_MASK;
148
149 mutex_unlock(&adc_dev->lock);
150
151 return val;
152
153 err_timeout:
154
155 mutex_unlock(&adc_dev->lock);
156
157 return -ETIMEDOUT;
158 }
159
mt6577_auxadc_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long info)160 static int mt6577_auxadc_read_raw(struct iio_dev *indio_dev,
161 struct iio_chan_spec const *chan,
162 int *val,
163 int *val2,
164 long info)
165 {
166 switch (info) {
167 case IIO_CHAN_INFO_PROCESSED:
168 *val = mt6577_auxadc_read(indio_dev, chan);
169 if (*val < 0) {
170 dev_err(indio_dev->dev.parent,
171 "failed to sample data on channel[%d]\n",
172 chan->channel);
173 return *val;
174 }
175 return IIO_VAL_INT;
176
177 default:
178 return -EINVAL;
179 }
180 }
181
182 static const struct iio_info mt6577_auxadc_info = {
183 .driver_module = THIS_MODULE,
184 .read_raw = &mt6577_auxadc_read_raw,
185 };
186
mt6577_auxadc_probe(struct platform_device * pdev)187 static int mt6577_auxadc_probe(struct platform_device *pdev)
188 {
189 struct mt6577_auxadc_device *adc_dev;
190 unsigned long adc_clk_rate;
191 struct resource *res;
192 struct iio_dev *indio_dev;
193 int ret;
194
195 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev));
196 if (!indio_dev)
197 return -ENOMEM;
198
199 adc_dev = iio_priv(indio_dev);
200 indio_dev->dev.parent = &pdev->dev;
201 indio_dev->name = dev_name(&pdev->dev);
202 indio_dev->info = &mt6577_auxadc_info;
203 indio_dev->modes = INDIO_DIRECT_MODE;
204 indio_dev->channels = mt6577_auxadc_iio_channels;
205 indio_dev->num_channels = ARRAY_SIZE(mt6577_auxadc_iio_channels);
206
207 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
208 adc_dev->reg_base = devm_ioremap_resource(&pdev->dev, res);
209 if (IS_ERR(adc_dev->reg_base)) {
210 dev_err(&pdev->dev, "failed to get auxadc base address\n");
211 return PTR_ERR(adc_dev->reg_base);
212 }
213
214 adc_dev->adc_clk = devm_clk_get(&pdev->dev, "main");
215 if (IS_ERR(adc_dev->adc_clk)) {
216 dev_err(&pdev->dev, "failed to get auxadc clock\n");
217 return PTR_ERR(adc_dev->adc_clk);
218 }
219
220 ret = clk_prepare_enable(adc_dev->adc_clk);
221 if (ret) {
222 dev_err(&pdev->dev, "failed to enable auxadc clock\n");
223 return ret;
224 }
225
226 adc_clk_rate = clk_get_rate(adc_dev->adc_clk);
227 if (!adc_clk_rate) {
228 ret = -EINVAL;
229 dev_err(&pdev->dev, "null clock rate\n");
230 goto err_disable_clk;
231 }
232
233 mutex_init(&adc_dev->lock);
234
235 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC,
236 MT6577_AUXADC_PDN_EN, 0);
237 mdelay(MT6577_AUXADC_POWER_READY_MS);
238
239 platform_set_drvdata(pdev, indio_dev);
240
241 ret = iio_device_register(indio_dev);
242 if (ret < 0) {
243 dev_err(&pdev->dev, "failed to register iio device\n");
244 goto err_power_off;
245 }
246
247 return 0;
248
249 err_power_off:
250 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC,
251 0, MT6577_AUXADC_PDN_EN);
252 err_disable_clk:
253 clk_disable_unprepare(adc_dev->adc_clk);
254 return ret;
255 }
256
mt6577_auxadc_remove(struct platform_device * pdev)257 static int mt6577_auxadc_remove(struct platform_device *pdev)
258 {
259 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
260 struct mt6577_auxadc_device *adc_dev = iio_priv(indio_dev);
261
262 iio_device_unregister(indio_dev);
263
264 mt6577_auxadc_mod_reg(adc_dev->reg_base + MT6577_AUXADC_MISC,
265 0, MT6577_AUXADC_PDN_EN);
266
267 clk_disable_unprepare(adc_dev->adc_clk);
268
269 return 0;
270 }
271
272 static const struct of_device_id mt6577_auxadc_of_match[] = {
273 { .compatible = "mediatek,mt2701-auxadc", },
274 { .compatible = "mediatek,mt8173-auxadc", },
275 { }
276 };
277 MODULE_DEVICE_TABLE(of, mt6577_auxadc_of_match);
278
279 static struct platform_driver mt6577_auxadc_driver = {
280 .driver = {
281 .name = "mt6577-auxadc",
282 .of_match_table = mt6577_auxadc_of_match,
283 },
284 .probe = mt6577_auxadc_probe,
285 .remove = mt6577_auxadc_remove,
286 };
287 module_platform_driver(mt6577_auxadc_driver);
288
289 MODULE_AUTHOR("Zhiyong Tao <zhiyong.tao@mediatek.com>");
290 MODULE_DESCRIPTION("MTK AUXADC Device Driver");
291 MODULE_LICENSE("GPL v2");
292