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/of_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 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
205 	tscadc->tscadc_base = devm_ioremap_resource(&pdev->dev, res);
206 	if (IS_ERR(tscadc->tscadc_base))
207 		return PTR_ERR(tscadc->tscadc_base);
208 
209 	tscadc->tscadc_phys_base = res->start;
210 	tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
211 					       tscadc->tscadc_base,
212 					       &tscadc_regmap_config);
213 	if (IS_ERR(tscadc->regmap)) {
214 		dev_err(&pdev->dev, "regmap init failed\n");
215 		return PTR_ERR(tscadc->regmap);
216 	}
217 
218 	spin_lock_init(&tscadc->reg_lock);
219 	init_waitqueue_head(&tscadc->reg_se_wait);
220 
221 	pm_runtime_enable(&pdev->dev);
222 	pm_runtime_get_sync(&pdev->dev);
223 
224 	/*
225 	 * The TSC_ADC_Subsystem has 2 clock domains: OCP_CLK and ADC_CLK.
226 	 * ADCs produce a 12-bit sample every 15 ADC_CLK cycles.
227 	 * am33xx ADCs expect to capture 200ksps.
228 	 * am47xx ADCs expect to capture 867ksps.
229 	 * We need ADC clocks respectively running at 3MHz and 13MHz.
230 	 * These frequencies are valid since TSC_ADC_SS controller design
231 	 * assumes the OCP clock is at least 6x faster than the ADC clock.
232 	 */
233 	clk = devm_clk_get(&pdev->dev, NULL);
234 	if (IS_ERR(clk)) {
235 		dev_err(&pdev->dev, "failed to get fck\n");
236 		err = PTR_ERR(clk);
237 		goto err_disable_clk;
238 	}
239 
240 	tscadc->clk_div = (clk_get_rate(clk) / tscadc->data->target_clk_rate) - 1;
241 	regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
242 
243 	/*
244 	 * Set the control register bits. tscadc->ctrl stores the configuration
245 	 * of the CTRL register but not the subsystem enable bit which must be
246 	 * added manually when timely.
247 	 */
248 	tscadc->ctrl = CNTRLREG_STEPID;
249 	if (ti_adc_with_touchscreen(tscadc)) {
250 		tscadc->ctrl |= CNTRLREG_TSC_STEPCONFIGWRT;
251 		if (use_tsc) {
252 			tscadc->ctrl |= CNTRLREG_TSC_ENB;
253 			if (tscmag_wires == 5)
254 				tscadc->ctrl |= CNTRLREG_TSC_5WIRE;
255 			else
256 				tscadc->ctrl |= CNTRLREG_TSC_4WIRE;
257 		}
258 	} else {
259 		tscadc->ctrl |= CNTRLREG_MAG_PREAMP_PWRDOWN |
260 				CNTRLREG_MAG_PREAMP_BYPASS;
261 	}
262 	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);
263 
264 	tscadc_idle_config(tscadc);
265 
266 	/* Enable the TSC module enable bit */
267 	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);
268 
269 	/* TSC or MAG Cell */
270 	if (use_tsc || use_mag) {
271 		cell = &tscadc->cells[cell_idx++];
272 		cell->name = tscadc->data->secondary_feature_name;
273 		cell->of_compatible = tscadc->data->secondary_feature_compatible;
274 		cell->platform_data = &tscadc;
275 		cell->pdata_size = sizeof(tscadc);
276 	}
277 
278 	/* ADC Cell */
279 	if (adc_channels > 0) {
280 		cell = &tscadc->cells[cell_idx++];
281 		cell->name = tscadc->data->adc_feature_name;
282 		cell->of_compatible = tscadc->data->adc_feature_compatible;
283 		cell->platform_data = &tscadc;
284 		cell->pdata_size = sizeof(tscadc);
285 	}
286 
287 	err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
288 			      tscadc->cells, cell_idx, NULL, 0, NULL);
289 	if (err < 0)
290 		goto err_disable_clk;
291 
292 	platform_set_drvdata(pdev, tscadc);
293 	return 0;
294 
295 err_disable_clk:
296 	pm_runtime_put_sync(&pdev->dev);
297 	pm_runtime_disable(&pdev->dev);
298 
299 	return err;
300 }
301 
302 static int ti_tscadc_remove(struct platform_device *pdev)
303 {
304 	struct ti_tscadc_dev *tscadc = platform_get_drvdata(pdev);
305 
306 	regmap_write(tscadc->regmap, REG_SE, 0x00);
307 
308 	pm_runtime_put_sync(&pdev->dev);
309 	pm_runtime_disable(&pdev->dev);
310 
311 	mfd_remove_devices(tscadc->dev);
312 
313 	return 0;
314 }
315 
316 static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
317 {
318 	return device_may_wakeup(dev);
319 }
320 
321 static int __maybe_unused tscadc_suspend(struct device *dev)
322 {
323 	struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
324 
325 	regmap_write(tscadc->regmap, REG_SE, 0x00);
326 	if (device_for_each_child(dev, NULL, ti_tscadc_can_wakeup)) {
327 		u32 ctrl;
328 
329 		regmap_read(tscadc->regmap, REG_CTRL, &ctrl);
330 		ctrl &= ~(CNTRLREG_POWERDOWN);
331 		ctrl |= CNTRLREG_SSENB;
332 		regmap_write(tscadc->regmap, REG_CTRL, ctrl);
333 	}
334 	pm_runtime_put_sync(dev);
335 
336 	return 0;
337 }
338 
339 static int __maybe_unused tscadc_resume(struct device *dev)
340 {
341 	struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
342 
343 	pm_runtime_get_sync(dev);
344 
345 	regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
346 	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);
347 	tscadc_idle_config(tscadc);
348 	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);
349 
350 	return 0;
351 }
352 
353 static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);
354 
355 static const struct ti_tscadc_data tscdata = {
356 	.adc_feature_name = "TI-am335x-adc",
357 	.adc_feature_compatible = "ti,am3359-adc",
358 	.secondary_feature_name = "TI-am335x-tsc",
359 	.secondary_feature_compatible = "ti,am3359-tsc",
360 	.target_clk_rate = TSC_ADC_CLK,
361 };
362 
363 static const struct ti_tscadc_data magdata = {
364 	.adc_feature_name = "TI-am43xx-adc",
365 	.adc_feature_compatible = "ti,am4372-adc",
366 	.secondary_feature_name = "TI-am43xx-mag",
367 	.secondary_feature_compatible = "ti,am4372-mag",
368 	.target_clk_rate = MAG_ADC_CLK,
369 };
370 
371 static const struct of_device_id ti_tscadc_dt_ids[] = {
372 	{ .compatible = "ti,am3359-tscadc", .data = &tscdata },
373 	{ .compatible = "ti,am4372-magadc", .data = &magdata },
374 	{ }
375 };
376 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
377 
378 static struct platform_driver ti_tscadc_driver = {
379 	.driver = {
380 		.name   = "ti_am3359-tscadc",
381 		.pm	= &tscadc_pm_ops,
382 		.of_match_table = ti_tscadc_dt_ids,
383 	},
384 	.probe	= ti_tscadc_probe,
385 	.remove	= ti_tscadc_remove,
386 
387 };
388 
389 module_platform_driver(ti_tscadc_driver);
390 
391 MODULE_DESCRIPTION("TI touchscreen/magnetic stripe reader/ADC MFD controller driver");
392 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
393 MODULE_LICENSE("GPL");
394