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From 4b64ce34aaf88c2869c74efad7cbe5167920625b Mon Sep 17 00:00:00 2001
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From: notro <notro@tronnes.org>
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Date: Sat, 26 Jan 2013 20:38:03 +0100
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Subject: [PATCH 056/196] spi-bcm2708: add 9-bit support using LoSSI mode
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---
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drivers/spi/spi-bcm2708.c | 30 ++++++++++++++++++++++++++++--
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1 file changed, 28 insertions(+), 2 deletions(-)
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diff --git a/drivers/spi/spi-bcm2708.c b/drivers/spi/spi-bcm2708.c
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index b74aa32..abaa5a6 100644
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--- a/drivers/spi/spi-bcm2708.c
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+++ b/drivers/spi/spi-bcm2708.c
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@@ -146,10 +146,31 @@ static inline void bcm2708_rd_fifo(struct bcm2708_spi *bs, int len)
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static inline void bcm2708_wr_fifo(struct bcm2708_spi *bs, int len)
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{
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u8 byte;
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+ u16 val;
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if (len > bs->len)
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len = bs->len;
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+ if (unlikely(bcm2708_rd(bs, SPI_CS) & SPI_CS_LEN)) {
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+ /* LoSSI mode */
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+ if (unlikely(len % 2)) {
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+ printk(KERN_ERR"bcm2708_wr_fifo: length must be even, skipping.\n");
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+ bs->len = 0;
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+ return;
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+ }
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+ while (len) {
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+ if (bs->tx_buf) {
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+ val = *(const u16 *)bs->tx_buf;
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+ bs->tx_buf += 2;
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+ } else
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+ val = 0;
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+ bcm2708_wr(bs, SPI_FIFO, val);
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+ bs->len -= 2;
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+ len -= 2;
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+ }
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+ return;
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+ }
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+
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while (len--) {
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byte = bs->tx_buf ? *bs->tx_buf++ : 0;
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bcm2708_wr(bs, SPI_FIFO, byte);
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@@ -234,8 +255,12 @@ static int bcm2708_setup_state(struct spi_master *master,
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switch (bpw) {
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case 8:
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break;
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+ case 9:
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+ /* Reading in LoSSI mode is a special case. See 'BCM2835 ARM Peripherals' datasheet */
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+ cs |= SPI_CS_LEN;
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+ break;
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default:
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- dev_dbg(dev, "setup: invalid bits_per_word %u (must be 8)\n",
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+ dev_dbg(dev, "setup: invalid bits_per_word %u (must be 8 or 9)\n",
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bpw);
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return -EINVAL;
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}
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@@ -283,7 +308,8 @@ static int bcm2708_process_transfer(struct bcm2708_spi *bs,
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ret = bcm2708_setup_state(spi->master, &spi->dev, &state,
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xfer->speed_hz ? xfer->speed_hz : spi->max_speed_hz,
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spi->chip_select, spi->mode,
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- spi->bits_per_word);
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+ xfer->bits_per_word ? xfer->bits_per_word :
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+ spi->bits_per_word);
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if (ret)
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return ret;
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--
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1.9.1
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