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