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@@ -66,7 +66,7 @@ void spi_free_slave(struct spi_slave *slave)
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int spi_claim_bus(struct spi_slave *slave)
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int spi_claim_bus(struct spi_slave *slave)
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{
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{
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struct davinci_spi_slave *ds = to_davinci_spi(slave);
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struct davinci_spi_slave *ds = to_davinci_spi(slave);
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- unsigned int scalar, data1_reg_val = 0;
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+ unsigned int scalar;
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/* Enable the SPI hardware */
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/* Enable the SPI hardware */
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writel(SPIGCR0_SPIRST_MASK, &ds->regs->gcr0);
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writel(SPIGCR0_SPIRST_MASK, &ds->regs->gcr0);
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@@ -93,11 +93,6 @@ int spi_claim_bus(struct spi_slave *slave)
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writel(8 | (scalar << SPIFMT_PRESCALE_SHIFT) |
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writel(8 | (scalar << SPIFMT_PRESCALE_SHIFT) |
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(1 << SPIFMT_PHASE_SHIFT), &ds->regs->fmt0);
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(1 << SPIFMT_PHASE_SHIFT), &ds->regs->fmt0);
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- /* hold cs active at end of transfer until explicitly de-asserted */
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- data1_reg_val = (1 << SPIDAT1_CSHOLD_SHIFT) |
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- (slave->cs << SPIDAT1_CSNR_SHIFT);
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- writel(data1_reg_val, &ds->regs->dat1);
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-
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/*
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/*
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* Including a minor delay. No science here. Should be good even with
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* Including a minor delay. No science here. Should be good even with
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* no delay
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* no delay
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@@ -113,8 +108,7 @@ int spi_claim_bus(struct spi_slave *slave)
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writel(0, &ds->regs->lvl);
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writel(0, &ds->regs->lvl);
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/* enable SPI */
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/* enable SPI */
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- writel((readl(&ds->regs->gcr1) |
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- SPIGCR1_SPIENA_MASK), &ds->regs->gcr1);
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+ writel((readl(&ds->regs->gcr1) | SPIGCR1_SPIENA_MASK), &ds->regs->gcr1);
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return 0;
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return 0;
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}
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}
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@@ -127,14 +121,125 @@ void spi_release_bus(struct spi_slave *slave)
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writel(SPIGCR0_SPIRST_MASK, &ds->regs->gcr0);
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writel(SPIGCR0_SPIRST_MASK, &ds->regs->gcr0);
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}
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}
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+/*
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+ * This functions needs to act like a macro to avoid pipeline reloads in the
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+ * loops below. Use always_inline. This gains us about 160KiB/s and the bloat
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+ * appears to be zero bytes (da830).
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+ */
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+__attribute__((always_inline))
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+static inline u32 davinci_spi_xfer_data(struct davinci_spi_slave *ds, u32 data)
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+{
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+ u32 buf_reg_val;
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+
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+ /* send out data */
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+ writel(data, &ds->regs->dat1);
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+
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+ /* wait for the data to clock in/out */
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+ while ((buf_reg_val = readl(&ds->regs->buf)) & SPIBUF_RXEMPTY_MASK)
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+ ;
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+
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+ return buf_reg_val;
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+}
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+
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+static int davinci_spi_read(struct spi_slave *slave, unsigned int len,
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+ u8 *rxp, unsigned long flags)
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+{
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+ struct davinci_spi_slave *ds = to_davinci_spi(slave);
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+ unsigned int data1_reg_val;
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+
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+ /* enable CS hold, CS[n] and clear the data bits */
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+ data1_reg_val = ((1 << SPIDAT1_CSHOLD_SHIFT) |
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+ (slave->cs << SPIDAT1_CSNR_SHIFT));
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+
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+ /* wait till TXFULL is deasserted */
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+ while (readl(&ds->regs->buf) & SPIBUF_TXFULL_MASK)
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+ ;
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+
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+ /* preload the TX buffer to avoid clock starvation */
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+ writel(data1_reg_val, &ds->regs->dat1);
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+
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+ /* keep reading 1 byte until only 1 byte left */
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+ while ((len--) > 1)
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+ *rxp++ = davinci_spi_xfer_data(ds, data1_reg_val);
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+
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+ /* clear CS hold when we reach the end */
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+ if (flags & SPI_XFER_END)
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+ data1_reg_val &= ~(1 << SPIDAT1_CSHOLD_SHIFT);
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+
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+ /* read the last byte */
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+ *rxp = davinci_spi_xfer_data(ds, data1_reg_val);
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+
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+ return 0;
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+}
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+
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+static int davinci_spi_write(struct spi_slave *slave, unsigned int len,
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+ const u8 *txp, unsigned long flags)
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+{
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+ struct davinci_spi_slave *ds = to_davinci_spi(slave);
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+ unsigned int data1_reg_val;
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+
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+ /* enable CS hold and clear the data bits */
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+ data1_reg_val = ((1 << SPIDAT1_CSHOLD_SHIFT) |
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+ (slave->cs << SPIDAT1_CSNR_SHIFT));
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+
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+ /* wait till TXFULL is deasserted */
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+ while (readl(&ds->regs->buf) & SPIBUF_TXFULL_MASK)
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+ ;
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+
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+ /* preload the TX buffer to avoid clock starvation */
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+ if (len > 2) {
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+ writel(data1_reg_val | *txp++, &ds->regs->dat1);
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+ len--;
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+ }
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+
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+ /* keep writing 1 byte until only 1 byte left */
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+ while ((len--) > 1)
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+ davinci_spi_xfer_data(ds, data1_reg_val | *txp++);
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+
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+ /* clear CS hold when we reach the end */
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+ if (flags & SPI_XFER_END)
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+ data1_reg_val &= ~(1 << SPIDAT1_CSHOLD_SHIFT);
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+
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+ /* write the last byte */
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+ davinci_spi_xfer_data(ds, data1_reg_val | *txp);
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+
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+ return 0;
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+}
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+
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+#ifndef CONFIG_SPI_HALF_DUPLEX
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+static int davinci_spi_read_write(struct spi_slave *slave, unsigned int len,
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+ u8 *rxp, const u8 *txp, unsigned long flags)
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+{
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+ struct davinci_spi_slave *ds = to_davinci_spi(slave);
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+ unsigned int data1_reg_val;
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+
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+ /* enable CS hold and clear the data bits */
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+ data1_reg_val = ((1 << SPIDAT1_CSHOLD_SHIFT) |
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+ (slave->cs << SPIDAT1_CSNR_SHIFT));
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+
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+ /* wait till TXFULL is deasserted */
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+ while (readl(&ds->regs->buf) & SPIBUF_TXFULL_MASK)
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+ ;
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+
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+ /* keep reading and writing 1 byte until only 1 byte left */
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+ while ((len--) > 1)
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+ *rxp++ = davinci_spi_xfer_data(ds, data1_reg_val | *txp++);
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+
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+ /* clear CS hold when we reach the end */
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+ if (flags & SPI_XFER_END)
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+ data1_reg_val &= ~(1 << SPIDAT1_CSHOLD_SHIFT);
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+
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+ /* read and write the last byte */
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+ *rxp = davinci_spi_xfer_data(ds, data1_reg_val | *txp);
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+
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+ return 0;
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+}
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+#endif
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+
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int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
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int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
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const void *dout, void *din, unsigned long flags)
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const void *dout, void *din, unsigned long flags)
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{
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{
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- struct davinci_spi_slave *ds = to_davinci_spi(slave);
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- unsigned int len, data1_reg_val = readl(&ds->regs->dat1);
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- unsigned int i_cnt = 0, o_cnt = 0, buf_reg_val;
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- const u8 *txp = dout; /* dout can be NULL for read operation */
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- u8 *rxp = din; /* din can be NULL for write operation */
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+ unsigned int len;
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if (bitlen == 0)
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if (bitlen == 0)
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/* Finish any previously submitted transfers */
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/* Finish any previously submitted transfers */
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@@ -154,63 +259,19 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
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len = bitlen / 8;
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len = bitlen / 8;
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- /* do an empty read to clear the current contents */
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- readl(&ds->regs->buf);
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-
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- /* keep writing and reading 1 byte until done */
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- while ((i_cnt < len) || (o_cnt < len)) {
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- /* read RX buffer and flags */
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- buf_reg_val = readl(&ds->regs->buf);
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-
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- /* if data is available */
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- if ((i_cnt < len) &&
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- (buf_reg_val & SPIBUF_RXEMPTY_MASK) == 0) {
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- /*
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- * If there is no read buffer simply
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- * ignore the read character
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- */
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- if (rxp)
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- *rxp++ = buf_reg_val & 0xFF;
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- /* increment read words count */
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- i_cnt++;
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- }
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-
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- /*
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- * if the tx buffer is empty and there
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- * is still data to transmit
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- */
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- if ((o_cnt < len) &&
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- ((buf_reg_val & SPIBUF_TXFULL_MASK) == 0)) {
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- /* write the data */
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- data1_reg_val &= ~0xFFFF;
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- if (txp)
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- data1_reg_val |= *txp++;
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- /*
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- * Write to DAT1 is required to keep
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- * the serial transfer going.
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- * We just terminate when we reach the end.
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- */
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- if ((o_cnt == (len - 1)) && (flags & SPI_XFER_END)) {
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- /* clear CS hold */
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- writel(data1_reg_val &
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- ~(1 << SPIDAT1_CSHOLD_SHIFT),
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- &ds->regs->dat1);
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- } else {
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- /* enable CS hold and write TX register */
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- data1_reg_val |= ((1 << SPIDAT1_CSHOLD_SHIFT) |
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- (slave->cs << SPIDAT1_CSNR_SHIFT));
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- writel(data1_reg_val, &ds->regs->dat1);
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- }
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- /* increment written words count */
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- o_cnt++;
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- }
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- }
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- return 0;
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+ if (!dout)
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+ return davinci_spi_read(slave, len, din, flags);
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+ else if (!din)
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+ return davinci_spi_write(slave, len, dout, flags);
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+#ifndef CONFIG_SPI_HALF_DUPLEX
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+ else
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+ return davinci_spi_read_write(slave, len, din, dout, flags);
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+#endif
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out:
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out:
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if (flags & SPI_XFER_END) {
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if (flags & SPI_XFER_END) {
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- writel(data1_reg_val &
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- ~(1 << SPIDAT1_CSHOLD_SHIFT), &ds->regs->dat1);
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+ u8 dummy = 0;
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+ davinci_spi_write(slave, 1, &dummy, flags);
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}
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}
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return 0;
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return 0;
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}
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}
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