1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * TI Touch Screen / ADC MFD driver
4  *
5  * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
6  */
7 
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/err.h>
11 #include <linux/io.h>
12 #include <linux/clk.h>
13 #include <linux/regmap.h>
14 #include <linux/mfd/core.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/of.h>
17 #include <linux/platform_device.h>
18 #include <linux/sched.h>
19 
20 #include <linux/mfd/ti_am335x_tscadc.h>
21 
22 static const struct regmap_config tscadc_regmap_config = {
23 	.name = "ti_tscadc",
24 	.reg_bits = 32,
25 	.reg_stride = 4,
26 	.val_bits = 32,
27 };
28 
29 void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tscadc, u32 val)
30 {
31 	unsigned long flags;
32 
33 	spin_lock_irqsave(&tscadc->reg_lock, flags);
34 	tscadc->reg_se_cache |= val;
35 	if (tscadc->adc_waiting)
36 		wake_up(&tscadc->reg_se_wait);
37 	else if (!tscadc->adc_in_use)
38 		regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
39 
40 	spin_unlock_irqrestore(&tscadc->reg_lock, flags);
41 }
42 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);
43 
44 static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tscadc)
45 {
46 	DEFINE_WAIT(wait);
47 	u32 reg;
48 
49 	regmap_read(tscadc->regmap, REG_ADCFSM, &reg);
50 	if (reg & SEQ_STATUS) {
51 		tscadc->adc_waiting = true;
52 		prepare_to_wait(&tscadc->reg_se_wait, &wait,
53 				TASK_UNINTERRUPTIBLE);
54 		spin_unlock_irq(&tscadc->reg_lock);
55 
56 		schedule();
57 
58 		spin_lock_irq(&tscadc->reg_lock);
59 		finish_wait(&tscadc->reg_se_wait, &wait);
60 
61 		/*
62 		 * Sequencer should either be idle or
63 		 * busy applying the charge step.
64 		 */
65 		regmap_read(tscadc->regmap, REG_ADCFSM, &reg);
66 		WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));
67 		tscadc->adc_waiting = false;
68 	}
69 	tscadc->adc_in_use = true;
70 }
71 
72 void am335x_tsc_se_set_once(struct ti_tscadc_dev *tscadc, u32 val)
73 {
74 	spin_lock_irq(&tscadc->reg_lock);
75 	am335x_tscadc_need_adc(tscadc);
76 
77 	regmap_write(tscadc->regmap, REG_SE, val);
78 	spin_unlock_irq(&tscadc->reg_lock);
79 }
80 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);
81 
82 void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tscadc)
83 {
84 	unsigned long flags;
85 
86 	spin_lock_irqsave(&tscadc->reg_lock, flags);
87 	tscadc->adc_in_use = false;
88 	regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
89 	spin_unlock_irqrestore(&tscadc->reg_lock, flags);
90 }
91 EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);
92 
93 void am335x_tsc_se_clr(struct ti_tscadc_dev *tscadc, u32 val)
94 {
95 	unsigned long flags;
96 
97 	spin_lock_irqsave(&tscadc->reg_lock, flags);
98 	tscadc->reg_se_cache &= ~val;
99 	regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
100 	spin_unlock_irqrestore(&tscadc->reg_lock, flags);
101 }
102 EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
103 
104 static void tscadc_idle_config(struct ti_tscadc_dev *tscadc)
105 {
106 	unsigned int idleconfig;
107 
108 	idleconfig = STEPCONFIG_INM_ADCREFM | STEPCONFIG_INP_ADCREFM;
109 	if (ti_adc_with_touchscreen(tscadc))
110 		idleconfig |= STEPCONFIG_YNN | STEPCONFIG_YPN;
111 
112 	regmap_write(tscadc->regmap, REG_IDLECONFIG, idleconfig);
113 }
114 
115 static	int ti_tscadc_probe(struct platform_device *pdev)
116 {
117 	struct ti_tscadc_dev *tscadc;
118 	struct resource *res;
119 	struct clk *clk;
120 	struct device_node *node;
121 	struct mfd_cell *cell;
122 	struct property *prop;
123 	const __be32 *cur;
124 	bool use_tsc = false, use_mag = false;
125 	u32 val;
126 	int err;
127 	int tscmag_wires = 0, adc_channels = 0, cell_idx = 0, total_channels;
128 	int readouts = 0, mag_tracks = 0;
129 
130 	/* Allocate memory for device */
131 	tscadc = devm_kzalloc(&pdev->dev, sizeof(*tscadc), GFP_KERNEL);
132 	if (!tscadc)
133 		return -ENOMEM;
134 
135 	tscadc->dev = &pdev->dev;
136 
137 	if (!pdev->dev.of_node) {
138 		dev_err(&pdev->dev, "Could not find valid DT data.\n");
139 		return -EINVAL;
140 	}
141 
142 	tscadc->data = of_device_get_match_data(&pdev->dev);
143 
144 	if (ti_adc_with_touchscreen(tscadc)) {
145 		node = of_get_child_by_name(pdev->dev.of_node, "tsc");
146 		of_property_read_u32(node, "ti,wires", &tscmag_wires);
147 		err = of_property_read_u32(node, "ti,coordinate-readouts",
148 					   &readouts);
149 		if (err < 0)
150 			of_property_read_u32(node, "ti,coordiante-readouts",
151 					     &readouts);
152 
153 		of_node_put(node);
154 
155 		if (tscmag_wires)
156 			use_tsc = true;
157 	} else {
158 		/*
159 		 * When adding support for the magnetic stripe reader, here is
160 		 * the place to look for the number of tracks used from device
161 		 * tree. Let's default to 0 for now.
162 		 */
163 		mag_tracks = 0;
164 		tscmag_wires = mag_tracks * 2;
165 		if (tscmag_wires)
166 			use_mag = true;
167 	}
168 
169 	node = of_get_child_by_name(pdev->dev.of_node, "adc");
170 	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
171 		adc_channels++;
172 		if (val > 7) {
173 			dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
174 				val);
175 			of_node_put(node);
176 			return -EINVAL;
177 		}
178 	}
179 
180 	of_node_put(node);
181 
182 	total_channels = tscmag_wires + adc_channels;
183 	if (total_channels > 8) {
184 		dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
185 		return -EINVAL;
186 	}
187 
188 	if (total_channels == 0) {
189 		dev_err(&pdev->dev, "Need at least one channel.\n");
190 		return -EINVAL;
191 	}
192 
193 	if (use_tsc && (readouts * 2 + 2 + adc_channels > 16)) {
194 		dev_err(&pdev->dev, "Too many step configurations requested\n");
195 		return -EINVAL;
196 	}
197 
198 	err = platform_get_irq(pdev, 0);
199 	if (err < 0)
200 		return err;
201 	else
202 		tscadc->irq = err;
203 
204 	tscadc->tscadc_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
205 	if (IS_ERR(tscadc->tscadc_base))
206 		return PTR_ERR(tscadc->tscadc_base);
207 
208 	tscadc->tscadc_phys_base = res->start;
209 	tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
210 					       tscadc->tscadc_base,
211 					       &tscadc_regmap_config);
212 	if (IS_ERR(tscadc->regmap)) {
213 		dev_err(&pdev->dev, "regmap init failed\n");
214 		return PTR_ERR(tscadc->regmap);
215 	}
216 
217 	spin_lock_init(&tscadc->reg_lock);
218 	init_waitqueue_head(&tscadc->reg_se_wait);
219 
220 	pm_runtime_enable(&pdev->dev);
221 	pm_runtime_get_sync(&pdev->dev);
222 
223 	/*
224 	 * The TSC_ADC_Subsystem has 2 clock domains: OCP_CLK and ADC_CLK.
225 	 * ADCs produce a 12-bit sample every 15 ADC_CLK cycles.
226 	 * am33xx ADCs expect to capture 200ksps.
227 	 * am47xx ADCs expect to capture 867ksps.
228 	 * We need ADC clocks respectively running at 3MHz and 13MHz.
229 	 * These frequencies are valid since TSC_ADC_SS controller design
230 	 * assumes the OCP clock is at least 6x faster than the ADC clock.
231 	 */
232 	clk = devm_clk_get(&pdev->dev, NULL);
233 	if (IS_ERR(clk)) {
234 		dev_err(&pdev->dev, "failed to get fck\n");
235 		err = PTR_ERR(clk);
236 		goto err_disable_clk;
237 	}
238 
239 	tscadc->clk_div = (clk_get_rate(clk) / tscadc->data->target_clk_rate) - 1;
240 	regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
241 
242 	/*
243 	 * Set the control register bits. tscadc->ctrl stores the configuration
244 	 * of the CTRL register but not the subsystem enable bit which must be
245 	 * added manually when timely.
246 	 */
247 	tscadc->ctrl = CNTRLREG_STEPID;
248 	if (ti_adc_with_touchscreen(tscadc)) {
249 		tscadc->ctrl |= CNTRLREG_TSC_STEPCONFIGWRT;
250 		if (use_tsc) {
251 			tscadc->ctrl |= CNTRLREG_TSC_ENB;
252 			if (tscmag_wires == 5)
253 				tscadc->ctrl |= CNTRLREG_TSC_5WIRE;
254 			else
255 				tscadc->ctrl |= CNTRLREG_TSC_4WIRE;
256 		}
257 	} else {
258 		tscadc->ctrl |= CNTRLREG_MAG_PREAMP_PWRDOWN |
259 				CNTRLREG_MAG_PREAMP_BYPASS;
260 	}
261 	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);
262 
263 	tscadc_idle_config(tscadc);
264 
265 	/* Enable the TSC module enable bit */
266 	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);
267 
268 	/* TSC or MAG Cell */
269 	if (use_tsc || use_mag) {
270 		cell = &tscadc->cells[cell_idx++];
271 		cell->name = tscadc->data->secondary_feature_name;
272 		cell->of_compatible = tscadc->data->secondary_feature_compatible;
273 		cell->platform_data = &tscadc;
274 		cell->pdata_size = sizeof(tscadc);
275 	}
276 
277 	/* ADC Cell */
278 	if (adc_channels > 0) {
279 		cell = &tscadc->cells[cell_idx++];
280 		cell->name = tscadc->data->adc_feature_name;
281 		cell->of_compatible = tscadc->data->adc_feature_compatible;
282 		cell->platform_data = &tscadc;
283 		cell->pdata_size = sizeof(tscadc);
284 	}
285 
286 	err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
287 			      tscadc->cells, cell_idx, NULL, 0, NULL);
288 	if (err < 0)
289 		goto err_disable_clk;
290 
291 	platform_set_drvdata(pdev, tscadc);
292 	return 0;
293 
294 err_disable_clk:
295 	pm_runtime_put_sync(&pdev->dev);
296 	pm_runtime_disable(&pdev->dev);
297 
298 	return err;
299 }
300 
301 static int ti_tscadc_remove(struct platform_device *pdev)
302 {
303 	struct ti_tscadc_dev *tscadc = platform_get_drvdata(pdev);
304 
305 	regmap_write(tscadc->regmap, REG_SE, 0x00);
306 
307 	pm_runtime_put_sync(&pdev->dev);
308 	pm_runtime_disable(&pdev->dev);
309 
310 	mfd_remove_devices(tscadc->dev);
311 
312 	return 0;
313 }
314 
315 static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
316 {
317 	return device_may_wakeup(dev);
318 }
319 
320 static int __maybe_unused tscadc_suspend(struct device *dev)
321 {
322 	struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
323 
324 	regmap_write(tscadc->regmap, REG_SE, 0x00);
325 	if (device_for_each_child(dev, NULL, ti_tscadc_can_wakeup)) {
326 		u32 ctrl;
327 
328 		regmap_read(tscadc->regmap, REG_CTRL, &ctrl);
329 		ctrl &= ~(CNTRLREG_POWERDOWN);
330 		ctrl |= CNTRLREG_SSENB;
331 		regmap_write(tscadc->regmap, REG_CTRL, ctrl);
332 	}
333 	pm_runtime_put_sync(dev);
334 
335 	return 0;
336 }
337 
338 static int __maybe_unused tscadc_resume(struct device *dev)
339 {
340 	struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
341 
342 	pm_runtime_get_sync(dev);
343 
344 	regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
345 	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);
346 	tscadc_idle_config(tscadc);
347 	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);
348 
349 	return 0;
350 }
351 
352 static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);
353 
354 static const struct ti_tscadc_data tscdata = {
355 	.adc_feature_name = "TI-am335x-adc",
356 	.adc_feature_compatible = "ti,am3359-adc",
357 	.secondary_feature_name = "TI-am335x-tsc",
358 	.secondary_feature_compatible = "ti,am3359-tsc",
359 	.target_clk_rate = TSC_ADC_CLK,
360 };
361 
362 static const struct ti_tscadc_data magdata = {
363 	.adc_feature_name = "TI-am43xx-adc",
364 	.adc_feature_compatible = "ti,am4372-adc",
365 	.secondary_feature_name = "TI-am43xx-mag",
366 	.secondary_feature_compatible = "ti,am4372-mag",
367 	.target_clk_rate = MAG_ADC_CLK,
368 };
369 
370 static const struct of_device_id ti_tscadc_dt_ids[] = {
371 	{ .compatible = "ti,am3359-tscadc", .data = &tscdata },
372 	{ .compatible = "ti,am4372-magadc", .data = &magdata },
373 	{ }
374 };
375 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
376 
377 static struct platform_driver ti_tscadc_driver = {
378 	.driver = {
379 		.name   = "ti_am3359-tscadc",
380 		.pm	= &tscadc_pm_ops,
381 		.of_match_table = ti_tscadc_dt_ids,
382 	},
383 	.probe	= ti_tscadc_probe,
384 	.remove	= ti_tscadc_remove,
385 
386 };
387 
388 module_platform_driver(ti_tscadc_driver);
389 
390 MODULE_DESCRIPTION("TI touchscreen/magnetic stripe reader/ADC MFD controller driver");
391 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
392 MODULE_LICENSE("GPL");
393