summaryrefslogtreecommitdiffstats
path: root/drivers/mfd/ti_am335x_tscadc.c
blob: fd111296b959255c5a7fdeb61fcd2649594ebbd7 (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
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
/*
 * TI Touch Screen / ADC MFD driver
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation version 2.
 *
 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
 * kind, whether express or implied; without even the implied warranty
 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/regmap.h>
#include <linux/mfd/core.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/sched.h>

#include <linux/mfd/ti_am335x_tscadc.h>

static const struct regmap_config tscadc_regmap_config = {
	.name = "ti_tscadc",
	.reg_bits = 32,
	.reg_stride = 4,
	.val_bits = 32,
};

void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tscadc, u32 val)
{
	unsigned long flags;

	spin_lock_irqsave(&tscadc->reg_lock, flags);
	tscadc->reg_se_cache |= val;
	if (tscadc->adc_waiting)
		wake_up(&tscadc->reg_se_wait);
	else if (!tscadc->adc_in_use)
		regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);

	spin_unlock_irqrestore(&tscadc->reg_lock, flags);
}
EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);

static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tscadc)
{
	DEFINE_WAIT(wait);
	u32 reg;

	regmap_read(tscadc->regmap, REG_ADCFSM, &reg);
	if (reg & SEQ_STATUS) {
		tscadc->adc_waiting = true;
		prepare_to_wait(&tscadc->reg_se_wait, &wait,
				TASK_UNINTERRUPTIBLE);
		spin_unlock_irq(&tscadc->reg_lock);

		schedule();

		spin_lock_irq(&tscadc->reg_lock);
		finish_wait(&tscadc->reg_se_wait, &wait);

		/*
		 * Sequencer should either be idle or
		 * busy applying the charge step.
		 */
		regmap_read(tscadc->regmap, REG_ADCFSM, &reg);
		WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));
		tscadc->adc_waiting = false;
	}
	tscadc->adc_in_use = true;
}

void am335x_tsc_se_set_once(struct ti_tscadc_dev *tscadc, u32 val)
{
	spin_lock_irq(&tscadc->reg_lock);
	am335x_tscadc_need_adc(tscadc);

	regmap_write(tscadc->regmap, REG_SE, val);
	spin_unlock_irq(&tscadc->reg_lock);
}
EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);

void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tscadc)
{
	unsigned long flags;

	spin_lock_irqsave(&tscadc->reg_lock, flags);
	tscadc->adc_in_use = false;
	regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
	spin_unlock_irqrestore(&tscadc->reg_lock, flags);
}
EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);

void am335x_tsc_se_clr(struct ti_tscadc_dev *tscadc, u32 val)
{
	unsigned long flags;

	spin_lock_irqsave(&tscadc->reg_lock, flags);
	tscadc->reg_se_cache &= ~val;
	regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
	spin_unlock_irqrestore(&tscadc->reg_lock, flags);
}
EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);

static void tscadc_idle_config(struct ti_tscadc_dev *tscadc)
{
	unsigned int idleconfig;

	idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
			STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;

	regmap_write(tscadc->regmap, REG_IDLECONFIG, idleconfig);
}

static	int ti_tscadc_probe(struct platform_device *pdev)
{
	struct ti_tscadc_dev	*tscadc;
	struct resource		*res;
	struct clk		*clk;
	struct device_node	*node;
	struct mfd_cell		*cell;
	struct property         *prop;
	const __be32            *cur;
	u32			val;
	int			err, ctrl;
	int			clock_rate;
	int			tsc_wires = 0, adc_channels = 0, total_channels;
	int			readouts = 0;

	if (!pdev->dev.of_node) {
		dev_err(&pdev->dev, "Could not find valid DT data.\n");
		return -EINVAL;
	}

	node = of_get_child_by_name(pdev->dev.of_node, "tsc");
	of_property_read_u32(node, "ti,wires", &tsc_wires);
	of_property_read_u32(node, "ti,coordiante-readouts", &readouts);

	node = of_get_child_by_name(pdev->dev.of_node, "adc");
	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
		adc_channels++;
		if (val > 7) {
			dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
					val);
			return -EINVAL;
		}
	}
	total_channels = tsc_wires + adc_channels;
	if (total_channels > 8) {
		dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
		return -EINVAL;
	}
	if (total_channels == 0) {
		dev_err(&pdev->dev, "Need atleast one channel.\n");
		return -EINVAL;
	}

	if (readouts * 2 + 2 + adc_channels > 16) {
		dev_err(&pdev->dev, "Too many step configurations requested\n");
		return -EINVAL;
	}

	/* Allocate memory for device */
	tscadc = devm_kzalloc(&pdev->dev, sizeof(*tscadc), GFP_KERNEL);
	if (!tscadc)
		return -ENOMEM;

	tscadc->dev = &pdev->dev;

	err = platform_get_irq(pdev, 0);
	if (err < 0) {
		dev_err(&pdev->dev, "no irq ID is specified.\n");
		goto ret;
	} else
		tscadc->irq = err;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	tscadc->tscadc_phys_base = res->start;
	tscadc->tscadc_base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(tscadc->tscadc_base))
		return PTR_ERR(tscadc->tscadc_base);

	tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
			tscadc->tscadc_base, &tscadc_regmap_config);
	if (IS_ERR(tscadc->regmap)) {
		dev_err(&pdev->dev, "regmap init failed\n");
		err = PTR_ERR(tscadc->regmap);
		goto ret;
	}

	spin_lock_init(&tscadc->reg_lock);
	init_waitqueue_head(&tscadc->reg_se_wait);

	pm_runtime_enable(&pdev->dev);
	pm_runtime_get_sync(&pdev->dev);

	/*
	 * The TSC_ADC_Subsystem has 2 clock domains
	 * OCP_CLK and ADC_CLK.
	 * The ADC clock is expected to run at target of 3MHz,
	 * and expected to capture 12-bit data at a rate of 200 KSPS.
	 * The TSC_ADC_SS controller design assumes the OCP clock is
	 * at least 6x faster than the ADC clock.
	 */
	clk = devm_clk_get(&pdev->dev, "adc_tsc_fck");
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "failed to get TSC fck\n");
		err = PTR_ERR(clk);
		goto err_disable_clk;
	}
	clock_rate = clk_get_rate(clk);
	tscadc->clk_div = clock_rate / ADC_CLK;

	/* TSCADC_CLKDIV needs to be configured to the value minus 1 */
	tscadc->clk_div--;
	regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);

	/* Set the control register bits */
	ctrl = CNTRLREG_STEPCONFIGWRT |	CNTRLREG_STEPID;
	regmap_write(tscadc->regmap, REG_CTRL, ctrl);

	/* Set register bits for Idle Config Mode */
	if (tsc_wires > 0) {
		tscadc->tsc_wires = tsc_wires;
		if (tsc_wires == 5)
			ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
		else
			ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
		tscadc_idle_config(tscadc);
	}

	/* Enable the TSC module enable bit */
	ctrl |= CNTRLREG_TSCSSENB;
	regmap_write(tscadc->regmap, REG_CTRL, ctrl);

	tscadc->used_cells = 0;
	tscadc->tsc_cell = -1;
	tscadc->adc_cell = -1;

	/* TSC Cell */
	if (tsc_wires > 0) {
		tscadc->tsc_cell = tscadc->used_cells;
		cell = &tscadc->cells[tscadc->used_cells++];
		cell->name = "TI-am335x-tsc";
		cell->of_compatible = "ti,am3359-tsc";
		cell->platform_data = &tscadc;
		cell->pdata_size = sizeof(tscadc);
	}

	/* ADC Cell */
	if (adc_channels > 0) {
		tscadc->adc_cell = tscadc->used_cells;
		cell = &tscadc->cells[tscadc->used_cells++];
		cell->name = "TI-am335x-adc";
		cell->of_compatible = "ti,am3359-adc";
		cell->platform_data = &tscadc;
		cell->pdata_size = sizeof(tscadc);
	}

	err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
			      tscadc->cells, tscadc->used_cells, NULL,
			      0, NULL);
	if (err < 0)
		goto err_disable_clk;

	platform_set_drvdata(pdev, tscadc);
	return 0;

err_disable_clk:
	pm_runtime_put_sync(&pdev->dev);
	pm_runtime_disable(&pdev->dev);
ret:
	return err;
}

static int ti_tscadc_remove(struct platform_device *pdev)
{
	struct ti_tscadc_dev	*tscadc = platform_get_drvdata(pdev);

	regmap_write(tscadc->regmap, REG_SE, 0x00);

	pm_runtime_put_sync(&pdev->dev);
	pm_runtime_disable(&pdev->dev);

	mfd_remove_devices(tscadc->dev);

	return 0;
}

static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
{
	return device_may_wakeup(dev);
}

static int __maybe_unused tscadc_suspend(struct device *dev)
{
	struct ti_tscadc_dev	*tscadc = dev_get_drvdata(dev);

	regmap_write(tscadc->regmap, REG_SE, 0x00);
	if (device_for_each_child(dev, NULL, ti_tscadc_can_wakeup)) {
		u32 ctrl;

		regmap_read(tscadc->regmap, REG_CTRL, &ctrl);
		ctrl &= ~(CNTRLREG_POWERDOWN);
		ctrl |= CNTRLREG_TSCSSENB;
		regmap_write(tscadc->regmap, REG_CTRL, ctrl);
	}
	pm_runtime_put_sync(dev);

	return 0;
}

static int __maybe_unused tscadc_resume(struct device *dev)
{
	struct ti_tscadc_dev	*tscadc = dev_get_drvdata(dev);
	u32 ctrl;

	pm_runtime_get_sync(dev);

	/* context restore */
	ctrl = CNTRLREG_STEPCONFIGWRT |	CNTRLREG_STEPID;
	regmap_write(tscadc->regmap, REG_CTRL, ctrl);

	if (tscadc->tsc_cell != -1) {
		if (tscadc->tsc_wires == 5)
			ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
		else
			ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
		tscadc_idle_config(tscadc);
	}
	ctrl |= CNTRLREG_TSCSSENB;
	regmap_write(tscadc->regmap, REG_CTRL, ctrl);

	regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);

	return 0;
}

static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);

static const struct of_device_id ti_tscadc_dt_ids[] = {
	{ .compatible = "ti,am3359-tscadc", },
	{ }
};
MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);

static struct platform_driver ti_tscadc_driver = {
	.driver = {
		.name   = "ti_am3359-tscadc",
		.pm	= &tscadc_pm_ops,
		.of_match_table = ti_tscadc_dt_ids,
	},
	.probe	= ti_tscadc_probe,
	.remove	= ti_tscadc_remove,

};

module_platform_driver(ti_tscadc_driver);

MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
MODULE_LICENSE("GPL");