drivers/spi/spi-altera-dfl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // DFL bus driver for Altera SPI Master
   4 //
   5 // Copyright (C) 2020 Intel Corporation, Inc.
   6 //
   7 // Authors:
   8 //   Matthew Gerlach <matthew.gerlach@linux.intel.com>
   9 //
  10
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/stddef.h>
  15 #include <linux/errno.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/io.h>
  18 #include <linux/bitfield.h>
  19 #include <linux/io-64-nonatomic-lo-hi.h>
  20 #include <linux/regmap.h>
  21 #include <linux/spi/spi.h>
  22 #include <linux/spi/altera.h>
  23 #include <linux/dfl.h>
  24
  25 #define FME_FEATURE_ID_MAX10_SPI        0xe
  26 #define FME_FEATURE_REV_MAX10_SPI_N5010 0x1
  27
  28 #define SPI_CORE_PARAMETER      0x8
  29 #define SHIFT_MODE              BIT_ULL(1)
  30 #define SHIFT_MODE_MSB          0
  31 #define SHIFT_MODE_LSB          1
  32 #define DATA_WIDTH              GENMASK_ULL(7, 2)
  33 #define NUM_CHIPSELECT          GENMASK_ULL(13, 8)
  34 #define CLK_POLARITY            BIT_ULL(14)
  35 #define CLK_PHASE               BIT_ULL(15)
  36 #define PERIPHERAL_ID           GENMASK_ULL(47, 32)
  37 #define SPI_CLK                 GENMASK_ULL(31, 22)
  38 #define SPI_INDIRECT_ACC_OFST   0x10
  39
  40 #define INDIRECT_ADDR           (SPI_INDIRECT_ACC_OFST+0x0)
  41 #define INDIRECT_WR             BIT_ULL(8)
  42 #define INDIRECT_RD             BIT_ULL(9)
  43 #define INDIRECT_RD_DATA        (SPI_INDIRECT_ACC_OFST+0x8)
  44 #define INDIRECT_DATA_MASK      GENMASK_ULL(31, 0)
  45 #define INDIRECT_DEBUG          BIT_ULL(32)
  46 #define INDIRECT_WR_DATA        (SPI_INDIRECT_ACC_OFST+0x10)
  47 #define INDIRECT_TIMEOUT        10000
  48
  49 static int indirect_bus_reg_read(void *context, unsigned int reg,
  50                                  unsigned int *val)
  51 {
  52         void __iomem *base = context;
  53         int loops;
  54         u64 v;
  55
  56         writeq((reg >> 2) | INDIRECT_RD, base + INDIRECT_ADDR);
  57
  58         loops = 0;
  59         while ((readq(base + INDIRECT_ADDR) & INDIRECT_RD) &&
  60                (loops++ < INDIRECT_TIMEOUT))
  61                 cpu_relax();
  62
  63         if (loops >= INDIRECT_TIMEOUT) {
  64                 pr_err("%s timed out %d\n", __func__, loops);
  65                 return -ETIME;
  66         }
  67
  68         v = readq(base + INDIRECT_RD_DATA);
  69
  70         *val = v & INDIRECT_DATA_MASK;
  71
  72         return 0;
  73 }
  74
  75 static int indirect_bus_reg_write(void *context, unsigned int reg,
  76                                   unsigned int val)
  77 {
  78         void __iomem *base = context;
  79         int loops;
  80
  81         writeq(val, base + INDIRECT_WR_DATA);
  82         writeq((reg >> 2) | INDIRECT_WR, base + INDIRECT_ADDR);
  83
  84         loops = 0;
  85         while ((readq(base + INDIRECT_ADDR) & INDIRECT_WR) &&
  86                (loops++ < INDIRECT_TIMEOUT))
  87                 cpu_relax();
  88
  89         if (loops >= INDIRECT_TIMEOUT) {
  90                 pr_err("%s timed out %d\n", __func__, loops);
  91                 return -ETIME;
  92         }
  93         return 0;
  94 }
  95
  96 static const struct regmap_config indirect_regbus_cfg = {
  97         .reg_bits = 32,
  98         .reg_stride = 4,
  99         .val_bits = 32,
 100         .fast_io = true,
 101         .max_register = 24,
 102
 103         .reg_write = indirect_bus_reg_write,
 104         .reg_read = indirect_bus_reg_read,
 105 };
 106
 107 static struct spi_board_info m10_bmc_info = {
 108         .modalias = "m10-d5005",
 109         .max_speed_hz = 12500000,
 110         .bus_num = 0,
 111         .chip_select = 0,
 112 };
 113
 114 static void config_spi_master(void __iomem *base, struct spi_master *master)
 115 {
 116         u64 v;
 117
 118         v = readq(base + SPI_CORE_PARAMETER);
 119
 120         master->mode_bits = SPI_CS_HIGH;
 121         if (FIELD_GET(CLK_POLARITY, v))
 122                 master->mode_bits |= SPI_CPOL;
 123         if (FIELD_GET(CLK_PHASE, v))
 124                 master->mode_bits |= SPI_CPHA;
 125
 126         master->num_chipselect = FIELD_GET(NUM_CHIPSELECT, v);
 127         master->bits_per_word_mask =
 128                 SPI_BPW_RANGE_MASK(1, FIELD_GET(DATA_WIDTH, v));
 129 }
 130
 131 static int dfl_spi_altera_probe(struct dfl_device *dfl_dev)
 132 {
 133         struct device *dev = &dfl_dev->dev;
 134         struct spi_master *master;
 135         struct altera_spi *hw;
 136         void __iomem *base;
 137         int err = -ENODEV;
 138
 139         master = spi_alloc_master(dev, sizeof(struct altera_spi));
 140         if (!master)
 141                 return -ENOMEM;
 142
 143         master->bus_num = dfl_dev->id;
 144
 145         hw = spi_master_get_devdata(master);
 146
 147         hw->dev = dev;
 148
 149         base = devm_ioremap_resource(dev, &dfl_dev->mmio_res);
 150
 151         if (IS_ERR(base))
 152                 return PTR_ERR(base);
 153
 154         config_spi_master(base, master);
 155         dev_dbg(dev, "%s cs %u bpm 0x%x mode 0x%x\n", __func__,
 156                 master->num_chipselect, master->bits_per_word_mask,
 157                 master->mode_bits);
 158
 159         hw->regmap = devm_regmap_init(dev, NULL, base, &indirect_regbus_cfg);
 160         if (IS_ERR(hw->regmap))
 161                 return PTR_ERR(hw->regmap);
 162
 163         hw->irq = -EINVAL;
 164
 165         altera_spi_init_master(master);
 166
 167         err = devm_spi_register_master(dev, master);
 168         if (err) {
 169                 dev_err(dev, "%s failed to register spi master %d\n", __func__, err);
 170                 goto exit;
 171         }
 172
 173         if (!spi_new_device(master,  &m10_bmc_info)) {
 174                 dev_err(dev, "%s failed to create SPI device: %s\n",
 175                         __func__, m10_bmc_info.modalias);
 176         }
 177
 178         return 0;
 179 exit:
 180         spi_master_put(master);
 181         return err;
 182 }
 183
 184 static const struct dfl_device_id dfl_spi_altera_ids[] = {
 185         { FME_ID, FME_FEATURE_ID_MAX10_SPI },
 186         { }
 187 };
 188
 189 static struct dfl_driver dfl_spi_altera_driver = {
 190         .drv    = {
 191                 .name       = "dfl-spi-altera",
 192         },
 193         .id_table = dfl_spi_altera_ids,
 194         .probe   = dfl_spi_altera_probe,
 195 };
 196
 197 module_dfl_driver(dfl_spi_altera_driver);
 198
 199 MODULE_DEVICE_TABLE(dfl, dfl_spi_altera_ids);
 200 MODULE_DESCRIPTION("DFL spi altera driver");
 201 MODULE_AUTHOR("Intel Corporation");
 202 MODULE_LICENSE("GPL v2");