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/of_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_YNN | STEPCONFIG_INM_ADCREFM |
 109                         STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
 110
 111         regmap_write(tscadc->regmap, REG_IDLECONFIG, idleconfig);
 112 }
 113
 114 static  int ti_tscadc_probe(struct platform_device *pdev)
 115 {
 116         struct ti_tscadc_dev *tscadc;
 117         struct resource *res;
 118         struct clk *clk;
 119         struct device_node *node;
 120         struct mfd_cell *cell;
 121         struct property *prop;
 122         const __be32 *cur;
 123         u32 val;
 124         int err, ctrl;
 125         int tsc_wires = 0, adc_channels = 0, total_channels;
 126         int readouts = 0;
 127
 128         if (!pdev->dev.of_node) {
 129                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 130                 return -EINVAL;
 131         }
 132
 133         node = of_get_child_by_name(pdev->dev.of_node, "tsc");
 134         of_property_read_u32(node, "ti,wires", &tsc_wires);
 135         of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
 136         of_node_put(node);
 137
 138         node = of_get_child_by_name(pdev->dev.of_node, "adc");
 139         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
 140                 adc_channels++;
 141                 if (val > 7) {
 142                         dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
 143                                 val);
 144                         of_node_put(node);
 145                         return -EINVAL;
 146                 }
 147         }
 148
 149         of_node_put(node);
 150
 151         total_channels = tsc_wires + adc_channels;
 152         if (total_channels > 8) {
 153                 dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
 154                 return -EINVAL;
 155         }
 156
 157         if (total_channels == 0) {
 158                 dev_err(&pdev->dev, "Need atleast one channel.\n");
 159                 return -EINVAL;
 160         }
 161
 162         if (readouts * 2 + 2 + adc_channels > 16) {
 163                 dev_err(&pdev->dev, "Too many step configurations requested\n");
 164                 return -EINVAL;
 165         }
 166
 167         /* Allocate memory for device */
 168         tscadc = devm_kzalloc(&pdev->dev, sizeof(*tscadc), GFP_KERNEL);
 169         if (!tscadc)
 170                 return -ENOMEM;
 171
 172         tscadc->dev = &pdev->dev;
 173
 174         err = platform_get_irq(pdev, 0);
 175         if (err < 0)
 176                 return err;
 177         else
 178                 tscadc->irq = err;
 179
 180         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 181         tscadc->tscadc_base = devm_ioremap_resource(&pdev->dev, res);
 182         if (IS_ERR(tscadc->tscadc_base))
 183                 return PTR_ERR(tscadc->tscadc_base);
 184
 185         tscadc->tscadc_phys_base = res->start;
 186         tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
 187                                                tscadc->tscadc_base,
 188                                                &tscadc_regmap_config);
 189         if (IS_ERR(tscadc->regmap)) {
 190                 dev_err(&pdev->dev, "regmap init failed\n");
 191                 return PTR_ERR(tscadc->regmap);
 192         }
 193
 194         spin_lock_init(&tscadc->reg_lock);
 195         init_waitqueue_head(&tscadc->reg_se_wait);
 196
 197         pm_runtime_enable(&pdev->dev);
 198         pm_runtime_get_sync(&pdev->dev);
 199
 200         /*
 201          * The TSC_ADC_Subsystem has 2 clock domains: OCP_CLK and ADC_CLK.
 202          * ADCs produce a 12-bit sample every 15 ADC_CLK cycles.
 203          * am33xx ADCs expect to capture 200ksps.
 204          * We need the ADC clocks to run at 3MHz.
 205          * This frequency is valid since TSC_ADC_SS controller design
 206          * assumes the OCP clock is at least 6x faster than the ADC clock.
 207          */
 208         clk = devm_clk_get(&pdev->dev, NULL);
 209         if (IS_ERR(clk)) {
 210                 dev_err(&pdev->dev, "failed to get TSC fck\n");
 211                 err = PTR_ERR(clk);
 212                 goto err_disable_clk;
 213         }
 214
 215         tscadc->clk_div = (clk_get_rate(clk) / ADC_CLK) - 1;
 216         regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
 217
 218         /* Set the control register bits */
 219         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 220         regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 221
 222         /* Set register bits for Idle Config Mode */
 223         if (tsc_wires > 0) {
 224                 tscadc->tsc_wires = tsc_wires;
 225                 if (tsc_wires == 5)
 226                         ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
 227                 else
 228                         ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 229                 tscadc_idle_config(tscadc);
 230         }
 231
 232         /* Enable the TSC module enable bit */
 233         ctrl |= CNTRLREG_TSCSSENB;
 234         regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 235
 236         tscadc->used_cells = 0;
 237         tscadc->tsc_cell = -1;
 238         tscadc->adc_cell = -1;
 239
 240         /* TSC Cell */
 241         if (tsc_wires > 0) {
 242                 tscadc->tsc_cell = tscadc->used_cells;
 243                 cell = &tscadc->cells[tscadc->used_cells++];
 244                 cell->name = "TI-am335x-tsc";
 245                 cell->of_compatible = "ti,am3359-tsc";
 246                 cell->platform_data = &tscadc;
 247                 cell->pdata_size = sizeof(tscadc);
 248         }
 249
 250         /* ADC Cell */
 251         if (adc_channels > 0) {
 252                 tscadc->adc_cell = tscadc->used_cells;
 253                 cell = &tscadc->cells[tscadc->used_cells++];
 254                 cell->name = "TI-am335x-adc";
 255                 cell->of_compatible = "ti,am3359-adc";
 256                 cell->platform_data = &tscadc;
 257                 cell->pdata_size = sizeof(tscadc);
 258         }
 259
 260         err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
 261                               tscadc->cells, tscadc->used_cells, NULL,
 262                               0, NULL);
 263         if (err < 0)
 264                 goto err_disable_clk;
 265
 266         platform_set_drvdata(pdev, tscadc);
 267         return 0;
 268
 269 err_disable_clk:
 270         pm_runtime_put_sync(&pdev->dev);
 271         pm_runtime_disable(&pdev->dev);
 272
 273         return err;
 274 }
 275
 276 static int ti_tscadc_remove(struct platform_device *pdev)
 277 {
 278         struct ti_tscadc_dev *tscadc = platform_get_drvdata(pdev);
 279
 280         regmap_write(tscadc->regmap, REG_SE, 0x00);
 281
 282         pm_runtime_put_sync(&pdev->dev);
 283         pm_runtime_disable(&pdev->dev);
 284
 285         mfd_remove_devices(tscadc->dev);
 286
 287         return 0;
 288 }
 289
 290 static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
 291 {
 292         return device_may_wakeup(dev);
 293 }
 294
 295 static int __maybe_unused tscadc_suspend(struct device *dev)
 296 {
 297         struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
 298
 299         regmap_write(tscadc->regmap, REG_SE, 0x00);
 300         if (device_for_each_child(dev, NULL, ti_tscadc_can_wakeup)) {
 301                 u32 ctrl;
 302
 303                 regmap_read(tscadc->regmap, REG_CTRL, &ctrl);
 304                 ctrl &= ~(CNTRLREG_POWERDOWN);
 305                 ctrl |= CNTRLREG_TSCSSENB;
 306                 regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 307         }
 308         pm_runtime_put_sync(dev);
 309
 310         return 0;
 311 }
 312
 313 static int __maybe_unused tscadc_resume(struct device *dev)
 314 {
 315         struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);
 316         u32 ctrl;
 317
 318         pm_runtime_get_sync(dev);
 319
 320         /* context restore */
 321         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 322         regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 323
 324         if (tscadc->tsc_cell != -1) {
 325                 if (tscadc->tsc_wires == 5)
 326                         ctrl |= CNTRLREG_5WIRE | CNTRLREG_TSCENB;
 327                 else
 328                         ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 329                 tscadc_idle_config(tscadc);
 330         }
 331         ctrl |= CNTRLREG_TSCSSENB;
 332         regmap_write(tscadc->regmap, REG_CTRL, ctrl);
 333
 334         regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
 335
 336         return 0;
 337 }
 338
 339 static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);
 340
 341 static const struct of_device_id ti_tscadc_dt_ids[] = {
 342         { .compatible = "ti,am3359-tscadc", },
 343         { }
 344 };
 345 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
 346
 347 static struct platform_driver ti_tscadc_driver = {
 348         .driver = {
 349                 .name   = "ti_am3359-tscadc",
 350                 .pm     = &tscadc_pm_ops,
 351                 .of_match_table = ti_tscadc_dt_ids,
 352         },
 353         .probe  = ti_tscadc_probe,
 354         .remove = ti_tscadc_remove,
 355
 356 };
 357
 358 module_platform_driver(ti_tscadc_driver);
 359
 360 MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 361 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 362 MODULE_LICENSE("GPL");