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Commit 75506d0e authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Mark Brown
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spi: fsl-espi: add (un)prepare_transfer_hardware calls to save power if SPI is not in use 



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: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent c592becb

drivers/spi/spi-fsl-espi.c

+35 −11
Original line number Diff line number Diff line
@@ -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)