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@ -3,6 +3,7 @@
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*
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* Copyright (C) 2012 Chris Boot
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* Copyright (C) 2013 Stephen Warren
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* Copyright (C) 2015 Martin Sperl
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*
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* This driver is inspired by:
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* spi-ath79.c, Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
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@ -29,6 +30,7 @@
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_irq.h>
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#include <linux/of_gpio.h>
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#include <linux/of_device.h>
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#include <linux/spi/spi.h>
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@ -66,8 +68,10 @@
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#define BCM2835_SPI_CS_CS_10 0x00000002
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#define BCM2835_SPI_CS_CS_01 0x00000001
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#define BCM2835_SPI_TIMEOUT_MS 30000
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#define BCM2835_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_NO_CS)
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#define BCM2835_SPI_POLLING_LIMIT_US 30
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#define BCM2835_SPI_TIMEOUT_MS 30000
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#define BCM2835_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \
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| SPI_NO_CS | SPI_3WIRE)
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#define DRV_NAME "spi-bcm2835"
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@ -75,10 +79,10 @@ struct bcm2835_spi {
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void __iomem *regs;
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struct clk *clk;
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int irq;
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struct completion done;
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const u8 *tx_buf;
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u8 *rx_buf;
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int len;
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int tx_len;
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int rx_len;
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};
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static inline u32 bcm2835_rd(struct bcm2835_spi *bs, unsigned reg)
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@ -91,205 +95,315 @@ static inline void bcm2835_wr(struct bcm2835_spi *bs, unsigned reg, u32 val)
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writel(val, bs->regs + reg);
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}
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static inline void bcm2835_rd_fifo(struct bcm2835_spi *bs, int len)
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static inline void bcm2835_rd_fifo(struct bcm2835_spi *bs)
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{
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u8 byte;
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while (len--) {
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while ((bs->rx_len) &&
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(bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_RXD)) {
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byte = bcm2835_rd(bs, BCM2835_SPI_FIFO);
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if (bs->rx_buf)
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*bs->rx_buf++ = byte;
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bs->rx_len--;
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}
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}
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static inline void bcm2835_wr_fifo(struct bcm2835_spi *bs, int len)
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static inline void bcm2835_wr_fifo(struct bcm2835_spi *bs)
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{
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u8 byte;
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if (len > bs->len)
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len = bs->len;
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while (len--) {
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while ((bs->tx_len) &&
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(bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_TXD)) {
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byte = bs->tx_buf ? *bs->tx_buf++ : 0;
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bcm2835_wr(bs, BCM2835_SPI_FIFO, byte);
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bs->len--;
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bs->tx_len--;
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}
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}
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static void bcm2835_spi_reset_hw(struct spi_master *master)
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{
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struct bcm2835_spi *bs = spi_master_get_devdata(master);
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u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
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/* Disable SPI interrupts and transfer */
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cs &= ~(BCM2835_SPI_CS_INTR |
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BCM2835_SPI_CS_INTD |
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BCM2835_SPI_CS_TA);
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/* and reset RX/TX FIFOS */
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cs |= BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX;
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/* and reset the SPI_HW */
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bcm2835_wr(bs, BCM2835_SPI_CS, cs);
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}
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static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id)
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{
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struct spi_master *master = dev_id;
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struct bcm2835_spi *bs = spi_master_get_devdata(master);
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u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
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/*
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* RXR - RX needs Reading. This means 12 (or more) bytes have been
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* transmitted and hence 12 (or more) bytes have been received.
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*
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* The FIFO is 16-bytes deep. We check for this interrupt to keep the
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* FIFO full; we have a 4-byte-time buffer for IRQ latency. We check
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* this before DONE (TX empty) just in case we delayed processing this
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* interrupt for some reason.
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*
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* We only check for this case if we have more bytes to TX; at the end
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* of the transfer, we ignore this pipelining optimization, and let
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* bcm2835_spi_finish_transfer() drain the RX FIFO.
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*/
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if (bs->len && (cs & BCM2835_SPI_CS_RXR)) {
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/* Read 12 bytes of data */
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bcm2835_rd_fifo(bs, 12);
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/* Read as many bytes as possible from FIFO */
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bcm2835_rd_fifo(bs);
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/* Write as many bytes as possible to FIFO */
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bcm2835_wr_fifo(bs);
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/* Write up to 12 bytes */
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bcm2835_wr_fifo(bs, 12);
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/*
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* We must have written something to the TX FIFO due to the
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* bs->len check above, so cannot be DONE. Hence, return
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* early. Note that DONE could also be set if we serviced an
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* RXR interrupt really late.
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*/
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return IRQ_HANDLED;
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/* based on flags decide if we can finish the transfer */
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if (bcm2835_rd(bs, BCM2835_SPI_CS) & BCM2835_SPI_CS_DONE) {
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/* Transfer complete - reset SPI HW */
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bcm2835_spi_reset_hw(master);
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/* wake up the framework */
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complete(&master->xfer_completion);
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}
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/*
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* DONE - TX empty. This occurs when we first enable the transfer
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* since we do not pre-fill the TX FIFO. At any other time, given that
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* we refill the TX FIFO above based on RXR, and hence ignore DONE if
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* RXR is set, DONE really does mean end-of-transfer.
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*/
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if (cs & BCM2835_SPI_CS_DONE) {
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if (bs->len) { /* First interrupt in a transfer */
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bcm2835_wr_fifo(bs, 16);
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} else { /* Transfer complete */
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/* Disable SPI interrupts */
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cs &= ~(BCM2835_SPI_CS_INTR | BCM2835_SPI_CS_INTD);
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bcm2835_wr(bs, BCM2835_SPI_CS, cs);
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/*
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* Wake up bcm2835_spi_transfer_one(), which will call
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* bcm2835_spi_finish_transfer(), to drain the RX FIFO.
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*/
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complete(&bs->done);
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}
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return IRQ_HANDLED;
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}
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return IRQ_NONE;
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return IRQ_HANDLED;
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}
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static int bcm2835_spi_start_transfer(struct spi_device *spi,
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struct spi_transfer *tfr)
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static int bcm2835_spi_transfer_one_poll(struct spi_master *master,
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struct spi_device *spi,
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struct spi_transfer *tfr,
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u32 cs,
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unsigned long xfer_time_us)
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{
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struct bcm2835_spi *bs = spi_master_get_devdata(spi->master);
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unsigned long spi_hz, clk_hz, cdiv;
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u32 cs = BCM2835_SPI_CS_INTR | BCM2835_SPI_CS_INTD | BCM2835_SPI_CS_TA;
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struct bcm2835_spi *bs = spi_master_get_devdata(master);
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unsigned long timeout = jiffies +
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max(4 * xfer_time_us * HZ / 1000000, 2uL);
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spi_hz = tfr->speed_hz;
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clk_hz = clk_get_rate(bs->clk);
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/* enable HW block without interrupts */
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bcm2835_wr(bs, BCM2835_SPI_CS, cs | BCM2835_SPI_CS_TA);
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if (spi_hz >= clk_hz / 2) {
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cdiv = 2; /* clk_hz/2 is the fastest we can go */
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} else if (spi_hz) {
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/* CDIV must be a power of two */
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cdiv = roundup_pow_of_two(DIV_ROUND_UP(clk_hz, spi_hz));
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if (cdiv >= 65536)
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cdiv = 0; /* 0 is the slowest we can go */
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} else
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cdiv = 0; /* 0 is the slowest we can go */
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if (spi->mode & SPI_CPOL)
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cs |= BCM2835_SPI_CS_CPOL;
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if (spi->mode & SPI_CPHA)
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cs |= BCM2835_SPI_CS_CPHA;
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if (!(spi->mode & SPI_NO_CS)) {
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if (spi->mode & SPI_CS_HIGH) {
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cs |= BCM2835_SPI_CS_CSPOL;
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cs |= BCM2835_SPI_CS_CSPOL0 << spi->chip_select;
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/* set timeout to 4x the expected time, or 2 jiffies */
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/* loop until finished the transfer */
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while (bs->rx_len) {
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/* read from fifo as much as possible */
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bcm2835_rd_fifo(bs);
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/* fill in tx fifo as much as possible */
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bcm2835_wr_fifo(bs);
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/* if we still expect some data after the read,
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* check for a possible timeout
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*/
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if (bs->rx_len && time_after(jiffies, timeout)) {
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/* Transfer complete - reset SPI HW */
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bcm2835_spi_reset_hw(master);
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/* and return timeout */
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return -ETIMEDOUT;
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}
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cs |= spi->chip_select;
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}
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reinit_completion(&bs->done);
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bs->tx_buf = tfr->tx_buf;
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bs->rx_buf = tfr->rx_buf;
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bs->len = tfr->len;
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/* Transfer complete - reset SPI HW */
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bcm2835_spi_reset_hw(master);
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/* and return without waiting for completion */
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return 0;
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}
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static int bcm2835_spi_transfer_one_irq(struct spi_master *master,
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struct spi_device *spi,
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struct spi_transfer *tfr,
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u32 cs)
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{
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struct bcm2835_spi *bs = spi_master_get_devdata(master);
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/* fill in fifo if we have gpio-cs
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* note that there have been rare events where the native-CS
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* flapped for <1us which may change the behaviour
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* with gpio-cs this does not happen, so it is implemented
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* only for this case
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*/
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if (gpio_is_valid(spi->cs_gpio)) {
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/* enable HW block, but without interrupts enabled
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* this would triggern an immediate interrupt
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*/
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bcm2835_wr(bs, BCM2835_SPI_CS,
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cs | BCM2835_SPI_CS_TA);
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/* fill in tx fifo as much as possible */
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bcm2835_wr_fifo(bs);
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}
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bcm2835_wr(bs, BCM2835_SPI_CLK, cdiv);
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/*
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* Enable the HW block. This will immediately trigger a DONE (TX
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* empty) interrupt, upon which we will fill the TX FIFO with the
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* first TX bytes. Pre-filling the TX FIFO here to avoid the
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* interrupt doesn't work:-(
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*/
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cs |= BCM2835_SPI_CS_INTR | BCM2835_SPI_CS_INTD | BCM2835_SPI_CS_TA;
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bcm2835_wr(bs, BCM2835_SPI_CS, cs);
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return 0;
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}
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static int bcm2835_spi_finish_transfer(struct spi_device *spi,
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struct spi_transfer *tfr, bool cs_change)
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{
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struct bcm2835_spi *bs = spi_master_get_devdata(spi->master);
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u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
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/* Drain RX FIFO */
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while (cs & BCM2835_SPI_CS_RXD) {
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bcm2835_rd_fifo(bs, 1);
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cs = bcm2835_rd(bs, BCM2835_SPI_CS);
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}
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if (tfr->delay_usecs)
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udelay(tfr->delay_usecs);
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if (cs_change)
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/* Clear TA flag */
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bcm2835_wr(bs, BCM2835_SPI_CS, cs & ~BCM2835_SPI_CS_TA);
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return 0;
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/* signal that we need to wait for completion */
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return 1;
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}
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static int bcm2835_spi_transfer_one(struct spi_master *master,
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struct spi_message *mesg)
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struct spi_device *spi,
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struct spi_transfer *tfr)
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{
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struct bcm2835_spi *bs = spi_master_get_devdata(master);
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struct spi_transfer *tfr;
|
|
|
|
|
struct spi_device *spi = mesg->spi;
|
|
|
|
|
int err = 0;
|
|
|
|
|
unsigned int timeout;
|
|
|
|
|
bool cs_change;
|
|
|
|
|
unsigned long spi_hz, clk_hz, cdiv;
|
|
|
|
|
unsigned long spi_used_hz, xfer_time_us;
|
|
|
|
|
u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
|
|
|
|
|
|
|
|
|
|
list_for_each_entry(tfr, &mesg->transfers, transfer_list) {
|
|
|
|
|
err = bcm2835_spi_start_transfer(spi, tfr);
|
|
|
|
|
if (err)
|
|
|
|
|
goto out;
|
|
|
|
|
/* set clock */
|
|
|
|
|
spi_hz = tfr->speed_hz;
|
|
|
|
|
clk_hz = clk_get_rate(bs->clk);
|
|
|
|
|
|
|
|
|
|
timeout = wait_for_completion_timeout(&bs->done,
|
|
|
|
|
msecs_to_jiffies(BCM2835_SPI_TIMEOUT_MS));
|
|
|
|
|
if (!timeout) {
|
|
|
|
|
err = -ETIMEDOUT;
|
|
|
|
|
goto out;
|
|
|
|
|
}
|
|
|
|
|
if (spi_hz >= clk_hz / 2) {
|
|
|
|
|
cdiv = 2; /* clk_hz/2 is the fastest we can go */
|
|
|
|
|
} else if (spi_hz) {
|
|
|
|
|
/* CDIV must be a multiple of two */
|
|
|
|
|
cdiv = DIV_ROUND_UP(clk_hz, spi_hz);
|
|
|
|
|
cdiv += (cdiv % 2);
|
|
|
|
|
|
|
|
|
|
cs_change = tfr->cs_change ||
|
|
|
|
|
list_is_last(&tfr->transfer_list, &mesg->transfers);
|
|
|
|
|
if (cdiv >= 65536)
|
|
|
|
|
cdiv = 0; /* 0 is the slowest we can go */
|
|
|
|
|
} else {
|
|
|
|
|
cdiv = 0; /* 0 is the slowest we can go */
|
|
|
|
|
}
|
|
|
|
|
spi_used_hz = cdiv ? (clk_hz / cdiv) : (clk_hz / 65536);
|
|
|
|
|
bcm2835_wr(bs, BCM2835_SPI_CLK, cdiv);
|
|
|
|
|
|
|
|
|
|
err = bcm2835_spi_finish_transfer(spi, tfr, cs_change);
|
|
|
|
|
if (err)
|
|
|
|
|
goto out;
|
|
|
|
|
/* handle all the modes */
|
|
|
|
|
if ((spi->mode & SPI_3WIRE) && (tfr->rx_buf))
|
|
|
|
|
cs |= BCM2835_SPI_CS_REN;
|
|
|
|
|
if (spi->mode & SPI_CPOL)
|
|
|
|
|
cs |= BCM2835_SPI_CS_CPOL;
|
|
|
|
|
if (spi->mode & SPI_CPHA)
|
|
|
|
|
cs |= BCM2835_SPI_CS_CPHA;
|
|
|
|
|
|
|
|
|
|
mesg->actual_length += (tfr->len - bs->len);
|
|
|
|
|
/* for gpio_cs set dummy CS so that no HW-CS get changed
|
|
|
|
|
* we can not run this in bcm2835_spi_set_cs, as it does
|
|
|
|
|
* not get called for cs_gpio cases, so we need to do it here
|
|
|
|
|
*/
|
|
|
|
|
if (gpio_is_valid(spi->cs_gpio) || (spi->mode & SPI_NO_CS))
|
|
|
|
|
cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
|
|
|
|
|
|
|
|
|
|
/* set transmit buffers and length */
|
|
|
|
|
bs->tx_buf = tfr->tx_buf;
|
|
|
|
|
bs->rx_buf = tfr->rx_buf;
|
|
|
|
|
bs->tx_len = tfr->len;
|
|
|
|
|
bs->rx_len = tfr->len;
|
|
|
|
|
|
|
|
|
|
/* calculate the estimated time in us the transfer runs */
|
|
|
|
|
xfer_time_us = tfr->len
|
|
|
|
|
* 9 /* clocks/byte - SPI-HW waits 1 clock after each byte */
|
|
|
|
|
* 1000000 / spi_used_hz;
|
|
|
|
|
|
|
|
|
|
/* for short requests run polling*/
|
|
|
|
|
if (xfer_time_us <= BCM2835_SPI_POLLING_LIMIT_US)
|
|
|
|
|
return bcm2835_spi_transfer_one_poll(master, spi, tfr,
|
|
|
|
|
cs, xfer_time_us);
|
|
|
|
|
|
|
|
|
|
return bcm2835_spi_transfer_one_irq(master, spi, tfr, cs);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void bcm2835_spi_handle_err(struct spi_master *master,
|
|
|
|
|
struct spi_message *msg)
|
|
|
|
|
{
|
|
|
|
|
bcm2835_spi_reset_hw(master);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void bcm2835_spi_set_cs(struct spi_device *spi, bool gpio_level)
|
|
|
|
|
{
|
|
|
|
|
/*
|
|
|
|
|
* we can assume that we are "native" as per spi_set_cs
|
|
|
|
|
* calling us ONLY when cs_gpio is not set
|
|
|
|
|
* we can also assume that we are CS < 3 as per bcm2835_spi_setup
|
|
|
|
|
* we would not get called because of error handling there.
|
|
|
|
|
* the level passed is the electrical level not enabled/disabled
|
|
|
|
|
* so it has to get translated back to enable/disable
|
|
|
|
|
* see spi_set_cs in spi.c for the implementation
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
struct spi_master *master = spi->master;
|
|
|
|
|
struct bcm2835_spi *bs = spi_master_get_devdata(master);
|
|
|
|
|
u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
|
|
|
|
|
bool enable;
|
|
|
|
|
|
|
|
|
|
/* calculate the enable flag from the passed gpio_level */
|
|
|
|
|
enable = (spi->mode & SPI_CS_HIGH) ? gpio_level : !gpio_level;
|
|
|
|
|
|
|
|
|
|
/* set flags for "reverse" polarity in the registers */
|
|
|
|
|
if (spi->mode & SPI_CS_HIGH) {
|
|
|
|
|
/* set the correct CS-bits */
|
|
|
|
|
cs |= BCM2835_SPI_CS_CSPOL;
|
|
|
|
|
cs |= BCM2835_SPI_CS_CSPOL0 << spi->chip_select;
|
|
|
|
|
} else {
|
|
|
|
|
/* clean the CS-bits */
|
|
|
|
|
cs &= ~BCM2835_SPI_CS_CSPOL;
|
|
|
|
|
cs &= ~(BCM2835_SPI_CS_CSPOL0 << spi->chip_select);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
out:
|
|
|
|
|
/* Clear FIFOs, and disable the HW block */
|
|
|
|
|
bcm2835_wr(bs, BCM2835_SPI_CS,
|
|
|
|
|
BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX);
|
|
|
|
|
mesg->status = err;
|
|
|
|
|
spi_finalize_current_message(master);
|
|
|
|
|
/* select the correct chip_select depending on disabled/enabled */
|
|
|
|
|
if (enable) {
|
|
|
|
|
/* set cs correctly */
|
|
|
|
|
if (spi->mode & SPI_NO_CS) {
|
|
|
|
|
/* use the "undefined" chip-select */
|
|
|
|
|
cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
|
|
|
|
|
} else {
|
|
|
|
|
/* set the chip select */
|
|
|
|
|
cs &= ~(BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01);
|
|
|
|
|
cs |= spi->chip_select;
|
|
|
|
|
}
|
|
|
|
|
} else {
|
|
|
|
|
/* disable CSPOL which puts HW-CS into deselected state */
|
|
|
|
|
cs &= ~BCM2835_SPI_CS_CSPOL;
|
|
|
|
|
/* use the "undefined" chip-select as precaution */
|
|
|
|
|
cs |= BCM2835_SPI_CS_CS_10 | BCM2835_SPI_CS_CS_01;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* finally set the calculated flags in SPI_CS */
|
|
|
|
|
bcm2835_wr(bs, BCM2835_SPI_CS, cs);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int chip_match_name(struct gpio_chip *chip, void *data)
|
|
|
|
|
{
|
|
|
|
|
return !strcmp(chip->label, data);
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int bcm2835_spi_setup(struct spi_device *spi)
|
|
|
|
|
{
|
|
|
|
|
int err;
|
|
|
|
|
struct gpio_chip *chip;
|
|
|
|
|
/*
|
|
|
|
|
* sanity checking the native-chipselects
|
|
|
|
|
*/
|
|
|
|
|
if (spi->mode & SPI_NO_CS)
|
|
|
|
|
return 0;
|
|
|
|
|
if (gpio_is_valid(spi->cs_gpio))
|
|
|
|
|
return 0;
|
|
|
|
|
if (spi->chip_select > 1) {
|
|
|
|
|
/* error in the case of native CS requested with CS > 1
|
|
|
|
|
* officially there is a CS2, but it is not documented
|
|
|
|
|
* which GPIO is connected with that...
|
|
|
|
|
*/
|
|
|
|
|
dev_err(&spi->dev,
|
|
|
|
|
"setup: only two native chip-selects are supported\n");
|
|
|
|
|
return -EINVAL;
|
|
|
|
|
}
|
|
|
|
|
/* now translate native cs to GPIO */
|
|
|
|
|
|
|
|
|
|
/* get the gpio chip for the base */
|
|
|
|
|
chip = gpiochip_find("pinctrl-bcm2835", chip_match_name);
|
|
|
|
|
if (!chip)
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
|
|
/* and calculate the real CS */
|
|
|
|
|
spi->cs_gpio = chip->base + 8 - spi->chip_select;
|
|
|
|
|
|
|
|
|
|
/* and set up the "mode" and level */
|
|
|
|
|
dev_info(&spi->dev, "setting up native-CS%i as GPIO %i\n",
|
|
|
|
|
spi->chip_select, spi->cs_gpio);
|
|
|
|
|
|
|
|
|
|
/* set up GPIO as output and pull to the correct level */
|
|
|
|
|
err = gpio_direction_output(spi->cs_gpio,
|
|
|
|
|
(spi->mode & SPI_CS_HIGH) ? 0 : 1);
|
|
|
|
|
if (err) {
|
|
|
|
|
dev_err(&spi->dev,
|
|
|
|
|
"could not set CS%i gpio %i as output: %i",
|
|
|
|
|
spi->chip_select, spi->cs_gpio, err);
|
|
|
|
|
return err;
|
|
|
|
|
}
|
|
|
|
|
/* the implementation of pinctrl-bcm2835 currently does not
|
|
|
|
|
* set the GPIO value when using gpio_direction_output
|
|
|
|
|
* so we are setting it here explicitly
|
|
|
|
|
*/
|
|
|
|
|
gpio_set_value(spi->cs_gpio, (spi->mode & SPI_CS_HIGH) ? 0 : 1);
|
|
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
}
|
|
|
|
@ -312,13 +426,14 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
|
|
|
|
|
master->mode_bits = BCM2835_SPI_MODE_BITS;
|
|
|
|
|
master->bits_per_word_mask = SPI_BPW_MASK(8);
|
|
|
|
|
master->num_chipselect = 3;
|
|
|
|
|
master->transfer_one_message = bcm2835_spi_transfer_one;
|
|
|
|
|
master->setup = bcm2835_spi_setup;
|
|
|
|
|
master->set_cs = bcm2835_spi_set_cs;
|
|
|
|
|
master->transfer_one = bcm2835_spi_transfer_one;
|
|
|
|
|
master->handle_err = bcm2835_spi_handle_err;
|
|
|
|
|
master->dev.of_node = pdev->dev.of_node;
|
|
|
|
|
|
|
|
|
|
bs = spi_master_get_devdata(master);
|
|
|
|
|
|
|
|
|
|
init_completion(&bs->done);
|
|
|
|
|
|
|
|
|
|
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
|
|
|
|
|
bs->regs = devm_ioremap_resource(&pdev->dev, res);
|
|
|
|
|
if (IS_ERR(bs->regs)) {
|
|
|
|
@ -343,13 +458,13 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
|
|
|
|
|
clk_prepare_enable(bs->clk);
|
|
|
|
|
|
|
|
|
|
err = devm_request_irq(&pdev->dev, bs->irq, bcm2835_spi_interrupt, 0,
|
|
|
|
|
dev_name(&pdev->dev), master);
|
|
|
|
|
dev_name(&pdev->dev), master);
|
|
|
|
|
if (err) {
|
|
|
|
|
dev_err(&pdev->dev, "could not request IRQ: %d\n", err);
|
|
|
|
|
goto out_clk_disable;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* initialise the hardware */
|
|
|
|
|
/* initialise the hardware with the default polarities */
|
|
|
|
|
bcm2835_wr(bs, BCM2835_SPI_CS,
|
|
|
|
|
BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX);
|
|
|
|
|
|
|
|
|
|