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