1 /* 2 * TI 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/init.h> 17 #include <linux/kernel.h> 18 #include <linux/err.h> 19 #include <linux/module.h> 20 #include <linux/slab.h> 21 #include <linux/interrupt.h> 22 #include <linux/platform_device.h> 23 #include <linux/io.h> 24 #include <linux/iio/iio.h> 25 #include <linux/of.h> 26 #include <linux/of_device.h> 27 28 #include <linux/mfd/ti_am335x_tscadc.h> 29 #include <linux/platform_data/ti_am335x_adc.h> 30 31 struct tiadc_device { 32 struct ti_tscadc_dev *mfd_tscadc; 33 int channels; 34 }; 35 36 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg) 37 { 38 return readl(adc->mfd_tscadc->tscadc_base + reg); 39 } 40 41 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg, 42 unsigned int val) 43 { 44 writel(val, adc->mfd_tscadc->tscadc_base + reg); 45 } 46 47 static u32 get_adc_step_mask(struct tiadc_device *adc_dev) 48 { 49 u32 step_en; 50 51 step_en = ((1 << adc_dev->channels) - 1); 52 step_en <<= TOTAL_STEPS - adc_dev->channels + 1; 53 return step_en; 54 } 55 56 static void tiadc_step_config(struct tiadc_device *adc_dev) 57 { 58 unsigned int stepconfig; 59 int i, channels = 0, steps; 60 u32 step_en; 61 62 /* 63 * There are 16 configurable steps and 8 analog input 64 * lines available which are shared between Touchscreen and ADC. 65 * 66 * Steps backwards i.e. from 16 towards 0 are used by ADC 67 * depending on number of input lines needed. 68 * Channel would represent which analog input 69 * needs to be given to ADC to digitalize data. 70 */ 71 72 steps = TOTAL_STEPS - adc_dev->channels; 73 channels = TOTAL_CHANNELS - adc_dev->channels; 74 75 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1; 76 77 for (i = (steps + 1); i <= TOTAL_STEPS; i++) { 78 tiadc_writel(adc_dev, REG_STEPCONFIG(i), 79 stepconfig | STEPCONFIG_INP(channels)); 80 tiadc_writel(adc_dev, REG_STEPDELAY(i), 81 STEPCONFIG_OPENDLY); 82 channels++; 83 } 84 step_en = get_adc_step_mask(adc_dev); 85 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); 86 } 87 88 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) 89 { 90 struct iio_chan_spec *chan_array; 91 int i; 92 93 indio_dev->num_channels = channels; 94 chan_array = kcalloc(indio_dev->num_channels, 95 sizeof(struct iio_chan_spec), GFP_KERNEL); 96 97 if (chan_array == NULL) 98 return -ENOMEM; 99 100 for (i = 0; i < (indio_dev->num_channels); i++) { 101 struct iio_chan_spec *chan = chan_array + i; 102 chan->type = IIO_VOLTAGE; 103 chan->indexed = 1; 104 chan->channel = i; 105 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 106 } 107 108 indio_dev->channels = chan_array; 109 110 return indio_dev->num_channels; 111 } 112 113 static void tiadc_channels_remove(struct iio_dev *indio_dev) 114 { 115 kfree(indio_dev->channels); 116 } 117 118 static int tiadc_read_raw(struct iio_dev *indio_dev, 119 struct iio_chan_spec const *chan, 120 int *val, int *val2, long mask) 121 { 122 struct tiadc_device *adc_dev = iio_priv(indio_dev); 123 int i; 124 unsigned int fifo1count, readx1; 125 126 /* 127 * When the sub-system is first enabled, 128 * the sequencer will always start with the 129 * lowest step (1) and continue until step (16). 130 * For ex: If we have enabled 4 ADC channels and 131 * currently use only 1 out of them, the 132 * sequencer still configures all the 4 steps, 133 * leading to 3 unwanted data. 134 * Hence we need to flush out this data. 135 */ 136 137 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 138 for (i = 0; i < fifo1count; i++) { 139 readx1 = tiadc_readl(adc_dev, REG_FIFO1); 140 if (i == chan->channel) 141 *val = readx1 & 0xfff; 142 } 143 am335x_tsc_se_update(adc_dev->mfd_tscadc); 144 145 return IIO_VAL_INT; 146 } 147 148 static const struct iio_info tiadc_info = { 149 .read_raw = &tiadc_read_raw, 150 }; 151 152 static int tiadc_probe(struct platform_device *pdev) 153 { 154 struct iio_dev *indio_dev; 155 struct tiadc_device *adc_dev; 156 struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev); 157 struct mfd_tscadc_board *pdata = tscadc_dev->dev->platform_data; 158 struct device_node *node = pdev->dev.of_node; 159 int err; 160 u32 val32; 161 162 if (!pdata && !node) { 163 dev_err(&pdev->dev, "Could not find platform data\n"); 164 return -EINVAL; 165 } 166 167 indio_dev = iio_device_alloc(sizeof(struct tiadc_device)); 168 if (indio_dev == NULL) { 169 dev_err(&pdev->dev, "failed to allocate iio device\n"); 170 err = -ENOMEM; 171 goto err_ret; 172 } 173 adc_dev = iio_priv(indio_dev); 174 175 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 176 177 if (pdata) 178 adc_dev->channels = pdata->adc_init->adc_channels; 179 else { 180 err = of_property_read_u32(node, 181 "ti,adc-channels", &val32); 182 if (err < 0) 183 goto err_free_device; 184 adc_dev->channels = val32; 185 } 186 187 indio_dev->dev.parent = &pdev->dev; 188 indio_dev->name = dev_name(&pdev->dev); 189 indio_dev->modes = INDIO_DIRECT_MODE; 190 indio_dev->info = &tiadc_info; 191 192 tiadc_step_config(adc_dev); 193 194 err = tiadc_channel_init(indio_dev, adc_dev->channels); 195 if (err < 0) 196 goto err_free_device; 197 198 err = iio_device_register(indio_dev); 199 if (err) 200 goto err_free_channels; 201 202 platform_set_drvdata(pdev, indio_dev); 203 204 return 0; 205 206 err_free_channels: 207 tiadc_channels_remove(indio_dev); 208 err_free_device: 209 iio_device_free(indio_dev); 210 err_ret: 211 return err; 212 } 213 214 static int tiadc_remove(struct platform_device *pdev) 215 { 216 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 217 struct tiadc_device *adc_dev = iio_priv(indio_dev); 218 u32 step_en; 219 220 iio_device_unregister(indio_dev); 221 tiadc_channels_remove(indio_dev); 222 223 step_en = get_adc_step_mask(adc_dev); 224 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 225 226 iio_device_free(indio_dev); 227 228 return 0; 229 } 230 231 #ifdef CONFIG_PM 232 static int tiadc_suspend(struct device *dev) 233 { 234 struct iio_dev *indio_dev = dev_get_drvdata(dev); 235 struct tiadc_device *adc_dev = iio_priv(indio_dev); 236 struct ti_tscadc_dev *tscadc_dev; 237 unsigned int idle; 238 239 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 240 if (!device_may_wakeup(tscadc_dev->dev)) { 241 idle = tiadc_readl(adc_dev, REG_CTRL); 242 idle &= ~(CNTRLREG_TSCSSENB); 243 tiadc_writel(adc_dev, REG_CTRL, (idle | 244 CNTRLREG_POWERDOWN)); 245 } 246 247 return 0; 248 } 249 250 static int tiadc_resume(struct device *dev) 251 { 252 struct iio_dev *indio_dev = dev_get_drvdata(dev); 253 struct tiadc_device *adc_dev = iio_priv(indio_dev); 254 unsigned int restore; 255 256 /* Make sure ADC is powered up */ 257 restore = tiadc_readl(adc_dev, REG_CTRL); 258 restore &= ~(CNTRLREG_POWERDOWN); 259 tiadc_writel(adc_dev, REG_CTRL, restore); 260 261 tiadc_step_config(adc_dev); 262 263 return 0; 264 } 265 266 static const struct dev_pm_ops tiadc_pm_ops = { 267 .suspend = tiadc_suspend, 268 .resume = tiadc_resume, 269 }; 270 #define TIADC_PM_OPS (&tiadc_pm_ops) 271 #else 272 #define TIADC_PM_OPS NULL 273 #endif 274 275 static const struct of_device_id ti_adc_dt_ids[] = { 276 { .compatible = "ti,am3359-adc", }, 277 { } 278 }; 279 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 280 281 static struct platform_driver tiadc_driver = { 282 .driver = { 283 .name = "tiadc", 284 .owner = THIS_MODULE, 285 .pm = TIADC_PM_OPS, 286 .of_match_table = of_match_ptr(ti_adc_dt_ids), 287 }, 288 .probe = tiadc_probe, 289 .remove = tiadc_remove, 290 }; 291 292 module_platform_driver(tiadc_driver); 293 294 MODULE_DESCRIPTION("TI ADC controller driver"); 295 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 296 MODULE_LICENSE("GPL"); 297