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spi: dw: program registers as soon as possible 

This patch refactors the code in pump_transfers() to reprogram the registers
immediately when we have a new configuration data. The behaviour is slightly
modified:
 - chip is always disabled and reenabled
 - CTRL0 is always reprogrammed

This change allows to do a further refactoring and simplier conversion to use
SPI core DMA routines in the future.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Andy Shevchenko 2015-03-02 14:58:56 +02:00 committed by Mark Brown
parent 45746e82cf
commit 0b2e8915ea
1 changed files with 15 additions and 23 deletions
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38
drivers/spi/spi-dw.c
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@ -409,6 +409,8 @@ static void pump_transfers(unsigned long data)
if (chip != dws->prev_chip)
cs_change = 1;
spi_enable_chip(dws, 0);
cr0 = chip->cr0;
/* Handle per transfer options for bpw and speed */
@ -423,6 +425,8 @@ static void pump_transfers(unsigned long data)
chip->speed_hz = speed;
chip->clk_div = clk_div;
spi_set_clk(dws, chip->clk_div);
}
}
if (transfer->bits_per_word) {
@ -451,44 +455,32 @@ static void pump_transfers(unsigned long data)
cr0 |= (chip->tmode << SPI_TMOD_OFFSET);
}
dw_writew(dws, DW_SPI_CTRL0, cr0);
spi_chip_sel(dws, spi, 1);
/* Check if current transfer is a DMA transaction */
dws->dma_mapped = map_dma_buffers(dws);
/* For poll mode just disable all interrupts */
spi_mask_intr(dws, 0xff);
/*
* Interrupt mode
* we only need set the TXEI IRQ, as TX/RX always happen syncronizely
*/
if (!dws->dma_mapped && !chip->poll_mode) {
txlevel = min_t(u16, dws->fifo_len / 2, dws->len / dws->n_bytes);
dw_writew(dws, DW_SPI_TXFLTR, txlevel);
/* Set the interrupt mask */
imask |= SPI_INT_TXEI | SPI_INT_TXOI |
SPI_INT_RXUI | SPI_INT_RXOI;
spi_umask_intr(dws, imask);
dws->transfer_handler = interrupt_transfer;
}
/*
* Reprogram registers only if
* 1. chip select changes
* 2. clk_div is changed
* 3. control value changes
*/
if (dw_readw(dws, DW_SPI_CTRL0) != cr0 || cs_change || clk_div || imask) {
spi_enable_chip(dws, 0);
dw_writew(dws, DW_SPI_CTRL0, cr0);
spi_set_clk(dws, chip->clk_div);
spi_chip_sel(dws, spi, 1);
/* Set the interrupt mask, for poll mode just disable all int */
spi_mask_intr(dws, 0xff);
if (imask)
spi_umask_intr(dws, imask);
if (txlevel)
dw_writew(dws, DW_SPI_TXFLTR, txlevel);
spi_enable_chip(dws, 1);
}
spi_enable_chip(dws, 1);
if (cs_change)
dws->prev_chip = chip;