spi: tegra20_slink: accept any word length

Original t20 slink could work with commands only
fully divisible by 8. This patch removes such
restriction, so commands of any bitlength now
can be passed and processed.

Tested-by: Andreas Westman Dorcsak <hedmoo@yahoo.com> # ASUS TF600T T30
Tested-by: Svyatoslav Ryhel <clamor95@gmail.com> # LG P895 T30
Tested-by: Thierry Reding <treding@nvidia.com> # T30 and T124
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Signed-off-by: Tom <twarren@nvidia.com>

diff --git a/drivers/spi/tegra20_slink.c b/drivers/spi/tegra20_slink.c
index 209ba8b0ccf2fa5f1ee53f15a62e1b329a34544e..d0e788539e0b92f4c56099d1dac29b68284d6eef 100644 (file)
--- a/drivers/spi/tegra20_slink.c
+++ b/drivers/spi/tegra20_slink.c
@@ -208,16 +208,14 @@ static int tegra30_spi_xfer(struct udevice *dev, unsigned int bitlen,
        u32 reg, tmpdout, tmpdin = 0;
        const u8 *dout = data_out;
        u8 *din = data_in;
-       int num_bytes;
-       int ret;
+       int num_bytes, overflow;
+       int ret = 0;
 
        debug("%s: slave %u:%u dout %p din %p bitlen %u\n",
              __func__, dev_seq(bus), spi_chip_select(dev), dout, din, bitlen);
-       if (bitlen % 8)
-               return -1;
-       num_bytes = bitlen / 8;
 
-       ret = 0;
+       num_bytes = DIV_ROUND_UP(bitlen, 8);
+       overflow = bitlen % 8;
 
        reg = readl(&regs->status);
        writel(reg, &regs->status);     /* Clear all SPI events via R/W */
@@ -254,8 +252,13 @@ static int tegra30_spi_xfer(struct udevice *dev, unsigned int bitlen,
 
                num_bytes -= bytes;
 
-               clrsetbits_le32(&regs->command, SLINK_CMD_BIT_LENGTH_MASK,
-                               bytes * 8 - 1);
+               if (overflow && !num_bytes)
+                       clrsetbits_le32(&regs->command, SLINK_CMD_BIT_LENGTH_MASK,
+                                       (bytes - 1) * 8 + overflow - 1);
+               else
+                       clrsetbits_le32(&regs->command, SLINK_CMD_BIT_LENGTH_MASK,
+                                       bytes * 8 - 1);
+
                writel(tmpdout, &regs->tx_fifo);
                setbits_le32(&regs->command, SLINK_CMD_GO);