drivers/spi/spi-altera.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Altera SPI driver
   4  *
   5  * Copyright (C) 2008 Thomas Chou <thomas@wytron.com.tw>
   6  *
   7  * Based on spi_s3c24xx.c, which is:
   8  * Copyright (c) 2006 Ben Dooks
   9  * Copyright (c) 2006 Simtec Electronics
  10  *      Ben Dooks <ben@simtec.co.uk>
  11  */
  12
  13 #include <linux/interrupt.h>
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/spi/altera.h>
  18 #include <linux/spi/spi.h>
  19 #include <linux/io.h>
  20 #include <linux/of.h>
  21
  22 #define DRV_NAME "spi_altera"
  23
  24 #define ALTERA_SPI_RXDATA       0
  25 #define ALTERA_SPI_TXDATA       4
  26 #define ALTERA_SPI_STATUS       8
  27 #define ALTERA_SPI_CONTROL      12
  28 #define ALTERA_SPI_SLAVE_SEL    20
  29
  30 #define ALTERA_SPI_STATUS_ROE_MSK       0x8
  31 #define ALTERA_SPI_STATUS_TOE_MSK       0x10
  32 #define ALTERA_SPI_STATUS_TMT_MSK       0x20
  33 #define ALTERA_SPI_STATUS_TRDY_MSK      0x40
  34 #define ALTERA_SPI_STATUS_RRDY_MSK      0x80
  35 #define ALTERA_SPI_STATUS_E_MSK         0x100
  36
  37 #define ALTERA_SPI_CONTROL_IROE_MSK     0x8
  38 #define ALTERA_SPI_CONTROL_ITOE_MSK     0x10
  39 #define ALTERA_SPI_CONTROL_ITRDY_MSK    0x40
  40 #define ALTERA_SPI_CONTROL_IRRDY_MSK    0x80
  41 #define ALTERA_SPI_CONTROL_IE_MSK       0x100
  42 #define ALTERA_SPI_CONTROL_SSO_MSK      0x400
  43
  44 #define ALTERA_SPI_MAX_CS               32
  45
  46 enum altera_spi_type {
  47         ALTERA_SPI_TYPE_UNKNOWN,
  48         ALTERA_SPI_TYPE_SUBDEV,
  49 };
  50
  51 struct altera_spi {
  52         int irq;
  53         int len;
  54         int count;
  55         int bytes_per_word;
  56         u32 imr;
  57
  58         /* data buffers */
  59         const unsigned char *tx;
  60         unsigned char *rx;
  61
  62         struct regmap *regmap;
  63         u32 regoff;
  64         struct device *dev;
  65 };
  66
  67 static const struct regmap_config spi_altera_config = {
  68         .reg_bits = 32,
  69         .reg_stride = 4,
  70         .val_bits = 32,
  71         .fast_io = true,
  72 };
  73
  74 static int altr_spi_writel(struct altera_spi *hw, unsigned int reg,
  75                            unsigned int val)
  76 {
  77         int ret;
  78
  79         ret = regmap_write(hw->regmap, hw->regoff + reg, val);
  80         if (ret)
  81                 dev_err(hw->dev, "fail to write reg 0x%x val 0x%x: %d\n",
  82                         reg, val, ret);
  83
  84         return ret;
  85 }
  86
  87 static int altr_spi_readl(struct altera_spi *hw, unsigned int reg,
  88                           unsigned int *val)
  89 {
  90         int ret;
  91
  92         ret = regmap_read(hw->regmap, hw->regoff + reg, val);
  93         if (ret)
  94                 dev_err(hw->dev, "fail to read reg 0x%x: %d\n", reg, ret);
  95
  96         return ret;
  97 }
  98
  99 static inline struct altera_spi *altera_spi_to_hw(struct spi_device *sdev)
 100 {
 101         return spi_master_get_devdata(sdev->master);
 102 }
 103
 104 static void altera_spi_set_cs(struct spi_device *spi, bool is_high)
 105 {
 106         struct altera_spi *hw = altera_spi_to_hw(spi);
 107
 108         if (is_high) {
 109                 hw->imr &= ~ALTERA_SPI_CONTROL_SSO_MSK;
 110                 altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
 111                 altr_spi_writel(hw, ALTERA_SPI_SLAVE_SEL, 0);
 112         } else {
 113                 altr_spi_writel(hw, ALTERA_SPI_SLAVE_SEL,
 114                                 BIT(spi->chip_select));
 115                 hw->imr |= ALTERA_SPI_CONTROL_SSO_MSK;
 116                 altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
 117         }
 118 }
 119
 120 static void altera_spi_tx_word(struct altera_spi *hw)
 121 {
 122         unsigned int txd = 0;
 123
 124         if (hw->tx) {
 125                 switch (hw->bytes_per_word) {
 126                 case 1:
 127                         txd = hw->tx[hw->count];
 128                         break;
 129                 case 2:
 130                         txd = (hw->tx[hw->count * 2]
 131                                 | (hw->tx[hw->count * 2 + 1] << 8));
 132                         break;
 133                 case 4:
 134                         txd = (hw->tx[hw->count * 4]
 135                                 | (hw->tx[hw->count * 4 + 1] << 8)
 136                                 | (hw->tx[hw->count * 4 + 2] << 16)
 137                                 | (hw->tx[hw->count * 4 + 3] << 24));
 138                         break;
 139
 140                 }
 141         }
 142
 143         altr_spi_writel(hw, ALTERA_SPI_TXDATA, txd);
 144 }
 145
 146 static void altera_spi_rx_word(struct altera_spi *hw)
 147 {
 148         unsigned int rxd;
 149
 150         altr_spi_readl(hw, ALTERA_SPI_RXDATA, &rxd);
 151         if (hw->rx) {
 152                 switch (hw->bytes_per_word) {
 153                 case 1:
 154                         hw->rx[hw->count] = rxd;
 155                         break;
 156                 case 2:
 157                         hw->rx[hw->count * 2] = rxd;
 158                         hw->rx[hw->count * 2 + 1] = rxd >> 8;
 159                         break;
 160                 case 4:
 161                         hw->rx[hw->count * 4] = rxd;
 162                         hw->rx[hw->count * 4 + 1] = rxd >> 8;
 163                         hw->rx[hw->count * 4 + 2] = rxd >> 16;
 164                         hw->rx[hw->count * 4 + 3] = rxd >> 24;
 165                         break;
 166
 167                 }
 168         }
 169
 170         hw->count++;
 171 }
 172
 173 static int altera_spi_txrx(struct spi_master *master,
 174         struct spi_device *spi, struct spi_transfer *t)
 175 {
 176         struct altera_spi *hw = spi_master_get_devdata(master);
 177         u32 val;
 178
 179         hw->tx = t->tx_buf;
 180         hw->rx = t->rx_buf;
 181         hw->count = 0;
 182         hw->bytes_per_word = DIV_ROUND_UP(t->bits_per_word, 8);
 183         hw->len = t->len / hw->bytes_per_word;
 184
 185         if (hw->irq >= 0) {
 186                 /* enable receive interrupt */
 187                 hw->imr |= ALTERA_SPI_CONTROL_IRRDY_MSK;
 188                 altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
 189
 190                 /* send the first byte */
 191                 altera_spi_tx_word(hw);
 192         } else {
 193                 while (hw->count < hw->len) {
 194                         altera_spi_tx_word(hw);
 195
 196                         for (;;) {
 197                                 altr_spi_readl(hw, ALTERA_SPI_STATUS, &val);
 198                                 if (val & ALTERA_SPI_STATUS_RRDY_MSK)
 199                                         break;
 200
 201                                 cpu_relax();
 202                         }
 203
 204                         altera_spi_rx_word(hw);
 205                 }
 206                 spi_finalize_current_transfer(master);
 207         }
 208
 209         return t->len;
 210 }
 211
 212 static irqreturn_t altera_spi_irq(int irq, void *dev)
 213 {
 214         struct spi_master *master = dev;
 215         struct altera_spi *hw = spi_master_get_devdata(master);
 216
 217         altera_spi_rx_word(hw);
 218
 219         if (hw->count < hw->len) {
 220                 altera_spi_tx_word(hw);
 221         } else {
 222                 /* disable receive interrupt */
 223                 hw->imr &= ~ALTERA_SPI_CONTROL_IRRDY_MSK;
 224                 altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
 225
 226                 spi_finalize_current_transfer(master);
 227         }
 228
 229         return IRQ_HANDLED;
 230 }
 231
 232 static int altera_spi_probe(struct platform_device *pdev)
 233 {
 234         const struct platform_device_id *platid = platform_get_device_id(pdev);
 235         struct altera_spi_platform_data *pdata = dev_get_platdata(&pdev->dev);
 236         enum altera_spi_type type = ALTERA_SPI_TYPE_UNKNOWN;
 237         struct altera_spi *hw;
 238         struct spi_master *master;
 239         int err = -ENODEV;
 240         u32 val;
 241         u16 i;
 242
 243         master = spi_alloc_master(&pdev->dev, sizeof(struct altera_spi));
 244         if (!master)
 245                 return err;
 246
 247         /* setup the master state. */
 248         master->bus_num = pdev->id;
 249
 250         if (pdata) {
 251                 if (pdata->num_chipselect > ALTERA_SPI_MAX_CS) {
 252                         dev_err(&pdev->dev,
 253                                 "Invalid number of chipselect: %hu\n",
 254                                 pdata->num_chipselect);
 255                         return -EINVAL;
 256                 }
 257
 258                 master->num_chipselect = pdata->num_chipselect;
 259                 master->mode_bits = pdata->mode_bits;
 260                 master->bits_per_word_mask = pdata->bits_per_word_mask;
 261         } else {
 262                 master->num_chipselect = 16;
 263                 master->mode_bits = SPI_CS_HIGH;
 264                 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
 265         }
 266
 267         master->dev.of_node = pdev->dev.of_node;
 268         master->transfer_one = altera_spi_txrx;
 269         master->set_cs = altera_spi_set_cs;
 270
 271         hw = spi_master_get_devdata(master);
 272         hw->dev = &pdev->dev;
 273
 274         if (platid)
 275                 type = platid->driver_data;
 276
 277         /* find and map our resources */
 278         if (type == ALTERA_SPI_TYPE_SUBDEV) {
 279                 struct resource *regoff;
 280
 281                 hw->regmap = dev_get_regmap(pdev->dev.parent, NULL);
 282                 if (!hw->regmap) {
 283                         dev_err(&pdev->dev, "get regmap failed\n");
 284                         goto exit;
 285                 }
 286
 287                 regoff = platform_get_resource(pdev, IORESOURCE_REG, 0);
 288                 if (regoff)
 289                         hw->regoff = regoff->start;
 290         } else {
 291                 void __iomem *res;
 292
 293                 res = devm_platform_ioremap_resource(pdev, 0);
 294                 if (IS_ERR(res)) {
 295                         err = PTR_ERR(res);
 296                         goto exit;
 297                 }
 298
 299                 hw->regmap = devm_regmap_init_mmio(&pdev->dev, res,
 300                                                    &spi_altera_config);
 301                 if (IS_ERR(hw->regmap)) {
 302                         dev_err(&pdev->dev, "regmap mmio init failed\n");
 303                         err = PTR_ERR(hw->regmap);
 304                         goto exit;
 305                 }
 306         }
 307
 308         /* program defaults into the registers */
 309         hw->imr = 0;            /* disable spi interrupts */
 310         altr_spi_writel(hw, ALTERA_SPI_CONTROL, hw->imr);
 311         altr_spi_writel(hw, ALTERA_SPI_STATUS, 0);      /* clear status reg */
 312         altr_spi_readl(hw, ALTERA_SPI_STATUS, &val);
 313         if (val & ALTERA_SPI_STATUS_RRDY_MSK)
 314                 altr_spi_readl(hw, ALTERA_SPI_RXDATA, &val); /* flush rxdata */
 315         /* irq is optional */
 316         hw->irq = platform_get_irq(pdev, 0);
 317         if (hw->irq >= 0) {
 318                 err = devm_request_irq(&pdev->dev, hw->irq, altera_spi_irq, 0,
 319                                        pdev->name, master);
 320                 if (err)
 321                         goto exit;
 322         }
 323
 324         err = devm_spi_register_master(&pdev->dev, master);
 325         if (err)
 326                 goto exit;
 327
 328         if (pdata) {
 329                 for (i = 0; i < pdata->num_devices; i++) {
 330                         if (!spi_new_device(master, pdata->devices + i))
 331                                 dev_warn(&pdev->dev,
 332                                          "unable to create SPI device: %s\n",
 333                                          pdata->devices[i].modalias);
 334                 }
 335         }
 336
 337         dev_info(&pdev->dev, "regoff %u, irq %d\n", hw->regoff, hw->irq);
 338
 339         return 0;
 340 exit:
 341         spi_master_put(master);
 342         return err;
 343 }
 344
 345 #ifdef CONFIG_OF
 346 static const struct of_device_id altera_spi_match[] = {
 347         { .compatible = "ALTR,spi-1.0", },
 348         { .compatible = "altr,spi-1.0", },
 349         {},
 350 };
 351 MODULE_DEVICE_TABLE(of, altera_spi_match);
 352 #endif /* CONFIG_OF */
 353
 354 static const struct platform_device_id altera_spi_ids[] = {
 355         { DRV_NAME,             ALTERA_SPI_TYPE_UNKNOWN },
 356         { "subdev_spi_altera",  ALTERA_SPI_TYPE_SUBDEV },
 357         { }
 358 };
 359 MODULE_DEVICE_TABLE(platform, altera_spi_ids);
 360
 361 static struct platform_driver altera_spi_driver = {
 362         .probe = altera_spi_probe,
 363         .driver = {
 364                 .name = DRV_NAME,
 365                 .pm = NULL,
 366                 .of_match_table = of_match_ptr(altera_spi_match),
 367         },
 368         .id_table       = altera_spi_ids,
 369 };
 370 module_platform_driver(altera_spi_driver);
 371
 372 MODULE_DESCRIPTION("Altera SPI driver");
 373 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
 374 MODULE_LICENSE("GPL");
 375 MODULE_ALIAS("platform:" DRV_NAME);