drivers/spi/ath79_spi.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2015-2016 Wills Wang <wills.wang@live.com>
   4  */
   5
   6 #include <common.h>
   7 #include <spi.h>
   8 #include <dm.h>
   9 #include <div64.h>
  10 #include <errno.h>
  11 #include <asm/io.h>
  12 #include <asm/addrspace.h>
  13 #include <asm/types.h>
  14 #include <dm/pinctrl.h>
  15 #include <mach/ar71xx_regs.h>
  16
  17 /* CLOCK_DIVIDER = 3 (SPI clock = 200 / 8 ~ 25 MHz) */
  18 #define ATH79_SPI_CLK_DIV(x)           (((x) >> 1) - 1)
  19 #define ATH79_SPI_RRW_DELAY_FACTOR     12000
  20 #define ATH79_SPI_MHZ                  (1000 * 1000)
  21
  22 struct ath79_spi_priv {
  23         void __iomem *regs;
  24         u32 rrw_delay;
  25 };
  26
  27 static void spi_cs_activate(struct udevice *dev)
  28 {
  29         struct udevice *bus = dev_get_parent(dev);
  30         struct ath79_spi_priv *priv = dev_get_priv(bus);
  31
  32         writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS);
  33         writel(AR71XX_SPI_IOC_CS_ALL, priv->regs + AR71XX_SPI_REG_IOC);
  34 }
  35
  36 static void spi_cs_deactivate(struct udevice *dev)
  37 {
  38         struct udevice *bus = dev_get_parent(dev);
  39         struct ath79_spi_priv *priv = dev_get_priv(bus);
  40
  41         writel(AR71XX_SPI_IOC_CS_ALL, priv->regs + AR71XX_SPI_REG_IOC);
  42         writel(0, priv->regs + AR71XX_SPI_REG_FS);
  43 }
  44
  45 static int ath79_spi_claim_bus(struct udevice *dev)
  46 {
  47         return 0;
  48 }
  49
  50 static int ath79_spi_release_bus(struct udevice *dev)
  51 {
  52         return 0;
  53 }
  54
  55 static int ath79_spi_xfer(struct udevice *dev, unsigned int bitlen,
  56                 const void *dout, void *din, unsigned long flags)
  57 {
  58         struct udevice *bus = dev_get_parent(dev);
  59         struct ath79_spi_priv *priv = dev_get_priv(bus);
  60         struct dm_spi_slave_platdata *slave = dev_get_parent_platdata(dev);
  61         u8 *rx = din;
  62         const u8 *tx = dout;
  63         u8 curbyte, curbitlen, restbits;
  64         u32 bytes = bitlen / 8;
  65         u32 out, in;
  66         u64 tick;
  67
  68         if (flags & SPI_XFER_BEGIN)
  69                 spi_cs_activate(dev);
  70
  71         restbits = (bitlen % 8);
  72         if (restbits)
  73                 bytes++;
  74
  75         out = AR71XX_SPI_IOC_CS_ALL & ~(AR71XX_SPI_IOC_CS(slave->cs));
  76         while (bytes > 0) {
  77                 bytes--;
  78                 curbyte = 0;
  79                 if (tx)
  80                         curbyte = *tx++;
  81
  82                 if (restbits && !bytes) {
  83                         curbitlen = restbits;
  84                         curbyte <<= 8 - restbits;
  85                 } else {
  86                         curbitlen = 8;
  87                 }
  88
  89                 for (curbyte <<= (8 - curbitlen); curbitlen; curbitlen--) {
  90                         if (curbyte & 0x80)
  91                                 out |= AR71XX_SPI_IOC_DO;
  92                         else
  93                                 out &= ~(AR71XX_SPI_IOC_DO);
  94
  95                         writel(out, priv->regs + AR71XX_SPI_REG_IOC);
  96
  97                         /* delay for low level */
  98                         if (priv->rrw_delay) {
  99                                 tick = get_ticks() + priv->rrw_delay;
 100                                 while (get_ticks() < tick)
 101                                         /*NOP*/;
 102                         }
 103
 104                         writel(out | AR71XX_SPI_IOC_CLK,
 105                                priv->regs + AR71XX_SPI_REG_IOC);
 106
 107                         /* delay for high level */
 108                         if (priv->rrw_delay) {
 109                                 tick = get_ticks() + priv->rrw_delay;
 110                                 while (get_ticks() < tick)
 111                                         /*NOP*/;
 112                         }
 113
 114                         curbyte <<= 1;
 115                 }
 116
 117                 if (!bytes)
 118                         writel(out, priv->regs + AR71XX_SPI_REG_IOC);
 119
 120                 in = readl(priv->regs + AR71XX_SPI_REG_RDS);
 121                 if (rx) {
 122                         if (restbits && !bytes)
 123                                 *rx++ = (in << (8 - restbits));
 124                         else
 125                                 *rx++ = in;
 126                 }
 127         }
 128
 129         if (flags & SPI_XFER_END)
 130                 spi_cs_deactivate(dev);
 131
 132         return 0;
 133 }
 134
 135
 136 static int ath79_spi_set_speed(struct udevice *bus, uint speed)
 137 {
 138         struct ath79_spi_priv *priv = dev_get_priv(bus);
 139         u32 val, div = 0;
 140         u64 time;
 141
 142         if (speed)
 143                 div = get_bus_freq(0) / speed;
 144
 145         if (div > 63)
 146                 div = 63;
 147
 148         if (div < 5)
 149                 div = 5;
 150
 151         /* calculate delay */
 152         time = get_tbclk();
 153         do_div(time, speed / 2);
 154         val = get_bus_freq(0) / ATH79_SPI_MHZ;
 155         val = ATH79_SPI_RRW_DELAY_FACTOR / val;
 156         if (time > val)
 157                 priv->rrw_delay = time - val + 1;
 158         else
 159                 priv->rrw_delay = 0;
 160
 161         writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS);
 162         clrsetbits_be32(priv->regs + AR71XX_SPI_REG_CTRL,
 163                         AR71XX_SPI_CTRL_DIV_MASK,
 164                         ATH79_SPI_CLK_DIV(div));
 165         writel(0, priv->regs + AR71XX_SPI_REG_FS);
 166         return 0;
 167 }
 168
 169 static int ath79_spi_set_mode(struct udevice *bus, uint mode)
 170 {
 171         return 0;
 172 }
 173
 174 static int ath79_spi_probe(struct udevice *bus)
 175 {
 176         struct ath79_spi_priv *priv = dev_get_priv(bus);
 177         fdt_addr_t addr;
 178
 179         addr = devfdt_get_addr(bus);
 180         if (addr == FDT_ADDR_T_NONE)
 181                 return -EINVAL;
 182
 183         priv->regs = map_physmem(addr,
 184                                  AR71XX_SPI_SIZE,
 185                                  MAP_NOCACHE);
 186
 187         /* Init SPI Hardware, disable remap, set clock */
 188         writel(AR71XX_SPI_FS_GPIO, priv->regs + AR71XX_SPI_REG_FS);
 189         writel(AR71XX_SPI_CTRL_RD | ATH79_SPI_CLK_DIV(8),
 190                priv->regs + AR71XX_SPI_REG_CTRL);
 191         writel(0, priv->regs + AR71XX_SPI_REG_FS);
 192
 193         return 0;
 194 }
 195
 196 static int ath79_cs_info(struct udevice *bus, uint cs,
 197                            struct spi_cs_info *info)
 198 {
 199         /* Always allow activity on CS 0/1/2 */
 200         if (cs >= 3)
 201                 return -ENODEV;
 202
 203         return 0;
 204 }
 205
 206 static const struct dm_spi_ops ath79_spi_ops = {
 207         .claim_bus  = ath79_spi_claim_bus,
 208         .release_bus    = ath79_spi_release_bus,
 209         .xfer       = ath79_spi_xfer,
 210         .set_speed  = ath79_spi_set_speed,
 211         .set_mode   = ath79_spi_set_mode,
 212         .cs_info    = ath79_cs_info,
 213 };
 214
 215 static const struct udevice_id ath79_spi_ids[] = {
 216         { .compatible = "qca,ar7100-spi" },
 217         {}
 218 };
 219
 220 U_BOOT_DRIVER(ath79_spi) = {
 221         .name   = "ath79_spi",
 222         .id = UCLASS_SPI,
 223         .of_match = ath79_spi_ids,
 224         .ops    = &ath79_spi_ops,
 225         .priv_auto_alloc_size = sizeof(struct ath79_spi_priv),
 226         .probe  = ath79_spi_probe,
 227 };