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
  26#include <linux/mfd/ti_am335x_tscadc.h>
  27#include <linux/input/ti_am335x_tsc.h>
  28#include <linux/platform_data/ti_am335x_adc.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
  51static void tscadc_idle_config(struct ti_tscadc_dev *config)
  52{
  53        unsigned int idleconfig;
  54
  55        idleconfig = STEPCONFIG_YNN | STEPCONFIG_INM_ADCREFM |
  56                        STEPCONFIG_INP_ADCREFM | STEPCONFIG_YPN;
  57
  58        tscadc_writel(config, REG_IDLECONFIG, idleconfig);
  59}
  60
  61static  int ti_tscadc_probe(struct platform_device *pdev)
  62{
  63        struct ti_tscadc_dev    *tscadc;
  64        struct resource         *res;
  65        struct clk              *clk;
  66        struct mfd_tscadc_board *pdata = pdev->dev.platform_data;
  67        struct mfd_cell         *cell;
  68        int                     err, ctrl;
  69        int                     clk_value, clock_rate;
  70        int                     tsc_wires, adc_channels = 0, total_channels;
  71
  72        if (!pdata) {
  73                dev_err(&pdev->dev, "Could not find platform data\n");
  74                return -EINVAL;
  75        }
  76
  77        if (pdata->adc_init)
  78                adc_channels = pdata->adc_init->adc_channels;
  79
  80        tsc_wires = pdata->tsc_init->wires;
  81        total_channels = tsc_wires + adc_channels;
  82
  83        if (total_channels > 8) {
  84                dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
  85                return -EINVAL;
  86        }
  87
  88        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  89        if (!res) {
  90                dev_err(&pdev->dev, "no memory resource defined.\n");
  91                return -EINVAL;
  92        }
  93
  94        /* Allocate memory for device */
  95        tscadc = devm_kzalloc(&pdev->dev,
  96                        sizeof(struct ti_tscadc_dev), GFP_KERNEL);
  97        if (!tscadc) {
  98                dev_err(&pdev->dev, "failed to allocate memory.\n");
  99                return -ENOMEM;
 100        }
 101        tscadc->dev = &pdev->dev;
 102
 103        err = platform_get_irq(pdev, 0);
 104        if (err < 0) {
 105                dev_err(&pdev->dev, "no irq ID is specified.\n");
 106                goto ret;
 107        } else
 108                tscadc->irq = err;
 109
 110        res = devm_request_mem_region(&pdev->dev,
 111                        res->start, resource_size(res), pdev->name);
 112        if (!res) {
 113                dev_err(&pdev->dev, "failed to reserve registers.\n");
 114                return -EBUSY;
 115        }
 116
 117        tscadc->tscadc_base = devm_ioremap(&pdev->dev,
 118                        res->start, resource_size(res));
 119        if (!tscadc->tscadc_base) {
 120                dev_err(&pdev->dev, "failed to map registers.\n");
 121                return -ENOMEM;
 122        }
 123
 124        tscadc->regmap_tscadc = devm_regmap_init_mmio(&pdev->dev,
 125                        tscadc->tscadc_base, &tscadc_regmap_config);
 126        if (IS_ERR(tscadc->regmap_tscadc)) {
 127                dev_err(&pdev->dev, "regmap init failed\n");
 128                err = PTR_ERR(tscadc->regmap_tscadc);
 129                goto ret;
 130        }
 131
 132        pm_runtime_enable(&pdev->dev);
 133        pm_runtime_get_sync(&pdev->dev);
 134
 135        /*
 136         * The TSC_ADC_Subsystem has 2 clock domains
 137         * OCP_CLK and ADC_CLK.
 138         * The ADC clock is expected to run at target of 3MHz,
 139         * and expected to capture 12-bit data at a rate of 200 KSPS.
 140         * The TSC_ADC_SS controller design assumes the OCP clock is
 141         * at least 6x faster than the ADC clock.
 142         */
 143        clk = clk_get(&pdev->dev, "adc_tsc_fck");
 144        if (IS_ERR(clk)) {
 145                dev_err(&pdev->dev, "failed to get TSC fck\n");
 146                err = PTR_ERR(clk);
 147                goto err_disable_clk;
 148        }
 149        clock_rate = clk_get_rate(clk);
 150        clk_put(clk);
 151        clk_value = clock_rate / ADC_CLK;
 152        if (clk_value < MAX_CLK_DIV) {
 153                dev_err(&pdev->dev, "clock input less than min clock requirement\n");
 154                err = -EINVAL;
 155                goto err_disable_clk;
 156        }
 157        /* TSCADC_CLKDIV needs to be configured to the value minus 1 */
 158        clk_value = clk_value - 1;
 159        tscadc_writel(tscadc, REG_CLKDIV, clk_value);
 160
 161        /* Set the control register bits */
 162        ctrl = CNTRLREG_STEPCONFIGWRT |
 163                        CNTRLREG_TSCENB |
 164                        CNTRLREG_STEPID |
 165                        CNTRLREG_4WIRE;
 166        tscadc_writel(tscadc, REG_CTRL, ctrl);
 167
 168        /* Set register bits for Idle Config Mode */
 169        tscadc_idle_config(tscadc);
 170
 171        /* Enable the TSC module enable bit */
 172        ctrl = tscadc_readl(tscadc, REG_CTRL);
 173        ctrl |= CNTRLREG_TSCSSENB;
 174        tscadc_writel(tscadc, REG_CTRL, ctrl);
 175
 176        /* TSC Cell */
 177        cell = &tscadc->cells[TSC_CELL];
 178        cell->name = "tsc";
 179        cell->platform_data = tscadc;
 180        cell->pdata_size = sizeof(*tscadc);
 181
 182        /* ADC Cell */
 183        cell = &tscadc->cells[ADC_CELL];
 184        cell->name = "tiadc";
 185        cell->platform_data = tscadc;
 186        cell->pdata_size = sizeof(*tscadc);
 187
 188        err = mfd_add_devices(&pdev->dev, pdev->id, tscadc->cells,
 189                        TSCADC_CELLS, NULL, 0, NULL);
 190        if (err < 0)
 191                goto err_disable_clk;
 192
 193        device_init_wakeup(&pdev->dev, true);
 194        platform_set_drvdata(pdev, tscadc);
 195
 196        return 0;
 197
 198err_disable_clk:
 199        pm_runtime_put_sync(&pdev->dev);
 200        pm_runtime_disable(&pdev->dev);
 201ret:
 202        return err;
 203}
 204
 205static int ti_tscadc_remove(struct platform_device *pdev)
 206{
 207        struct ti_tscadc_dev    *tscadc = platform_get_drvdata(pdev);
 208
 209        tscadc_writel(tscadc, REG_SE, 0x00);
 210
 211        pm_runtime_put_sync(&pdev->dev);
 212        pm_runtime_disable(&pdev->dev);
 213
 214        mfd_remove_devices(tscadc->dev);
 215
 216        return 0;
 217}
 218
 219#ifdef CONFIG_PM
 220static int tscadc_suspend(struct device *dev)
 221{
 222        struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 223
 224        tscadc_writel(tscadc_dev, REG_SE, 0x00);
 225        pm_runtime_put_sync(dev);
 226
 227        return 0;
 228}
 229
 230static int tscadc_resume(struct device *dev)
 231{
 232        struct ti_tscadc_dev    *tscadc_dev = dev_get_drvdata(dev);
 233        unsigned int restore, ctrl;
 234
 235        pm_runtime_get_sync(dev);
 236
 237        /* context restore */
 238        ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_TSCENB |
 239                        CNTRLREG_STEPID | CNTRLREG_4WIRE;
 240        tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
 241        tscadc_idle_config(tscadc_dev);
 242        tscadc_writel(tscadc_dev, REG_SE, STPENB_STEPENB);
 243        restore = tscadc_readl(tscadc_dev, REG_CTRL);
 244        tscadc_writel(tscadc_dev, REG_CTRL,
 245                        (restore | CNTRLREG_TSCSSENB));
 246
 247        return 0;
 248}
 249
 250static const struct dev_pm_ops tscadc_pm_ops = {
 251        .suspend = tscadc_suspend,
 252        .resume = tscadc_resume,
 253};
 254#define TSCADC_PM_OPS (&tscadc_pm_ops)
 255#else
 256#define TSCADC_PM_OPS NULL
 257#endif
 258
 259static struct platform_driver ti_tscadc_driver = {
 260        .driver = {
 261                .name   = "ti_tscadc",
 262                .owner  = THIS_MODULE,
 263                .pm     = TSCADC_PM_OPS,
 264        },
 265        .probe  = ti_tscadc_probe,
 266        .remove = ti_tscadc_remove,
 267
 268};
 269
 270module_platform_driver(ti_tscadc_driver);
 271
 272MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 273MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 274MODULE_LICENSE("GPL");
 275
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