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
  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
  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 static 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
  61 static  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
 198 err_disable_clk:
 199         pm_runtime_put_sync(&pdev->dev);
 200         pm_runtime_disable(&pdev->dev);
 201 ret:
 202         return err;
 203 }
 204
 205 static 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
 220 static 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
 230 static 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
 250 static 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
 259 static 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
 270 module_platform_driver(ti_tscadc_driver);
 271
 272 MODULE_DESCRIPTION("TI touchscreen / ADC MFD controller driver");
 273 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 274 MODULE_LICENSE("GPL");