drivers/spi/spi-sh-hspi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SuperH HSPI bus driver
   4  *
   5  * Copyright (C) 2011  Kuninori Morimoto
   6  *
   7  * Based on spi-sh.c:
   8  * Based on pxa2xx_spi.c:
   9  * Copyright (C) 2011 Renesas Solutions Corp.
  10  * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
  11  */
  12
  13 #include <linux/clk.h>
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/timer.h>
  17 #include <linux/delay.h>
  18 #include <linux/list.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/pm_runtime.h>
  22 #include <linux/io.h>
  23 #include <linux/spi/spi.h>
  24 #include <linux/spi/sh_hspi.h>
  25
  26 #define SPCR    0x00
  27 #define SPSR    0x04
  28 #define SPSCR   0x08
  29 #define SPTBR   0x0C
  30 #define SPRBR   0x10
  31 #define SPCR2   0x14
  32
  33 /* SPSR */
  34 #define RXFL    (1 << 2)
  35
  36 struct hspi_priv {
  37         void __iomem *addr;
  38         struct spi_master *master;
  39         struct device *dev;
  40         struct clk *clk;
  41 };
  42
  43 /*
  44  *              basic function
  45  */
  46 static void hspi_write(struct hspi_priv *hspi, int reg, u32 val)
  47 {
  48         iowrite32(val, hspi->addr + reg);
  49 }
  50
  51 static u32 hspi_read(struct hspi_priv *hspi, int reg)
  52 {
  53         return ioread32(hspi->addr + reg);
  54 }
  55
  56 static void hspi_bit_set(struct hspi_priv *hspi, int reg, u32 mask, u32 set)
  57 {
  58         u32 val = hspi_read(hspi, reg);
  59
  60         val &= ~mask;
  61         val |= set & mask;
  62
  63         hspi_write(hspi, reg, val);
  64 }
  65
  66 /*
  67  *              transfer function
  68  */
  69 static int hspi_status_check_timeout(struct hspi_priv *hspi, u32 mask, u32 val)
  70 {
  71         int t = 256;
  72
  73         while (t--) {
  74                 if ((mask & hspi_read(hspi, SPSR)) == val)
  75                         return 0;
  76
  77                 udelay(10);
  78         }
  79
  80         dev_err(hspi->dev, "timeout\n");
  81         return -ETIMEDOUT;
  82 }
  83
  84 /*
  85  *              spi master function
  86  */
  87
  88 #define hspi_hw_cs_enable(hspi)         hspi_hw_cs_ctrl(hspi, 0)
  89 #define hspi_hw_cs_disable(hspi)        hspi_hw_cs_ctrl(hspi, 1)
  90 static void hspi_hw_cs_ctrl(struct hspi_priv *hspi, int hi)
  91 {
  92         hspi_bit_set(hspi, SPSCR, (1 << 6), (hi) << 6);
  93 }
  94
  95 static void hspi_hw_setup(struct hspi_priv *hspi,
  96                           struct spi_message *msg,
  97                           struct spi_transfer *t)
  98 {
  99         struct spi_device *spi = msg->spi;
 100         struct device *dev = hspi->dev;
 101         u32 spcr, idiv_clk;
 102         u32 rate, best_rate, min, tmp;
 103
 104         /*
 105          * find best IDIV/CLKCx settings
 106          */
 107         min = ~0;
 108         best_rate = 0;
 109         spcr = 0;
 110         for (idiv_clk = 0x00; idiv_clk <= 0x3F; idiv_clk++) {
 111                 rate = clk_get_rate(hspi->clk);
 112
 113                 /* IDIV calculation */
 114                 if (idiv_clk & (1 << 5))
 115                         rate /= 128;
 116                 else
 117                         rate /= 16;
 118
 119                 /* CLKCx calculation */
 120                 rate /= (((idiv_clk & 0x1F) + 1) * 2);
 121
 122                 /* save best settings */
 123                 tmp = abs(t->speed_hz - rate);
 124                 if (tmp < min) {
 125                         min = tmp;
 126                         spcr = idiv_clk;
 127                         best_rate = rate;
 128                 }
 129         }
 130
 131         if (spi->mode & SPI_CPHA)
 132                 spcr |= 1 << 7;
 133         if (spi->mode & SPI_CPOL)
 134                 spcr |= 1 << 6;
 135
 136         dev_dbg(dev, "speed %d/%d\n", t->speed_hz, best_rate);
 137
 138         hspi_write(hspi, SPCR, spcr);
 139         hspi_write(hspi, SPSR, 0x0);
 140         hspi_write(hspi, SPSCR, 0x21);  /* master mode / CS control */
 141 }
 142
 143 static int hspi_transfer_one_message(struct spi_master *master,
 144                                      struct spi_message *msg)
 145 {
 146         struct hspi_priv *hspi = spi_master_get_devdata(master);
 147         struct spi_transfer *t;
 148         u32 tx;
 149         u32 rx;
 150         int ret, i;
 151         unsigned int cs_change;
 152         const int nsecs = 50;
 153
 154         dev_dbg(hspi->dev, "%s\n", __func__);
 155
 156         cs_change = 1;
 157         ret = 0;
 158         list_for_each_entry(t, &msg->transfers, transfer_list) {
 159
 160                 if (cs_change) {
 161                         hspi_hw_setup(hspi, msg, t);
 162                         hspi_hw_cs_enable(hspi);
 163                         ndelay(nsecs);
 164                 }
 165                 cs_change = t->cs_change;
 166
 167                 for (i = 0; i < t->len; i++) {
 168
 169                         /* wait remains */
 170                         ret = hspi_status_check_timeout(hspi, 0x1, 0);
 171                         if (ret < 0)
 172                                 break;
 173
 174                         tx = 0;
 175                         if (t->tx_buf)
 176                                 tx = (u32)((u8 *)t->tx_buf)[i];
 177
 178                         hspi_write(hspi, SPTBR, tx);
 179
 180                         /* wait receive */
 181                         ret = hspi_status_check_timeout(hspi, 0x4, 0x4);
 182                         if (ret < 0)
 183                                 break;
 184
 185                         rx = hspi_read(hspi, SPRBR);
 186                         if (t->rx_buf)
 187                                 ((u8 *)t->rx_buf)[i] = (u8)rx;
 188
 189                 }
 190
 191                 msg->actual_length += t->len;
 192
 193                 if (t->delay_usecs)
 194                         udelay(t->delay_usecs);
 195
 196                 if (cs_change) {
 197                         ndelay(nsecs);
 198                         hspi_hw_cs_disable(hspi);
 199                         ndelay(nsecs);
 200                 }
 201         }
 202
 203         msg->status = ret;
 204         if (!cs_change) {
 205                 ndelay(nsecs);
 206                 hspi_hw_cs_disable(hspi);
 207         }
 208         spi_finalize_current_message(master);
 209
 210         return ret;
 211 }
 212
 213 static int hspi_probe(struct platform_device *pdev)
 214 {
 215         struct resource *res;
 216         struct spi_master *master;
 217         struct hspi_priv *hspi;
 218         struct clk *clk;
 219         int ret;
 220
 221         /* get base addr */
 222         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 223         if (!res) {
 224                 dev_err(&pdev->dev, "invalid resource\n");
 225                 return -EINVAL;
 226         }
 227
 228         master = spi_alloc_master(&pdev->dev, sizeof(*hspi));
 229         if (!master) {
 230                 dev_err(&pdev->dev, "spi_alloc_master error.\n");
 231                 return -ENOMEM;
 232         }
 233
 234         clk = clk_get(&pdev->dev, NULL);
 235         if (IS_ERR(clk)) {
 236                 dev_err(&pdev->dev, "couldn't get clock\n");
 237                 ret = -EINVAL;
 238                 goto error0;
 239         }
 240
 241         hspi = spi_master_get_devdata(master);
 242         platform_set_drvdata(pdev, hspi);
 243
 244         /* init hspi */
 245         hspi->master    = master;
 246         hspi->dev       = &pdev->dev;
 247         hspi->clk       = clk;
 248         hspi->addr      = devm_ioremap(hspi->dev,
 249                                        res->start, resource_size(res));
 250         if (!hspi->addr) {
 251                 dev_err(&pdev->dev, "ioremap error.\n");
 252                 ret = -ENOMEM;
 253                 goto error1;
 254         }
 255
 256         pm_runtime_enable(&pdev->dev);
 257
 258         master->bus_num         = pdev->id;
 259         master->mode_bits       = SPI_CPOL | SPI_CPHA;
 260         master->dev.of_node     = pdev->dev.of_node;
 261         master->auto_runtime_pm = true;
 262         master->transfer_one_message            = hspi_transfer_one_message;
 263         master->bits_per_word_mask = SPI_BPW_MASK(8);
 264
 265         ret = devm_spi_register_master(&pdev->dev, master);
 266         if (ret < 0) {
 267                 dev_err(&pdev->dev, "spi_register_master error.\n");
 268                 goto error2;
 269         }
 270
 271         return 0;
 272
 273  error2:
 274         pm_runtime_disable(&pdev->dev);
 275  error1:
 276         clk_put(clk);
 277  error0:
 278         spi_master_put(master);
 279
 280         return ret;
 281 }
 282
 283 static int hspi_remove(struct platform_device *pdev)
 284 {
 285         struct hspi_priv *hspi = platform_get_drvdata(pdev);
 286
 287         pm_runtime_disable(&pdev->dev);
 288
 289         clk_put(hspi->clk);
 290
 291         return 0;
 292 }
 293
 294 static const struct of_device_id hspi_of_match[] = {
 295         { .compatible = "renesas,hspi", },
 296         { /* sentinel */ }
 297 };
 298 MODULE_DEVICE_TABLE(of, hspi_of_match);
 299
 300 static struct platform_driver hspi_driver = {
 301         .probe = hspi_probe,
 302         .remove = hspi_remove,
 303         .driver = {
 304                 .name = "sh-hspi",
 305                 .of_match_table = hspi_of_match,
 306         },
 307 };
 308 module_platform_driver(hspi_driver);
 309
 310 MODULE_DESCRIPTION("SuperH HSPI bus driver");
 311 MODULE_LICENSE("GPL v2");
 312 MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");
 313 MODULE_ALIAS("platform:sh-hspi");