drivers/mfd/ti_am335x_tscadc.c

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