drivers/mfd/ti_am335x_tscadc.c

   1 /*
   2  * TI Touch Screen / ADC MFD driver
   3  *
   4  * Copyright (C) 2012 Texas Instruments Incorporated - https://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
  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
  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, &reg);
  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, &reg);
  74                 WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));
  75                 tscadc->adc_waiting = false;
  76         }
  77         tscadc->adc_in_use = true;
  78 }
  79
  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
  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
 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
 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
 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;
 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                 return -ENOMEM;
 174
 175         tscadc->dev = &pdev->dev;
 176
 177         err = platform_get_irq(pdev, 0);
 178         if (err < 0)
 179                 goto ret;
 180         else
 181                 tscadc->irq = err;
 182
 183         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 184         tscadc->tscadc_base = devm_ioremap_resource(&pdev->dev, res);
 185         if (IS_ERR(tscadc->tscadc_base))
 186                 return PTR_ERR(tscadc->tscadc_base);
 187
 188         tscadc->tscadc_phys_base = res->start;
 189         tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
 190                         tscadc->tscadc_base, &tscadc_regmap_config);
 191         if (IS_ERR(tscadc->regmap)) {
 192                 dev_err(&pdev->dev, "regmap init failed\n");
 193                 err = PTR_ERR(tscadc->regmap);
 194                 goto ret;
 195         }
 196
 197         spin_lock_init(&tscadc->reg_lock);
 198         init_waitqueue_head(&tscadc->reg_se_wait);
 199
 200         pm_runtime_enable(&pdev->dev);
 201         pm_runtime_get_sync(&pdev->dev);
 202
 203         /*
 204          * The TSC_ADC_Subsystem has 2 clock domains
 205          * OCP_CLK and ADC_CLK.
 206          * The ADC clock is expected to run at target of 3MHz,
 207          * and expected to capture 12-bit data at a rate of 200 KSPS.
 208          * The TSC_ADC_SS controller design assumes the OCP clock is
 209          * at least 6x faster than the ADC clock.
 210          */
 211         clk = devm_clk_get(&pdev->dev, "adc_tsc_fck");
 212         if (IS_ERR(clk)) {
 213                 dev_err(&pdev->dev, "failed to get TSC fck\n");
 214                 err = PTR_ERR(clk);
 215                 goto err_disable_clk;
 216         }
 217         clock_rate = clk_get_rate(clk);
 218         tscadc->clk_div = clock_rate / ADC_CLK;
 219
 220         /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
 221         tscadc->clk_div--;
 222         regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
 223
 224         /* Set the control register bits */
 225         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 226         regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 227
 228         /* Set register bits for Idle Config Mode */
 229         if (tsc_wires > 0) {
 230                 tscadc->tsc_wires = tsc_wires;
 231                 if (tsc_wires == 5)
 232                         ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
 233                 else
 234                         ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 235                 tscadc_idle_config(tscadc);
 236         }
 237
 238         /* Enable the TSC module enable bit */
 239         ctrl |= CNTRLREG_TSCSSENB;
 240         regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 241
 242         tscadc->used_cells = 0;
 243         tscadc->tsc_cell = -1;
 244         tscadc->adc_cell = -1;
 245
 246         /* TSC Cell */
 247         if (tsc_wires > 0) {
 248                 tscadc->tsc_cell = tscadc->used_cells;
 249                 cell = &tscadc->cells[tscadc->used_cells++];
 250                 cell->name = "TI-am335x-tsc";
 251                 cell->of_compatible = "ti,am3359-tsc";
 252                 cell->platform_data = &tscadc;
 253                 cell->pdata_size = sizeof(tscadc);
 254         }
 255
 256         /* ADC Cell */
 257         if (adc_channels > 0) {
 258                 tscadc->adc_cell = tscadc->used_cells;
 259                 cell = &tscadc->cells[tscadc->used_cells++];
 260                 cell->name = "TI-am335x-adc";
 261                 cell->of_compatible = "ti,am3359-adc";
 262                 cell->platform_data = &tscadc;
 263                 cell->pdata_size = sizeof(tscadc);
 264         }
 265
 266         err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
 267                               tscadc->cells, tscadc->used_cells, NULL,
 268                               0, NULL);
 269         if (err < 0)
 270                 goto err_disable_clk;
 271
 272         platform_set_drvdata(pdev, tscadc);
 273         return 0;
 274
 275 err_disable_clk:
 276         pm_runtime_put_sync(&pdev->dev);
 277         pm_runtime_disable(&pdev->dev);
 278 ret:
 279         return err;
 280 }
 281
 282 static int ti_tscadc_remove(struct platform_device *pdev)
 283 {
 284         struct ti_tscadc_dev    *tscadc = platform_get_drvdata(pdev);
 285
 286         regmap_write(tscadc->regmap, REG_SE, 0x00);
 287
 288         pm_runtime_put_sync(&pdev->dev);
 289         pm_runtime_disable(&pdev->dev);
 290
 291         mfd_remove_devices(tscadc->dev);
 292
 293         return 0;
 294 }
 295
 296 static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
 297 {
 298         return device_may_wakeup(dev);
 299 }
 300
 301 static int __maybe_unused tscadc_suspend(struct device *dev)
 302 {
 303         struct ti_tscadc_dev    *tscadc = dev_get_drvdata(dev);
 304
 305         regmap_write(tscadc->regmap, REG_SE, 0x00);
 306         if (device_for_each_child(dev, NULL, ti_tscadc_can_wakeup)) {
 307                 u32 ctrl;
 308
 309                 regmap_read(tscadc->regmap, REG_CTRL, &ctrl);
 310                 ctrl &= ~(CNTRLREG_POWERDOWN);
 311                 ctrl |= CNTRLREG_TSCSSENB;
 312                 regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 313         }
 314         pm_runtime_put_sync(dev);
 315
 316         return 0;
 317 }
 318
 319 static int __maybe_unused tscadc_resume(struct device *dev)
 320 {
 321         struct ti_tscadc_dev    *tscadc = dev_get_drvdata(dev);
 322         u32 ctrl;
 323
 324         pm_runtime_get_sync(dev);
 325
 326         /* context restore */
 327         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 328         regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 329
 330         if (tscadc->tsc_cell != -1) {
 331                 if (tscadc->tsc_wires == 5)
 332                         ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
 333                 else
 334                         ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 335                 tscadc_idle_config(tscadc);
 336         }
 337         ctrl |= CNTRLREG_TSCSSENB;
 338         regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 339
 340         regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
 341
 342         return 0;
 343 }
 344
 345 static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);
 346
 347 static const struct of_device_id ti_tscadc_dt_ids[] = {
 348         { .compatible = "ti,am3359-tscadc", },
 349         { }
 350 };
 351 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
 352
 353 static struct platform_driver ti_tscadc_driver = {
 354         .driver = {
 355                 .name   = "ti_am3359-tscadc",
 356                 .pm     = &tscadc_pm_ops,
 357                 .of_match_table = ti_tscadc_dt_ids,
 358         },
 359         .probe  = ti_tscadc_probe,
 360         .remove = ti_tscadc_remove,
 361
 362 };
 363
 364 module_platform_driver(ti_tscadc_driver);
 365
 366 MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 367 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 368 MODULE_LICENSE("GPL");