drivers/spi/spi-cs42l43.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // CS42L43 SPI Controller Driver
   4 //
   5 // Copyright (C) 2022-2023 Cirrus Logic, Inc. and
   6 //                         Cirrus Logic International Semiconductor Ltd.
   7
   8 #include <linux/bits.h>
   9 #include <linux/bitfield.h>
  10 #include <linux/device.h>
  11 #include <linux/errno.h>
  12 #include <linux/mfd/cs42l43.h>
  13 #include <linux/mfd/cs42l43-regs.h>
  14 #include <linux/module.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/pm_runtime.h>
  17 #include <linux/regmap.h>
  18 #include <linux/spi/spi.h>
  19 #include <linux/units.h>
  20
  21 #define CS42L43_FIFO_SIZE               16
  22 #define CS42L43_SPI_ROOT_HZ             (40 * HZ_PER_MHZ)
  23 #define CS42L43_SPI_MAX_LENGTH          65532
  24
  25 enum cs42l43_spi_cmd {
  26         CS42L43_WRITE,
  27         CS42L43_READ
  28 };
  29
  30 struct cs42l43_spi {
  31         struct device *dev;
  32         struct regmap *regmap;
  33         struct spi_controller *ctlr;
  34 };
  35
  36 static const unsigned int cs42l43_clock_divs[] = {
  37         2, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30
  38 };
  39
  40 static int cs42l43_spi_tx(struct regmap *regmap, const u8 *buf, unsigned int len)
  41 {
  42         const u8 *end = buf + len;
  43         u32 val = 0;
  44         int ret;
  45
  46         while (buf < end) {
  47                 const u8 *block = min(buf + CS42L43_FIFO_SIZE, end);
  48
  49                 while (buf < block) {
  50                         const u8 *word = min(buf + sizeof(u32), block);
  51                         int pad = (buf + sizeof(u32)) - word;
  52
  53                         while (buf < word) {
  54                                 val >>= BITS_PER_BYTE;
  55                                 val |= FIELD_PREP(GENMASK(31, 24), *buf);
  56
  57                                 buf++;
  58                         }
  59
  60                         val >>= pad * BITS_PER_BYTE;
  61
  62                         regmap_write(regmap, CS42L43_TX_DATA, val);
  63                 }
  64
  65                 regmap_write(regmap, CS42L43_TRAN_CONFIG8, CS42L43_SPI_TX_DONE_MASK);
  66
  67                 ret = regmap_read_poll_timeout(regmap, CS42L43_TRAN_STATUS1,
  68                                                val, (val & CS42L43_SPI_TX_REQUEST_MASK),
  69                                                1000, 5000);
  70                 if (ret)
  71                         return ret;
  72         }
  73
  74         return 0;
  75 }
  76
  77 static int cs42l43_spi_rx(struct regmap *regmap, u8 *buf, unsigned int len)
  78 {
  79         u8 *end = buf + len;
  80         u32 val;
  81         int ret;
  82
  83         while (buf < end) {
  84                 u8 *block = min(buf + CS42L43_FIFO_SIZE, end);
  85
  86                 ret = regmap_read_poll_timeout(regmap, CS42L43_TRAN_STATUS1,
  87                                                val, (val & CS42L43_SPI_RX_REQUEST_MASK),
  88                                                1000, 5000);
  89                 if (ret)
  90                         return ret;
  91
  92                 while (buf < block) {
  93                         u8 *word = min(buf + sizeof(u32), block);
  94
  95                         ret = regmap_read(regmap, CS42L43_RX_DATA, &val);
  96                         if (ret)
  97                                 return ret;
  98
  99                         while (buf < word) {
 100                                 *buf = FIELD_GET(GENMASK(7, 0), val);
 101
 102                                 val >>= BITS_PER_BYTE;
 103                                 buf++;
 104                         }
 105                 }
 106
 107                 regmap_write(regmap, CS42L43_TRAN_CONFIG8, CS42L43_SPI_RX_DONE_MASK);
 108         }
 109
 110         return 0;
 111 }
 112
 113 static int cs42l43_transfer_one(struct spi_controller *ctlr, struct spi_device *spi,
 114                                 struct spi_transfer *tfr)
 115 {
 116         struct cs42l43_spi *priv = spi_controller_get_devdata(spi->controller);
 117         int i, ret = -EINVAL;
 118
 119         for (i = 0; i < ARRAY_SIZE(cs42l43_clock_divs); i++) {
 120                 if (CS42L43_SPI_ROOT_HZ / cs42l43_clock_divs[i] <= tfr->speed_hz)
 121                         break;
 122         }
 123
 124         if (i == ARRAY_SIZE(cs42l43_clock_divs))
 125                 return -EINVAL;
 126
 127         regmap_write(priv->regmap, CS42L43_SPI_CLK_CONFIG1, i);
 128
 129         if (tfr->tx_buf) {
 130                 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG3, CS42L43_WRITE);
 131                 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG4, tfr->len - 1);
 132         } else if (tfr->rx_buf) {
 133                 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG3, CS42L43_READ);
 134                 regmap_write(priv->regmap, CS42L43_TRAN_CONFIG5, tfr->len - 1);
 135         }
 136
 137         regmap_write(priv->regmap, CS42L43_TRAN_CONFIG1, CS42L43_SPI_START_MASK);
 138
 139         if (tfr->tx_buf)
 140                 ret = cs42l43_spi_tx(priv->regmap, (const u8 *)tfr->tx_buf, tfr->len);
 141         else if (tfr->rx_buf)
 142                 ret = cs42l43_spi_rx(priv->regmap, (u8 *)tfr->rx_buf, tfr->len);
 143
 144         return ret;
 145 }
 146
 147 static void cs42l43_set_cs(struct spi_device *spi, bool is_high)
 148 {
 149         struct cs42l43_spi *priv = spi_controller_get_devdata(spi->controller);
 150
 151         if (spi_get_chipselect(spi, 0) == 0)
 152                 regmap_write(priv->regmap, CS42L43_SPI_CONFIG2, !is_high);
 153 }
 154
 155 static int cs42l43_prepare_message(struct spi_controller *ctlr, struct spi_message *msg)
 156 {
 157         struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
 158         struct spi_device *spi = msg->spi;
 159         unsigned int spi_config1 = 0;
 160
 161         /* select another internal CS, which doesn't exist, so CS 0 is not used */
 162         if (spi_get_csgpiod(spi, 0))
 163                 spi_config1 |= 1 << CS42L43_SPI_SS_SEL_SHIFT;
 164         if (spi->mode & SPI_CPOL)
 165                 spi_config1 |= CS42L43_SPI_CPOL_MASK;
 166         if (spi->mode & SPI_CPHA)
 167                 spi_config1 |= CS42L43_SPI_CPHA_MASK;
 168         if (spi->mode & SPI_3WIRE)
 169                 spi_config1 |= CS42L43_SPI_THREE_WIRE_MASK;
 170
 171         regmap_write(priv->regmap, CS42L43_SPI_CONFIG1, spi_config1);
 172
 173         return 0;
 174 }
 175
 176 static int cs42l43_prepare_transfer_hardware(struct spi_controller *ctlr)
 177 {
 178         struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
 179         int ret;
 180
 181         ret = regmap_write(priv->regmap, CS42L43_BLOCK_EN2, CS42L43_SPI_MSTR_EN_MASK);
 182         if (ret)
 183                 dev_err(priv->dev, "Failed to enable SPI controller: %d\n", ret);
 184
 185         return ret;
 186 }
 187
 188 static int cs42l43_unprepare_transfer_hardware(struct spi_controller *ctlr)
 189 {
 190         struct cs42l43_spi *priv = spi_controller_get_devdata(ctlr);
 191         int ret;
 192
 193         ret = regmap_write(priv->regmap, CS42L43_BLOCK_EN2, 0);
 194         if (ret)
 195                 dev_err(priv->dev, "Failed to disable SPI controller: %d\n", ret);
 196
 197         return ret;
 198 }
 199
 200 static size_t cs42l43_spi_max_length(struct spi_device *spi)
 201 {
 202         return CS42L43_SPI_MAX_LENGTH;
 203 }
 204
 205 static int cs42l43_spi_probe(struct platform_device *pdev)
 206 {
 207         struct cs42l43 *cs42l43 = dev_get_drvdata(pdev->dev.parent);
 208         struct cs42l43_spi *priv;
 209         struct fwnode_handle *fwnode = dev_fwnode(cs42l43->dev);
 210         int ret;
 211
 212         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 213         if (!priv)
 214                 return -ENOMEM;
 215
 216         priv->ctlr = devm_spi_alloc_master(&pdev->dev, sizeof(*priv->ctlr));
 217         if (!priv->ctlr)
 218                 return -ENOMEM;
 219
 220         spi_controller_set_devdata(priv->ctlr, priv);
 221
 222         priv->dev = &pdev->dev;
 223         priv->regmap = cs42l43->regmap;
 224
 225         priv->ctlr->prepare_message = cs42l43_prepare_message;
 226         priv->ctlr->prepare_transfer_hardware = cs42l43_prepare_transfer_hardware;
 227         priv->ctlr->unprepare_transfer_hardware = cs42l43_unprepare_transfer_hardware;
 228         priv->ctlr->transfer_one = cs42l43_transfer_one;
 229         priv->ctlr->set_cs = cs42l43_set_cs;
 230         priv->ctlr->max_transfer_size = cs42l43_spi_max_length;
 231
 232         if (is_of_node(fwnode))
 233                 fwnode = fwnode_get_named_child_node(fwnode, "spi");
 234
 235         device_set_node(&priv->ctlr->dev, fwnode);
 236
 237         priv->ctlr->mode_bits = SPI_3WIRE | SPI_MODE_X_MASK;
 238         priv->ctlr->flags = SPI_CONTROLLER_HALF_DUPLEX;
 239         priv->ctlr->bits_per_word_mask = SPI_BPW_MASK(8) | SPI_BPW_MASK(16) |
 240                                          SPI_BPW_MASK(32);
 241         priv->ctlr->min_speed_hz = CS42L43_SPI_ROOT_HZ /
 242                                    cs42l43_clock_divs[ARRAY_SIZE(cs42l43_clock_divs) - 1];
 243         priv->ctlr->max_speed_hz = CS42L43_SPI_ROOT_HZ / cs42l43_clock_divs[0];
 244         priv->ctlr->use_gpio_descriptors = true;
 245         priv->ctlr->auto_runtime_pm = true;
 246
 247         devm_pm_runtime_enable(priv->dev);
 248         pm_runtime_idle(priv->dev);
 249
 250         regmap_write(priv->regmap, CS42L43_TRAN_CONFIG6, CS42L43_FIFO_SIZE - 1);
 251         regmap_write(priv->regmap, CS42L43_TRAN_CONFIG7, CS42L43_FIFO_SIZE - 1);
 252
 253         // Disable Watchdog timer and enable stall
 254         regmap_write(priv->regmap, CS42L43_SPI_CONFIG3, 0);
 255         regmap_write(priv->regmap, CS42L43_SPI_CONFIG4, CS42L43_SPI_STALL_ENA_MASK);
 256
 257         ret = devm_spi_register_controller(priv->dev, priv->ctlr);
 258         if (ret) {
 259                 dev_err(priv->dev, "Failed to register SPI controller: %d\n", ret);
 260         }
 261
 262         return ret;
 263 }
 264
 265 static const struct platform_device_id cs42l43_spi_id_table[] = {
 266         { "cs42l43-spi", },
 267         {}
 268 };
 269 MODULE_DEVICE_TABLE(platform, cs42l43_spi_id_table);
 270
 271 static struct platform_driver cs42l43_spi_driver = {
 272         .driver = {
 273                 .name   = "cs42l43-spi",
 274         },
 275         .probe          = cs42l43_spi_probe,
 276         .id_table       = cs42l43_spi_id_table,
 277 };
 278 module_platform_driver(cs42l43_spi_driver);
 279
 280 MODULE_DESCRIPTION("CS42L43 SPI Driver");
 281 MODULE_AUTHOR("Lucas Tanure <tanureal@opensource.cirrus.com>");
 282 MODULE_AUTHOR("Maciej Strozek <mstrozek@opensource.cirrus.com>");
 283 MODULE_LICENSE("GPL");