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spi: fsl-espi: add (un)prepare_transfer_hardware calls to save power if SPI is not in use

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Use (un)prepare_transfer_hardware calls to set fsl-espi to
low-power idle if not in use. Reference manual states:

"The eSPI is in a idle state and consumes minimal power.
The eSPI BRG is not functioning and the input clock is disabled"

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Heiner Kallweit 2014-12-03 07:56:19 +01:00 committed by Mark Brown
parent c592becbe7
commit 75506d0e00
1 changed files with 35 additions and 11 deletions
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46
drivers/spi/spi-fsl-espi.c
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@ -588,6 +588,38 @@ static void fsl_espi_remove(struct mpc8xxx_spi *mspi)
iounmap(mspi->reg_base);
}
static int fsl_espi_suspend(struct spi_master *master)
{
struct mpc8xxx_spi *mpc8xxx_spi;
struct fsl_espi_reg *reg_base;
u32 regval;
mpc8xxx_spi = spi_master_get_devdata(master);
reg_base = mpc8xxx_spi->reg_base;
regval = mpc8xxx_spi_read_reg(&reg_base->mode);
regval &= ~SPMODE_ENABLE;
mpc8xxx_spi_write_reg(&reg_base->mode, regval);
return 0;
}
static int fsl_espi_resume(struct spi_master *master)
{
struct mpc8xxx_spi *mpc8xxx_spi;
struct fsl_espi_reg *reg_base;
u32 regval;
mpc8xxx_spi = spi_master_get_devdata(master);
reg_base = mpc8xxx_spi->reg_base;
regval = mpc8xxx_spi_read_reg(&reg_base->mode);
regval |= SPMODE_ENABLE;
mpc8xxx_spi_write_reg(&reg_base->mode, regval);
return 0;
}
static struct spi_master * fsl_espi_probe(struct device *dev,
struct resource *mem, unsigned int irq)
{
@ -614,6 +646,8 @@ static struct spi_master * fsl_espi_probe(struct device *dev,
master->setup = fsl_espi_setup;
master->cleanup = fsl_espi_cleanup;
master->transfer_one_message = fsl_espi_do_one_msg;
master->prepare_transfer_hardware = fsl_espi_resume;
master->unprepare_transfer_hardware = fsl_espi_suspend;
mpc8xxx_spi = spi_master_get_devdata(master);
mpc8xxx_spi->spi_remove = fsl_espi_remove;
@ -761,25 +795,15 @@ static int of_fsl_espi_remove(struct platform_device *dev)
static int of_fsl_espi_suspend(struct device *dev)
{
struct spi_master *master = dev_get_drvdata(dev);
struct mpc8xxx_spi *mpc8xxx_spi;
struct fsl_espi_reg *reg_base;
u32 regval;
int ret;
mpc8xxx_spi = spi_master_get_devdata(master);
reg_base = mpc8xxx_spi->reg_base;
ret = spi_master_suspend(master);
if (ret) {
dev_warn(dev, "cannot suspend master\n");
return ret;
}
regval = mpc8xxx_spi_read_reg(&reg_base->mode);
regval &= ~SPMODE_ENABLE;
mpc8xxx_spi_write_reg(&reg_base->mode, regval);
return 0;
return fsl_espi_suspend(master);
}
static int of_fsl_espi_resume(struct device *dev)