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spi: davinci: enable and power-up SPI only when required 

Enable SPI only when active transfers are in progress. Keep
it in local low power when not in use.

Signed-off-by: Brian Niebuhr <bniebuhr@efjohnson.com>
Tested-By: Michael Williamson <michael.williamson@criticallink.com>
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
This commit is contained in:
Brian Niebuhr 2010-10-06 18:25:43 +05:30 committed by Sekhar Nori
parent 3409e408ab
commit 3f27b57c16
1 changed files with 6 additions and 2 deletions
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8
drivers/spi/davinci_spi.c
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@ -49,7 +49,6 @@
#define SPIFMT_WDELAY_SHIFT 24
#define SPIFMT_PRESCALE_SHIFT 8
/* SPIPC0 */
#define SPIPC0_DIFUN_MASK BIT(11) /* MISO */
#define SPIPC0_DOFUN_MASK BIT(10) /* MOSI */
@ -67,6 +66,7 @@
/* SPIGCR1 */
#define SPIGCR1_CLKMOD_MASK BIT(1)
#define SPIGCR1_MASTER_MASK BIT(0)
#define SPIGCR1_POWERDOWN_MASK BIT(8)
#define SPIGCR1_LOOPBACK_MASK BIT(16)
#define SPIGCR1_SPIENA_MASK BIT(24)
@ -556,7 +556,7 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
data1_reg_val = ioread32(davinci_spi->base + SPIDAT1);
/* Enable SPI */
clear_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
INIT_COMPLETION(davinci_spi->done);
@ -693,6 +693,9 @@ static int davinci_spi_bufs(struct spi_device *spi, struct spi_transfer *t)
clear_io_bits(davinci_spi->base + SPIINT, SPIINT_DMA_REQ_EN);
}
clear_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_SPIENA_MASK);
set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
/*
* Check for bit error, desync error,parity error,timeout error and
* receive overflow errors
@ -937,6 +940,7 @@ static int davinci_spi_probe(struct platform_device *pdev)
/* master mode default */
set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_CLKMOD_MASK);
set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_MASTER_MASK);
set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_POWERDOWN_MASK);
ret = spi_bitbang_start(&davinci_spi->bitbang);
if (ret)