1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2019 Nuvoton Technology corporation.
3
4 #include <linux/clk.h>
5 #include <linux/device.h>
6 #include <linux/mfd/syscon.h>
7 #include <linux/io.h>
8 #include <linux/iio/iio.h>
9 #include <linux/interrupt.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/regmap.h>
14 #include <linux/regulator/consumer.h>
15 #include <linux/spinlock.h>
16 #include <linux/uaccess.h>
17
18 struct npcm_adc {
19 bool int_status;
20 u32 adc_sample_hz;
21 struct device *dev;
22 void __iomem *regs;
23 struct clk *adc_clk;
24 wait_queue_head_t wq;
25 struct regulator *vref;
26 struct regmap *rst_regmap;
27 };
28
29 /* NPCM7xx reset module */
30 #define NPCM7XX_IPSRST1_OFFSET 0x020
31 #define NPCM7XX_IPSRST1_ADC_RST BIT(27)
32
33 /* ADC registers */
34 #define NPCM_ADCCON 0x00
35 #define NPCM_ADCDATA 0x04
36
37 /* ADCCON Register Bits */
38 #define NPCM_ADCCON_ADC_INT_EN BIT(21)
39 #define NPCM_ADCCON_REFSEL BIT(19)
40 #define NPCM_ADCCON_ADC_INT_ST BIT(18)
41 #define NPCM_ADCCON_ADC_EN BIT(17)
42 #define NPCM_ADCCON_ADC_RST BIT(16)
43 #define NPCM_ADCCON_ADC_CONV BIT(13)
44
45 #define NPCM_ADCCON_CH_MASK GENMASK(27, 24)
46 #define NPCM_ADCCON_CH(x) ((x) << 24)
47 #define NPCM_ADCCON_DIV_SHIFT 1
48 #define NPCM_ADCCON_DIV_MASK GENMASK(8, 1)
49 #define NPCM_ADC_DATA_MASK(x) ((x) & GENMASK(9, 0))
50
51 #define NPCM_ADC_ENABLE (NPCM_ADCCON_ADC_EN | NPCM_ADCCON_ADC_INT_EN)
52
53 /* ADC General Definition */
54 #define NPCM_RESOLUTION_BITS 10
55 #define NPCM_INT_VREF_MV 2000
56
57 #define NPCM_ADC_CHAN(ch) { \
58 .type = IIO_VOLTAGE, \
59 .indexed = 1, \
60 .channel = ch, \
61 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
62 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
63 BIT(IIO_CHAN_INFO_SAMP_FREQ), \
64 }
65
66 static const struct iio_chan_spec npcm_adc_iio_channels[] = {
67 NPCM_ADC_CHAN(0),
68 NPCM_ADC_CHAN(1),
69 NPCM_ADC_CHAN(2),
70 NPCM_ADC_CHAN(3),
71 NPCM_ADC_CHAN(4),
72 NPCM_ADC_CHAN(5),
73 NPCM_ADC_CHAN(6),
74 NPCM_ADC_CHAN(7),
75 };
76
npcm_adc_isr(int irq,void * data)77 static irqreturn_t npcm_adc_isr(int irq, void *data)
78 {
79 u32 regtemp;
80 struct iio_dev *indio_dev = data;
81 struct npcm_adc *info = iio_priv(indio_dev);
82
83 regtemp = ioread32(info->regs + NPCM_ADCCON);
84 if (regtemp & NPCM_ADCCON_ADC_INT_ST) {
85 iowrite32(regtemp, info->regs + NPCM_ADCCON);
86 wake_up_interruptible(&info->wq);
87 info->int_status = true;
88 }
89
90 return IRQ_HANDLED;
91 }
92
npcm_adc_read(struct npcm_adc * info,int * val,u8 channel)93 static int npcm_adc_read(struct npcm_adc *info, int *val, u8 channel)
94 {
95 int ret;
96 u32 regtemp;
97
98 /* Select ADC channel */
99 regtemp = ioread32(info->regs + NPCM_ADCCON);
100 regtemp &= ~NPCM_ADCCON_CH_MASK;
101 info->int_status = false;
102 iowrite32(regtemp | NPCM_ADCCON_CH(channel) |
103 NPCM_ADCCON_ADC_CONV, info->regs + NPCM_ADCCON);
104
105 ret = wait_event_interruptible_timeout(info->wq, info->int_status,
106 msecs_to_jiffies(10));
107 if (ret == 0) {
108 regtemp = ioread32(info->regs + NPCM_ADCCON);
109 if ((regtemp & NPCM_ADCCON_ADC_CONV) && info->rst_regmap) {
110 /* if conversion failed - reset ADC module */
111 regmap_write(info->rst_regmap, NPCM7XX_IPSRST1_OFFSET,
112 NPCM7XX_IPSRST1_ADC_RST);
113 msleep(100);
114 regmap_write(info->rst_regmap, NPCM7XX_IPSRST1_OFFSET,
115 0x0);
116 msleep(100);
117
118 /* Enable ADC and start conversion module */
119 iowrite32(NPCM_ADC_ENABLE | NPCM_ADCCON_ADC_CONV,
120 info->regs + NPCM_ADCCON);
121 dev_err(info->dev, "RESET ADC Complete\n");
122 }
123 return -ETIMEDOUT;
124 }
125 if (ret < 0)
126 return ret;
127
128 *val = NPCM_ADC_DATA_MASK(ioread32(info->regs + NPCM_ADCDATA));
129
130 return 0;
131 }
132
npcm_adc_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)133 static int npcm_adc_read_raw(struct iio_dev *indio_dev,
134 struct iio_chan_spec const *chan, int *val,
135 int *val2, long mask)
136 {
137 int ret;
138 int vref_uv;
139 struct npcm_adc *info = iio_priv(indio_dev);
140
141 switch (mask) {
142 case IIO_CHAN_INFO_RAW:
143 mutex_lock(&indio_dev->mlock);
144 ret = npcm_adc_read(info, val, chan->channel);
145 mutex_unlock(&indio_dev->mlock);
146 if (ret) {
147 dev_err(info->dev, "NPCM ADC read failed\n");
148 return ret;
149 }
150 return IIO_VAL_INT;
151 case IIO_CHAN_INFO_SCALE:
152 if (!IS_ERR(info->vref)) {
153 vref_uv = regulator_get_voltage(info->vref);
154 *val = vref_uv / 1000;
155 } else {
156 *val = NPCM_INT_VREF_MV;
157 }
158 *val2 = NPCM_RESOLUTION_BITS;
159 return IIO_VAL_FRACTIONAL_LOG2;
160 case IIO_CHAN_INFO_SAMP_FREQ:
161 *val = info->adc_sample_hz;
162 return IIO_VAL_INT;
163 default:
164 return -EINVAL;
165 }
166
167 return 0;
168 }
169
170 static const struct iio_info npcm_adc_iio_info = {
171 .read_raw = &npcm_adc_read_raw,
172 };
173
174 static const struct of_device_id npcm_adc_match[] = {
175 { .compatible = "nuvoton,npcm750-adc", },
176 { /* sentinel */ }
177 };
178 MODULE_DEVICE_TABLE(of, npcm_adc_match);
179
npcm_adc_probe(struct platform_device * pdev)180 static int npcm_adc_probe(struct platform_device *pdev)
181 {
182 int ret;
183 int irq;
184 u32 div;
185 u32 reg_con;
186 struct resource *res;
187 struct npcm_adc *info;
188 struct iio_dev *indio_dev;
189 struct device *dev = &pdev->dev;
190 struct device_node *np = pdev->dev.of_node;
191
192 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
193 if (!indio_dev)
194 return -ENOMEM;
195 info = iio_priv(indio_dev);
196
197 info->dev = &pdev->dev;
198
199 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
200 info->regs = devm_ioremap_resource(&pdev->dev, res);
201 if (IS_ERR(info->regs))
202 return PTR_ERR(info->regs);
203
204 info->adc_clk = devm_clk_get(&pdev->dev, NULL);
205 if (IS_ERR(info->adc_clk)) {
206 dev_warn(&pdev->dev, "ADC clock failed: can't read clk\n");
207 return PTR_ERR(info->adc_clk);
208 }
209
210 /* calculate ADC clock sample rate */
211 reg_con = ioread32(info->regs + NPCM_ADCCON);
212 div = reg_con & NPCM_ADCCON_DIV_MASK;
213 div = div >> NPCM_ADCCON_DIV_SHIFT;
214 info->adc_sample_hz = clk_get_rate(info->adc_clk) / ((div + 1) * 2);
215
216 if (of_device_is_compatible(np, "nuvoton,npcm750-adc")) {
217 info->rst_regmap = syscon_regmap_lookup_by_compatible
218 ("nuvoton,npcm750-rst");
219 if (IS_ERR(info->rst_regmap)) {
220 dev_err(&pdev->dev, "Failed to find nuvoton,npcm750-rst\n");
221 ret = PTR_ERR(info->rst_regmap);
222 goto err_disable_clk;
223 }
224 }
225
226 irq = platform_get_irq(pdev, 0);
227 if (irq <= 0) {
228 ret = -EINVAL;
229 goto err_disable_clk;
230 }
231
232 ret = devm_request_irq(&pdev->dev, irq, npcm_adc_isr, 0,
233 "NPCM_ADC", indio_dev);
234 if (ret < 0) {
235 dev_err(dev, "failed requesting interrupt\n");
236 goto err_disable_clk;
237 }
238
239 reg_con = ioread32(info->regs + NPCM_ADCCON);
240 info->vref = devm_regulator_get_optional(&pdev->dev, "vref");
241 if (!IS_ERR(info->vref)) {
242 ret = regulator_enable(info->vref);
243 if (ret) {
244 dev_err(&pdev->dev, "Can't enable ADC reference voltage\n");
245 goto err_disable_clk;
246 }
247
248 iowrite32(reg_con & ~NPCM_ADCCON_REFSEL,
249 info->regs + NPCM_ADCCON);
250 } else {
251 /*
252 * Any error which is not ENODEV indicates the regulator
253 * has been specified and so is a failure case.
254 */
255 if (PTR_ERR(info->vref) != -ENODEV) {
256 ret = PTR_ERR(info->vref);
257 goto err_disable_clk;
258 }
259
260 /* Use internal reference */
261 iowrite32(reg_con | NPCM_ADCCON_REFSEL,
262 info->regs + NPCM_ADCCON);
263 }
264
265 init_waitqueue_head(&info->wq);
266
267 reg_con = ioread32(info->regs + NPCM_ADCCON);
268 reg_con |= NPCM_ADC_ENABLE;
269
270 /* Enable the ADC Module */
271 iowrite32(reg_con, info->regs + NPCM_ADCCON);
272
273 /* Start ADC conversion */
274 iowrite32(reg_con | NPCM_ADCCON_ADC_CONV, info->regs + NPCM_ADCCON);
275
276 platform_set_drvdata(pdev, indio_dev);
277 indio_dev->name = dev_name(&pdev->dev);
278 indio_dev->dev.parent = &pdev->dev;
279 indio_dev->info = &npcm_adc_iio_info;
280 indio_dev->modes = INDIO_DIRECT_MODE;
281 indio_dev->channels = npcm_adc_iio_channels;
282 indio_dev->num_channels = ARRAY_SIZE(npcm_adc_iio_channels);
283
284 ret = iio_device_register(indio_dev);
285 if (ret) {
286 dev_err(&pdev->dev, "Couldn't register the device.\n");
287 goto err_iio_register;
288 }
289
290 pr_info("NPCM ADC driver probed\n");
291
292 return 0;
293
294 err_iio_register:
295 iowrite32(reg_con & ~NPCM_ADCCON_ADC_EN, info->regs + NPCM_ADCCON);
296 if (!IS_ERR(info->vref))
297 regulator_disable(info->vref);
298 err_disable_clk:
299 clk_disable_unprepare(info->adc_clk);
300
301 return ret;
302 }
303
npcm_adc_remove(struct platform_device * pdev)304 static int npcm_adc_remove(struct platform_device *pdev)
305 {
306 struct iio_dev *indio_dev = platform_get_drvdata(pdev);
307 struct npcm_adc *info = iio_priv(indio_dev);
308 u32 regtemp;
309
310 iio_device_unregister(indio_dev);
311
312 regtemp = ioread32(info->regs + NPCM_ADCCON);
313 iowrite32(regtemp & ~NPCM_ADCCON_ADC_EN, info->regs + NPCM_ADCCON);
314 if (!IS_ERR(info->vref))
315 regulator_disable(info->vref);
316 clk_disable_unprepare(info->adc_clk);
317
318 return 0;
319 }
320
321 static struct platform_driver npcm_adc_driver = {
322 .probe = npcm_adc_probe,
323 .remove = npcm_adc_remove,
324 .driver = {
325 .name = "npcm_adc",
326 .of_match_table = npcm_adc_match,
327 },
328 };
329
330 module_platform_driver(npcm_adc_driver);
331
332 MODULE_DESCRIPTION("Nuvoton NPCM ADC Driver");
333 MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
334 MODULE_LICENSE("GPL v2");
335
