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Commit c62ebb3d authored by Phil Edworthy's avatar Phil Edworthy Committed by Wolfram Sang
Browse files

i2c: designware: Add support for an interface clock 



The Synopsys I2C Controller has an interface clock, but most SoCs hide
this away. However, on some SoCs you need to explicitly enable the
interface clock in order to access the registers. Therefore, add
support for an optional interface clock.

Signed-off-by: default avatarPhil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: default avatarGareth Williams <gareth.williams.jx@renesas.com>
Acked-by: default avatarWolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: default avatarJarkko Nikula <jarkko.nikula@linux.intel.com>
Tested-by: default avatarJarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent bdfdf4b2

drivers/i2c/busses/i2c-designware-common.c

+16 −2
Original line number Diff line number Diff line
@@ -251,13 +251,27 @@ unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev) 


int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare)

{

	int ret;



	if (IS_ERR(dev->clk))

		return PTR_ERR(dev->clk);



	if (prepare)

		return clk_prepare_enable(dev->clk);

	if (prepare) {

		/* Optional interface clock */

		ret = clk_prepare_enable(dev->pclk);

		if (ret)

			return ret;



		ret = clk_prepare_enable(dev->clk);

		if (ret)

			clk_disable_unprepare(dev->pclk);



		return ret;

	}



	clk_disable_unprepare(dev->clk);

	clk_disable_unprepare(dev->pclk);



	return 0;

}

EXPORT_SYMBOL_GPL(i2c_dw_prepare_clk);

drivers/i2c/busses/i2c-designware-core.h

+2 −0
Original line number Diff line number Diff line
@@ -177,6 +177,7 @@ 
 * @base: IO registers pointer

 * @cmd_complete: tx completion indicator

 * @clk: input reference clock

 * @pclk: clock required to access the registers

 * @slave: represent an I2C slave device

 * @cmd_err: run time hadware error code

 * @msgs: points to an array of messages currently being transferred
@@ -227,6 +228,7 @@ struct dw_i2c_dev { 
	void __iomem		*ext;

	struct completion	cmd_complete;

	struct clk		*clk;

	struct clk		*pclk;

	struct reset_control	*rst;

	struct i2c_client		*slave;

	u32			(*get_clk_rate_khz) (struct dw_i2c_dev *dev);

drivers/i2c/busses/i2c-designware-platdrv.c

+5 −0
Original line number Diff line number Diff line
@@ -344,6 +344,11 @@ static int dw_i2c_plat_probe(struct platform_device *pdev) 
	else

		i2c_dw_configure_master(dev);



	/* Optional interface clock */

	dev->pclk = devm_clk_get_optional(&pdev->dev, "pclk");

	if (IS_ERR(dev->pclk))

		return PTR_ERR(dev->pclk);



	dev->clk = devm_clk_get(&pdev->dev, NULL);

	if (!i2c_dw_prepare_clk(dev, true)) {

		u64 clk_khz;