drivers/input/touchscreen/sun4i-ts.c

   1 /*
   2  * Allwinner sunxi resistive touchscreen controller driver
   3  *
   4  * Copyright (C) 2013 - 2014 Hans de Goede <hdegoede@redhat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 /*
  18  * The sun4i-ts controller is capable of detecting a second touch, but when a
  19  * second touch is present then the accuracy becomes so bad the reported touch
  20  * location is not useable.
  21  *
  22  * The original android driver contains some complicated heuristics using the
  23  * aprox. distance between the 2 touches to see if the user is making a pinch
  24  * open / close movement, and then reports emulated multi-touch events around
  25  * the last touch coordinate (as the dual-touch coordinates are worthless).
  26  *
  27  * These kinds of heuristics are just asking for trouble (and don't belong
  28  * in the kernel). So this driver offers straight forward, reliable single
  29  * touch functionality only.
  30  */
  31
  32 #include <linux/err.h>
  33 #include <linux/init.h>
  34 #include <linux/input.h>
  35 #include <linux/interrupt.h>
  36 #include <linux/io.h>
  37 #include <linux/module.h>
  38 #include <linux/of_platform.h>
  39 #include <linux/platform_device.h>
  40 #include <linux/slab.h>
  41
  42 #define TP_CTRL0                0x00
  43 #define TP_CTRL1                0x04
  44 #define TP_CTRL2                0x08
  45 #define TP_CTRL3                0x0c
  46 #define TP_INT_FIFOC            0x10
  47 #define TP_INT_FIFOS            0x14
  48 #define TP_TPR                  0x18
  49 #define TP_CDAT                 0x1c
  50 #define TEMP_DATA               0x20
  51 #define TP_DATA                 0x24
  52
  53 /* TP_CTRL0 bits */
  54 #define ADC_FIRST_DLY(x)        ((x) << 24) /* 8 bits */
  55 #define ADC_FIRST_DLY_MODE(x)   ((x) << 23)
  56 #define ADC_CLK_SEL(x)          ((x) << 22)
  57 #define ADC_CLK_DIV(x)          ((x) << 20) /* 3 bits */
  58 #define FS_DIV(x)               ((x) << 16) /* 4 bits */
  59 #define T_ACQ(x)                ((x) << 0) /* 16 bits */
  60
  61 /* TP_CTRL1 bits */
  62 #define STYLUS_UP_DEBOUN(x)     ((x) << 12) /* 8 bits */
  63 #define STYLUS_UP_DEBOUN_EN(x)  ((x) << 9)
  64 #define TOUCH_PAN_CALI_EN(x)    ((x) << 6)
  65 #define TP_DUAL_EN(x)           ((x) << 5)
  66 #define TP_MODE_EN(x)           ((x) << 4)
  67 #define TP_ADC_SELECT(x)        ((x) << 3)
  68 #define ADC_CHAN_SELECT(x)      ((x) << 0)  /* 3 bits */
  69
  70 /* TP_CTRL2 bits */
  71 #define TP_SENSITIVE_ADJUST(x)  ((x) << 28) /* 4 bits */
  72 #define TP_MODE_SELECT(x)       ((x) << 26) /* 2 bits */
  73 #define PRE_MEA_EN(x)           ((x) << 24)
  74 #define PRE_MEA_THRE_CNT(x)     ((x) << 0) /* 24 bits */
  75
  76 /* TP_CTRL3 bits */
  77 #define FILTER_EN(x)            ((x) << 2)
  78 #define FILTER_TYPE(x)          ((x) << 0)  /* 2 bits */
  79
  80 /* TP_INT_FIFOC irq and fifo mask / control bits */
  81 #define TEMP_IRQ_EN(x)          ((x) << 18)
  82 #define OVERRUN_IRQ_EN(x)       ((x) << 17)
  83 #define DATA_IRQ_EN(x)          ((x) << 16)
  84 #define TP_DATA_XY_CHANGE(x)    ((x) << 13)
  85 #define FIFO_TRIG(x)            ((x) << 8)  /* 5 bits */
  86 #define DATA_DRQ_EN(x)          ((x) << 7)
  87 #define FIFO_FLUSH(x)           ((x) << 4)
  88 #define TP_UP_IRQ_EN(x)         ((x) << 1)
  89 #define TP_DOWN_IRQ_EN(x)       ((x) << 0)
  90
  91 /* TP_INT_FIFOS irq and fifo status bits */
  92 #define TEMP_DATA_PENDING       BIT(18)
  93 #define FIFO_OVERRUN_PENDING    BIT(17)
  94 #define FIFO_DATA_PENDING       BIT(16)
  95 #define TP_IDLE_FLG             BIT(2)
  96 #define TP_UP_PENDING           BIT(1)
  97 #define TP_DOWN_PENDING         BIT(0)
  98
  99 /* TP_TPR bits */
 100 #define TEMP_ENABLE(x)          ((x) << 16)
 101 #define TEMP_PERIOD(x)          ((x) << 0)  /* t = x * 256 * 16 / clkin */
 102
 103 struct sun4i_ts_data {
 104         struct device *dev;
 105         struct input_dev *input;
 106         void __iomem *base;
 107         unsigned int irq;
 108         bool ignore_fifo_data;
 109 };
 110
 111 static irqreturn_t sun4i_ts_irq(int irq, void *dev_id)
 112 {
 113         struct sun4i_ts_data *ts = dev_id;
 114         u32 reg_val, x, y;
 115
 116         reg_val  = readl(ts->base + TP_INT_FIFOS);
 117
 118         if (reg_val & FIFO_DATA_PENDING) {
 119                 x = readl(ts->base + TP_DATA);
 120                 y = readl(ts->base + TP_DATA);
 121                 /* The 1st location reported after an up event is unreliable */
 122                 if (!ts->ignore_fifo_data) {
 123                         input_report_abs(ts->input, ABS_X, x);
 124                         input_report_abs(ts->input, ABS_Y, y);
 125                         /*
 126                          * The hardware has a separate down status bit, but
 127                          * that gets set before we get the first location,
 128                          * resulting in reporting a click on the old location.
 129                          */
 130                         input_report_key(ts->input, BTN_TOUCH, 1);
 131                         input_sync(ts->input);
 132                 } else {
 133                         ts->ignore_fifo_data = false;
 134                 }
 135         }
 136
 137         if (reg_val & TP_UP_PENDING) {
 138                 ts->ignore_fifo_data = true;
 139                 input_report_key(ts->input, BTN_TOUCH, 0);
 140                 input_sync(ts->input);
 141         }
 142
 143         writel(reg_val, ts->base + TP_INT_FIFOS);
 144
 145         return IRQ_HANDLED;
 146 }
 147
 148 static int sun4i_ts_open(struct input_dev *dev)
 149 {
 150         struct sun4i_ts_data *ts = input_get_drvdata(dev);
 151
 152         /* Flush, set trig level to 1, enable data and up irqs */
 153         writel(DATA_IRQ_EN(1) | FIFO_TRIG(1) | FIFO_FLUSH(1) | TP_UP_IRQ_EN(1),
 154                ts->base + TP_INT_FIFOC);
 155
 156         return 0;
 157 }
 158
 159 static void sun4i_ts_close(struct input_dev *dev)
 160 {
 161         struct sun4i_ts_data *ts = input_get_drvdata(dev);
 162
 163         /* Deactivate all IRQs */
 164         writel(0, ts->base + TP_INT_FIFOC);
 165 }
 166
 167 static int sun4i_ts_probe(struct platform_device *pdev)
 168 {
 169         struct sun4i_ts_data *ts;
 170         struct device *dev = &pdev->dev;
 171         int error;
 172
 173         ts = devm_kzalloc(dev, sizeof(struct sun4i_ts_data), GFP_KERNEL);
 174         if (!ts)
 175                 return -ENOMEM;
 176
 177         ts->dev = dev;
 178         ts->ignore_fifo_data = true;
 179
 180         ts->input = devm_input_allocate_device(dev);
 181         if (!ts->input)
 182                 return -ENOMEM;
 183
 184         ts->input->name = pdev->name;
 185         ts->input->phys = "sun4i_ts/input0";
 186         ts->input->open = sun4i_ts_open;
 187         ts->input->close = sun4i_ts_close;
 188         ts->input->id.bustype = BUS_HOST;
 189         ts->input->id.vendor = 0x0001;
 190         ts->input->id.product = 0x0001;
 191         ts->input->id.version = 0x0100;
 192         ts->input->evbit[0] =  BIT(EV_SYN) | BIT(EV_KEY) | BIT(EV_ABS);
 193         __set_bit(BTN_TOUCH, ts->input->keybit);
 194         input_set_abs_params(ts->input, ABS_X, 0, 4095, 0, 0);
 195         input_set_abs_params(ts->input, ABS_Y, 0, 4095, 0, 0);
 196         input_set_drvdata(ts->input, ts);
 197
 198         ts->base = devm_ioremap_resource(dev,
 199                               platform_get_resource(pdev, IORESOURCE_MEM, 0));
 200         if (IS_ERR(ts->base))
 201                 return PTR_ERR(ts->base);
 202
 203         ts->irq = platform_get_irq(pdev, 0);
 204         error = devm_request_irq(dev, ts->irq, sun4i_ts_irq, 0, "sun4i-ts", ts);
 205         if (error)
 206                 return error;
 207
 208         /*
 209          * Select HOSC clk, clkin = clk / 6, adc samplefreq = clkin / 8192,
 210          * t_acq = clkin / (16 * 64)
 211          */
 212         writel(ADC_CLK_SEL(0) | ADC_CLK_DIV(2) | FS_DIV(7) | T_ACQ(63),
 213                ts->base + TP_CTRL0);
 214
 215         /*
 216          * sensitive_adjust = 15 : max, which is not all that sensitive,
 217          * tp_mode = 0 : only x and y coordinates, as we don't use dual touch
 218          */
 219         writel(TP_SENSITIVE_ADJUST(15) | TP_MODE_SELECT(0),
 220                ts->base + TP_CTRL2);
 221
 222         /* Enable median filter, type 1 : 5/3 */
 223         writel(FILTER_EN(1) | FILTER_TYPE(1), ts->base + TP_CTRL3);
 224
 225         /* Enable temperature measurement, period 1953 (2 seconds) */
 226         writel(TEMP_ENABLE(1) | TEMP_PERIOD(1953), ts->base + TP_TPR);
 227
 228         /*
 229          * Set stylus up debounce to aprox 10 ms, enable debounce, and
 230          * finally enable tp mode.
 231          */
 232         writel(STYLUS_UP_DEBOUN(5) | STYLUS_UP_DEBOUN_EN(1) | TP_MODE_EN(1),
 233                ts->base + TP_CTRL1);
 234
 235         error = input_register_device(ts->input);
 236         if (error)
 237                 return error;
 238
 239         platform_set_drvdata(pdev, ts);
 240         return 0;
 241 }
 242
 243 static const struct of_device_id sun4i_ts_of_match[] = {
 244         { .compatible = "allwinner,sun4i-a10-ts", },
 245         { /* sentinel */ }
 246 };
 247 MODULE_DEVICE_TABLE(of, sun4i_ts_of_match);
 248
 249 static struct platform_driver sun4i_ts_driver = {
 250         .driver = {
 251                 .owner  = THIS_MODULE,
 252                 .name   = "sun4i-ts",
 253                 .of_match_table = of_match_ptr(sun4i_ts_of_match),
 254         },
 255         .probe  = sun4i_ts_probe,
 256 };
 257
 258 module_platform_driver(sun4i_ts_driver);
 259
 260 MODULE_DESCRIPTION("Allwinner sun4i resistive touchscreen controller driver");
 261 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 262 MODULE_LICENSE("GPL");