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