summaryrefslogtreecommitdiff
path: root/drivers/iio/adc/npcm_adc.c
blob: 910f3585fa54b022a756660f693d70baf100b4af (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2019 Nuvoton Technology corporation.

#include <linux/clk.h>
#include <linux/device.h>
#include <linux/mfd/syscon.h>
#include <linux/io.h>
#include <linux/iio/iio.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>

struct npcm_adc {
	bool int_status;
	u32 adc_sample_hz;
	struct device *dev;
	void __iomem *regs;
	struct clk *adc_clk;
	wait_queue_head_t wq;
	struct regulator *vref;
	struct regmap *rst_regmap;
};

/* NPCM7xx reset module */
#define NPCM7XX_IPSRST1_OFFSET		0x020
#define NPCM7XX_IPSRST1_ADC_RST		BIT(27)

/* ADC registers */
#define NPCM_ADCCON	 0x00
#define NPCM_ADCDATA	 0x04

/* ADCCON Register Bits */
#define NPCM_ADCCON_ADC_INT_EN		BIT(21)
#define NPCM_ADCCON_REFSEL		BIT(19)
#define NPCM_ADCCON_ADC_INT_ST		BIT(18)
#define NPCM_ADCCON_ADC_EN		BIT(17)
#define NPCM_ADCCON_ADC_RST		BIT(16)
#define NPCM_ADCCON_ADC_CONV		BIT(13)

#define NPCM_ADCCON_CH_MASK		GENMASK(27, 24)
#define NPCM_ADCCON_CH(x)		((x) << 24)
#define NPCM_ADCCON_DIV_SHIFT		1
#define NPCM_ADCCON_DIV_MASK		GENMASK(8, 1)
#define NPCM_ADC_DATA_MASK(x)		((x) & GENMASK(9, 0))

#define NPCM_ADC_ENABLE		(NPCM_ADCCON_ADC_EN | NPCM_ADCCON_ADC_INT_EN)

/* ADC General Definition */
#define NPCM_RESOLUTION_BITS		10
#define NPCM_INT_VREF_MV		2000

#define NPCM_ADC_CHAN(ch) {					\
	.type = IIO_VOLTAGE,					\
	.indexed = 1,						\
	.channel = ch,						\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),		\
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |	\
				BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
}

static const struct iio_chan_spec npcm_adc_iio_channels[] = {
	NPCM_ADC_CHAN(0),
	NPCM_ADC_CHAN(1),
	NPCM_ADC_CHAN(2),
	NPCM_ADC_CHAN(3),
	NPCM_ADC_CHAN(4),
	NPCM_ADC_CHAN(5),
	NPCM_ADC_CHAN(6),
	NPCM_ADC_CHAN(7),
};

static irqreturn_t npcm_adc_isr(int irq, void *data)
{
	u32 regtemp;
	struct iio_dev *indio_dev = data;
	struct npcm_adc *info = iio_priv(indio_dev);

	regtemp = ioread32(info->regs + NPCM_ADCCON);
	if (regtemp & NPCM_ADCCON_ADC_INT_ST) {
		iowrite32(regtemp, info->regs + NPCM_ADCCON);
		wake_up_interruptible(&info->wq);
		info->int_status = true;
	}

	return IRQ_HANDLED;
}

static int npcm_adc_read(struct npcm_adc *info, int *val, u8 channel)
{
	int ret;
	u32 regtemp;

	/* Select ADC channel */
	regtemp = ioread32(info->regs + NPCM_ADCCON);
	regtemp &= ~NPCM_ADCCON_CH_MASK;
	info->int_status = false;
	iowrite32(regtemp | NPCM_ADCCON_CH(channel) |
		  NPCM_ADCCON_ADC_CONV, info->regs + NPCM_ADCCON);

	ret = wait_event_interruptible_timeout(info->wq, info->int_status,
					       msecs_to_jiffies(10));
	if (ret == 0) {
		regtemp = ioread32(info->regs + NPCM_ADCCON);
		if ((regtemp & NPCM_ADCCON_ADC_CONV) && info->rst_regmap) {
			/* if conversion failed - reset ADC module */
			regmap_write(info->rst_regmap, NPCM7XX_IPSRST1_OFFSET,
				     NPCM7XX_IPSRST1_ADC_RST);
			msleep(100);
			regmap_write(info->rst_regmap, NPCM7XX_IPSRST1_OFFSET,
				     0x0);
			msleep(100);

			/* Enable ADC and start conversion module */
			iowrite32(NPCM_ADC_ENABLE | NPCM_ADCCON_ADC_CONV,
				  info->regs + NPCM_ADCCON);
			dev_err(info->dev, "RESET ADC Complete\n");
		}
		return -ETIMEDOUT;
	}
	if (ret < 0)
		return ret;

	*val = NPCM_ADC_DATA_MASK(ioread32(info->regs + NPCM_ADCDATA));

	return 0;
}

static int npcm_adc_read_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan, int *val,
			     int *val2, long mask)
{
	int ret;
	int vref_uv;
	struct npcm_adc *info = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&indio_dev->mlock);
		ret = npcm_adc_read(info, val, chan->channel);
		mutex_unlock(&indio_dev->mlock);
		if (ret) {
			dev_err(info->dev, "NPCM ADC read failed\n");
			return ret;
		}
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		if (!IS_ERR(info->vref)) {
			vref_uv = regulator_get_voltage(info->vref);
			*val = vref_uv / 1000;
		} else {
			*val = NPCM_INT_VREF_MV;
		}
		*val2 = NPCM_RESOLUTION_BITS;
		return IIO_VAL_FRACTIONAL_LOG2;
	case IIO_CHAN_INFO_SAMP_FREQ:
		*val = info->adc_sample_hz;
		return IIO_VAL_INT;
	default:
		return -EINVAL;
	}

	return 0;
}

static const struct iio_info npcm_adc_iio_info = {
	.read_raw = &npcm_adc_read_raw,
};

static const struct of_device_id npcm_adc_match[] = {
	{ .compatible = "nuvoton,npcm750-adc", },
	{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, npcm_adc_match);

static int npcm_adc_probe(struct platform_device *pdev)
{
	int ret;
	int irq;
	u32 div;
	u32 reg_con;
	struct resource *res;
	struct npcm_adc *info;
	struct iio_dev *indio_dev;
	struct device *dev = &pdev->dev;
	struct device_node *np = pdev->dev.of_node;

	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*info));
	if (!indio_dev)
		return -ENOMEM;
	info = iio_priv(indio_dev);

	info->dev = &pdev->dev;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	info->regs = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(info->regs))
		return PTR_ERR(info->regs);

	info->adc_clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(info->adc_clk)) {
		dev_warn(&pdev->dev, "ADC clock failed: can't read clk\n");
		return PTR_ERR(info->adc_clk);
	}

	/* calculate ADC clock sample rate */
	reg_con = ioread32(info->regs + NPCM_ADCCON);
	div = reg_con & NPCM_ADCCON_DIV_MASK;
	div = div >> NPCM_ADCCON_DIV_SHIFT;
	info->adc_sample_hz = clk_get_rate(info->adc_clk) / ((div + 1) * 2);

	if (of_device_is_compatible(np, "nuvoton,npcm750-adc")) {
		info->rst_regmap = syscon_regmap_lookup_by_compatible
			("nuvoton,npcm750-rst");
		if (IS_ERR(info->rst_regmap)) {
			dev_err(&pdev->dev, "Failed to find nuvoton,npcm750-rst\n");
			ret = PTR_ERR(info->rst_regmap);
			goto err_disable_clk;
		}
	}

	irq = platform_get_irq(pdev, 0);
	if (irq <= 0) {
		ret = -EINVAL;
		goto err_disable_clk;
	}

	ret = devm_request_irq(&pdev->dev, irq, npcm_adc_isr, 0,
			       "NPCM_ADC", indio_dev);
	if (ret < 0) {
		dev_err(dev, "failed requesting interrupt\n");
		goto err_disable_clk;
	}

	reg_con = ioread32(info->regs + NPCM_ADCCON);
	info->vref = devm_regulator_get_optional(&pdev->dev, "vref");
	if (!IS_ERR(info->vref)) {
		ret = regulator_enable(info->vref);
		if (ret) {
			dev_err(&pdev->dev, "Can't enable ADC reference voltage\n");
			goto err_disable_clk;
		}

		iowrite32(reg_con & ~NPCM_ADCCON_REFSEL,
			  info->regs + NPCM_ADCCON);
	} else {
		/*
		 * Any error which is not ENODEV indicates the regulator
		 * has been specified and so is a failure case.
		 */
		if (PTR_ERR(info->vref) != -ENODEV) {
			ret = PTR_ERR(info->vref);
			goto err_disable_clk;
		}

		/* Use internal reference */
		iowrite32(reg_con | NPCM_ADCCON_REFSEL,
			  info->regs + NPCM_ADCCON);
	}

	init_waitqueue_head(&info->wq);

	reg_con = ioread32(info->regs + NPCM_ADCCON);
	reg_con |= NPCM_ADC_ENABLE;

	/* Enable the ADC Module */
	iowrite32(reg_con, info->regs + NPCM_ADCCON);

	/* Start ADC conversion */
	iowrite32(reg_con | NPCM_ADCCON_ADC_CONV, info->regs + NPCM_ADCCON);

	platform_set_drvdata(pdev, indio_dev);
	indio_dev->name = dev_name(&pdev->dev);
	indio_dev->dev.parent = &pdev->dev;
	indio_dev->info = &npcm_adc_iio_info;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = npcm_adc_iio_channels;
	indio_dev->num_channels = ARRAY_SIZE(npcm_adc_iio_channels);

	ret = iio_device_register(indio_dev);
	if (ret) {
		dev_err(&pdev->dev, "Couldn't register the device.\n");
		goto err_iio_register;
	}

	pr_info("NPCM ADC driver probed\n");

	return 0;

err_iio_register:
	iowrite32(reg_con & ~NPCM_ADCCON_ADC_EN, info->regs + NPCM_ADCCON);
	if (!IS_ERR(info->vref))
		regulator_disable(info->vref);
err_disable_clk:
	clk_disable_unprepare(info->adc_clk);

	return ret;
}

static int npcm_adc_remove(struct platform_device *pdev)
{
	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
	struct npcm_adc *info = iio_priv(indio_dev);
	u32 regtemp;

	iio_device_unregister(indio_dev);

	regtemp = ioread32(info->regs + NPCM_ADCCON);
	iowrite32(regtemp & ~NPCM_ADCCON_ADC_EN, info->regs + NPCM_ADCCON);
	if (!IS_ERR(info->vref))
		regulator_disable(info->vref);
	clk_disable_unprepare(info->adc_clk);

	return 0;
}

static struct platform_driver npcm_adc_driver = {
	.probe		= npcm_adc_probe,
	.remove		= npcm_adc_remove,
	.driver		= {
		.name	= "npcm_adc",
		.of_match_table = npcm_adc_match,
	},
};

module_platform_driver(npcm_adc_driver);

MODULE_DESCRIPTION("Nuvoton NPCM ADC Driver");
MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
MODULE_LICENSE("GPL v2");