linux/drivers/mfd/ti_am335x_tscadc.c
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   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
  30static 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
  38static 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
  44static 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
  51void am335x_tsc_se_update(struct ti_tscadc_dev *tsadc)
  52{
  53        tscadc_writel(tsadc, REG_SE, tsadc->reg_se_cache);
  54}
  55EXPORT_SYMBOL_GPL(am335x_tsc_se_update);
  56
  57void am335x_tsc_se_set(struct ti_tscadc_dev *tsadc, u32 val)
  58{
  59        spin_lock(&tsadc->reg_lock);
  60        tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE);
  61        tsadc->reg_se_cache |= val;
  62        am335x_tsc_se_update(tsadc);
  63        spin_unlock(&tsadc->reg_lock);
  64}
  65EXPORT_SYMBOL_GPL(am335x_tsc_se_set);
  66
  67void am335x_tsc_se_clr(struct ti_tscadc_dev *tsadc, u32 val)
  68{
  69        spin_lock(&tsadc->reg_lock);
  70        tsadc->reg_se_cache = tscadc_readl(tsadc, REG_SE);
  71        tsadc->reg_se_cache &= ~val;
  72        am335x_tsc_se_update(tsadc);
  73        spin_unlock(&tsadc->reg_lock);
  74}
  75EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);
  76
  77static 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
  87static  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
 201        /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
 202        clk_value = clk_value - 1;
 203        tscadc_writel(tscadc, REG_CLKDIV, clk_value);
 204
 205        /* Set the control register bits */
 206        ctrl = CNTRLREG_STEPCONFIGWRT |
 207                        CNTRLREG_STEPID;
 208        if (tsc_wires > 0)
 209                ctrl |= CNTRLREG_4WIRE | CNTRLREG_TSCENB;
 210        tscadc_writel(tscadc, REG_CTRL, ctrl);
 211
 212        /* Set register bits for Idle Config Mode */
 213        if (tsc_wires > 0)
 214                tscadc_idle_config(tscadc);
 215
 216        /* Enable the TSC module enable bit */
 217        ctrl = tscadc_readl(tscadc, REG_CTRL);
 218        ctrl |= CNTRLREG_TSCSSENB;
 219        tscadc_writel(tscadc, REG_CTRL, ctrl);
 220
 221        tscadc->used_cells = 0;
 222        tscadc->tsc_cell = -1;
 223        tscadc->adc_cell = -1;
 224
 225        /* TSC Cell */
 226        if (tsc_wires > 0) {
 227                tscadc->tsc_cell = tscadc->used_cells;
 228                cell = &tscadc->cells[tscadc->used_cells++];
 229                cell->name = "TI-am335x-tsc";
 230                cell->of_compatible = "ti,am3359-tsc";
 231                cell->platform_data = &tscadc;
 232                cell->pdata_size = sizeof(tscadc);
 233        }
 234
 235        /* ADC Cell */
 236        if (adc_channels > 0) {
 237                tscadc->adc_cell = tscadc->used_cells;
 238                cell = &tscadc->cells[tscadc->used_cells++];
 239                cell->name = "TI-am335x-adc";
 240                cell->of_compatible = "ti,am3359-adc";
 241                cell->platform_data = &tscadc;
 242                cell->pdata_size = sizeof(tscadc);
 243        }
 244
 245        err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
 246                        tscadc->used_cells, NULL, 0, NULL);
 247        if (err < 0)
 248                goto err_disable_clk;
 249
 250        device_init_wakeup(&pdev->dev, true);
 251        platform_set_drvdata(pdev, tscadc);
 252        return 0;
 253
 254err_disable_clk:
 255        pm_runtime_put_sync(&pdev->dev);
 256        pm_runtime_disable(&pdev->dev);
 257ret:
 258        return err;
 259}
 260
 261static int ti_tscadc_remove(struct platform_device *pdev)
 262{
 263        struct ti_tscadc_dev    *tscadc = platform_get_drvdata(pdev);
 264
 265        tscadc_writel(tscadc, REG_SE, 0x00);
 266
 267        pm_runtime_put_sync(&pdev->dev);
 268        pm_runtime_disable(&pdev->dev);
 269
 270        mfd_remove_devices(tscadc->dev);
 271
 272        return 0;
 273}
 274
 275#ifdef CONFIG_PM
 276static int tscadc_suspend(struct device *dev)
 277{
 278        struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 279
 280        tscadc_writel(tscadc_dev, REG_SE, 0x00);
 281        pm_runtime_put_sync(dev);
 282
 283        return 0;
 284}
 285
 286static int tscadc_resume(struct device *dev)
 287{
 288        struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 289        unsigned int restore, ctrl;
 290
 291        pm_runtime_get_sync(dev);
 292
 293        /* context restore */
 294        ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
 295        if (tscadc_dev->tsc_cell != -1)
 296                ctrl |= CNTRLREG_TSCENB | CNTRLREG_4WIRE;
 297        tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
 298
 299        if (tscadc_dev->tsc_cell != -1)
 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
 309static 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
 318static const struct of_device_id ti_tscadc_dt_ids[] = {
 319        { .compatible = "ti,am3359-tscadc", },
 320        { }
 321};
 322MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);
 323
 324static 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
 336module_platform_driver(ti_tscadc_driver);
 337
 338MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 339MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 340MODULE_LICENSE("GPL");
 341
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