Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 1 | /* |
| 2 | * ST SPEAr ADC driver |
| 3 | * |
| 4 | * Copyright 2012 Stefan Roese <sr@denx.de> |
| 5 | * |
| 6 | * Licensed under the GPL-2. |
| 7 | */ |
| 8 | |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/platform_device.h> |
| 11 | #include <linux/interrupt.h> |
| 12 | #include <linux/device.h> |
| 13 | #include <linux/kernel.h> |
| 14 | #include <linux/slab.h> |
| 15 | #include <linux/io.h> |
| 16 | #include <linux/clk.h> |
| 17 | #include <linux/err.h> |
| 18 | #include <linux/completion.h> |
| 19 | #include <linux/of.h> |
| 20 | #include <linux/of_address.h> |
| 21 | |
Jonathan Cameron | 06458e2 | 2012-04-25 15:54:58 +0100 | [diff] [blame] | 22 | #include <linux/iio/iio.h> |
| 23 | #include <linux/iio/sysfs.h> |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 24 | |
| 25 | /* |
| 26 | * SPEAR registers definitions |
| 27 | */ |
| 28 | |
| 29 | #define SCAN_RATE_LO(x) ((x) & 0xFFFF) |
| 30 | #define SCAN_RATE_HI(x) (((x) >> 0x10) & 0xFFFF) |
| 31 | #define CLK_LOW(x) (((x) & 0xf) << 0) |
| 32 | #define CLK_HIGH(x) (((x) & 0xf) << 4) |
| 33 | |
| 34 | /* Bit definitions for SPEAR_ADC_STATUS */ |
| 35 | #define START_CONVERSION (1 << 0) |
| 36 | #define CHANNEL_NUM(x) ((x) << 1) |
| 37 | #define ADC_ENABLE (1 << 4) |
| 38 | #define AVG_SAMPLE(x) ((x) << 5) |
| 39 | #define VREF_INTERNAL (1 << 9) |
| 40 | |
| 41 | #define DATA_MASK 0x03ff |
| 42 | #define DATA_BITS 10 |
| 43 | |
| 44 | #define MOD_NAME "spear-adc" |
| 45 | |
| 46 | #define ADC_CHANNEL_NUM 8 |
| 47 | |
| 48 | #define CLK_MIN 2500000 |
| 49 | #define CLK_MAX 20000000 |
| 50 | |
| 51 | struct adc_regs_spear3xx { |
| 52 | u32 status; |
| 53 | u32 average; |
| 54 | u32 scan_rate; |
| 55 | u32 clk; /* Not avail for 1340 & 1310 */ |
| 56 | u32 ch_ctrl[ADC_CHANNEL_NUM]; |
| 57 | u32 ch_data[ADC_CHANNEL_NUM]; |
| 58 | }; |
| 59 | |
| 60 | struct chan_data { |
| 61 | u32 lsb; |
| 62 | u32 msb; |
| 63 | }; |
| 64 | |
| 65 | struct adc_regs_spear6xx { |
| 66 | u32 status; |
| 67 | u32 pad[2]; |
| 68 | u32 clk; |
| 69 | u32 ch_ctrl[ADC_CHANNEL_NUM]; |
| 70 | struct chan_data ch_data[ADC_CHANNEL_NUM]; |
| 71 | u32 scan_rate_lo; |
| 72 | u32 scan_rate_hi; |
| 73 | struct chan_data average; |
| 74 | }; |
| 75 | |
| 76 | struct spear_adc_info { |
| 77 | struct device_node *np; |
| 78 | struct adc_regs_spear3xx __iomem *adc_base_spear3xx; |
| 79 | struct adc_regs_spear6xx __iomem *adc_base_spear6xx; |
| 80 | struct clk *clk; |
| 81 | struct completion completion; |
| 82 | u32 current_clk; |
| 83 | u32 sampling_freq; |
| 84 | u32 avg_samples; |
| 85 | u32 vref_external; |
| 86 | u32 value; |
| 87 | }; |
| 88 | |
| 89 | /* |
| 90 | * Functions to access some SPEAr ADC register. Abstracted into |
| 91 | * static inline functions, because of different register offsets |
| 92 | * on different SoC variants (SPEAr300 vs SPEAr600 etc). |
| 93 | */ |
| 94 | static void spear_adc_set_status(struct spear_adc_info *info, u32 val) |
| 95 | { |
| 96 | __raw_writel(val, &info->adc_base_spear6xx->status); |
| 97 | } |
| 98 | |
| 99 | static void spear_adc_set_clk(struct spear_adc_info *info, u32 val) |
| 100 | { |
| 101 | u32 clk_high, clk_low, count; |
| 102 | u32 apb_clk = clk_get_rate(info->clk); |
| 103 | |
| 104 | count = (apb_clk + val - 1) / val; |
| 105 | clk_low = count / 2; |
| 106 | clk_high = count - clk_low; |
| 107 | info->current_clk = apb_clk / count; |
| 108 | |
| 109 | __raw_writel(CLK_LOW(clk_low) | CLK_HIGH(clk_high), |
| 110 | &info->adc_base_spear6xx->clk); |
| 111 | } |
| 112 | |
| 113 | static void spear_adc_set_ctrl(struct spear_adc_info *info, int n, |
| 114 | u32 val) |
| 115 | { |
| 116 | __raw_writel(val, &info->adc_base_spear6xx->ch_ctrl[n]); |
| 117 | } |
| 118 | |
| 119 | static u32 spear_adc_get_average(struct spear_adc_info *info) |
| 120 | { |
| 121 | if (of_device_is_compatible(info->np, "st,spear600-adc")) { |
| 122 | return __raw_readl(&info->adc_base_spear6xx->average.msb) & |
| 123 | DATA_MASK; |
| 124 | } else { |
| 125 | return __raw_readl(&info->adc_base_spear3xx->average) & |
| 126 | DATA_MASK; |
| 127 | } |
| 128 | } |
| 129 | |
| 130 | static void spear_adc_set_scanrate(struct spear_adc_info *info, u32 rate) |
| 131 | { |
| 132 | if (of_device_is_compatible(info->np, "st,spear600-adc")) { |
| 133 | __raw_writel(SCAN_RATE_LO(rate), |
| 134 | &info->adc_base_spear6xx->scan_rate_lo); |
| 135 | __raw_writel(SCAN_RATE_HI(rate), |
| 136 | &info->adc_base_spear6xx->scan_rate_hi); |
| 137 | } else { |
| 138 | __raw_writel(rate, &info->adc_base_spear3xx->scan_rate); |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | static int spear_read_raw(struct iio_dev *indio_dev, |
| 143 | struct iio_chan_spec const *chan, |
| 144 | int *val, |
| 145 | int *val2, |
| 146 | long mask) |
| 147 | { |
| 148 | struct spear_adc_info *info = iio_priv(indio_dev); |
| 149 | u32 scale_mv; |
| 150 | u32 status; |
| 151 | |
| 152 | switch (mask) { |
Jonathan Cameron | b11f98f | 2012-04-15 17:41:18 +0100 | [diff] [blame] | 153 | case IIO_CHAN_INFO_RAW: |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 154 | mutex_lock(&indio_dev->mlock); |
| 155 | |
| 156 | status = CHANNEL_NUM(chan->channel) | |
| 157 | AVG_SAMPLE(info->avg_samples) | |
| 158 | START_CONVERSION | ADC_ENABLE; |
| 159 | if (info->vref_external == 0) |
| 160 | status |= VREF_INTERNAL; |
| 161 | |
| 162 | spear_adc_set_status(info, status); |
| 163 | wait_for_completion(&info->completion); /* set by ISR */ |
| 164 | *val = info->value; |
| 165 | |
| 166 | mutex_unlock(&indio_dev->mlock); |
| 167 | |
| 168 | return IIO_VAL_INT; |
| 169 | |
| 170 | case IIO_CHAN_INFO_SCALE: |
| 171 | scale_mv = (info->vref_external * 1000) >> DATA_BITS; |
| 172 | *val = scale_mv / 1000; |
| 173 | *val2 = (scale_mv % 1000) * 1000; |
| 174 | return IIO_VAL_INT_PLUS_MICRO; |
| 175 | } |
| 176 | |
| 177 | return -EINVAL; |
| 178 | } |
| 179 | |
| 180 | #define SPEAR_ADC_CHAN(idx) { \ |
| 181 | .type = IIO_VOLTAGE, \ |
| 182 | .indexed = 1, \ |
Jonathan Cameron | f1e067b | 2013-03-04 21:06:04 +0000 | [diff] [blame] | 183 | .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ |
| 184 | .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 185 | .channel = idx, \ |
| 186 | .scan_type = { \ |
| 187 | .sign = 'u', \ |
| 188 | .storagebits = 16, \ |
| 189 | }, \ |
| 190 | } |
| 191 | |
Lars-Peter Clausen | f4e4b95 | 2012-08-09 08:51:00 +0100 | [diff] [blame] | 192 | static const struct iio_chan_spec spear_adc_iio_channels[] = { |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 193 | SPEAR_ADC_CHAN(0), |
| 194 | SPEAR_ADC_CHAN(1), |
| 195 | SPEAR_ADC_CHAN(2), |
| 196 | SPEAR_ADC_CHAN(3), |
| 197 | SPEAR_ADC_CHAN(4), |
| 198 | SPEAR_ADC_CHAN(5), |
| 199 | SPEAR_ADC_CHAN(6), |
| 200 | SPEAR_ADC_CHAN(7), |
| 201 | }; |
| 202 | |
| 203 | static irqreturn_t spear_adc_isr(int irq, void *dev_id) |
| 204 | { |
| 205 | struct spear_adc_info *info = (struct spear_adc_info *)dev_id; |
| 206 | |
| 207 | /* Read value to clear IRQ */ |
| 208 | info->value = spear_adc_get_average(info); |
| 209 | complete(&info->completion); |
| 210 | |
| 211 | return IRQ_HANDLED; |
| 212 | } |
| 213 | |
| 214 | static int spear_adc_configure(struct spear_adc_info *info) |
| 215 | { |
| 216 | int i; |
| 217 | |
| 218 | /* Reset ADC core */ |
| 219 | spear_adc_set_status(info, 0); |
| 220 | __raw_writel(0, &info->adc_base_spear6xx->clk); |
| 221 | for (i = 0; i < 8; i++) |
| 222 | spear_adc_set_ctrl(info, i, 0); |
| 223 | spear_adc_set_scanrate(info, 0); |
| 224 | |
| 225 | spear_adc_set_clk(info, info->sampling_freq); |
| 226 | |
| 227 | return 0; |
| 228 | } |
| 229 | |
| 230 | static ssize_t spear_adc_read_frequency(struct device *dev, |
| 231 | struct device_attribute *attr, |
| 232 | char *buf) |
| 233 | { |
Lars-Peter Clausen | 62c5183 | 2012-05-12 15:39:42 +0200 | [diff] [blame] | 234 | struct iio_dev *indio_dev = dev_to_iio_dev(dev); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 235 | struct spear_adc_info *info = iio_priv(indio_dev); |
| 236 | |
| 237 | return sprintf(buf, "%d\n", info->current_clk); |
| 238 | } |
| 239 | |
| 240 | static ssize_t spear_adc_write_frequency(struct device *dev, |
| 241 | struct device_attribute *attr, |
| 242 | const char *buf, |
| 243 | size_t len) |
| 244 | { |
Lars-Peter Clausen | 62c5183 | 2012-05-12 15:39:42 +0200 | [diff] [blame] | 245 | struct iio_dev *indio_dev = dev_to_iio_dev(dev); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 246 | struct spear_adc_info *info = iio_priv(indio_dev); |
| 247 | u32 clk_high, clk_low, count; |
| 248 | u32 apb_clk = clk_get_rate(info->clk); |
| 249 | unsigned long lval; |
| 250 | int ret; |
| 251 | |
| 252 | ret = kstrtoul(buf, 10, &lval); |
| 253 | if (ret) |
| 254 | return ret; |
| 255 | |
| 256 | mutex_lock(&indio_dev->mlock); |
| 257 | |
| 258 | if ((lval < CLK_MIN) || (lval > CLK_MAX)) { |
| 259 | ret = -EINVAL; |
| 260 | goto out; |
| 261 | } |
| 262 | |
| 263 | count = (apb_clk + lval - 1) / lval; |
| 264 | clk_low = count / 2; |
| 265 | clk_high = count - clk_low; |
| 266 | info->current_clk = apb_clk / count; |
| 267 | spear_adc_set_clk(info, lval); |
| 268 | |
| 269 | out: |
| 270 | mutex_unlock(&indio_dev->mlock); |
| 271 | |
| 272 | return ret ? ret : len; |
| 273 | } |
| 274 | |
| 275 | static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO, |
| 276 | spear_adc_read_frequency, |
| 277 | spear_adc_write_frequency); |
| 278 | |
| 279 | static struct attribute *spear_attributes[] = { |
| 280 | &iio_dev_attr_sampling_frequency.dev_attr.attr, |
| 281 | NULL |
| 282 | }; |
| 283 | |
| 284 | static const struct attribute_group spear_attribute_group = { |
| 285 | .attrs = spear_attributes, |
| 286 | }; |
| 287 | |
| 288 | static const struct iio_info spear_adc_iio_info = { |
| 289 | .read_raw = &spear_read_raw, |
| 290 | .attrs = &spear_attribute_group, |
| 291 | .driver_module = THIS_MODULE, |
| 292 | }; |
| 293 | |
Bill Pemberton | 4ae1c61 | 2012-11-19 13:21:57 -0500 | [diff] [blame] | 294 | static int spear_adc_probe(struct platform_device *pdev) |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 295 | { |
| 296 | struct device_node *np = pdev->dev.of_node; |
| 297 | struct device *dev = &pdev->dev; |
| 298 | struct spear_adc_info *info; |
| 299 | struct iio_dev *iodev = NULL; |
| 300 | int ret = -ENODEV; |
| 301 | int irq; |
| 302 | |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 303 | iodev = devm_iio_device_alloc(dev, sizeof(struct spear_adc_info)); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 304 | if (!iodev) { |
| 305 | dev_err(dev, "failed allocating iio device\n"); |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 306 | return -ENOMEM; |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 307 | } |
| 308 | |
| 309 | info = iio_priv(iodev); |
| 310 | info->np = np; |
| 311 | |
| 312 | /* |
| 313 | * SPEAr600 has a different register layout than other SPEAr SoC's |
| 314 | * (e.g. SPEAr3xx). Let's provide two register base addresses |
| 315 | * to support multi-arch kernels. |
| 316 | */ |
| 317 | info->adc_base_spear6xx = of_iomap(np, 0); |
| 318 | if (!info->adc_base_spear6xx) { |
| 319 | dev_err(dev, "failed mapping memory\n"); |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 320 | return -ENOMEM; |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 321 | } |
| 322 | info->adc_base_spear3xx = |
| 323 | (struct adc_regs_spear3xx *)info->adc_base_spear6xx; |
| 324 | |
| 325 | info->clk = clk_get(dev, NULL); |
| 326 | if (IS_ERR(info->clk)) { |
| 327 | dev_err(dev, "failed getting clock\n"); |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 328 | goto errout1; |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 329 | } |
| 330 | |
Julia Lawall | f5ed9c3 | 2012-08-26 17:00:00 +0100 | [diff] [blame] | 331 | ret = clk_prepare_enable(info->clk); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 332 | if (ret) { |
| 333 | dev_err(dev, "failed enabling clock\n"); |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 334 | goto errout2; |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 335 | } |
| 336 | |
| 337 | irq = platform_get_irq(pdev, 0); |
| 338 | if ((irq < 0) || (irq >= NR_IRQS)) { |
| 339 | dev_err(dev, "failed getting interrupt resource\n"); |
| 340 | ret = -EINVAL; |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 341 | goto errout3; |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 342 | } |
| 343 | |
| 344 | ret = devm_request_irq(dev, irq, spear_adc_isr, 0, MOD_NAME, info); |
| 345 | if (ret < 0) { |
| 346 | dev_err(dev, "failed requesting interrupt\n"); |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 347 | goto errout3; |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 348 | } |
| 349 | |
| 350 | if (of_property_read_u32(np, "sampling-frequency", |
| 351 | &info->sampling_freq)) { |
| 352 | dev_err(dev, "sampling-frequency missing in DT\n"); |
| 353 | ret = -EINVAL; |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 354 | goto errout3; |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 355 | } |
| 356 | |
| 357 | /* |
| 358 | * Optional avg_samples defaults to 0, resulting in single data |
| 359 | * conversion |
| 360 | */ |
| 361 | of_property_read_u32(np, "average-samples", &info->avg_samples); |
| 362 | |
| 363 | /* |
| 364 | * Optional vref_external defaults to 0, resulting in internal vref |
| 365 | * selection |
| 366 | */ |
| 367 | of_property_read_u32(np, "vref-external", &info->vref_external); |
| 368 | |
| 369 | spear_adc_configure(info); |
| 370 | |
| 371 | platform_set_drvdata(pdev, iodev); |
| 372 | |
| 373 | init_completion(&info->completion); |
| 374 | |
| 375 | iodev->name = MOD_NAME; |
| 376 | iodev->dev.parent = dev; |
| 377 | iodev->info = &spear_adc_iio_info; |
| 378 | iodev->modes = INDIO_DIRECT_MODE; |
| 379 | iodev->channels = spear_adc_iio_channels; |
| 380 | iodev->num_channels = ARRAY_SIZE(spear_adc_iio_channels); |
| 381 | |
| 382 | ret = iio_device_register(iodev); |
| 383 | if (ret) |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 384 | goto errout3; |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 385 | |
| 386 | dev_info(dev, "SPEAR ADC driver loaded, IRQ %d\n", irq); |
| 387 | |
| 388 | return 0; |
| 389 | |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 390 | errout3: |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 391 | clk_disable_unprepare(info->clk); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 392 | errout2: |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 393 | clk_put(info->clk); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 394 | errout1: |
Sachin Kamat | 8c7f6d5 | 2013-07-22 12:02:00 +0100 | [diff] [blame] | 395 | iounmap(info->adc_base_spear6xx); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 396 | return ret; |
| 397 | } |
| 398 | |
Bill Pemberton | 447d4f2 | 2012-11-19 13:26:37 -0500 | [diff] [blame] | 399 | static int spear_adc_remove(struct platform_device *pdev) |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 400 | { |
| 401 | struct iio_dev *iodev = platform_get_drvdata(pdev); |
| 402 | struct spear_adc_info *info = iio_priv(iodev); |
| 403 | |
| 404 | iio_device_unregister(iodev); |
Julia Lawall | f5ed9c3 | 2012-08-26 17:00:00 +0100 | [diff] [blame] | 405 | clk_disable_unprepare(info->clk); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 406 | clk_put(info->clk); |
| 407 | iounmap(info->adc_base_spear6xx); |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 408 | |
| 409 | return 0; |
| 410 | } |
| 411 | |
Sachin Kamat | e89b674 | 2013-06-07 12:06:00 +0100 | [diff] [blame] | 412 | #ifdef CONFIG_OF |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 413 | static const struct of_device_id spear_adc_dt_ids[] = { |
| 414 | { .compatible = "st,spear600-adc", }, |
| 415 | { /* sentinel */ } |
| 416 | }; |
| 417 | MODULE_DEVICE_TABLE(of, spear_adc_dt_ids); |
Sachin Kamat | e89b674 | 2013-06-07 12:06:00 +0100 | [diff] [blame] | 418 | #endif |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 419 | |
| 420 | static struct platform_driver spear_adc_driver = { |
| 421 | .probe = spear_adc_probe, |
Bill Pemberton | e543acf | 2012-11-19 13:21:38 -0500 | [diff] [blame] | 422 | .remove = spear_adc_remove, |
Stefan Roese | b3201b5 | 2012-04-12 11:05:35 +0200 | [diff] [blame] | 423 | .driver = { |
| 424 | .name = MOD_NAME, |
| 425 | .owner = THIS_MODULE, |
| 426 | .of_match_table = of_match_ptr(spear_adc_dt_ids), |
| 427 | }, |
| 428 | }; |
| 429 | |
| 430 | module_platform_driver(spear_adc_driver); |
| 431 | |
| 432 | MODULE_AUTHOR("Stefan Roese <sr@denx.de>"); |
| 433 | MODULE_DESCRIPTION("SPEAr ADC driver"); |
| 434 | MODULE_LICENSE("GPL"); |