drivers/mfd/ti_am335x_tscadc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * TI Touch Screen / ADC MFD driver
   4  *
   5  * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/slab.h>
  10 #include <linux/err.h>
  11 #include <linux/io.h>
  12 #include <linux/clk.h>
  13 #include <linux/regmap.h>
  14 #include <linux/mfd/core.h>
  15 #include <linux/pm_runtime.h>
  16 #include <linux/of.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/sched.h>
  19
  20 #include <linux/mfd/ti_am335x_tscadc.h>
  21
  22 static const struct regmap_config tscadc_regmap_config = {
  23         .name = "ti_tscadc",
  24         .reg_bits = 32,
  25         .reg_stride = 4,
  26         .val_bits = 32,
  27 };
  28
  29 void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tscadc, u32 val)
  30 {
  31         unsigned long flags;
  32
  33         spin_lock_irqsave(&tscadc->reg_lock, flags);
  34         tscadc->reg_se_cache |= val;
  35         if (tscadc->adc_waiting)
  36                 wake_up(&tscadc->reg_se_wait);
  37         else if (!tscadc->adc_in_use)
  38                 regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
  39
  40         spin_unlock_irqrestore(&tscadc->reg_lock, flags);
  41 }
  42 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);
  43
  44 static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tscadc)
  45 {
  46         DEFINE_WAIT(wait);
  47         u32 reg;
  48
  49         regmap_read(tscadc->regmap, REG_ADCFSM, &reg);
  50         if (reg & SEQ_STATUS) {
  51                 tscadc->adc_waiting = true;
  52                 prepare_to_wait(&tscadc->reg_se_wait, &wait,
  53                                 TASK_UNINTERRUPTIBLE);
  54                 spin_unlock_irq(&tscadc->reg_lock);
  55
  56                 schedule();
  57
  58                 spin_lock_irq(&tscadc->reg_lock);
  59                 finish_wait(&tscadc->reg_se_wait, &wait);
  60
  61                 /*
  62                  * Sequencer should either be idle or
  63                  * busy applying the charge step.
  64                  */
  65                 regmap_read(tscadc->regmap, REG_ADCFSM, &reg);
  66                 WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));
  67                 tscadc->adc_waiting = false;
  68         }
  69         tscadc->adc_in_use = true;
  70 }
  71
  72 void am335x_tsc_se_set_once(struct ti_tscadc_dev *tscadc, u32 val)
  73 {
  74         spin_lock_irq(&tscadc->reg_lock);
  75         am335x_tscadc_need_adc(tscadc);
  76
  77         regmap_write(tscadc->regmap, REG_SE, val);
  78         spin_unlock_irq(&tscadc->reg_lock);
  79 }
  80 EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);
  81
  82 void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tscadc)
  83 {
  84         unsigned long flags;
  85
  86         spin_lock_irqsave(&tscadc->reg_lock, flags);
  87         tscadc->adc_in_use = false;
  88         regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
  89         spin_unlock_irqrestore(&tscadc->reg_lock, flags);
  90 }
  91 EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);
  92
  93 void am335x_tsc_se_clr(struct ti_tscadc_dev *tscadc, u32 val)
  94 {
  95         unsigned long flags;
  96
  97         spin_lock_irqsave(&tscadc->reg_lock, flags);
  98         tscadc->reg_se_cache &= ~val;
  99         regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
 100         spin_unlock_irqrestore(&tscadc->reg_lock, flags);
 101 }
 102 EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
 103
 104 static void tscadc_idle_config(struct ti_tscadc_dev *tscadc)
 105 {
 106         unsigned int idleconfig;
 107
 108         idleconfig = STEPCONFIG_INM_ADCREFM | STEPCONFIG_INP_ADCREFM;
 109         if (ti_adc_with_touchscreen(tscadc))
 110                 idleconfig |= STEPCONFIG_YNN | STEPCONFIG_YPN;
 111
 112         regmap_write(tscadc->regmap, REG_IDLECONFIG, idleconfig);
 113 }
 114
 115 static  int ti_tscadc_probe(struct platform_device *pdev)
 116 {
 117         struct ti_tscadc_dev *tscadc;
 118         struct resource *res;
 119         struct clk *clk;
 120         struct device_node *node;
 121         struct mfd_cell *cell;
 122         bool use_tsc = false, use_mag = false;
 123         u32 val;
 124         int err;
 125         int tscmag_wires = 0, adc_channels = 0, cell_idx = 0, total_channels;
 126         int readouts = 0, mag_tracks = 0;
 127
 128         /* Allocate memory for device */
 129         tscadc = devm_kzalloc(&pdev->dev, sizeof(*tscadc), GFP_KERNEL);
 130         if (!tscadc)
 131                 return -ENOMEM;
 132
 133         tscadc->dev = &pdev->dev;
 134
 135         if (!pdev->dev.of_node) {
 136                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 137                 return -EINVAL;
 138         }
 139
 140         tscadc->data = of_device_get_match_data(&pdev->dev);
 141
 142         if (ti_adc_with_touchscreen(tscadc)) {
 143                 node = of_get_child_by_name(pdev->dev.of_node, "tsc");
 144                 of_property_read_u32(node, "ti,wires", &tscmag_wires);
 145                 err = of_property_read_u32(node, "ti,coordinate-readouts",
 146                                            &readouts);
 147                 if (err < 0)
 148                         of_property_read_u32(node, "ti,coordiante-readouts",
 149                                              &readouts);
 150
 151                 of_node_put(node);
 152
 153                 if (tscmag_wires)
 154                         use_tsc = true;
 155         } else {
 156                 /*
 157                  * When adding support for the magnetic stripe reader, here is
 158                  * the place to look for the number of tracks used from device
 159                  * tree. Let's default to 0 for now.
 160                  */
 161                 mag_tracks = 0;
 162                 tscmag_wires = mag_tracks * 2;
 163                 if (tscmag_wires)
 164                         use_mag = true;
 165         }
 166
 167         node = of_get_child_by_name(pdev->dev.of_node, "adc");
 168         of_property_for_each_u32(node, "ti,adc-channels", val) {
 169                 adc_channels++;
 170                 if (val > 7) {
 171                         dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
 172                                 val);
 173                         of_node_put(node);
 174                         return -EINVAL;
 175                 }
 176         }
 177
 178         of_node_put(node);
 179
 180         total_channels = tscmag_wires + adc_channels;
 181         if (total_channels > 8) {
 182                 dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
 183                 return -EINVAL;
 184         }
 185
 186         if (total_channels == 0) {
 187                 dev_err(&pdev->dev, "Need at least one channel.\n");
 188                 return -EINVAL;
 189         }
 190
 191         if (use_tsc && (readouts * 2 + 2 + adc_channels > 16)) {
 192                 dev_err(&pdev->dev, "Too many step configurations requested\n");
 193                 return -EINVAL;
 194         }
 195
 196         err = platform_get_irq(pdev, 0);
 197         if (err < 0)
 198                 return err;
 199         else
 200                 tscadc->irq = err;
 201
 202         tscadc->tscadc_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
 203         if (IS_ERR(tscadc->tscadc_base))
 204                 return PTR_ERR(tscadc->tscadc_base);
 205
 206         tscadc->tscadc_phys_base = res->start;
 207         tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
 208                                                tscadc->tscadc_base,
 209                                                &tscadc_regmap_config);
 210         if (IS_ERR(tscadc->regmap)) {
 211                 dev_err(&pdev->dev, "regmap init failed\n");
 212                 return PTR_ERR(tscadc->regmap);
 213         }
 214
 215         spin_lock_init(&tscadc->reg_lock);
 216         init_waitqueue_head(&tscadc->reg_se_wait);
 217
 218         pm_runtime_enable(&pdev->dev);
 219         pm_runtime_get_sync(&pdev->dev);
 220
 221         /*
 222          * The TSC_ADC_Subsystem has 2 clock domains: OCP_CLK and ADC_CLK.
 223          * ADCs produce a 12-bit sample every 15 ADC_CLK cycles.
 224          * am33xx ADCs expect to capture 200ksps.
 225          * am47xx ADCs expect to capture 867ksps.
 226          * We need ADC clocks respectively running at 3MHz and 13MHz.
 227          * These frequencies are valid since TSC_ADC_SS controller design
 228          * assumes the OCP clock is at least 6x faster than the ADC clock.
 229          */
 230         clk = devm_clk_get(&pdev->dev, NULL);
 231         if (IS_ERR(clk)) {
 232                 dev_err(&pdev->dev, "failed to get fck\n");
 233                 err = PTR_ERR(clk);
 234                 goto err_disable_clk;
 235         }
 236
 237         tscadc->clk_div = (clk_get_rate(clk) / tscadc->data->target_clk_rate) - 1;
 238         regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
 239
 240         /*
 241          * Set the control register bits. tscadc->ctrl stores the configuration
 242          * of the CTRL register but not the subsystem enable bit which must be
 243          * added manually when timely.
 244          */
 245         tscadc->ctrl = CNTRLREG_STEPID;
 246         if (ti_adc_with_touchscreen(tscadc)) {
 247                 tscadc->ctrl |= CNTRLREG_TSC_STEPCONFIGWRT;
 248                 if (use_tsc) {
 249                         tscadc->ctrl |= CNTRLREG_TSC_ENB;
 250                         if (tscmag_wires == 5)
 251                                 tscadc->ctrl |= CNTRLREG_TSC_5WIRE;
 252                         else
 253                                 tscadc->ctrl |= CNTRLREG_TSC_4WIRE;
 254                 }
 255         } else {
 256                 tscadc->ctrl |= CNTRLREG_MAG_PREAMP_PWRDOWN |
 257                                 CNTRLREG_MAG_PREAMP_BYPASS;
 258         }
 259         regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);
 260
 261         tscadc_idle_config(tscadc);
 262
 263         /* Enable the TSC module enable bit */
 264         regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);
 265
 266         /* TSC or MAG Cell */
 267         if (use_tsc || use_mag) {
 268                 cell = &tscadc->cells[cell_idx++];
 269                 cell->name = tscadc->data->secondary_feature_name;
 270                 cell->of_compatible = tscadc->data->secondary_feature_compatible;
 271                 cell->platform_data = &tscadc;
 272                 cell->pdata_size = sizeof(tscadc);
 273         }
 274
 275         /* ADC Cell */
 276         if (adc_channels > 0) {
 277                 cell = &tscadc->cells[cell_idx++];
 278                 cell->name = tscadc->data->adc_feature_name;
 279                 cell->of_compatible = tscadc->data->adc_feature_compatible;
 280                 cell->platform_data = &tscadc;
 281                 cell->pdata_size = sizeof(tscadc);
 282         }
 283
 284         err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
 285                               tscadc->cells, cell_idx, NULL, 0, NULL);
 286         if (err < 0)
 287                 goto err_disable_clk;
 288
 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
 296         return err;
 297 }
 298
 299 static void ti_tscadc_remove(struct platform_device *pdev)
 300 {
 301         struct ti_tscadc_dev *tscadc = platform_get_drvdata(pdev);
 302
 303         regmap_write(tscadc->regmap, 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
 311 static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
 312 {
 313         return device_may_wakeup(dev);
 314 }
 315
 316 static int __maybe_unused tscadc_suspend(struct device *dev)
 317 {
 318         struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
 319
 320         regmap_write(tscadc->regmap, REG_SE, 0x00);
 321         if (device_for_each_child(dev, NULL, ti_tscadc_can_wakeup)) {
 322                 u32 ctrl;
 323
 324                 regmap_read(tscadc->regmap, REG_CTRL, &ctrl);
 325                 ctrl &= ~(CNTRLREG_POWERDOWN);
 326                 ctrl |= CNTRLREG_SSENB;
 327                 regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 328         }
 329         pm_runtime_put_sync(dev);
 330
 331         return 0;
 332 }
 333
 334 static int __maybe_unused tscadc_resume(struct device *dev)
 335 {
 336         struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
 337
 338         pm_runtime_get_sync(dev);
 339
 340         regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
 341         regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);
 342         tscadc_idle_config(tscadc);
 343         regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);
 344
 345         return 0;
 346 }
 347
 348 static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);
 349
 350 static const struct ti_tscadc_data tscdata = {
 351         .adc_feature_name = "TI-am335x-adc",
 352         .adc_feature_compatible = "ti,am3359-adc",
 353         .secondary_feature_name = "TI-am335x-tsc",
 354         .secondary_feature_compatible = "ti,am3359-tsc",
 355         .target_clk_rate = TSC_ADC_CLK,
 356 };
 357
 358 static const struct ti_tscadc_data magdata = {
 359         .adc_feature_name = "TI-am43xx-adc",
 360         .adc_feature_compatible = "ti,am4372-adc",
 361         .secondary_feature_name = "TI-am43xx-mag",
 362         .secondary_feature_compatible = "ti,am4372-mag",
 363         .target_clk_rate = MAG_ADC_CLK,
 364 };
 365
 366 static const struct of_device_id ti_tscadc_dt_ids[] = {
 367         { .compatible = "ti,am3359-tscadc", .data = &tscdata },
 368         { .compatible = "ti,am4372-magadc", .data = &magdata },
 369         { }
 370 };
 371 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
 372
 373 static struct platform_driver ti_tscadc_driver = {
 374         .driver = {
 375                 .name   = "ti_am3359-tscadc",
 376                 .pm     = &tscadc_pm_ops,
 377                 .of_match_table = ti_tscadc_dt_ids,
 378         },
 379         .probe  = ti_tscadc_probe,
 380         .remove = ti_tscadc_remove,
 381
 382 };
 383
 384 module_platform_driver(ti_tscadc_driver);
 385
 386 MODULE_DESCRIPTION("TI touchscreen/magnetic stripe reader/ADC MFD controller driver");
 387 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 388 MODULE_LICENSE("GPL");