1 /*
2 * TI Touch Screen / ADC MFD driver
3 *
4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation version 2.
9 *
10 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
11 * kind, whether express or implied; without even the implied warranty
12 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 */
15
16 #include <linux/module.h>
17 #include <linux/slab.h>
18 #include <linux/err.h>
19 #include <linux/io.h>
20 #include <linux/clk.h>
21 #include <linux/regmap.h>
22 #include <linux/mfd/core.h>
23 #include <linux/pm_runtime.h>
24 #include <linux/of.h>
25 #include <linux/of_device.h>
26 #include <linux/sched.h>
27
28 #include <linux/mfd/ti_am335x_tscadc.h>
29
30 static const struct regmap_config tscadc_regmap_config = {
31 .name = "ti_tscadc",
32 .reg_bits = 32,
33 .reg_stride = 4,
34 .val_bits = 32,
35 };
36
am335x_tsc_se_set_cache(struct ti_tscadc_dev * tscadc,u32 val)37 void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tscadc, u32 val)
38 {
39 unsigned long flags;
40
41 spin_lock_irqsave(&tscadc->reg_lock, flags);
42 tscadc->reg_se_cache |= val;
43 if (tscadc->adc_waiting)
44 wake_up(&tscadc->reg_se_wait);
45 else if (!tscadc->adc_in_use)
46 regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
47
48 spin_unlock_irqrestore(&tscadc->reg_lock, flags);
49 }
50 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);
51
am335x_tscadc_need_adc(struct ti_tscadc_dev * tscadc)52 static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tscadc)
53 {
54 DEFINE_WAIT(wait);
55 u32 reg;
56
57 regmap_read(tscadc->regmap, REG_ADCFSM, ®);
58 if (reg & SEQ_STATUS) {
59 tscadc->adc_waiting = true;
60 prepare_to_wait(&tscadc->reg_se_wait, &wait,
61 TASK_UNINTERRUPTIBLE);
62 spin_unlock_irq(&tscadc->reg_lock);
63
64 schedule();
65
66 spin_lock_irq(&tscadc->reg_lock);
67 finish_wait(&tscadc->reg_se_wait, &wait);
68
69 /*
70 * Sequencer should either be idle or
71 * busy applying the charge step.
72 */
73 regmap_read(tscadc->regmap, REG_ADCFSM, ®);
74 WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));
75 tscadc->adc_waiting = false;
76 }
77 tscadc->adc_in_use = true;
78 }
79
am335x_tsc_se_set_once(struct ti_tscadc_dev * tscadc,u32 val)80 void am335x_tsc_se_set_once(struct ti_tscadc_dev *tscadc, u32 val)
81 {
82 spin_lock_irq(&tscadc->reg_lock);
83 am335x_tscadc_need_adc(tscadc);
84
85 regmap_write(tscadc->regmap, REG_SE, val);
86 spin_unlock_irq(&tscadc->reg_lock);
87 }
88 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);
89
am335x_tsc_se_adc_done(struct ti_tscadc_dev * tscadc)90 void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tscadc)
91 {
92 unsigned long flags;
93
94 spin_lock_irqsave(&tscadc->reg_lock, flags);
95 tscadc->adc_in_use = false;
96 regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
97 spin_unlock_irqrestore(&tscadc->reg_lock, flags);
98 }
99 EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);
100
am335x_tsc_se_clr(struct ti_tscadc_dev * tscadc,u32 val)101 void am335x_tsc_se_clr(struct ti_tscadc_dev *tscadc, u32 val)
102 {
103 unsigned long flags;
104
105 spin_lock_irqsave(&tscadc->reg_lock, flags);
106 tscadc->reg_se_cache &= ~val;
107 regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
108 spin_unlock_irqrestore(&tscadc->reg_lock, flags);
109 }
110 EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
111
tscadc_idle_config(struct ti_tscadc_dev * tscadc)112 static void tscadc_idle_config(struct ti_tscadc_dev *tscadc)
113 {
114 unsigned int idleconfig;
115
116 idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
117 STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
118
119 regmap_write(tscadc->regmap, REG_IDLECONFIG, idleconfig);
120 }
121
ti_tscadc_probe(struct platform_device * pdev)122 static int ti_tscadc_probe(struct platform_device *pdev)
123 {
124 struct ti_tscadc_dev *tscadc;
125 struct resource *res;
126 struct clk *clk;
127 struct device_node *node = pdev->dev.of_node;
128 struct mfd_cell *cell;
129 struct property *prop;
130 const __be32 *cur;
131 u32 val;
132 int err, ctrl;
133 int clock_rate;
134 int tsc_wires = 0, adc_channels = 0, total_channels;
135 int readouts = 0;
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 node = of_get_child_by_name(pdev->dev.of_node, "tsc");
143 of_property_read_u32(node, "ti,wires", &tsc_wires);
144 of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
145
146 node = of_get_child_by_name(pdev->dev.of_node, "adc");
147 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
148 adc_channels++;
149 if (val > 7) {
150 dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
151 val);
152 return -EINVAL;
153 }
154 }
155 total_channels = tsc_wires + adc_channels;
156 if (total_channels > 8) {
157 dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
158 return -EINVAL;
159 }
160 if (total_channels == 0) {
161 dev_err(&pdev->dev, "Need atleast one channel.\n");
162 return -EINVAL;
163 }
164
165 if (readouts * 2 + 2 + adc_channels > 16) {
166 dev_err(&pdev->dev, "Too many step configurations requested\n");
167 return -EINVAL;
168 }
169
170 /* Allocate memory for device */
171 tscadc = devm_kzalloc(&pdev->dev, sizeof(*tscadc), GFP_KERNEL);
172 if (!tscadc) {
173 dev_err(&pdev->dev, "failed to allocate memory.\n");
174 return -ENOMEM;
175 }
176 tscadc->dev = &pdev->dev;
177
178 err = platform_get_irq(pdev, 0);
179 if (err < 0) {
180 dev_err(&pdev->dev, "no irq ID is specified.\n");
181 goto ret;
182 } else
183 tscadc->irq = err;
184
185 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
186 tscadc->tscadc_base = devm_ioremap_resource(&pdev->dev, res);
187 if (IS_ERR(tscadc->tscadc_base))
188 return PTR_ERR(tscadc->tscadc_base);
189
190 tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
191 tscadc->tscadc_base, &tscadc_regmap_config);
192 if (IS_ERR(tscadc->regmap)) {
193 dev_err(&pdev->dev, "regmap init failed\n");
194 err = PTR_ERR(tscadc->regmap);
195 goto ret;
196 }
197
198 spin_lock_init(&tscadc->reg_lock);
199 init_waitqueue_head(&tscadc->reg_se_wait);
200
201 pm_runtime_enable(&pdev->dev);
202 pm_runtime_get_sync(&pdev->dev);
203
204 /*
205 * The TSC_ADC_Subsystem has 2 clock domains
206 * OCP_CLK and ADC_CLK.
207 * The ADC clock is expected to run at target of 3MHz,
208 * and expected to capture 12-bit data at a rate of 200 KSPS.
209 * The TSC_ADC_SS controller design assumes the OCP clock is
210 * at least 6x faster than the ADC clock.
211 */
212 clk = clk_get(&pdev->dev, "adc_tsc_fck");
213 if (IS_ERR(clk)) {
214 dev_err(&pdev->dev, "failed to get TSC fck\n");
215 err = PTR_ERR(clk);
216 goto err_disable_clk;
217 }
218 clock_rate = clk_get_rate(clk);
219 clk_put(clk);
220 tscadc->clk_div = clock_rate / ADC_CLK;
221
222 /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
223 tscadc->clk_div--;
224 regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
225
226 /* Set the control register bits */
227 ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
228 regmap_write(tscadc->regmap, REG_CTRL, ctrl);
229
230 /* Set register bits for Idle Config Mode */
231 if (tsc_wires > 0) {
232 tscadc->tsc_wires = tsc_wires;
233 if (tsc_wires == 5)
234 ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
235 else
236 ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
237 tscadc_idle_config(tscadc);
238 }
239
240 /* Enable the TSC module enable bit */
241 ctrl |= CNTRLREG_TSCSSENB;
242 regmap_write(tscadc->regmap, REG_CTRL, ctrl);
243
244 tscadc->used_cells = 0;
245 tscadc->tsc_cell = -1;
246 tscadc->adc_cell = -1;
247
248 /* TSC Cell */
249 if (tsc_wires > 0) {
250 tscadc->tsc_cell = tscadc->used_cells;
251 cell = &tscadc->cells[tscadc->used_cells++];
252 cell->name = "TI-am335x-tsc";
253 cell->of_compatible = "ti,am3359-tsc";
254 cell->platform_data = &tscadc;
255 cell->pdata_size = sizeof(tscadc);
256 }
257
258 /* ADC Cell */
259 if (adc_channels > 0) {
260 tscadc->adc_cell = tscadc->used_cells;
261 cell = &tscadc->cells[tscadc->used_cells++];
262 cell->name = "TI-am335x-adc";
263 cell->of_compatible = "ti,am3359-adc";
264 cell->platform_data = &tscadc;
265 cell->pdata_size = sizeof(tscadc);
266 }
267
268 err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
269 tscadc->used_cells, NULL, 0, NULL);
270 if (err < 0)
271 goto err_disable_clk;
272
273 device_init_wakeup(&pdev->dev, true);
274 platform_set_drvdata(pdev, tscadc);
275 return 0;
276
277 err_disable_clk:
278 pm_runtime_put_sync(&pdev->dev);
279 pm_runtime_disable(&pdev->dev);
280 ret:
281 return err;
282 }
283
ti_tscadc_remove(struct platform_device * pdev)284 static int ti_tscadc_remove(struct platform_device *pdev)
285 {
286 struct ti_tscadc_dev *tscadc = platform_get_drvdata(pdev);
287
288 regmap_write(tscadc->regmap, REG_SE, 0x00);
289
290 pm_runtime_put_sync(&pdev->dev);
291 pm_runtime_disable(&pdev->dev);
292
293 mfd_remove_devices(tscadc->dev);
294
295 return 0;
296 }
297
tscadc_suspend(struct device * dev)298 static int __maybe_unused tscadc_suspend(struct device *dev)
299 {
300 struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
301
302 regmap_write(tscadc->regmap, REG_SE, 0x00);
303 pm_runtime_put_sync(dev);
304
305 return 0;
306 }
307
tscadc_resume(struct device * dev)308 static int __maybe_unused tscadc_resume(struct device *dev)
309 {
310 struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
311 u32 ctrl;
312
313 pm_runtime_get_sync(dev);
314
315 /* context restore */
316 ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
317 regmap_write(tscadc->regmap, REG_CTRL, ctrl);
318
319 if (tscadc->tsc_cell != -1) {
320 if (tscadc->tsc_wires == 5)
321 ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
322 else
323 ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
324 tscadc_idle_config(tscadc);
325 }
326 ctrl |= CNTRLREG_TSCSSENB;
327 regmap_write(tscadc->regmap, REG_CTRL, ctrl);
328
329 regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
330
331 return 0;
332 }
333
334 static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);
335
336 static const struct of_device_id ti_tscadc_dt_ids[] = {
337 { .compatible = "ti,am3359-tscadc", },
338 { }
339 };
340 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
341
342 static struct platform_driver ti_tscadc_driver = {
343 .driver = {
344 .name = "ti_am3359-tscadc",
345 .pm = &tscadc_pm_ops,
346 .of_match_table = ti_tscadc_dt_ids,
347 },
348 .probe = ti_tscadc_probe,
349 .remove = ti_tscadc_remove,
350
351 };
352
353 module_platform_driver(ti_tscadc_driver);
354
355 MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
356 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
357 MODULE_LICENSE("GPL");
358