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path: root/drivers/spi/spi-bcm2835.c
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Diffstat (limited to 'drivers/spi/spi-bcm2835.c')
-rw-r--r--drivers/spi/spi-bcm2835.c51
1 files changed, 25 insertions, 26 deletions
diff --git a/drivers/spi/spi-bcm2835.c b/drivers/spi/spi-bcm2835.c
index 237bd306c268..c45d76c848c8 100644
--- a/drivers/spi/spi-bcm2835.c
+++ b/drivers/spi/spi-bcm2835.c
@@ -86,6 +86,7 @@ MODULE_PARM_DESC(polling_limit_us,
* @clk: core clock, divided to calculate serial clock
* @irq: interrupt, signals TX FIFO empty or RX FIFO ¾ full
* @tfr: SPI transfer currently processed
+ * @ctlr: SPI controller reverse lookup
* @tx_buf: pointer whence next transmitted byte is read
* @rx_buf: pointer where next received byte is written
* @tx_len: remaining bytes to transmit
@@ -125,6 +126,7 @@ struct bcm2835_spi {
struct clk *clk;
int irq;
struct spi_transfer *tfr;
+ struct spi_controller *ctlr;
const u8 *tx_buf;
u8 *rx_buf;
int tx_len;
@@ -243,13 +245,13 @@ static inline void bcm2835_rd_fifo_count(struct bcm2835_spi *bs, int count)
bs->rx_len -= count;
- while (count > 0) {
+ do {
val = bcm2835_rd(bs, BCM2835_SPI_FIFO);
len = min(count, 4);
memcpy(bs->rx_buf, &val, len);
bs->rx_buf += len;
count -= 4;
- }
+ } while (count > 0);
}
/**
@@ -269,7 +271,7 @@ static inline void bcm2835_wr_fifo_count(struct bcm2835_spi *bs, int count)
bs->tx_len -= count;
- while (count > 0) {
+ do {
if (bs->tx_buf) {
len = min(count, 4);
memcpy(&val, bs->tx_buf, len);
@@ -279,7 +281,7 @@ static inline void bcm2835_wr_fifo_count(struct bcm2835_spi *bs, int count)
}
bcm2835_wr(bs, BCM2835_SPI_FIFO, val);
count -= 4;
- }
+ } while (count > 0);
}
/**
@@ -308,12 +310,11 @@ static inline void bcm2835_rd_fifo_blind(struct bcm2835_spi *bs, int count)
count = min(count, bs->rx_len);
bs->rx_len -= count;
- while (count) {
+ do {
val = bcm2835_rd(bs, BCM2835_SPI_FIFO);
if (bs->rx_buf)
*bs->rx_buf++ = val;
- count--;
- }
+ } while (--count);
}
/**
@@ -328,16 +329,14 @@ static inline void bcm2835_wr_fifo_blind(struct bcm2835_spi *bs, int count)
count = min(count, bs->tx_len);
bs->tx_len -= count;
- while (count) {
+ do {
val = bs->tx_buf ? *bs->tx_buf++ : 0;
bcm2835_wr(bs, BCM2835_SPI_FIFO, val);
- count--;
- }
+ } while (--count);
}
-static void bcm2835_spi_reset_hw(struct spi_controller *ctlr)
+static void bcm2835_spi_reset_hw(struct bcm2835_spi *bs)
{
- struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr);
u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
/* Disable SPI interrupts and transfer */
@@ -363,8 +362,7 @@ static void bcm2835_spi_reset_hw(struct spi_controller *ctlr)
static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id)
{
- struct spi_controller *ctlr = dev_id;
- struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr);
+ struct bcm2835_spi *bs = dev_id;
u32 cs = bcm2835_rd(bs, BCM2835_SPI_CS);
/*
@@ -386,9 +384,9 @@ static irqreturn_t bcm2835_spi_interrupt(int irq, void *dev_id)
if (!bs->rx_len) {
/* Transfer complete - reset SPI HW */
- bcm2835_spi_reset_hw(ctlr);
+ bcm2835_spi_reset_hw(bs);
/* wake up the framework */
- complete(&ctlr->xfer_completion);
+ complete(&bs->ctlr->xfer_completion);
}
return IRQ_HANDLED;
@@ -607,7 +605,7 @@ static void bcm2835_spi_dma_rx_done(void *data)
bcm2835_spi_undo_prologue(bs);
/* reset fifo and HW */
- bcm2835_spi_reset_hw(ctlr);
+ bcm2835_spi_reset_hw(bs);
/* and mark as completed */;
complete(&ctlr->xfer_completion);
@@ -641,7 +639,7 @@ static void bcm2835_spi_dma_tx_done(void *data)
dmaengine_terminate_async(ctlr->dma_rx);
bcm2835_spi_undo_prologue(bs);
- bcm2835_spi_reset_hw(ctlr);
+ bcm2835_spi_reset_hw(bs);
complete(&ctlr->xfer_completion);
}
@@ -825,14 +823,14 @@ static int bcm2835_spi_transfer_one_dma(struct spi_controller *ctlr,
if (!bs->rx_buf && !bs->tx_dma_active &&
cmpxchg(&bs->rx_dma_active, true, false)) {
dmaengine_terminate_async(ctlr->dma_rx);
- bcm2835_spi_reset_hw(ctlr);
+ bcm2835_spi_reset_hw(bs);
}
/* wait for wakeup in framework */
return 1;
err_reset_hw:
- bcm2835_spi_reset_hw(ctlr);
+ bcm2835_spi_reset_hw(bs);
bcm2835_spi_undo_prologue(bs);
return ret;
}
@@ -1074,7 +1072,7 @@ static int bcm2835_spi_transfer_one_poll(struct spi_controller *ctlr,
}
/* Transfer complete - reset SPI HW */
- bcm2835_spi_reset_hw(ctlr);
+ bcm2835_spi_reset_hw(bs);
/* and return without waiting for completion */
return 0;
}
@@ -1084,7 +1082,7 @@ static int bcm2835_spi_transfer_one(struct spi_controller *ctlr,
struct spi_transfer *tfr)
{
struct bcm2835_spi *bs = spi_controller_get_devdata(ctlr);
- unsigned long spi_hz, clk_hz, cdiv, spi_used_hz;
+ unsigned long spi_hz, clk_hz, cdiv;
unsigned long hz_per_byte, byte_limit;
u32 cs = bs->prepare_cs[spi->chip_select];
@@ -1104,7 +1102,7 @@ static int bcm2835_spi_transfer_one(struct spi_controller *ctlr,
} else {
cdiv = 0; /* 0 is the slowest we can go */
}
- spi_used_hz = cdiv ? (clk_hz / cdiv) : (clk_hz / 65536);
+ tfr->effective_speed_hz = cdiv ? (clk_hz / cdiv) : (clk_hz / 65536);
bcm2835_wr(bs, BCM2835_SPI_CLK, cdiv);
/* handle all the 3-wire mode */
@@ -1124,7 +1122,7 @@ static int bcm2835_spi_transfer_one(struct spi_controller *ctlr,
* per 300,000 Hz of bus clock.
*/
hz_per_byte = polling_limit_us ? (9 * 1000000) / polling_limit_us : 0;
- byte_limit = hz_per_byte ? spi_used_hz / hz_per_byte : 1;
+ byte_limit = hz_per_byte ? tfr->effective_speed_hz / hz_per_byte : 1;
/* run in polling mode for short transfers */
if (tfr->len < byte_limit)
@@ -1182,7 +1180,7 @@ static void bcm2835_spi_handle_err(struct spi_controller *ctlr,
bcm2835_spi_undo_prologue(bs);
/* and reset */
- bcm2835_spi_reset_hw(ctlr);
+ bcm2835_spi_reset_hw(bs);
}
static int chip_match_name(struct gpio_chip *chip, void *data)
@@ -1311,6 +1309,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
ctlr->dev.of_node = pdev->dev.of_node;
bs = spi_controller_get_devdata(ctlr);
+ bs->ctlr = ctlr;
bs->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(bs->regs)) {
@@ -1345,7 +1344,7 @@ static int bcm2835_spi_probe(struct platform_device *pdev)
BCM2835_SPI_CS_CLEAR_RX | BCM2835_SPI_CS_CLEAR_TX);
err = devm_request_irq(&pdev->dev, bs->irq, bcm2835_spi_interrupt, 0,
- dev_name(&pdev->dev), ctlr);
+ dev_name(&pdev->dev), bs);
if (err) {
dev_err(&pdev->dev, "could not request IRQ: %d\n", err);
goto out_dma_release;
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.