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 unsigned int tscadc_readl(struct ti_tscadc_dev *tsadc, unsigned int reg)
  31 {
  32         unsigned int val;
  33
  34         regmap_read(tsadc->regmap_tscadc, reg, &val);
  35         return val;
  36 }
  37
  38 static void tscadc_writel(struct ti_tscadc_dev *tsadc, unsigned int reg,
  39                                         unsigned int val)
  40 {
  41         regmap_write(tsadc->regmap_tscadc, reg, val);
  42 }
  43
  44 static const struct regmap_config tscadc_regmap_config = {
  45         .name = "ti_tscadc",
  46         .reg_bits = 32,
  47         .reg_stride = 4,
  48         .val_bits = 32,
  49 };
  50
  51 void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tsadc, u32 val)
  52 {
  53         unsigned long flags;
  54
  55         spin_lock_irqsave(&tsadc->reg_lock, flags);
  56         tsadc->reg_se_cache |= val;
  57         if (tsadc->adc_waiting)
  58                 wake_up(&tsadc->reg_se_wait);
  59         else if (!tsadc->adc_in_use)
  60                 tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
  61
  62         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
  63 }
  64 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);
  65
  66 static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tsadc)
  67 {
  68         DEFINE_WAIT(wait);
  69         u32 reg;
  70
  71         reg = tscadc_readl(tsadc, REG_ADCFSM);
  72         if (reg & SEQ_STATUS) {
  73                 tsadc->adc_waiting = true;
  74                 prepare_to_wait(&tsadc->reg_se_wait, &wait,
  75                                 TASK_UNINTERRUPTIBLE);
  76                 spin_unlock_irq(&tsadc->reg_lock);
  77
  78                 schedule();
  79
  80                 spin_lock_irq(&tsadc->reg_lock);
  81                 finish_wait(&tsadc->reg_se_wait, &wait);
  82
  83                 /*
  84                  * Sequencer should either be idle or
  85                  * busy applying the charge step.
  86                  */
  87                 reg = tscadc_readl(tsadc, REG_ADCFSM);
  88                 WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));
  89                 tsadc->adc_waiting = false;
  90         }
  91         tsadc->adc_in_use = true;
  92 }
  93
  94 void am335x_tsc_se_set_once(struct ti_tscadc_dev *tsadc, u32 val)
  95 {
  96         spin_lock_irq(&tsadc->reg_lock);
  97         am335x_tscadc_need_adc(tsadc);
  98
  99         tscadc_writel(tsadc, REG_SE, val);
 100         spin_unlock_irq(&tsadc->reg_lock);
 101 }
 102 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);
 103
 104 void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tsadc)
 105 {
 106         unsigned long flags;
 107
 108         spin_lock_irqsave(&tsadc->reg_lock, flags);
 109         tsadc->adc_in_use = false;
 110         tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
 111         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
 112 }
 113 EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);
 114
 115 void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val)
 116 {
 117         unsigned long flags;
 118
 119         spin_lock_irqsave(&tsadc->reg_lock, flags);
 120         tsadc->reg_se_cache &= ~val;
 121         tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
 122         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
 123 }
 124 EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
 125
 126 static void tscadc_idle_config(struct ti_tscadc_dev *config)
 127 {
 128         unsigned int idleconfig;
 129
 130         idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
 131                         STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
 132
 133         tscadc_writel(config, REG_IDLECONFIG, idleconfig);
 134 }
 135
 136 static  int ti_tscadc_probe(struct platform_device *pdev)
 137 {
 138         struct ti_tscadc_dev    *tscadc;
 139         struct resource         *res;
 140         struct clk              *clk;
 141         struct device_node      *node = pdev->dev.of_node;
 142         struct mfd_cell         *cell;
 143         struct property         *prop;
 144         const __be32            *cur;
 145         u32                     val;
 146         int                     err, ctrl;
 147         int                     clock_rate;
 148         int                     tsc_wires = 0, adc_channels = 0, total_channels;
 149         int                     readouts = 0;
 150
 151         if (!pdev->dev.of_node) {
 152                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 153                 return -EINVAL;
 154         }
 155
 156         node = of_get_child_by_name(pdev->dev.of_node, "tsc");
 157         of_property_read_u32(node, "ti,wires", &tsc_wires);
 158         of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
 159
 160         node = of_get_child_by_name(pdev->dev.of_node, "adc");
 161         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
 162                 adc_channels++;
 163                 if (val > 7) {
 164                         dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
 165                                         val);
 166                         return -EINVAL;
 167                 }
 168         }
 169         total_channels = tsc_wires + adc_channels;
 170         if (total_channels > 8) {
 171                 dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
 172                 return -EINVAL;
 173         }
 174         if (total_channels == 0) {
 175                 dev_err(&pdev->dev, "Need atleast one channel.\n");
 176                 return -EINVAL;
 177         }
 178
 179         if (readouts * 2 + 2 + adc_channels > 16) {
 180                 dev_err(&pdev->dev, "Too many step configurations requested\n");
 181                 return -EINVAL;
 182         }
 183
 184         /* Allocate memory for device */
 185         tscadc = devm_kzalloc(&pdev->dev,
 186                         sizeof(struct ti_tscadc_dev), GFP_KERNEL);
 187         if (!tscadc) {
 188                 dev_err(&pdev->dev, "failed to allocate memory.\n");
 189                 return -ENOMEM;
 190         }
 191         tscadc->dev = &pdev->dev;
 192
 193         err = platform_get_irq(pdev, 0);
 194         if (err < 0) {
 195                 dev_err(&pdev->dev, "no irq ID is specified.\n");
 196                 goto ret;
 197         } else
 198                 tscadc->irq = err;
 199
 200         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 201         tscadc->tscadc_base = devm_ioremap_resource(&pdev->dev, res);
 202         if (IS_ERR(tscadc->tscadc_base))
 203                 return PTR_ERR(tscadc->tscadc_base);
 204
 205         tscadc->regmap_tscadc = devm_regmap_init_mmio(&pdev->dev,
 206                         tscadc->tscadc_base, &tscadc_regmap_config);
 207         if (IS_ERR(tscadc->regmap_tscadc)) {
 208                 dev_err(&pdev->dev, "regmap init failed\n");
 209                 err = PTR_ERR(tscadc->regmap_tscadc);
 210                 goto ret;
 211         }
 212
 213         spin_lock_init(&tscadc->reg_lock);
 214         init_waitqueue_head(&tscadc->reg_se_wait);
 215
 216         pm_runtime_enable(&pdev->dev);
 217         pm_runtime_get_sync(&pdev->dev);
 218
 219         /*
 220          * The TSC_ADC_Subsystem has 2 clock domains
 221          * OCP_CLK and ADC_CLK.
 222          * The ADC clock is expected to run at target of 3MHz,
 223          * and expected to capture 12-bit data at a rate of 200 KSPS.
 224          * The TSC_ADC_SS controller design assumes the OCP clock is
 225          * at least 6x faster than the ADC clock.
 226          */
 227         clk = clk_get(&pdev->dev, "adc_tsc_fck");
 228         if (IS_ERR(clk)) {
 229                 dev_err(&pdev->dev, "failed to get TSC fck\n");
 230                 err = PTR_ERR(clk);
 231                 goto err_disable_clk;
 232         }
 233         clock_rate = clk_get_rate(clk);
 234         clk_put(clk);
 235         tscadc->clk_div = clock_rate / ADC_CLK;
 236
 237         /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
 238         tscadc->clk_div--;
 239         tscadc_writel(tscadc, REG_CLKDIV, tscadc->clk_div);
 240
 241         /* Set the control register bits */
 242         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 243         tscadc_writel(tscadc, REG_CTRL, ctrl);
 244
 245         /* Set register bits for Idle Config Mode */
 246         if (tsc_wires > 0) {
 247                 tscadc->tsc_wires = tsc_wires;
 248                 if (tsc_wires == 5)
 249                         ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
 250                 else
 251                         ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 252                 tscadc_idle_config(tscadc);
 253         }
 254
 255         /* Enable the TSC module enable bit */
 256         ctrl |= CNTRLREG_TSCSSENB;
 257         tscadc_writel(tscadc, REG_CTRL, ctrl);
 258
 259         tscadc->used_cells = 0;
 260         tscadc->tsc_cell = -1;
 261         tscadc->adc_cell = -1;
 262
 263         /* TSC Cell */
 264         if (tsc_wires > 0) {
 265                 tscadc->tsc_cell = tscadc->used_cells;
 266                 cell = &tscadc->cells[tscadc->used_cells++];
 267                 cell->name = "TI-am335x-tsc";
 268                 cell->of_compatible = "ti,am3359-tsc";
 269                 cell->platform_data = &tscadc;
 270                 cell->pdata_size = sizeof(tscadc);
 271         }
 272
 273         /* ADC Cell */
 274         if (adc_channels > 0) {
 275                 tscadc->adc_cell = tscadc->used_cells;
 276                 cell = &tscadc->cells[tscadc->used_cells++];
 277                 cell->name = "TI-am335x-adc";
 278                 cell->of_compatible = "ti,am3359-adc";
 279                 cell->platform_data = &tscadc;
 280                 cell->pdata_size = sizeof(tscadc);
 281         }
 282
 283         err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
 284                         tscadc->used_cells, NULL, 0, NULL);
 285         if (err < 0)
 286                 goto err_disable_clk;
 287
 288         device_init_wakeup(&pdev->dev, true);
 289         platform_set_drvdata(pdev, tscadc);
 290         return 0;
 291
 292 err_disable_clk:
 293         pm_runtime_put_sync(&pdev->dev);
 294         pm_runtime_disable(&pdev->dev);
 295 ret:
 296         return err;
 297 }
 298
 299 static int ti_tscadc_remove(struct platform_device *pdev)
 300 {
 301         struct ti_tscadc_dev    *tscadc = platform_get_drvdata(pdev);
 302
 303         tscadc_writel(tscadc, REG_SE, 0x00);
 304
 305         pm_runtime_put_sync(&pdev->dev);
 306         pm_runtime_disable(&pdev->dev);
 307
 308         mfd_remove_devices(tscadc->dev);
 309
 310         return 0;
 311 }
 312
 313 #ifdef CONFIG_PM
 314 static int tscadc_suspend(struct device *dev)
 315 {
 316         struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 317
 318         tscadc_writel(tscadc_dev, REG_SE, 0x00);
 319         pm_runtime_put_sync(dev);
 320
 321         return 0;
 322 }
 323
 324 static int tscadc_resume(struct device *dev)
 325 {
 326         struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 327         u32 ctrl;
 328
 329         pm_runtime_get_sync(dev);
 330
 331         /* context restore */
 332         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 333         tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
 334
 335         if (tscadc_dev->tsc_cell != -1) {
 336                 if (tscadc_dev->tsc_wires == 5)
 337                         ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
 338                 else
 339                         ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 340                 tscadc_idle_config(tscadc_dev);
 341         }
 342         ctrl |= CNTRLREG_TSCSSENB;
 343         tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
 344
 345         tscadc_writel(tscadc_dev, REG_CLKDIV, tscadc_dev->clk_div);
 346
 347         return 0;
 348 }
 349
 350 static const struct dev_pm_ops tscadc_pm_ops = {
 351         .suspend = tscadc_suspend,
 352         .resume = tscadc_resume,
 353 };
 354 #define TSCADC_PM_OPS (&tscadc_pm_ops)
 355 #else
 356 #define TSCADC_PM_OPS NULL
 357 #endif
 358
 359 static const struct of_device_id ti_tscadc_dt_ids[] = {
 360         { .compatible = "ti,am3359-tscadc", },
 361         { }
 362 };
 363 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
 364
 365 static struct platform_driver ti_tscadc_driver = {
 366         .driver = {
 367                 .name   = "ti_am3359-tscadc",
 368                 .pm     = TSCADC_PM_OPS,
 369                 .of_match_table = ti_tscadc_dt_ids,
 370         },
 371         .probe  = ti_tscadc_probe,
 372         .remove = ti_tscadc_remove,
 373
 374 };
 375
 376 module_platform_driver(ti_tscadc_driver);
 377
 378 MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 379 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 380 MODULE_LICENSE("GPL");