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
am335x_tsc_se_set_cache(struct ti_tscadc_dev * tscadc,u32 val)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
am335x_tscadc_need_adc(struct ti_tscadc_dev * tscadc)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, ®);
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, ®);
66 WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));
67 tscadc->adc_waiting = false;
68 }
69 tscadc->adc_in_use = true;
70 }
71
am335x_tsc_se_set_once(struct ti_tscadc_dev * tscadc,u32 val)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
am335x_tsc_se_adc_done(struct ti_tscadc_dev * tscadc)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
am335x_tsc_se_clr(struct ti_tscadc_dev * tscadc,u32 val)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
tscadc_idle_config(struct ti_tscadc_dev * tscadc)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
ti_tscadc_probe(struct platform_device * pdev)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
ti_tscadc_remove(struct platform_device * pdev)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
ti_tscadc_can_wakeup(struct device * dev,void * data)315 static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
316 {
317 return device_may_wakeup(dev);
318 }
319
tscadc_suspend(struct device * dev)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
tscadc_resume(struct device * dev)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