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Linux/drivers/input/touchscreen/atmel_tsadcc.c

  1 /*
  2  *  Atmel Touch Screen Driver
  3  *
  4  *  Copyright (c) 2008 ATMEL
  5  *  Copyright (c) 2008 Dan Liang
  6  *  Copyright (c) 2008 TimeSys Corporation
  7  *  Copyright (c) 2008 Justin Waters
  8  *
  9  *  Based on touchscreen code from Atmel Corporation.
 10  *
 11  *  This program is free software; you can redistribute it and/or modify
 12  *  it under the terms of the GNU General Public License version 2 as
 13  *  published by the Free Software Foundation.
 14  */
 15 #include <linux/err.h>
 16 #include <linux/kernel.h>
 17 #include <linux/module.h>
 18 #include <linux/input.h>
 19 #include <linux/slab.h>
 20 #include <linux/interrupt.h>
 21 #include <linux/clk.h>
 22 #include <linux/platform_device.h>
 23 #include <linux/io.h>
 24 #include <linux/platform_data/atmel.h>
 25 #include <mach/cpu.h>
 26 
 27 /* Register definitions based on AT91SAM9RL64 preliminary draft datasheet */
 28 
 29 #define ATMEL_TSADCC_CR         0x00    /* Control register */
 30 #define   ATMEL_TSADCC_SWRST    (1 << 0)        /* Software Reset*/
 31 #define   ATMEL_TSADCC_START    (1 << 1)        /* Start conversion */
 32 
 33 #define ATMEL_TSADCC_MR         0x04    /* Mode register */
 34 #define   ATMEL_TSADCC_TSAMOD   (3    <<  0)    /* ADC mode */
 35 #define     ATMEL_TSADCC_TSAMOD_ADC_ONLY_MODE   (0x0)   /* ADC Mode */
 36 #define     ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE    (0x1)   /* Touch Screen Only Mode */
 37 #define   ATMEL_TSADCC_LOWRES   (1    <<  4)    /* Resolution selection */
 38 #define   ATMEL_TSADCC_SLEEP    (1    <<  5)    /* Sleep mode */
 39 #define   ATMEL_TSADCC_PENDET   (1    <<  6)    /* Pen Detect selection */
 40 #define   ATMEL_TSADCC_PRES     (1    <<  7)    /* Pressure Measurement Selection */
 41 #define   ATMEL_TSADCC_PRESCAL  (0x3f <<  8)    /* Prescalar Rate Selection */
 42 #define   ATMEL_TSADCC_EPRESCAL (0xff <<  8)    /* Prescalar Rate Selection (Extended) */
 43 #define   ATMEL_TSADCC_STARTUP  (0x7f << 16)    /* Start Up time */
 44 #define   ATMEL_TSADCC_SHTIM    (0xf  << 24)    /* Sample & Hold time */
 45 #define   ATMEL_TSADCC_PENDBC   (0xf  << 28)    /* Pen Detect debouncing time */
 46 
 47 #define ATMEL_TSADCC_TRGR       0x08    /* Trigger register */
 48 #define   ATMEL_TSADCC_TRGMOD   (7      <<  0)  /* Trigger mode */
 49 #define     ATMEL_TSADCC_TRGMOD_NONE            (0 << 0)
 50 #define     ATMEL_TSADCC_TRGMOD_EXT_RISING      (1 << 0)
 51 #define     ATMEL_TSADCC_TRGMOD_EXT_FALLING     (2 << 0)
 52 #define     ATMEL_TSADCC_TRGMOD_EXT_ANY         (3 << 0)
 53 #define     ATMEL_TSADCC_TRGMOD_PENDET          (4 << 0)
 54 #define     ATMEL_TSADCC_TRGMOD_PERIOD          (5 << 0)
 55 #define     ATMEL_TSADCC_TRGMOD_CONTINUOUS      (6 << 0)
 56 #define   ATMEL_TSADCC_TRGPER   (0xffff << 16)  /* Trigger period */
 57 
 58 #define ATMEL_TSADCC_TSR        0x0C    /* Touch Screen register */
 59 #define   ATMEL_TSADCC_TSFREQ   (0xf <<  0)     /* TS Frequency in Interleaved mode */
 60 #define   ATMEL_TSADCC_TSSHTIM  (0xf << 24)     /* Sample & Hold time */
 61 
 62 #define ATMEL_TSADCC_CHER       0x10    /* Channel Enable register */
 63 #define ATMEL_TSADCC_CHDR       0x14    /* Channel Disable register */
 64 #define ATMEL_TSADCC_CHSR       0x18    /* Channel Status register */
 65 #define   ATMEL_TSADCC_CH(n)    (1 << (n))      /* Channel number */
 66 
 67 #define ATMEL_TSADCC_SR         0x1C    /* Status register */
 68 #define   ATMEL_TSADCC_EOC(n)   (1 << ((n)+0))  /* End of conversion for channel N */
 69 #define   ATMEL_TSADCC_OVRE(n)  (1 << ((n)+8))  /* Overrun error for channel N */
 70 #define   ATMEL_TSADCC_DRDY     (1 << 16)       /* Data Ready */
 71 #define   ATMEL_TSADCC_GOVRE    (1 << 17)       /* General Overrun Error */
 72 #define   ATMEL_TSADCC_ENDRX    (1 << 18)       /* End of RX Buffer */
 73 #define   ATMEL_TSADCC_RXBUFF   (1 << 19)       /* TX Buffer full */
 74 #define   ATMEL_TSADCC_PENCNT   (1 << 20)       /* Pen contact */
 75 #define   ATMEL_TSADCC_NOCNT    (1 << 21)       /* No contact */
 76 
 77 #define ATMEL_TSADCC_LCDR       0x20    /* Last Converted Data register */
 78 #define   ATMEL_TSADCC_DATA     (0x3ff << 0)    /* Channel data */
 79 
 80 #define ATMEL_TSADCC_IER        0x24    /* Interrupt Enable register */
 81 #define ATMEL_TSADCC_IDR        0x28    /* Interrupt Disable register */
 82 #define ATMEL_TSADCC_IMR        0x2C    /* Interrupt Mask register */
 83 #define ATMEL_TSADCC_CDR0       0x30    /* Channel Data 0 */
 84 #define ATMEL_TSADCC_CDR1       0x34    /* Channel Data 1 */
 85 #define ATMEL_TSADCC_CDR2       0x38    /* Channel Data 2 */
 86 #define ATMEL_TSADCC_CDR3       0x3C    /* Channel Data 3 */
 87 #define ATMEL_TSADCC_CDR4       0x40    /* Channel Data 4 */
 88 #define ATMEL_TSADCC_CDR5       0x44    /* Channel Data 5 */
 89 
 90 #define ATMEL_TSADCC_XPOS       0x50
 91 #define ATMEL_TSADCC_Z1DAT      0x54
 92 #define ATMEL_TSADCC_Z2DAT      0x58
 93 
 94 #define PRESCALER_VAL(x)        ((x) >> 8)
 95 
 96 #define ADC_DEFAULT_CLOCK       100000
 97 
 98 struct atmel_tsadcc {
 99         struct input_dev        *input;
100         char                    phys[32];
101         struct clk              *clk;
102         int                     irq;
103         unsigned int            prev_absx;
104         unsigned int            prev_absy;
105         unsigned char           bufferedmeasure;
106 };
107 
108 static void __iomem             *tsc_base;
109 
110 #define atmel_tsadcc_read(reg)          __raw_readl(tsc_base + (reg))
111 #define atmel_tsadcc_write(reg, val)    __raw_writel((val), tsc_base + (reg))
112 
113 static irqreturn_t atmel_tsadcc_interrupt(int irq, void *dev)
114 {
115         struct atmel_tsadcc     *ts_dev = (struct atmel_tsadcc *)dev;
116         struct input_dev        *input_dev = ts_dev->input;
117 
118         unsigned int status;
119         unsigned int reg;
120 
121         status = atmel_tsadcc_read(ATMEL_TSADCC_SR);
122         status &= atmel_tsadcc_read(ATMEL_TSADCC_IMR);
123 
124         if (status & ATMEL_TSADCC_NOCNT) {
125                 /* Contact lost */
126                 reg = atmel_tsadcc_read(ATMEL_TSADCC_MR) | ATMEL_TSADCC_PENDBC;
127 
128                 atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
129                 atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
130                 atmel_tsadcc_write(ATMEL_TSADCC_IDR,
131                                    ATMEL_TSADCC_EOC(3) | ATMEL_TSADCC_NOCNT);
132                 atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);
133 
134                 input_report_key(input_dev, BTN_TOUCH, 0);
135                 ts_dev->bufferedmeasure = 0;
136                 input_sync(input_dev);
137 
138         } else if (status & ATMEL_TSADCC_PENCNT) {
139                 /* Pen detected */
140                 reg = atmel_tsadcc_read(ATMEL_TSADCC_MR);
141                 reg &= ~ATMEL_TSADCC_PENDBC;
142 
143                 atmel_tsadcc_write(ATMEL_TSADCC_IDR, ATMEL_TSADCC_PENCNT);
144                 atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
145                 atmel_tsadcc_write(ATMEL_TSADCC_IER,
146                                    ATMEL_TSADCC_EOC(3) | ATMEL_TSADCC_NOCNT);
147                 atmel_tsadcc_write(ATMEL_TSADCC_TRGR,
148                                    ATMEL_TSADCC_TRGMOD_PERIOD | (0x0FFF << 16));
149 
150         } else if (status & ATMEL_TSADCC_EOC(3)) {
151                 /* Conversion finished */
152 
153                 if (ts_dev->bufferedmeasure) {
154                         /* Last measurement is always discarded, since it can
155                          * be erroneous.
156                          * Always report previous measurement */
157                         input_report_abs(input_dev, ABS_X, ts_dev->prev_absx);
158                         input_report_abs(input_dev, ABS_Y, ts_dev->prev_absy);
159                         input_report_key(input_dev, BTN_TOUCH, 1);
160                         input_sync(input_dev);
161                 } else
162                         ts_dev->bufferedmeasure = 1;
163 
164                 /* Now make new measurement */
165                 ts_dev->prev_absx = atmel_tsadcc_read(ATMEL_TSADCC_CDR3) << 10;
166                 ts_dev->prev_absx /= atmel_tsadcc_read(ATMEL_TSADCC_CDR2);
167 
168                 ts_dev->prev_absy = atmel_tsadcc_read(ATMEL_TSADCC_CDR1) << 10;
169                 ts_dev->prev_absy /= atmel_tsadcc_read(ATMEL_TSADCC_CDR0);
170         }
171 
172         return IRQ_HANDLED;
173 }
174 
175 /*
176  * The functions for inserting/removing us as a module.
177  */
178 
179 static int atmel_tsadcc_probe(struct platform_device *pdev)
180 {
181         struct atmel_tsadcc     *ts_dev;
182         struct input_dev        *input_dev;
183         struct resource         *res;
184         struct at91_tsadcc_data *pdata = dev_get_platdata(&pdev->dev);
185         int             err;
186         unsigned int    prsc;
187         unsigned int    reg;
188 
189         if (!pdata)
190                 return -EINVAL;
191 
192         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
193         if (!res) {
194                 dev_err(&pdev->dev, "no mmio resource defined.\n");
195                 return -ENXIO;
196         }
197 
198         /* Allocate memory for device */
199         ts_dev = kzalloc(sizeof(struct atmel_tsadcc), GFP_KERNEL);
200         if (!ts_dev) {
201                 dev_err(&pdev->dev, "failed to allocate memory.\n");
202                 return -ENOMEM;
203         }
204         platform_set_drvdata(pdev, ts_dev);
205 
206         input_dev = input_allocate_device();
207         if (!input_dev) {
208                 dev_err(&pdev->dev, "failed to allocate input device.\n");
209                 err = -EBUSY;
210                 goto err_free_mem;
211         }
212 
213         ts_dev->irq = platform_get_irq(pdev, 0);
214         if (ts_dev->irq < 0) {
215                 dev_err(&pdev->dev, "no irq ID is designated.\n");
216                 err = -ENODEV;
217                 goto err_free_dev;
218         }
219 
220         if (!request_mem_region(res->start, resource_size(res),
221                                 "atmel tsadcc regs")) {
222                 dev_err(&pdev->dev, "resources is unavailable.\n");
223                 err = -EBUSY;
224                 goto err_free_dev;
225         }
226 
227         tsc_base = ioremap(res->start, resource_size(res));
228         if (!tsc_base) {
229                 dev_err(&pdev->dev, "failed to map registers.\n");
230                 err = -ENOMEM;
231                 goto err_release_mem;
232         }
233 
234         err = request_irq(ts_dev->irq, atmel_tsadcc_interrupt, 0,
235                         pdev->dev.driver->name, ts_dev);
236         if (err) {
237                 dev_err(&pdev->dev, "failed to allocate irq.\n");
238                 goto err_unmap_regs;
239         }
240 
241         ts_dev->clk = clk_get(&pdev->dev, "tsc_clk");
242         if (IS_ERR(ts_dev->clk)) {
243                 dev_err(&pdev->dev, "failed to get ts_clk\n");
244                 err = PTR_ERR(ts_dev->clk);
245                 goto err_free_irq;
246         }
247 
248         ts_dev->input = input_dev;
249         ts_dev->bufferedmeasure = 0;
250 
251         snprintf(ts_dev->phys, sizeof(ts_dev->phys),
252                  "%s/input0", dev_name(&pdev->dev));
253 
254         input_dev->name = "atmel touch screen controller";
255         input_dev->phys = ts_dev->phys;
256         input_dev->dev.parent = &pdev->dev;
257 
258         __set_bit(EV_ABS, input_dev->evbit);
259         input_set_abs_params(input_dev, ABS_X, 0, 0x3FF, 0, 0);
260         input_set_abs_params(input_dev, ABS_Y, 0, 0x3FF, 0, 0);
261 
262         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
263 
264         /* clk_enable() always returns 0, no need to check it */
265         clk_enable(ts_dev->clk);
266 
267         prsc = clk_get_rate(ts_dev->clk);
268         dev_info(&pdev->dev, "Master clock is set at: %d Hz\n", prsc);
269 
270         if (!pdata->adc_clock)
271                 pdata->adc_clock = ADC_DEFAULT_CLOCK;
272 
273         prsc = (prsc / (2 * pdata->adc_clock)) - 1;
274 
275         /* saturate if this value is too high */
276         if (cpu_is_at91sam9rl()) {
277                 if (prsc > PRESCALER_VAL(ATMEL_TSADCC_PRESCAL))
278                         prsc = PRESCALER_VAL(ATMEL_TSADCC_PRESCAL);
279         } else {
280                 if (prsc > PRESCALER_VAL(ATMEL_TSADCC_EPRESCAL))
281                         prsc = PRESCALER_VAL(ATMEL_TSADCC_EPRESCAL);
282         }
283 
284         dev_info(&pdev->dev, "Prescaler is set at: %d\n", prsc);
285 
286         reg = ATMEL_TSADCC_TSAMOD_TS_ONLY_MODE          |
287                 ((0x00 << 5) & ATMEL_TSADCC_SLEEP)      |       /* Normal Mode */
288                 ((0x01 << 6) & ATMEL_TSADCC_PENDET)     |       /* Enable Pen Detect */
289                 (prsc << 8)                             |
290                 ((0x26 << 16) & ATMEL_TSADCC_STARTUP)   |
291                 ((pdata->pendet_debounce << 28) & ATMEL_TSADCC_PENDBC);
292 
293         atmel_tsadcc_write(ATMEL_TSADCC_CR, ATMEL_TSADCC_SWRST);
294         atmel_tsadcc_write(ATMEL_TSADCC_MR, reg);
295         atmel_tsadcc_write(ATMEL_TSADCC_TRGR, ATMEL_TSADCC_TRGMOD_NONE);
296         atmel_tsadcc_write(ATMEL_TSADCC_TSR,
297                 (pdata->ts_sample_hold_time << 24) & ATMEL_TSADCC_TSSHTIM);
298 
299         atmel_tsadcc_read(ATMEL_TSADCC_SR);
300         atmel_tsadcc_write(ATMEL_TSADCC_IER, ATMEL_TSADCC_PENCNT);
301 
302         /* All went ok, so register to the input system */
303         err = input_register_device(input_dev);
304         if (err)
305                 goto err_fail;
306 
307         return 0;
308 
309 err_fail:
310         clk_disable(ts_dev->clk);
311         clk_put(ts_dev->clk);
312 err_free_irq:
313         free_irq(ts_dev->irq, ts_dev);
314 err_unmap_regs:
315         iounmap(tsc_base);
316 err_release_mem:
317         release_mem_region(res->start, resource_size(res));
318 err_free_dev:
319         input_free_device(input_dev);
320 err_free_mem:
321         kfree(ts_dev);
322         return err;
323 }
324 
325 static int atmel_tsadcc_remove(struct platform_device *pdev)
326 {
327         struct atmel_tsadcc *ts_dev = platform_get_drvdata(pdev);
328         struct resource *res;
329 
330         free_irq(ts_dev->irq, ts_dev);
331 
332         input_unregister_device(ts_dev->input);
333 
334         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
335         iounmap(tsc_base);
336         release_mem_region(res->start, resource_size(res));
337 
338         clk_disable(ts_dev->clk);
339         clk_put(ts_dev->clk);
340 
341         kfree(ts_dev);
342 
343         return 0;
344 }
345 
346 static struct platform_driver atmel_tsadcc_driver = {
347         .probe          = atmel_tsadcc_probe,
348         .remove         = atmel_tsadcc_remove,
349         .driver         = {
350                 .name   = "atmel_tsadcc",
351         },
352 };
353 module_platform_driver(atmel_tsadcc_driver);
354 
355 MODULE_LICENSE("GPL");
356 MODULE_DESCRIPTION("Atmel TouchScreen Driver");
357 MODULE_AUTHOR("Dan Liang <dan.liang@atmel.com>");
358 
359 

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