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
  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_update(struct ti_tscadc_dev *tsadc)
  52 {
  53         tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
  54 }
  55 EXPORT_SYMBOL_GPL(am335x_tsc_se_update);
  56
  57 void am335x_tsc_se_set(struct ti_tscadc_dev *tsadc, u32 val)
  58 {
  59         unsigned long flags;
  60
  61         spin_lock_irqsave(&tsadc->reg_lock, flags);
  62         tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE);
  63         tsadc->reg_se_cache |= val;
  64         am335x_tsc_se_update(tsadc);
  65         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
  66 }
  67 EXPORT_SYMBOL_GPL(am335x_tsc_se_set);
  68
  69 void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val)
  70 {
  71         unsigned long flags;
  72
  73         spin_lock_irqsave(&tsadc->reg_lock, flags);
  74         tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE);
  75         tsadc->reg_se_cache &= ~val;
  76         am335x_tsc_se_update(tsadc);
  77         spin_unlock_irqrestore(&tsadc->reg_lock, flags);
  78 }
  79 EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
  80
  81 static void tscadc_idle_config(struct ti_tscadc_dev *config)
  82 {
  83         unsigned int idleconfig;
  84
  85         idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
  86                         STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
  87
  88         tscadc_writel(config, REG_IDLECONFIG, idleconfig);
  89 }
  90
  91 static  int ti_tscadc_probe(struct platform_device *pdev)
  92 {
  93         struct ti_tscadc_dev    *tscadc;
  94         struct resource         *res;
  95         struct clk              *clk;
  96         struct device_node      *node = pdev->dev.of_node;
  97         struct mfd_cell         *cell;
  98         struct property         *prop;
  99         const __be32            *cur;
 100         u32                     val;
 101         int                     err, ctrl;
 102         int                     clock_rate;
 103         int                     tsc_wires = 0, adc_channels = 0, total_channels;
 104         int                     readouts = 0;
 105
 106         if (!pdev->dev.of_node) {
 107                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 108                 return -EINVAL;
 109         }
 110
 111         node = of_get_child_by_name(pdev->dev.of_node, "tsc");
 112         of_property_read_u32(node, "ti,wires", &tsc_wires);
 113         of_property_read_u32(node, "ti,coordiante-readouts", &readouts);
 114
 115         node = of_get_child_by_name(pdev->dev.of_node, "adc");
 116         of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
 117                 adc_channels++;
 118                 if (val > 7) {
 119                         dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
 120                                         val);
 121                         return -EINVAL;
 122                 }
 123         }
 124         total_channels = tsc_wires + adc_channels;
 125         if (total_channels > 8) {
 126                 dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
 127                 return -EINVAL;
 128         }
 129         if (total_channels == 0) {
 130                 dev_err(&pdev->dev, "Need atleast one channel.\n");
 131                 return -EINVAL;
 132         }
 133
 134         if (readouts * 2 + 2 + adc_channels > 16) {
 135                 dev_err(&pdev->dev, "Too many step configurations requested\n");
 136                 return -EINVAL;
 137         }
 138
 139         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 140         if (!res) {
 141                 dev_err(&pdev->dev, "no memory resource defined.\n");
 142                 return -EINVAL;
 143         }
 144
 145         /* Allocate memory for device */
 146         tscadc = devm_kzalloc(&pdev->dev,
 147                         sizeof(struct ti_tscadc_dev), GFP_KERNEL);
 148         if (!tscadc) {
 149                 dev_err(&pdev->dev, "failed to allocate memory.\n");
 150                 return -ENOMEM;
 151         }
 152         tscadc->dev = &pdev->dev;
 153
 154         err = platform_get_irq(pdev, 0);
 155         if (err < 0) {
 156                 dev_err(&pdev->dev, "no irq ID is specified.\n");
 157                 goto ret;
 158         } else
 159                 tscadc->irq = err;
 160
 161         res = devm_request_mem_region(&pdev->dev,
 162                         res->start, resource_size(res), pdev->name);
 163         if (!res) {
 164                 dev_err(&pdev->dev, "failed to reserve registers.\n");
 165                 return -EBUSY;
 166         }
 167
 168         tscadc->tscadc_base = devm_ioremap(&pdev->dev,
 169                         res->start, resource_size(res));
 170         if (!tscadc->tscadc_base) {
 171                 dev_err(&pdev->dev, "failed to map registers.\n");
 172                 return -ENOMEM;
 173         }
 174
 175         tscadc->regmap_tscadc = devm_regmap_init_mmio(&pdev->dev,
 176                         tscadc->tscadc_base, &tscadc_regmap_config);
 177         if (IS_ERR(tscadc->regmap_tscadc)) {
 178                 dev_err(&pdev->dev, "regmap init failed\n");
 179                 err = PTR_ERR(tscadc->regmap_tscadc);
 180                 goto ret;
 181         }
 182
 183         spin_lock_init(&tscadc->reg_lock);
 184         pm_runtime_enable(&pdev->dev);
 185         pm_runtime_get_sync(&pdev->dev);
 186
 187         /*
 188          * The TSC_ADC_Subsystem has 2 clock domains
 189          * OCP_CLK and ADC_CLK.
 190          * The ADC clock is expected to run at target of 3MHz,
 191          * and expected to capture 12-bit data at a rate of 200 KSPS.
 192          * The TSC_ADC_SS controller design assumes the OCP clock is
 193          * at least 6x faster than the ADC clock.
 194          */
 195         clk = clk_get(&pdev->dev, "adc_tsc_fck");
 196         if (IS_ERR(clk)) {
 197                 dev_err(&pdev->dev, "failed to get TSC fck\n");
 198                 err = PTR_ERR(clk);
 199                 goto err_disable_clk;
 200         }
 201         clock_rate = clk_get_rate(clk);
 202         clk_put(clk);
 203         tscadc->clk_div = clock_rate / ADC_CLK;
 204
 205         /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
 206         tscadc->clk_div--;
 207         tscadc_writel(tscadc, REG_CLKDIV, tscadc->clk_div);
 208
 209         /* Set the control register bits */
 210         ctrl = CNTRLREG_STEPCONFIGWRT |
 211                         CNTRLREG_STEPID;
 212         if (tsc_wires > 0)
 213                 ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 214         tscadc_writel(tscadc, REG_CTRL, ctrl);
 215
 216         /* Set register bits for Idle Config Mode */
 217         if (tsc_wires > 0)
 218                 tscadc_idle_config(tscadc);
 219
 220         /* Enable the TSC module enable bit */
 221         ctrl = tscadc_readl(tscadc, REG_CTRL);
 222         ctrl |= CNTRLREG_TSCSSENB;
 223         tscadc_writel(tscadc, REG_CTRL, ctrl);
 224
 225         tscadc->used_cells = 0;
 226         tscadc->tsc_cell = -1;
 227         tscadc->adc_cell = -1;
 228
 229         /* TSC Cell */
 230         if (tsc_wires > 0) {
 231                 tscadc->tsc_cell = tscadc->used_cells;
 232                 cell = &tscadc->cells[tscadc->used_cells++];
 233                 cell->name = "TI-am335x-tsc";
 234                 cell->of_compatible = "ti,am3359-tsc";
 235                 cell->platform_data = &tscadc;
 236                 cell->pdata_size = sizeof(tscadc);
 237         }
 238
 239         /* ADC Cell */
 240         if (adc_channels > 0) {
 241                 tscadc->adc_cell = tscadc->used_cells;
 242                 cell = &tscadc->cells[tscadc->used_cells++];
 243                 cell->name = "TI-am335x-adc";
 244                 cell->of_compatible = "ti,am3359-adc";
 245                 cell->platform_data = &tscadc;
 246                 cell->pdata_size = sizeof(tscadc);
 247         }
 248
 249         err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
 250                         tscadc->used_cells, NULL, 0, NULL);
 251         if (err < 0)
 252                 goto err_disable_clk;
 253
 254         device_init_wakeup(&pdev->dev, true);
 255         platform_set_drvdata(pdev, tscadc);
 256         return 0;
 257
 258 err_disable_clk:
 259         pm_runtime_put_sync(&pdev->dev);
 260         pm_runtime_disable(&pdev->dev);
 261 ret:
 262         return err;
 263 }
 264
 265 static int ti_tscadc_remove(struct platform_device *pdev)
 266 {
 267         struct ti_tscadc_dev    *tscadc = platform_get_drvdata(pdev);
 268
 269         tscadc_writel(tscadc, REG_SE, 0x00);
 270
 271         pm_runtime_put_sync(&pdev->dev);
 272         pm_runtime_disable(&pdev->dev);
 273
 274         mfd_remove_devices(tscadc->dev);
 275
 276         return 0;
 277 }
 278
 279 #ifdef CONFIG_PM
 280 static int tscadc_suspend(struct device *dev)
 281 {
 282         struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 283
 284         tscadc_writel(tscadc_dev, REG_SE, 0x00);
 285         pm_runtime_put_sync(dev);
 286
 287         return 0;
 288 }
 289
 290 static int tscadc_resume(struct device *dev)
 291 {
 292         struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 293         unsigned int restore, ctrl;
 294
 295         pm_runtime_get_sync(dev);
 296
 297         /* context restore */
 298         ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 299         if (tscadc_dev->tsc_cell != -1)
 300                 ctrl |= CNTRLREG_TSCENB | CNTRLREG_4WIRE;
 301         tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
 302
 303         if (tscadc_dev->tsc_cell != -1)
 304                 tscadc_idle_config(tscadc_dev);
 305         am335x_tsc_se_update(tscadc_dev);
 306         restore = tscadc_readl(tscadc_dev, REG_CTRL);
 307         tscadc_writel(tscadc_dev, REG_CTRL,
 308                         (restore | CNTRLREG_TSCSSENB));
 309
 310         tscadc_writel(tscadc_dev, REG_CLKDIV, tscadc_dev->clk_div);
 311
 312         return 0;
 313 }
 314
 315 static const struct dev_pm_ops tscadc_pm_ops = {
 316         .suspend = tscadc_suspend,
 317         .resume = tscadc_resume,
 318 };
 319 #define TSCADC_PM_OPS (&tscadc_pm_ops)
 320 #else
 321 #define TSCADC_PM_OPS NULL
 322 #endif
 323
 324 static const struct of_device_id ti_tscadc_dt_ids[] = {
 325         { .compatible = "ti,am3359-tscadc", },
 326         { }
 327 };
 328 MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
 329
 330 static struct platform_driver ti_tscadc_driver = {
 331         .driver = {
 332                 .name   = "ti_am3359-tscadc",
 333                 .owner  = THIS_MODULE,
 334                 .pm     = TSCADC_PM_OPS,
 335                 .of_match_table = ti_tscadc_dt_ids,
 336         },
 337         .probe  = ti_tscadc_probe,
 338         .remove = ti_tscadc_remove,
 339
 340 };
 341
 342 module_platform_driver(ti_tscadc_driver);
 343
 344 MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 345 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 346 MODULE_LICENSE("GPL");