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From 75c9b03f90ca974cb072d96f423884b773ca5425 Mon Sep 17 00:00:00 2001
From: notro <notro@tronnes.org>
Date: Sat, 26 Jan 2013 20:38:03 +0100
Subject: [PATCH 056/174] spi-bcm2708: add 9-bit support using LoSSI mode
---
drivers/spi/spi-bcm2708.c | 30 ++++++++++++++++++++++++++++--
1 file changed, 28 insertions(+), 2 deletions(-)
--- a/drivers/spi/spi-bcm2708.c
+++ b/drivers/spi/spi-bcm2708.c
@@ -146,10 +146,31 @@ static inline void bcm2708_rd_fifo(struc
static inline void bcm2708_wr_fifo(struct bcm2708_spi *bs, int len)
{
u8 byte;
+ u16 val;
if (len > bs->len)
len = bs->len;
+ if (unlikely(bcm2708_rd(bs, SPI_CS) & SPI_CS_LEN)) {
+ /* LoSSI mode */
+ if (unlikely(len % 2)) {
+ printk(KERN_ERR"bcm2708_wr_fifo: length must be even, skipping.\n");
+ bs->len = 0;
+ return;
+ }
+ while (len) {
+ if (bs->tx_buf) {
+ val = *(const u16 *)bs->tx_buf;
+ bs->tx_buf += 2;
+ } else
+ val = 0;
+ bcm2708_wr(bs, SPI_FIFO, val);
+ bs->len -= 2;
+ len -= 2;
+ }
+ return;
+ }
+
while (len--) {
byte = bs->tx_buf ? *bs->tx_buf++ : 0;
bcm2708_wr(bs, SPI_FIFO, byte);
@@ -234,8 +255,12 @@ static int bcm2708_setup_state(struct sp
switch (bpw) {
case 8:
break;
+ case 9:
+ /* Reading in LoSSI mode is a special case. See 'BCM2835 ARM Peripherals' datasheet */
+ cs |= SPI_CS_LEN;
+ break;
default:
- dev_dbg(dev, "setup: invalid bits_per_word %u (must be 8)\n",
+ dev_dbg(dev, "setup: invalid bits_per_word %u (must be 8 or 9)\n",
bpw);
return -EINVAL;
}
@@ -283,7 +308,8 @@ static int bcm2708_process_transfer(stru
ret = bcm2708_setup_state(spi->master, &spi->dev, &state,
xfer->speed_hz ? xfer->speed_hz : spi->max_speed_hz,
spi->chip_select, spi->mode,
- spi->bits_per_word);
+ xfer->bits_per_word ? xfer->bits_per_word :
+ spi->bits_per_word);
if (ret)
return ret;
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