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 u32 step_en; 64 65 /* 66 * There are 16 configurable steps and 8 analog input 67 * lines available which are shared between Touchscreen and ADC. 68 * 69 * Steps backwards i.e. from 16 towards 0 are used by ADC 70 * depending on number of input lines needed. 71 * Channel would represent which analog input 72 * needs to be given to ADC to digitalize data. 73 */ 74 75 steps = TOTAL_STEPS - adc_dev->channels; 76 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1; 77 78 for (i = 0; i < adc_dev->channels; i++) { 79 int chan; 80 81 chan = adc_dev->channel_line[i]; 82 tiadc_writel(adc_dev, REG_STEPCONFIG(steps), 83 stepconfig | STEPCONFIG_INP(chan)); 84 tiadc_writel(adc_dev, REG_STEPDELAY(steps), 85 STEPCONFIG_OPENDLY); 86 adc_dev->channel_step[i] = steps; 87 steps++; 88 } 89 step_en = get_adc_step_mask(adc_dev); 90 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); 91 } 92 93 static const char * const chan_name_ain[] = { 94 "AIN0", 95 "AIN1", 96 "AIN2", 97 "AIN3", 98 "AIN4", 99 "AIN5", 100 "AIN6", 101 "AIN7", 102 }; 103 104 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) 105 { 106 struct tiadc_device *adc_dev = iio_priv(indio_dev); 107 struct iio_chan_spec *chan_array; 108 struct iio_chan_spec *chan; 109 int i; 110 111 indio_dev->num_channels = channels; 112 chan_array = kcalloc(channels, 113 sizeof(struct iio_chan_spec), GFP_KERNEL); 114 if (chan_array == NULL) 115 return -ENOMEM; 116 117 chan = chan_array; 118 for (i = 0; i < channels; i++, chan++) { 119 120 chan->type = IIO_VOLTAGE; 121 chan->indexed = 1; 122 chan->channel = adc_dev->channel_line[i]; 123 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 124 chan->datasheet_name = chan_name_ain[chan->channel]; 125 chan->scan_type.sign = 'u'; 126 chan->scan_type.realbits = 12; 127 chan->scan_type.storagebits = 32; 128 } 129 130 indio_dev->channels = chan_array; 131 132 return 0; 133 } 134 135 static void tiadc_channels_remove(struct iio_dev *indio_dev) 136 { 137 kfree(indio_dev->channels); 138 } 139 140 static int tiadc_read_raw(struct iio_dev *indio_dev, 141 struct iio_chan_spec const *chan, 142 int *val, int *val2, long mask) 143 { 144 struct tiadc_device *adc_dev = iio_priv(indio_dev); 145 int i; 146 unsigned int fifo1count, read; 147 u32 step = UINT_MAX; 148 bool found = false; 149 150 /* 151 * When the sub-system is first enabled, 152 * the sequencer will always start with the 153 * lowest step (1) and continue until step (16). 154 * For ex: If we have enabled 4 ADC channels and 155 * currently use only 1 out of them, the 156 * sequencer still configures all the 4 steps, 157 * leading to 3 unwanted data. 158 * Hence we need to flush out this data. 159 */ 160 161 for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) { 162 if (chan->channel == adc_dev->channel_line[i]) { 163 step = adc_dev->channel_step[i]; 164 break; 165 } 166 } 167 if (WARN_ON_ONCE(step == UINT_MAX)) 168 return -EINVAL; 169 170 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 171 for (i = 0; i < fifo1count; i++) { 172 read = tiadc_readl(adc_dev, REG_FIFO1); 173 if (read >> 16 == step) { 174 *val = read & 0xfff; 175 found = true; 176 } 177 } 178 am335x_tsc_se_update(adc_dev->mfd_tscadc); 179 if (found == false) 180 return -EBUSY; 181 return IIO_VAL_INT; 182 } 183 184 static const struct iio_info tiadc_info = { 185 .read_raw = &tiadc_read_raw, 186 .driver_module = THIS_MODULE, 187 }; 188 189 static int tiadc_probe(struct platform_device *pdev) 190 { 191 struct iio_dev *indio_dev; 192 struct tiadc_device *adc_dev; 193 struct device_node *node = pdev->dev.of_node; 194 struct property *prop; 195 const __be32 *cur; 196 int err; 197 u32 val; 198 int channels = 0; 199 200 if (!node) { 201 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 202 return -EINVAL; 203 } 204 205 indio_dev = iio_device_alloc(sizeof(struct tiadc_device)); 206 if (indio_dev == NULL) { 207 dev_err(&pdev->dev, "failed to allocate iio device\n"); 208 err = -ENOMEM; 209 goto err_ret; 210 } 211 adc_dev = iio_priv(indio_dev); 212 213 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 214 215 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { 216 adc_dev->channel_line[channels] = val; 217 channels++; 218 } 219 adc_dev->channels = channels; 220 221 indio_dev->dev.parent = &pdev->dev; 222 indio_dev->name = dev_name(&pdev->dev); 223 indio_dev->modes = INDIO_DIRECT_MODE; 224 indio_dev->info = &tiadc_info; 225 226 tiadc_step_config(adc_dev); 227 228 err = tiadc_channel_init(indio_dev, adc_dev->channels); 229 if (err < 0) 230 goto err_free_device; 231 232 err = iio_device_register(indio_dev); 233 if (err) 234 goto err_free_channels; 235 236 platform_set_drvdata(pdev, indio_dev); 237 238 return 0; 239 240 err_free_channels: 241 tiadc_channels_remove(indio_dev); 242 err_free_device: 243 iio_device_free(indio_dev); 244 err_ret: 245 return err; 246 } 247 248 static int tiadc_remove(struct platform_device *pdev) 249 { 250 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 251 struct tiadc_device *adc_dev = iio_priv(indio_dev); 252 u32 step_en; 253 254 iio_device_unregister(indio_dev); 255 tiadc_channels_remove(indio_dev); 256 257 step_en = get_adc_step_mask(adc_dev); 258 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 259 260 iio_device_free(indio_dev); 261 262 return 0; 263 } 264 265 #ifdef CONFIG_PM 266 static int tiadc_suspend(struct device *dev) 267 { 268 struct iio_dev *indio_dev = dev_get_drvdata(dev); 269 struct tiadc_device *adc_dev = iio_priv(indio_dev); 270 struct ti_tscadc_dev *tscadc_dev; 271 unsigned int idle; 272 273 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 274 if (!device_may_wakeup(tscadc_dev->dev)) { 275 idle = tiadc_readl(adc_dev, REG_CTRL); 276 idle &= ~(CNTRLREG_TSCSSENB); 277 tiadc_writel(adc_dev, REG_CTRL, (idle | 278 CNTRLREG_POWERDOWN)); 279 } 280 281 return 0; 282 } 283 284 static int tiadc_resume(struct device *dev) 285 { 286 struct iio_dev *indio_dev = dev_get_drvdata(dev); 287 struct tiadc_device *adc_dev = iio_priv(indio_dev); 288 unsigned int restore; 289 290 /* Make sure ADC is powered up */ 291 restore = tiadc_readl(adc_dev, REG_CTRL); 292 restore &= ~(CNTRLREG_POWERDOWN); 293 tiadc_writel(adc_dev, REG_CTRL, restore); 294 295 tiadc_step_config(adc_dev); 296 297 return 0; 298 } 299 300 static const struct dev_pm_ops tiadc_pm_ops = { 301 .suspend = tiadc_suspend, 302 .resume = tiadc_resume, 303 }; 304 #define TIADC_PM_OPS (&tiadc_pm_ops) 305 #else 306 #define TIADC_PM_OPS NULL 307 #endif 308 309 static const struct of_device_id ti_adc_dt_ids[] = { 310 { .compatible = "ti,am3359-adc", }, 311 { } 312 }; 313 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 314 315 static struct platform_driver tiadc_driver = { 316 .driver = { 317 .name = "TI-am335x-adc", 318 .owner = THIS_MODULE, 319 .pm = TIADC_PM_OPS, 320 .of_match_table = of_match_ptr(ti_adc_dt_ids), 321 }, 322 .probe = tiadc_probe, 323 .remove = tiadc_remove, 324 }; 325 module_platform_driver(tiadc_driver); 326 327 MODULE_DESCRIPTION("TI ADC controller driver"); 328 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 329 MODULE_LICENSE("GPL"); 330