[PATCH v2 07/16] spi: tegra20_slink: accept any word length

[Svyatoslav Ryhel]

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 <hed...@yahoo.com> # ASUS TF600T T30
Tested-by: Svyatoslav Ryhel <clamo...@gmail.com> # LG P895 T30
Signed-off-by: Svyatoslav Ryhel <clamo...@gmail.com>
---
 drivers/spi/tegra20_slink.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/spi/tegra20_slink.c b/drivers/spi/tegra20_slink.c
index 209ba8b0cc..d0e788539e 100644
--- 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);
 
-- 
2.37.2