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 #include <linux/iio/machine.h> 28 #include <linux/iio/driver.h> 29 30 #include <linux/mfd/ti_am335x_tscadc.h> 31 32 struct tiadc_device { 33 struct ti_tscadc_dev *mfd_tscadc; 34 int channels; 35 u8 channel_line[8]; 36 u8 channel_step[8]; 37 }; 38 39 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg) 40 { 41 return readl(adc->mfd_tscadc->tscadc_base + reg); 42 } 43 44 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg, 45 unsigned int val) 46 { 47 writel(val, adc->mfd_tscadc->tscadc_base + reg); 48 } 49 50 static u32 get_adc_step_mask(struct tiadc_device *adc_dev) 51 { 52 u32 step_en; 53 54 step_en = ((1 << adc_dev->channels) - 1); 55 step_en <<= TOTAL_STEPS - adc_dev->channels + 1; 56 return step_en; 57 } 58 59 static void tiadc_step_config(struct tiadc_device *adc_dev) 60 { 61 unsigned int stepconfig; 62 int i, steps; 63 64 /* 65 * There are 16 configurable steps and 8 analog input 66 * lines available which are shared between Touchscreen and ADC. 67 * 68 * Steps backwards i.e. from 16 towards 0 are used by ADC 69 * depending on number of input lines needed. 70 * Channel would represent which analog input 71 * needs to be given to ADC to digitalize data. 72 */ 73 74 steps = TOTAL_STEPS - adc_dev->channels; 75 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1; 76 77 for (i = 0; i < adc_dev->channels; i++) { 78 int chan; 79 80 chan = adc_dev->channel_line[i]; 81 tiadc_writel(adc_dev, REG_STEPCONFIG(steps), 82 stepconfig | STEPCONFIG_INP(chan)); 83 tiadc_writel(adc_dev, REG_STEPDELAY(steps), 84 STEPCONFIG_OPENDLY); 85 adc_dev->channel_step[i] = steps; 86 steps++; 87 } 88 89 } 90 91 static const char * const chan_name_ain[] = { 92 "AIN0", 93 "AIN1", 94 "AIN2", 95 "AIN3", 96 "AIN4", 97 "AIN5", 98 "AIN6", 99 "AIN7", 100 }; 101 102 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) 103 { 104 struct tiadc_device *adc_dev = iio_priv(indio_dev); 105 struct iio_chan_spec *chan_array; 106 struct iio_chan_spec *chan; 107 int i; 108 109 indio_dev->num_channels = channels; 110 chan_array = kcalloc(channels, 111 sizeof(struct iio_chan_spec), GFP_KERNEL); 112 if (chan_array == NULL) 113 return -ENOMEM; 114 115 chan = chan_array; 116 for (i = 0; i < channels; i++, chan++) { 117 118 chan->type = IIO_VOLTAGE; 119 chan->indexed = 1; 120 chan->channel = adc_dev->channel_line[i]; 121 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 122 chan->datasheet_name = chan_name_ain[chan->channel]; 123 chan->scan_type.sign = 'u'; 124 chan->scan_type.realbits = 12; 125 chan->scan_type.storagebits = 16; 126 } 127 128 indio_dev->channels = chan_array; 129 130 return 0; 131 } 132 133 static void tiadc_channels_remove(struct iio_dev *indio_dev) 134 { 135 kfree(indio_dev->channels); 136 } 137 138 static int tiadc_read_raw(struct iio_dev *indio_dev, 139 struct iio_chan_spec const *chan, 140 int *val, int *val2, long mask) 141 { 142 struct tiadc_device *adc_dev = iio_priv(indio_dev); 143 int i, map_val; 144 unsigned int fifo1count, read, stepid; 145 u32 step = UINT_MAX; 146 bool found = false; 147 u32 step_en; 148 unsigned long timeout = jiffies + usecs_to_jiffies 149 (IDLE_TIMEOUT * adc_dev->channels); 150 step_en = get_adc_step_mask(adc_dev); 151 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); 152 153 /* Wait for ADC sequencer to complete sampling */ 154 while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) { 155 if (time_after(jiffies, timeout)) 156 return -EAGAIN; 157 } 158 map_val = chan->channel + TOTAL_CHANNELS; 159 160 /* 161 * When the sub-system is first enabled, 162 * the sequencer will always start with the 163 * lowest step (1) and continue until step (16). 164 * For ex: If we have enabled 4 ADC channels and 165 * currently use only 1 out of them, the 166 * sequencer still configures all the 4 steps, 167 * leading to 3 unwanted data. 168 * Hence we need to flush out this data. 169 */ 170 171 for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) { 172 if (chan->channel == adc_dev->channel_line[i]) { 173 step = adc_dev->channel_step[i]; 174 break; 175 } 176 } 177 if (WARN_ON_ONCE(step == UINT_MAX)) 178 return -EINVAL; 179 180 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 181 for (i = 0; i < fifo1count; i++) { 182 read = tiadc_readl(adc_dev, REG_FIFO1); 183 stepid = read & FIFOREAD_CHNLID_MASK; 184 stepid = stepid >> 0x10; 185 186 if (stepid == map_val) { 187 read = read & FIFOREAD_DATA_MASK; 188 found = true; 189 *val = (u16) read; 190 } 191 } 192 193 if (found == false) 194 return -EBUSY; 195 return IIO_VAL_INT; 196 } 197 198 static const struct iio_info tiadc_info = { 199 .read_raw = &tiadc_read_raw, 200 .driver_module = THIS_MODULE, 201 }; 202 203 static int tiadc_probe(struct platform_device *pdev) 204 { 205 struct iio_dev *indio_dev; 206 struct tiadc_device *adc_dev; 207 struct device_node *node = pdev->dev.of_node; 208 struct property *prop; 209 const __be32 *cur; 210 int err; 211 u32 val; 212 int channels = 0; 213 214 if (!node) { 215 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 216 return -EINVAL; 217 } 218 219 indio_dev = devm_iio_device_alloc(&pdev->dev, 220 sizeof(struct tiadc_device)); 221 if (indio_dev == NULL) { 222 dev_err(&pdev->dev, "failed to allocate iio device\n"); 223 return -ENOMEM; 224 } 225 adc_dev = iio_priv(indio_dev); 226 227 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 228 229 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { 230 adc_dev->channel_line[channels] = val; 231 channels++; 232 } 233 adc_dev->channels = channels; 234 235 indio_dev->dev.parent = &pdev->dev; 236 indio_dev->name = dev_name(&pdev->dev); 237 indio_dev->modes = INDIO_DIRECT_MODE; 238 indio_dev->info = &tiadc_info; 239 240 tiadc_step_config(adc_dev); 241 242 err = tiadc_channel_init(indio_dev, adc_dev->channels); 243 if (err < 0) 244 return err; 245 246 err = iio_device_register(indio_dev); 247 if (err) 248 goto err_free_channels; 249 250 platform_set_drvdata(pdev, indio_dev); 251 252 return 0; 253 254 err_free_channels: 255 tiadc_channels_remove(indio_dev); 256 return err; 257 } 258 259 static int tiadc_remove(struct platform_device *pdev) 260 { 261 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 262 struct tiadc_device *adc_dev = iio_priv(indio_dev); 263 u32 step_en; 264 265 iio_device_unregister(indio_dev); 266 tiadc_channels_remove(indio_dev); 267 268 step_en = get_adc_step_mask(adc_dev); 269 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 270 271 return 0; 272 } 273 274 #ifdef CONFIG_PM 275 static int tiadc_suspend(struct device *dev) 276 { 277 struct iio_dev *indio_dev = dev_get_drvdata(dev); 278 struct tiadc_device *adc_dev = iio_priv(indio_dev); 279 struct ti_tscadc_dev *tscadc_dev; 280 unsigned int idle; 281 282 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 283 if (!device_may_wakeup(tscadc_dev->dev)) { 284 idle = tiadc_readl(adc_dev, REG_CTRL); 285 idle &= ~(CNTRLREG_TSCSSENB); 286 tiadc_writel(adc_dev, REG_CTRL, (idle | 287 CNTRLREG_POWERDOWN)); 288 } 289 290 return 0; 291 } 292 293 static int tiadc_resume(struct device *dev) 294 { 295 struct iio_dev *indio_dev = dev_get_drvdata(dev); 296 struct tiadc_device *adc_dev = iio_priv(indio_dev); 297 unsigned int restore; 298 299 /* Make sure ADC is powered up */ 300 restore = tiadc_readl(adc_dev, REG_CTRL); 301 restore &= ~(CNTRLREG_POWERDOWN); 302 tiadc_writel(adc_dev, REG_CTRL, restore); 303 304 tiadc_step_config(adc_dev); 305 306 return 0; 307 } 308 309 static const struct dev_pm_ops tiadc_pm_ops = { 310 .suspend = tiadc_suspend, 311 .resume = tiadc_resume, 312 }; 313 #define TIADC_PM_OPS (&tiadc_pm_ops) 314 #else 315 #define TIADC_PM_OPS NULL 316 #endif 317 318 static const struct of_device_id ti_adc_dt_ids[] = { 319 { .compatible = "ti,am3359-adc", }, 320 { } 321 }; 322 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 323 324 static struct platform_driver tiadc_driver = { 325 .driver = { 326 .name = "TI-am335x-adc", 327 .owner = THIS_MODULE, 328 .pm = TIADC_PM_OPS, 329 .of_match_table = of_match_ptr(ti_adc_dt_ids), 330 }, 331 .probe = tiadc_probe, 332 .remove = tiadc_remove, 333 }; 334 module_platform_driver(tiadc_driver); 335 336 MODULE_DESCRIPTION("TI ADC controller driver"); 337 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 338 MODULE_LICENSE("GPL"); 339