target/linux/ramips/patches-3.18/0050-SPI-ralink-add-Ralink-SoC-spi-driver.patch

   1 From fc006d0622ab8c43086b2c9018c03012db332033 Mon Sep 17 00:00:00 2001
   2 From: John Crispin <blogic@openwrt.org>
   3 Date: Sun, 27 Jul 2014 11:15:12 +0100
   4 Subject: [PATCH 50/57] SPI: ralink: add Ralink SoC spi driver
   5
   6 Add the driver needed to make SPI work on Ralink SoC.
   7
   8 Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
   9 Acked-by: John Crispin <blogic@openwrt.org>
  10 ---
  11  drivers/spi/Kconfig      |    6 +
  12  drivers/spi/Makefile     |    1 +
  13  drivers/spi/spi-rt2880.c |  432 ++++++++++++++++++++++++++++++++++++++++++++++
  14  3 files changed, 439 insertions(+)
  15  create mode 100644 drivers/spi/spi-rt2880.c
  16
  17 --- a/drivers/spi/Kconfig
  18 +++ b/drivers/spi/Kconfig
  19 @@ -433,6 +433,12 @@ config SPI_QUP
  20           This driver can also be built as a module.  If so, the module
  21           will be called spi_qup.
  22
  23 +config SPI_RT2880
  24 +       tristate "Ralink RT288x SPI Controller"
  25 +       depends on RALINK
  26 +       help
  27 +         This selects a driver for the Ralink RT288x/RT305x SPI Controller.
  28 +
  29  config SPI_S3C24XX
  30         tristate "Samsung S3C24XX series SPI"
  31         depends on ARCH_S3C24XX
  32 --- a/drivers/spi/Makefile
  33 +++ b/drivers/spi/Makefile
  34 @@ -65,6 +65,7 @@ obj-$(CONFIG_SPI_PXA2XX_PCI)          += spi-pxa
  35  obj-$(CONFIG_SPI_QUP)                  += spi-qup.o
  36  obj-$(CONFIG_SPI_ROCKCHIP)             += spi-rockchip.o
  37  obj-$(CONFIG_SPI_RSPI)                 += spi-rspi.o
  38 +obj-$(CONFIG_SPI_RT2880)               += spi-rt2880.o
  39  obj-$(CONFIG_SPI_S3C24XX)              += spi-s3c24xx-hw.o
  40  spi-s3c24xx-hw-y                       := spi-s3c24xx.o
  41  spi-s3c24xx-hw-$(CONFIG_SPI_S3C24XX_FIQ) += spi-s3c24xx-fiq.o
  42 --- /dev/null
  43 +++ b/drivers/spi/spi-rt2880.c
  44 @@ -0,0 +1,479 @@
  45 +/*
  46 + * spi-rt2880.c -- Ralink RT288x/RT305x SPI controller driver
  47 + *
  48 + * Copyright (C) 2011 Sergiy <piratfm@gmail.com>
  49 + * Copyright (C) 2011-2013 Gabor Juhos <juhosg@openwrt.org>
  50 + *
  51 + * Some parts are based on spi-orion.c:
  52 + *   Author: Shadi Ammouri <shadi@marvell.com>
  53 + *   Copyright (C) 2007-2008 Marvell Ltd.
  54 + *
  55 + * This program is free software; you can redistribute it and/or modify
  56 + * it under the terms of the GNU General Public License version 2 as
  57 + * published by the Free Software Foundation.
  58 + */
  59 +
  60 +#include <linux/init.h>
  61 +#include <linux/module.h>
  62 +#include <linux/clk.h>
  63 +#include <linux/err.h>
  64 +#include <linux/delay.h>
  65 +#include <linux/io.h>
  66 +#include <linux/reset.h>
  67 +#include <linux/spi/spi.h>
  68 +#include <linux/platform_device.h>
  69 +
  70 +#define DRIVER_NAME                    "spi-rt2880"
  71 +/* only one slave is supported*/
  72 +#define RALINK_NUM_CHIPSELECTS         1
  73 +
  74 +#define RAMIPS_SPI_STAT                        0x00
  75 +#define RAMIPS_SPI_CFG                 0x10
  76 +#define RAMIPS_SPI_CTL                 0x14
  77 +#define RAMIPS_SPI_DATA                        0x20
  78 +#define RAMIPS_SPI_ADDR                        0x24
  79 +#define RAMIPS_SPI_BS                  0x28
  80 +#define RAMIPS_SPI_USER                        0x2C
  81 +#define RAMIPS_SPI_TXFIFO              0x30
  82 +#define RAMIPS_SPI_RXFIFO              0x34
  83 +#define RAMIPS_SPI_FIFO_STAT           0x38
  84 +#define RAMIPS_SPI_MODE                        0x3C
  85 +#define RAMIPS_SPI_DEV_OFFSET          0x40
  86 +#define RAMIPS_SPI_DMA                 0x80
  87 +#define RAMIPS_SPI_DMASTAT             0x84
  88 +#define RAMIPS_SPI_ARBITER             0xF0
  89 +
  90 +/* SPISTAT register bit field */
  91 +#define SPISTAT_BUSY                   BIT(0)
  92 +
  93 +/* SPICFG register bit field */
  94 +#define SPICFG_ADDRMODE                        BIT(12)
  95 +#define SPICFG_RXENVDIS                        BIT(11)
  96 +#define SPICFG_RXCAP                   BIT(10)
  97 +#define SPICFG_SPIENMODE               BIT(9)
  98 +#define SPICFG_MSBFIRST                        BIT(8)
  99 +#define SPICFG_SPICLKPOL               BIT(6)
 100 +#define SPICFG_RXCLKEDGE_FALLING       BIT(5)
 101 +#define SPICFG_TXCLKEDGE_FALLING       BIT(4)
 102 +#define SPICFG_HIZSPI                  BIT(3)
 103 +#define SPICFG_SPICLK_PRESCALE_MASK    0x7
 104 +#define SPICFG_SPICLK_DIV2             0
 105 +#define SPICFG_SPICLK_DIV4             1
 106 +#define SPICFG_SPICLK_DIV8             2
 107 +#define SPICFG_SPICLK_DIV16            3
 108 +#define SPICFG_SPICLK_DIV32            4
 109 +#define SPICFG_SPICLK_DIV64            5
 110 +#define SPICFG_SPICLK_DIV128           6
 111 +#define SPICFG_SPICLK_DISABLE          7
 112 +
 113 +/* SPICTL register bit field */
 114 +#define SPICTL_START                   BIT(4)
 115 +#define SPICTL_HIZSDO                  BIT(3)
 116 +#define SPICTL_STARTWR                 BIT(2)
 117 +#define SPICTL_STARTRD                 BIT(1)
 118 +#define SPICTL_SPIENA                  BIT(0)
 119 +
 120 +/* SPIUSER register bit field */
 121 +#define SPIUSER_USERMODE               BIT(21)
 122 +#define SPIUSER_INSTR_PHASE            BIT(20)
 123 +#define SPIUSER_ADDR_PHASE_MASK                0x7
 124 +#define SPIUSER_ADDR_PHASE_OFFSET      17
 125 +#define SPIUSER_MODE_PHASE             BIT(16)
 126 +#define SPIUSER_DUMMY_PHASE_MASK       0x3
 127 +#define SPIUSER_DUMMY_PHASE_OFFSET     14
 128 +#define SPIUSER_DATA_PHASE_MASK                0x3
 129 +#define SPIUSER_DATA_PHASE_OFFSET      12
 130 +#define SPIUSER_DATA_READ              (BIT(0) << SPIUSER_DATA_PHASE_OFFSET)
 131 +#define SPIUSER_DATA_WRITE             (BIT(1) << SPIUSER_DATA_PHASE_OFFSET)
 132 +#define SPIUSER_ADDR_TYPE_OFFSET       9
 133 +#define SPIUSER_MODE_TYPE_OFFSET       6
 134 +#define SPIUSER_DUMMY_TYPE_OFFSET      3
 135 +#define SPIUSER_DATA_TYPE_OFFSET       0
 136 +#define SPIUSER_TRANSFER_MASK          0x7
 137 +#define SPIUSER_TRANSFER_SINGLE                BIT(0)
 138 +#define SPIUSER_TRANSFER_DUAL          BIT(1)
 139 +#define SPIUSER_TRANSFER_QUAD          BIT(2)
 140 +
 141 +#define SPIUSER_TRANSFER_TYPE(type) ( \
 142 +       (type << SPIUSER_ADDR_TYPE_OFFSET) | \
 143 +       (type << SPIUSER_MODE_TYPE_OFFSET) | \
 144 +       (type << SPIUSER_DUMMY_TYPE_OFFSET) | \
 145 +       (type << SPIUSER_DATA_TYPE_OFFSET) \
 146 +)
 147 +
 148 +/* SPIFIFOSTAT register bit field */
 149 +#define SPIFIFOSTAT_TXEMPTY            BIT(19)
 150 +#define SPIFIFOSTAT_RXEMPTY            BIT(18)
 151 +#define SPIFIFOSTAT_TXFULL             BIT(17)
 152 +#define SPIFIFOSTAT_RXFULL             BIT(16)
 153 +#define SPIFIFOSTAT_FIFO_MASK          0xff
 154 +#define SPIFIFOSTAT_TX_OFFSET          8
 155 +#define SPIFIFOSTAT_RX_OFFSET          0
 156 +
 157 +#define SPI_FIFO_DEPTH                 16
 158 +
 159 +/* SPIMODE register bit field */
 160 +#define SPIMODE_MODE_OFFSET            24
 161 +#define SPIMODE_DUMMY_OFFSET           0
 162 +
 163 +/* SPIARB register bit field */
 164 +#define SPICTL_ARB_EN                  BIT(31)
 165 +#define SPICTL_CSCTL1                  BIT(16)
 166 +#define SPI1_POR                       BIT(1)
 167 +#define SPI0_POR                       BIT(0)
 168 +
 169 +struct rt2880_spi {
 170 +       struct spi_master       *master;
 171 +       void __iomem            *base;
 172 +       unsigned int            sys_freq;
 173 +       unsigned int            speed;
 174 +       u16                     wait_loops;
 175 +       struct clk              *clk;
 176 +};
 177 +
 178 +static inline struct rt2880_spi *spidev_to_rt2880_spi(struct spi_device *spi)
 179 +{
 180 +       return spi_master_get_devdata(spi->master);
 181 +}
 182 +
 183 +static inline u32 rt2880_spi_read(struct rt2880_spi *rs, u32 reg)
 184 +{
 185 +       return ioread32(rs->base + reg);
 186 +}
 187 +
 188 +static inline void rt2880_spi_write(struct rt2880_spi *rs, u32 reg,
 189 +               const u32 val)
 190 +{
 191 +       iowrite32(val, rs->base + reg);
 192 +}
 193 +
 194 +static inline void rt2880_spi_setbits(struct rt2880_spi *rs, u32 reg, u32 mask)
 195 +{
 196 +       void __iomem *addr = rs->base + reg;
 197 +
 198 +       iowrite32((ioread32(addr) | mask), addr);
 199 +}
 200 +
 201 +static inline void rt2880_spi_clrbits(struct rt2880_spi *rs, u32 reg, u32 mask)
 202 +{
 203 +       void __iomem *addr = rs->base + reg;
 204 +
 205 +       iowrite32((ioread32(addr) & ~mask), addr);
 206 +}
 207 +
 208 +static int rt2880_spi_baudrate_set(struct spi_device *spi, unsigned int speed)
 209 +{
 210 +       struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
 211 +       u32 rate;
 212 +       u32 prescale;
 213 +       u32 reg;
 214 +
 215 +       dev_dbg(&spi->dev, "speed:%u\n", speed);
 216 +
 217 +       /*
 218 +        * the supported rates are: 2, 4, 8, ... 128
 219 +        * round up as we look for equal or less speed
 220 +        */
 221 +       rate = DIV_ROUND_UP(rs->sys_freq, speed);
 222 +       dev_dbg(&spi->dev, "rate-1:%u\n", rate);
 223 +       rate = roundup_pow_of_two(rate);
 224 +       dev_dbg(&spi->dev, "rate-2:%u\n", rate);
 225 +
 226 +       /* check if requested speed is too small */
 227 +       if (rate > 128)
 228 +               return -EINVAL;
 229 +
 230 +       if (rate < 2)
 231 +               rate = 2;
 232 +
 233 +       /* Convert the rate to SPI clock divisor value. */
 234 +       prescale = ilog2(rate / 2);
 235 +       dev_dbg(&spi->dev, "prescale:%u\n", prescale);
 236 +
 237 +       reg = rt2880_spi_read(rs, RAMIPS_SPI_CFG);
 238 +       reg = ((reg & ~SPICFG_SPICLK_PRESCALE_MASK) | prescale);
 239 +       rt2880_spi_write(rs, RAMIPS_SPI_CFG, reg);
 240 +
 241 +       /* some tolerance. double and add 100 */
 242 +       rs->wait_loops = (8 * HZ * loops_per_jiffy) /
 243 +               (clk_get_rate(rs->clk) / rate);
 244 +       rs->wait_loops = (rs->wait_loops << 1) + 100;
 245 +       rs->speed = speed;
 246 +       return 0;
 247 +}
 248 +
 249 +/*
 250 + * called only when no transfer is active on the bus
 251 + */
 252 +static int
 253 +rt2880_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
 254 +{
 255 +       struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
 256 +       unsigned int speed = spi->max_speed_hz;
 257 +       int rc;
 258 +
 259 +       if ((t != NULL) && t->speed_hz)
 260 +               speed = t->speed_hz;
 261 +
 262 +       if (rs->speed != speed) {
 263 +               dev_dbg(&spi->dev, "speed_hz:%u\n", speed);
 264 +               rc = rt2880_spi_baudrate_set(spi, speed);
 265 +               if (rc)
 266 +                       return rc;
 267 +       }
 268 +
 269 +       return 0;
 270 +}
 271 +
 272 +static void rt2880_spi_set_cs(struct rt2880_spi *rs, int enable)
 273 +{
 274 +       if (enable)
 275 +               rt2880_spi_clrbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
 276 +       else
 277 +               rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_SPIENA);
 278 +}
 279 +
 280 +static int rt2880_spi_wait_ready(struct rt2880_spi *rs, int len)
 281 +{
 282 +       int loop = rs->wait_loops * len;
 283 +
 284 +       while ((rt2880_spi_read(rs, RAMIPS_SPI_STAT) & SPISTAT_BUSY) && --loop)
 285 +               cpu_relax();
 286 +
 287 +       if (loop)
 288 +               return 0;
 289 +
 290 +       return -ETIMEDOUT;
 291 +}
 292 +
 293 +static unsigned int
 294 +rt2880_spi_write_read(struct spi_device *spi, struct spi_transfer *xfer)
 295 +{
 296 +       struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
 297 +       unsigned count = 0;
 298 +       u8 *rx = xfer->rx_buf;
 299 +       const u8 *tx = xfer->tx_buf;
 300 +       int err;
 301 +
 302 +       dev_dbg(&spi->dev, "read (%d): %s %s\n", xfer->len,
 303 +                 (tx != NULL) ? "tx" : "  ",
 304 +                 (rx != NULL) ? "rx" : "  ");
 305 +
 306 +       if (tx) {
 307 +               for (count = 0; count < xfer->len; count++) {
 308 +                       rt2880_spi_write(rs, RAMIPS_SPI_DATA, tx[count]);
 309 +                       rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTWR);
 310 +                       err = rt2880_spi_wait_ready(rs, 1);
 311 +                       if (err) {
 312 +                               dev_err(&spi->dev, "TX failed, err=%d\n", err);
 313 +                               goto out;
 314 +                       }
 315 +               }
 316 +       }
 317 +
 318 +       if (rx) {
 319 +               for (count = 0; count < xfer->len; count++) {
 320 +                       rt2880_spi_setbits(rs, RAMIPS_SPI_CTL, SPICTL_STARTRD);
 321 +                       err = rt2880_spi_wait_ready(rs, 1);
 322 +                       if (err) {
 323 +                               dev_err(&spi->dev, "RX failed, err=%d\n", err);
 324 +                               goto out;
 325 +                       }
 326 +                       rx[count] = (u8) rt2880_spi_read(rs, RAMIPS_SPI_DATA);
 327 +               }
 328 +       }
 329 +
 330 +out:
 331 +       return count;
 332 +}
 333 +
 334 +static int rt2880_spi_transfer_one_message(struct spi_master *master,
 335 +                                          struct spi_message *m)
 336 +{
 337 +       struct rt2880_spi *rs = spi_master_get_devdata(master);
 338 +       struct spi_device *spi = m->spi;
 339 +       struct spi_transfer *t = NULL;
 340 +       int par_override = 0;
 341 +       int status = 0;
 342 +       int cs_active = 0;
 343 +
 344 +       /* Load defaults */
 345 +       status = rt2880_spi_setup_transfer(spi, NULL);
 346 +       if (status < 0)
 347 +               goto msg_done;
 348 +
 349 +       list_for_each_entry(t, &m->transfers, transfer_list) {
 350 +               if (t->tx_buf == NULL && t->rx_buf == NULL && t->len) {
 351 +                       dev_err(&spi->dev,
 352 +                               "message rejected: invalid transfer data buffers\n");
 353 +                       status = -EIO;
 354 +                       goto msg_done;
 355 +               }
 356 +
 357 +               if (t->speed_hz && t->speed_hz < (rs->sys_freq / 128)) {
 358 +                       dev_err(&spi->dev,
 359 +                               "message rejected: device min speed (%d Hz) exceeds required transfer speed (%d Hz)\n",
 360 +                               (rs->sys_freq / 128), t->speed_hz);
 361 +                       status = -EIO;
 362 +                       goto msg_done;
 363 +               }
 364 +
 365 +               if (par_override || t->speed_hz || t->bits_per_word) {
 366 +                       par_override = 1;
 367 +                       status = rt2880_spi_setup_transfer(spi, t);
 368 +                       if (status < 0)
 369 +                               goto msg_done;
 370 +                       if (!t->speed_hz && !t->bits_per_word)
 371 +                               par_override = 0;
 372 +               }
 373 +
 374 +               if (!cs_active) {
 375 +                       rt2880_spi_set_cs(rs, 1);
 376 +                       cs_active = 1;
 377 +               }
 378 +
 379 +               if (t->len)
 380 +                       m->actual_length += rt2880_spi_write_read(spi, t);
 381 +
 382 +               if (t->delay_usecs)
 383 +                       udelay(t->delay_usecs);
 384 +
 385 +               if (t->cs_change) {
 386 +                       rt2880_spi_set_cs(rs, 0);
 387 +                       cs_active = 0;
 388 +               }
 389 +       }
 390 +
 391 +msg_done:
 392 +       if (cs_active)
 393 +               rt2880_spi_set_cs(rs, 0);
 394 +
 395 +       m->status = status;
 396 +       spi_finalize_current_message(master);
 397 +
 398 +       return 0;
 399 +}
 400 +
 401 +static int rt2880_spi_setup(struct spi_device *spi)
 402 +{
 403 +       struct rt2880_spi *rs = spidev_to_rt2880_spi(spi);
 404 +
 405 +       if ((spi->max_speed_hz == 0) ||
 406 +           (spi->max_speed_hz > (rs->sys_freq / 2)))
 407 +               spi->max_speed_hz = (rs->sys_freq / 2);
 408 +
 409 +       if (spi->max_speed_hz < (rs->sys_freq / 128)) {
 410 +               dev_err(&spi->dev, "setup: requested speed is too low %d Hz\n",
 411 +                       spi->max_speed_hz);
 412 +               return -EINVAL;
 413 +       }
 414 +
 415 +       /*
 416 +        * baudrate & width will be set rt2880_spi_setup_transfer
 417 +        */
 418 +       return 0;
 419 +}
 420 +
 421 +static void rt2880_spi_reset(struct rt2880_spi *rs)
 422 +{
 423 +       rt2880_spi_write(rs, RAMIPS_SPI_CFG,
 424 +                        SPICFG_MSBFIRST | SPICFG_TXCLKEDGE_FALLING |
 425 +                        SPICFG_SPICLK_DIV16 | SPICFG_SPICLKPOL);
 426 +       rt2880_spi_write(rs, RAMIPS_SPI_CTL, SPICTL_HIZSDO | SPICTL_SPIENA);
 427 +}
 428 +
 429 +static int rt2880_spi_probe(struct platform_device *pdev)
 430 +{
 431 +       struct spi_master *master;
 432 +       struct rt2880_spi *rs;
 433 +       unsigned long flags;
 434 +       void __iomem *base;
 435 +       struct resource *r;
 436 +       int status = 0;
 437 +       struct clk *clk;
 438 +
 439 +       r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 440 +       base = devm_ioremap_resource(&pdev->dev, r);
 441 +       if (IS_ERR(base))
 442 +               return PTR_ERR(base);
 443 +
 444 +       clk = devm_clk_get(&pdev->dev, NULL);
 445 +       if (IS_ERR(clk)) {
 446 +               dev_err(&pdev->dev, "unable to get SYS clock, err=%d\n",
 447 +                       status);
 448 +               return PTR_ERR(clk);
 449 +       }
 450 +
 451 +       status = clk_prepare_enable(clk);
 452 +       if (status)
 453 +               return status;
 454 +
 455 +       master = spi_alloc_master(&pdev->dev, sizeof(*rs));
 456 +       if (master == NULL) {
 457 +               dev_dbg(&pdev->dev, "master allocation failed\n");
 458 +               return -ENOMEM;
 459 +       }
 460 +
 461 +       /* we support only mode 0, and no options */
 462 +       master->mode_bits = 0;
 463 +
 464 +       master->setup = rt2880_spi_setup;
 465 +       master->transfer_one_message = rt2880_spi_transfer_one_message;
 466 +       master->num_chipselect = RALINK_NUM_CHIPSELECTS;
 467 +       master->bits_per_word_mask = SPI_BPW_MASK(8);
 468 +       master->dev.of_node = pdev->dev.of_node;
 469 +
 470 +       dev_set_drvdata(&pdev->dev, master);
 471 +
 472 +       rs = spi_master_get_devdata(master);
 473 +       rs->base = base;
 474 +       rs->clk = clk;
 475 +       rs->master = master;
 476 +       rs->sys_freq = clk_get_rate(rs->clk);
 477 +       dev_dbg(&pdev->dev, "sys_freq: %u\n", rs->sys_freq);
 478 +
 479 +       device_reset(&pdev->dev);
 480 +
 481 +       rt2880_spi_reset(rs);
 482 +
 483 +       return spi_register_master(master);
 484 +}
 485 +
 486 +static int rt2880_spi_remove(struct platform_device *pdev)
 487 +{
 488 +       struct spi_master *master;
 489 +       struct rt2880_spi *rs;
 490 +
 491 +       master = dev_get_drvdata(&pdev->dev);
 492 +       rs = spi_master_get_devdata(master);
 493 +
 494 +       clk_disable(rs->clk);
 495 +       spi_unregister_master(master);
 496 +
 497 +       return 0;
 498 +}
 499 +
 500 +MODULE_ALIAS("platform:" DRIVER_NAME);
 501 +
 502 +static const struct of_device_id rt2880_spi_match[] = {
 503 +       { .compatible = "ralink,rt2880-spi" },
 504 +       {},
 505 +};
 506 +MODULE_DEVICE_TABLE(of, rt2880_spi_match);
 507 +
 508 +static struct platform_driver rt2880_spi_driver = {
 509 +       .driver = {
 510 +               .name = DRIVER_NAME,
 511 +               .owner = THIS_MODULE,
 512 +               .of_match_table = rt2880_spi_match,
 513 +       },
 514 +       .probe = rt2880_spi_probe,
 515 +       .remove = rt2880_spi_remove,
 516 +};
 517 +
 518 +module_platform_driver(rt2880_spi_driver);
 519 +
 520 +MODULE_DESCRIPTION("Ralink SPI driver");
 521 +MODULE_AUTHOR("Sergiy <piratfm@gmail.com>");
 522 +MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 523 +MODULE_LICENSE("GPL");