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/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/err.h>
  20 #include <linux/io.h>
  21 #include <linux/clk.h>
  22 #include <linux/regmap.h>
  23 #include <linux/mfd/core.h>
  24 #include <linux/pm_runtime.h>
  25 #include <linux/of.h>
  26 #include <linux/of_device.h>
  27 #include <linux/sched.h>
  28
  29 #include <linux/mfd/ti_am335x_tscadc.h>
  30
  31 static unsigned int tscadc_readl(struct ti_tscadc_dev *tsadc, unsigned int reg)
  32 {
  33         unsigned int val;
  34
  35         regmap_read(tsadc->regmap_tscadc, reg, &val);
  36         return val;
  37 }
  38
  39 static void tscadc_writel(struct ti_tscadc_dev *tsadc, unsigned int reg,
  40                                         unsigned int val)
  41 {
  42         regmap_write(tsadc->regmap_tscadc, reg, val);
  43 }
  44
  45 static const struct regmap_config tscadc_regmap_config = {
  46         .name = "ti_tscadc",
  47         .reg_bits = 32,
  48         .reg_stride = 4,
  49         .val_bits = 32,
  50 };
  51
  52 void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tsadc, u32 val)
  53 {
  54         unsigned long flags;
  55
  56         spin_lock_irqsave(&tsadc->reg_lock, flags);
  57         tsadc->reg_se_cache |= val;
  58         if (tsadc->adc_waiting)
  59                 wake_up(&tsadc->reg_se_wait);
  60         else if (!tsadc->adc_in_use)
  61                 tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
  62
  63         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
  64 }
  65 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);
  66
  67 static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
  68 {
  69         DEFINE_WAIT(wait);
  70         u32 reg;
  71
  72         /*
  73          * disable TSC steps so it does not run while the ADC is using it. If
  74          * write 0 while it is running (it just started or was already running)
  75          * then it completes all steps that were enabled and stops then.
  76          */
  77         tscadc_writel(tsadc, REG_SE, 0);
  78         reg = tscadc_readl(tsadc, REG_ADCFSM);
  79         if (reg & SEQ_STATUS) {
  80                 tsadc->adc_waiting = true;
  81                 prepare_to_wait(&tsadc->reg_se_wait, &wait,
  82                                 TASK_UNINTERRUPTIBLE);
  83                 spin_unlock_irq(&tsadc->reg_lock);
  84
  85                 schedule();
  86
  87                 spin_lock_irq(&tsadc->reg_lock);
  88                 finish_wait(&tsadc->reg_se_wait, &wait);
  89
  90                 reg = tscadc_readl(tsadc, REG_ADCFSM);
  91                 WARN_ON(reg & SEQ_STATUS);
  92                 tsadc->adc_waiting = false;
  93         }
  94         tsadc->adc_in_use = true;
  95 }
  96
  97 void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val)
  98 {
  99         spin_lock_irq(&tsadc->reg_lock);
 100         tsadc->reg_se_cache |= val;
 101         am335x_tscadc_need_adc(tsadc);
 102
 103         tscadc_writel(tsadc, REG_SE, val);
 104         spin_unlock_irq(&tsadc->reg_lock);
 105 }
 106 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);
 107
 108 void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tsadc)
 109 {
 110         unsigned long flags;
 111
 112         spin_lock_irqsave(&tsadc->reg_lock, flags);
 113         tsadc->adc_in_use = false;
 114         tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
 115         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
 116 }
 117 EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);
 118
 119 void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val)
 120 {
 121         unsigned long flags;
 122
 123         spin_lock_irqsave(&tsadc->reg_lock, flags);
 124         tsadc->reg_se_cache &= ~val;
 125         tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
 126         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
 127 }
 128 EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
 129
 130 static void tscadc_idle_config(struct ti_tscadc_dev *config)
 131 {
 132         unsigned int idleconfig;
 133
 134         idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
 135                         STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
 136
 137         tscadc_writel(config, REG_IDLECONFIG, idleconfig);
 138 }
 139
 140 static  int ti_tscadc_probe(struct platform_device *pdev)
 141 {
 142         struct ti_tscadc_dev    *tscadc;
 143         struct resource         *res;
 144         struct clk              *clk;
 145         struct device_node      *node = pdev->dev.of_node;
 146         struct mfd_cell         *cell;
 147         struct property         *prop;
 148         const __be32            *cur;
 149         u32                     val;
 150         int                     err, ctrl;
 151         int                     clock_rate;
 152         int                     tsc_wires = 0, adc_channels = 0, total_channels;
 153         int                     readouts = 0;
 154
 155         if (!pdev->dev.of_node) {
 156                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 157                 return -EINVAL;
 158         }
 159
 160         node = of_get_child_by_name(pdev->dev.of_node, "tsc");
 161         of_property_read_u32(node, "ti,wires", &tsc_wires);
 162         of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
 163
 164         node = of_get_child_by_name(pdev->dev.of_node, "adc");
 165         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
 166                 adc_channels++;
 167                 if (val > 7) {
 168                         dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
 169                                         val);
 170                         return -EINVAL;
 171                 }
 172         }
 173         total_channels = tsc_wires + adc_channels;
 174         if (total_channels > 8) {
 175                 dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
 176                 return -EINVAL;
 177         }
 178         if (total_channels == 0) {
 179                 dev_err(&pdev->dev, "Need atleast one channel.\n");
 180                 return -EINVAL;
 181         }
 182
 183         if (readouts * 2 + 2 + adc_channels > 16) {
 184                 dev_err(&pdev->dev, "Too many step configurations requested\n");
 185                 return -EINVAL;
 186         }
 187
 188         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 189         if (!res) {
 190                 dev_err(&pdev->dev, "no memory resource defined.\n");
 191                 return -EINVAL;
 192         }
 193
 194         /* Allocate memory for device */
 195         tscadc = devm_kzalloc(&pdev->dev,
 196                         sizeof(struct ti_tscadc_dev), GFP_KERNEL);
 197         if (!tscadc) {
 198                 dev_err(&pdev->dev, "failed to allocate memory.\n");
 199                 return -ENOMEM;
 200         }
 201         tscadc->dev = &pdev->dev;
 202
 203         err = platform_get_irq(pdev, 0);
 204         if (err < 0) {
 205                 dev_err(&pdev->dev, "no irq ID is specified.\n");
 206                 goto ret;
 207         } else
 208                 tscadc->irq = err;
 209
 210         res = devm_request_mem_region(&pdev->dev,
 211                         res->start, resource_size(res), pdev->name);
 212         if (!res) {
 213                 dev_err(&pdev->dev, "failed to reserve registers.\n");
 214                 return -EBUSY;
 215         }
 216
 217         tscadc->tscadc_base = devm_ioremap(&pdev->dev,
 218                         res->start, resource_size(res));
 219         if (!tscadc->tscadc_base) {
 220                 dev_err(&pdev->dev, "failed to map registers.\n");
 221                 return -ENOMEM;
 222         }
 223
 224         tscadc->regmap_tscadc = devm_regmap_init_mmio(&pdev->dev,
 225                         tscadc->tscadc_base, &tscadc_regmap_config);
 226         if (IS_ERR(tscadc->regmap_tscadc)) {
 227                 dev_err(&pdev->dev, "regmap init failed\n");
 228                 err = PTR_ERR(tscadc->regmap_tscadc);
 229                 goto ret;
 230         }
 231
 232         spin_lock_init(&tscadc->reg_lock);
 233         init_waitqueue_head(&tscadc->reg_se_wait);
 234
 235         pm_runtime_enable(&pdev->dev);
 236         pm_runtime_get_sync(&pdev->dev);
 237
 238         /*
 239          * The TSC_ADC_Subsystem has 2 clock domains
 240          * OCP_CLK and ADC_CLK.
 241          * The ADC clock is expected to run at target of 3MHz,
 242          * and expected to capture 12-bit data at a rate of 200 KSPS.
 243          * The TSC_ADC_SS controller design assumes the OCP clock is
 244          * at least 6x faster than the ADC clock.
 245          */
 246         clk = clk_get(&pdev->dev, "adc_tsc_fck");
 247         if (IS_ERR(clk)) {
 248                 dev_err(&pdev->dev, "failed to get TSC fck\n");
 249                 err = PTR_ERR(clk);
 250                 goto err_disable_clk;
 251         }
 252         clock_rate = clk_get_rate(clk);
 253         clk_put(clk);
 254         tscadc->clk_div = clock_rate / ADC_CLK;
 255
 256         /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
 257         tscadc->clk_div--;
 258         tscadc_writel(tscadc, REG_CLKDIV, tscadc->clk_div);
 259
 260         /* Set the control register bits */
 261         ctrl = CNTRLREG_STEPCONFIGWRT |
 262                         CNTRLREG_STEPID;
 263         if (tsc_wires > 0)
 264                 ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 265         tscadc_writel(tscadc, REG_CTRL, ctrl);
 266
 267         /* Set register bits for Idle Config Mode */
 268         if (tsc_wires > 0)
 269                 tscadc_idle_config(tscadc);
 270
 271         /* Enable the TSC module enable bit */
 272         ctrl = tscadc_readl(tscadc, REG_CTRL);
 273         ctrl |= CNTRLREG_TSCSSENB;
 274         tscadc_writel(tscadc, REG_CTRL, ctrl);
 275
 276         tscadc->used_cells = 0;
 277         tscadc->tsc_cell = -1;
 278         tscadc->adc_cell = -1;
 279
 280         /* TSC Cell */
 281         if (tsc_wires > 0) {
 282                 tscadc->tsc_cell = tscadc->used_cells;
 283                 cell = &tscadc->cells[tscadc->used_cells++];
 284                 cell->name = "TI-am335x-tsc";
 285                 cell->of_compatible = "ti,am3359-tsc";
 286                 cell->platform_data = &tscadc;
 287                 cell->pdata_size = sizeof(tscadc);
 288         }
 289
 290         /* ADC Cell */
 291         if (adc_channels > 0) {
 292                 tscadc->adc_cell = tscadc->used_cells;
 293                 cell = &tscadc->cells[tscadc->used_cells++];
 294                 cell->name = "TI-am335x-adc";
 295                 cell->of_compatible = "ti,am3359-adc";
 296                 cell->platform_data = &tscadc;
 297                 cell->pdata_size = sizeof(tscadc);
 298         }
 299
 300         err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
 301                         tscadc->used_cells, NULL, 0, NULL);
 302         if (err < 0)
 303                 goto err_disable_clk;
 304
 305         device_init_wakeup(&pdev->dev, true);
 306         platform_set_drvdata(pdev, tscadc);
 307         return 0;
 308
 309 err_disable_clk:
 310         pm_runtime_put_sync(&pdev->dev);
 311         pm_runtime_disable(&pdev->dev);
 312 ret:
 313         return err;
 314 }
 315
 316 static int ti_tscadc_remove(struct platform_device *pdev)
 317 {
 318         struct ti_tscadc_dev    *tscadc = platform_get_drvdata(pdev);
 319
 320         tscadc_writel(tscadc, REG_SE, 0x00);
 321
 322         pm_runtime_put_sync(&pdev->dev);
 323         pm_runtime_disable(&pdev->dev);
 324
 325         mfd_remove_devices(tscadc->dev);
 326
 327         return 0;
 328 }
 329
 330 #ifdef CONFIG_PM
 331 static int tscadc_suspend(struct device *dev)
 332 {
 333         struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 334
 335         tscadc_writel(tscadc_dev, REG_SE, 0x00);
 336         pm_runtime_put_sync(dev);
 337
 338         return 0;
 339 }
 340
 341 static int tscadc_resume(struct device *dev)
 342 {
 343         struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 344         unsigned int restore, ctrl;
 345
 346         pm_runtime_get_sync(dev);
 347
 348         /* context restore */
 349         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 350         if (tscadc_dev->tsc_cell != -1)
 351                 ctrl |= CNTRLREG_TSCENB | CNTRLREG_4WIRE;
 352         tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
 353
 354         if (tscadc_dev->tsc_cell != -1)
 355                 tscadc_idle_config(tscadc_dev);
 356         restore = tscadc_readl(tscadc_dev, REG_CTRL);
 357         tscadc_writel(tscadc_dev, REG_CTRL,
 358                         (restore | CNTRLREG_TSCSSENB));
 359
 360         tscadc_writel(tscadc_dev, REG_CLKDIV, tscadc_dev->clk_div);
 361
 362         return 0;
 363 }
 364
 365 static const struct dev_pm_ops tscadc_pm_ops = {
 366         .suspend = tscadc_suspend,
 367         .resume = tscadc_resume,
 368 };
 369 #define TSCADC_PM_OPS (&tscadc_pm_ops)
 370 #else
 371 #define TSCADC_PM_OPS NULL
 372 #endif
 373
 374 static const struct of_device_id ti_tscadc_dt_ids[] = {
 375         { .compatible = "ti,am3359-tscadc", },
 376         { }
 377 };
 378 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
 379
 380 static struct platform_driver ti_tscadc_driver = {
 381         .driver = {
 382                 .name   = "ti_am3359-tscadc",
 383                 .owner  = THIS_MODULE,
 384                 .pm     = TSCADC_PM_OPS,
 385                 .of_match_table = ti_tscadc_dt_ids,
 386         },
 387         .probe  = ti_tscadc_probe,
 388         .remove = ti_tscadc_remove,
 389
 390 };
 391
 392 module_platform_driver(ti_tscadc_driver);
 393
 394 MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 395 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 396 MODULE_LICENSE("GPL");