1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2014-2015 Imagination Technologies Ltd. 4 */ 5 6 #include <linux/clk.h> 7 #include <linux/delay.h> 8 #include <linux/err.h> 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/of.h> 12 #include <linux/of_device.h> 13 #include <linux/platform_device.h> 14 #include <linux/regulator/consumer.h> 15 #include <linux/slab.h> 16 17 #include <linux/iio/buffer.h> 18 #include <linux/iio/iio.h> 19 #include <linux/iio/sysfs.h> 20 #include <linux/iio/trigger.h> 21 #include <linux/iio/trigger_consumer.h> 22 #include <linux/iio/triggered_buffer.h> 23 24 /* Registers */ 25 #define CC10001_ADC_CONFIG 0x00 26 #define CC10001_ADC_START_CONV BIT(4) 27 #define CC10001_ADC_MODE_SINGLE_CONV BIT(5) 28 29 #define CC10001_ADC_DDATA_OUT 0x04 30 #define CC10001_ADC_EOC 0x08 31 #define CC10001_ADC_EOC_SET BIT(0) 32 33 #define CC10001_ADC_CHSEL_SAMPLED 0x0c 34 #define CC10001_ADC_POWER_DOWN 0x10 35 #define CC10001_ADC_POWER_DOWN_SET BIT(0) 36 37 #define CC10001_ADC_DEBUG 0x14 38 #define CC10001_ADC_DATA_COUNT 0x20 39 40 #define CC10001_ADC_DATA_MASK GENMASK(9, 0) 41 #define CC10001_ADC_NUM_CHANNELS 8 42 #define CC10001_ADC_CH_MASK GENMASK(2, 0) 43 44 #define CC10001_INVALID_SAMPLED 0xffff 45 #define CC10001_MAX_POLL_COUNT 20 46 47 /* 48 * As per device specification, wait six clock cycles after power-up to 49 * activate START. Since adding two more clock cycles delay does not 50 * impact the performance too much, we are adding two additional cycles delay 51 * intentionally here. 52 */ 53 #define CC10001_WAIT_CYCLES 8 54 55 struct cc10001_adc_device { 56 void __iomem *reg_base; 57 struct clk *adc_clk; 58 struct regulator *reg; 59 u16 *buf; 60 61 bool shared; 62 struct mutex lock; 63 unsigned int start_delay_ns; 64 unsigned int eoc_delay_ns; 65 }; 66 67 static inline void cc10001_adc_write_reg(struct cc10001_adc_device *adc_dev, 68 u32 reg, u32 val) 69 { 70 writel(val, adc_dev->reg_base + reg); 71 } 72 73 static inline u32 cc10001_adc_read_reg(struct cc10001_adc_device *adc_dev, 74 u32 reg) 75 { 76 return readl(adc_dev->reg_base + reg); 77 } 78 79 static void cc10001_adc_power_up(struct cc10001_adc_device *adc_dev) 80 { 81 cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_DOWN, 0); 82 ndelay(adc_dev->start_delay_ns); 83 } 84 85 static void cc10001_adc_power_down(struct cc10001_adc_device *adc_dev) 86 { 87 cc10001_adc_write_reg(adc_dev, CC10001_ADC_POWER_DOWN, 88 CC10001_ADC_POWER_DOWN_SET); 89 } 90 91 static void cc10001_adc_start(struct cc10001_adc_device *adc_dev, 92 unsigned int channel) 93 { 94 u32 val; 95 96 /* Channel selection and mode of operation */ 97 val = (channel & CC10001_ADC_CH_MASK) | CC10001_ADC_MODE_SINGLE_CONV; 98 cc10001_adc_write_reg(adc_dev, CC10001_ADC_CONFIG, val); 99 100 udelay(1); 101 val = cc10001_adc_read_reg(adc_dev, CC10001_ADC_CONFIG); 102 val = val | CC10001_ADC_START_CONV; 103 cc10001_adc_write_reg(adc_dev, CC10001_ADC_CONFIG, val); 104 } 105 106 static u16 cc10001_adc_poll_done(struct iio_dev *indio_dev, 107 unsigned int channel, 108 unsigned int delay) 109 { 110 struct cc10001_adc_device *adc_dev = iio_priv(indio_dev); 111 unsigned int poll_count = 0; 112 113 while (!(cc10001_adc_read_reg(adc_dev, CC10001_ADC_EOC) & 114 CC10001_ADC_EOC_SET)) { 115 116 ndelay(delay); 117 if (poll_count++ == CC10001_MAX_POLL_COUNT) 118 return CC10001_INVALID_SAMPLED; 119 } 120 121 poll_count = 0; 122 while ((cc10001_adc_read_reg(adc_dev, CC10001_ADC_CHSEL_SAMPLED) & 123 CC10001_ADC_CH_MASK) != channel) { 124 125 ndelay(delay); 126 if (poll_count++ == CC10001_MAX_POLL_COUNT) 127 return CC10001_INVALID_SAMPLED; 128 } 129 130 /* Read the 10 bit output register */ 131 return cc10001_adc_read_reg(adc_dev, CC10001_ADC_DDATA_OUT) & 132 CC10001_ADC_DATA_MASK; 133 } 134 135 static irqreturn_t cc10001_adc_trigger_h(int irq, void *p) 136 { 137 struct cc10001_adc_device *adc_dev; 138 struct iio_poll_func *pf = p; 139 struct iio_dev *indio_dev; 140 unsigned int delay_ns; 141 unsigned int channel; 142 unsigned int scan_idx; 143 bool sample_invalid; 144 u16 *data; 145 int i; 146 147 indio_dev = pf->indio_dev; 148 adc_dev = iio_priv(indio_dev); 149 data = adc_dev->buf; 150 151 mutex_lock(&adc_dev->lock); 152 153 if (!adc_dev->shared) 154 cc10001_adc_power_up(adc_dev); 155 156 /* Calculate delay step for eoc and sampled data */ 157 delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT; 158 159 i = 0; 160 sample_invalid = false; 161 for_each_set_bit(scan_idx, indio_dev->active_scan_mask, 162 indio_dev->masklength) { 163 164 channel = indio_dev->channels[scan_idx].channel; 165 cc10001_adc_start(adc_dev, channel); 166 167 data[i] = cc10001_adc_poll_done(indio_dev, channel, delay_ns); 168 if (data[i] == CC10001_INVALID_SAMPLED) { 169 dev_warn(&indio_dev->dev, 170 "invalid sample on channel %d\n", channel); 171 sample_invalid = true; 172 goto done; 173 } 174 i++; 175 } 176 177 done: 178 if (!adc_dev->shared) 179 cc10001_adc_power_down(adc_dev); 180 181 mutex_unlock(&adc_dev->lock); 182 183 if (!sample_invalid) 184 iio_push_to_buffers_with_timestamp(indio_dev, data, 185 iio_get_time_ns(indio_dev)); 186 iio_trigger_notify_done(indio_dev->trig); 187 188 return IRQ_HANDLED; 189 } 190 191 static u16 cc10001_adc_read_raw_voltage(struct iio_dev *indio_dev, 192 struct iio_chan_spec const *chan) 193 { 194 struct cc10001_adc_device *adc_dev = iio_priv(indio_dev); 195 unsigned int delay_ns; 196 u16 val; 197 198 if (!adc_dev->shared) 199 cc10001_adc_power_up(adc_dev); 200 201 /* Calculate delay step for eoc and sampled data */ 202 delay_ns = adc_dev->eoc_delay_ns / CC10001_MAX_POLL_COUNT; 203 204 cc10001_adc_start(adc_dev, chan->channel); 205 206 val = cc10001_adc_poll_done(indio_dev, chan->channel, delay_ns); 207 208 if (!adc_dev->shared) 209 cc10001_adc_power_down(adc_dev); 210 211 return val; 212 } 213 214 static int cc10001_adc_read_raw(struct iio_dev *indio_dev, 215 struct iio_chan_spec const *chan, 216 int *val, int *val2, long mask) 217 { 218 struct cc10001_adc_device *adc_dev = iio_priv(indio_dev); 219 int ret; 220 221 switch (mask) { 222 case IIO_CHAN_INFO_RAW: 223 if (iio_buffer_enabled(indio_dev)) 224 return -EBUSY; 225 mutex_lock(&adc_dev->lock); 226 *val = cc10001_adc_read_raw_voltage(indio_dev, chan); 227 mutex_unlock(&adc_dev->lock); 228 229 if (*val == CC10001_INVALID_SAMPLED) 230 return -EIO; 231 return IIO_VAL_INT; 232 233 case IIO_CHAN_INFO_SCALE: 234 ret = regulator_get_voltage(adc_dev->reg); 235 if (ret < 0) 236 return ret; 237 238 *val = ret / 1000; 239 *val2 = chan->scan_type.realbits; 240 return IIO_VAL_FRACTIONAL_LOG2; 241 242 default: 243 return -EINVAL; 244 } 245 } 246 247 static int cc10001_update_scan_mode(struct iio_dev *indio_dev, 248 const unsigned long *scan_mask) 249 { 250 struct cc10001_adc_device *adc_dev = iio_priv(indio_dev); 251 252 kfree(adc_dev->buf); 253 adc_dev->buf = kmalloc(indio_dev->scan_bytes, GFP_KERNEL); 254 if (!adc_dev->buf) 255 return -ENOMEM; 256 257 return 0; 258 } 259 260 static const struct iio_info cc10001_adc_info = { 261 .read_raw = &cc10001_adc_read_raw, 262 .update_scan_mode = &cc10001_update_scan_mode, 263 }; 264 265 static int cc10001_adc_channel_init(struct iio_dev *indio_dev, 266 unsigned long channel_map) 267 { 268 struct iio_chan_spec *chan_array, *timestamp; 269 unsigned int bit, idx = 0; 270 271 indio_dev->num_channels = bitmap_weight(&channel_map, 272 CC10001_ADC_NUM_CHANNELS) + 1; 273 274 chan_array = devm_kcalloc(&indio_dev->dev, indio_dev->num_channels, 275 sizeof(struct iio_chan_spec), 276 GFP_KERNEL); 277 if (!chan_array) 278 return -ENOMEM; 279 280 for_each_set_bit(bit, &channel_map, CC10001_ADC_NUM_CHANNELS) { 281 struct iio_chan_spec *chan = &chan_array[idx]; 282 283 chan->type = IIO_VOLTAGE; 284 chan->indexed = 1; 285 chan->channel = bit; 286 chan->scan_index = idx; 287 chan->scan_type.sign = 'u'; 288 chan->scan_type.realbits = 10; 289 chan->scan_type.storagebits = 16; 290 chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE); 291 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 292 idx++; 293 } 294 295 timestamp = &chan_array[idx]; 296 timestamp->type = IIO_TIMESTAMP; 297 timestamp->channel = -1; 298 timestamp->scan_index = idx; 299 timestamp->scan_type.sign = 's'; 300 timestamp->scan_type.realbits = 64; 301 timestamp->scan_type.storagebits = 64; 302 303 indio_dev->channels = chan_array; 304 305 return 0; 306 } 307 308 static int cc10001_adc_probe(struct platform_device *pdev) 309 { 310 struct device_node *node = pdev->dev.of_node; 311 struct cc10001_adc_device *adc_dev; 312 unsigned long adc_clk_rate; 313 struct iio_dev *indio_dev; 314 unsigned long channel_map; 315 int ret; 316 317 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*adc_dev)); 318 if (indio_dev == NULL) 319 return -ENOMEM; 320 321 adc_dev = iio_priv(indio_dev); 322 323 channel_map = GENMASK(CC10001_ADC_NUM_CHANNELS - 1, 0); 324 if (!of_property_read_u32(node, "adc-reserved-channels", &ret)) { 325 adc_dev->shared = true; 326 channel_map &= ~ret; 327 } 328 329 adc_dev->reg = devm_regulator_get(&pdev->dev, "vref"); 330 if (IS_ERR(adc_dev->reg)) 331 return PTR_ERR(adc_dev->reg); 332 333 ret = regulator_enable(adc_dev->reg); 334 if (ret) 335 return ret; 336 337 indio_dev->name = dev_name(&pdev->dev); 338 indio_dev->info = &cc10001_adc_info; 339 indio_dev->modes = INDIO_DIRECT_MODE; 340 341 adc_dev->reg_base = devm_platform_ioremap_resource(pdev, 0); 342 if (IS_ERR(adc_dev->reg_base)) { 343 ret = PTR_ERR(adc_dev->reg_base); 344 goto err_disable_reg; 345 } 346 347 adc_dev->adc_clk = devm_clk_get(&pdev->dev, "adc"); 348 if (IS_ERR(adc_dev->adc_clk)) { 349 dev_err(&pdev->dev, "failed to get the clock\n"); 350 ret = PTR_ERR(adc_dev->adc_clk); 351 goto err_disable_reg; 352 } 353 354 ret = clk_prepare_enable(adc_dev->adc_clk); 355 if (ret) { 356 dev_err(&pdev->dev, "failed to enable the clock\n"); 357 goto err_disable_reg; 358 } 359 360 adc_clk_rate = clk_get_rate(adc_dev->adc_clk); 361 if (!adc_clk_rate) { 362 ret = -EINVAL; 363 dev_err(&pdev->dev, "null clock rate!\n"); 364 goto err_disable_clk; 365 } 366 367 adc_dev->eoc_delay_ns = NSEC_PER_SEC / adc_clk_rate; 368 adc_dev->start_delay_ns = adc_dev->eoc_delay_ns * CC10001_WAIT_CYCLES; 369 370 /* 371 * There is only one register to power-up/power-down the AUX ADC. 372 * If the ADC is shared among multiple CPUs, always power it up here. 373 * If the ADC is used only by the MIPS, power-up/power-down at runtime. 374 */ 375 if (adc_dev->shared) 376 cc10001_adc_power_up(adc_dev); 377 378 /* Setup the ADC channels available on the device */ 379 ret = cc10001_adc_channel_init(indio_dev, channel_map); 380 if (ret < 0) 381 goto err_disable_clk; 382 383 mutex_init(&adc_dev->lock); 384 385 ret = iio_triggered_buffer_setup(indio_dev, NULL, 386 &cc10001_adc_trigger_h, NULL); 387 if (ret < 0) 388 goto err_disable_clk; 389 390 ret = iio_device_register(indio_dev); 391 if (ret < 0) 392 goto err_cleanup_buffer; 393 394 platform_set_drvdata(pdev, indio_dev); 395 396 return 0; 397 398 err_cleanup_buffer: 399 iio_triggered_buffer_cleanup(indio_dev); 400 err_disable_clk: 401 clk_disable_unprepare(adc_dev->adc_clk); 402 err_disable_reg: 403 regulator_disable(adc_dev->reg); 404 return ret; 405 } 406 407 static int cc10001_adc_remove(struct platform_device *pdev) 408 { 409 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 410 struct cc10001_adc_device *adc_dev = iio_priv(indio_dev); 411 412 cc10001_adc_power_down(adc_dev); 413 iio_device_unregister(indio_dev); 414 iio_triggered_buffer_cleanup(indio_dev); 415 clk_disable_unprepare(adc_dev->adc_clk); 416 regulator_disable(adc_dev->reg); 417 418 return 0; 419 } 420 421 static const struct of_device_id cc10001_adc_dt_ids[] = { 422 { .compatible = "cosmic,10001-adc", }, 423 { } 424 }; 425 MODULE_DEVICE_TABLE(of, cc10001_adc_dt_ids); 426 427 static struct platform_driver cc10001_adc_driver = { 428 .driver = { 429 .name = "cc10001-adc", 430 .of_match_table = cc10001_adc_dt_ids, 431 }, 432 .probe = cc10001_adc_probe, 433 .remove = cc10001_adc_remove, 434 }; 435 module_platform_driver(cc10001_adc_driver); 436 437 MODULE_AUTHOR("Phani Movva <Phani.Movva@imgtec.com>"); 438 MODULE_DESCRIPTION("Cosmic Circuits ADC driver"); 439 MODULE_LICENSE("GPL v2"); 440