Commit 043f42ed authored by Christoph Muellner's avatar Christoph Muellner Committed by Kishon Vijay Abraham I
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phy: rockchip-emmc: Allow to set drive impedance via DTS. 



The rockchip-emmc PHY can be configured with different
drive impedance values. Currenlty a value of 50 Ohm is
hard coded into the driver.

This patch introduces the DTS property 'drive-impedance-ohm'
for the rockchip-emmc phy node, which uses the value from the DTS
to setup the drive impedance accordingly.

Signed-off-by: default avatarChristoph Muellner <christoph.muellner@theobroma-systems.com>
Signed-off-by: default avatarPhilipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: default avatarHeiko Stuebner <heiko@sntech.de>
Signed-off-by: default avatarKishon Vijay Abraham I <kishon@ti.com>
parent 3f6d1767

drivers/phy/rockchip/phy-rockchip-emmc.c

+28 −2
Original line number Diff line number Diff line
@@ -87,6 +87,7 @@ struct rockchip_emmc_phy { 
	unsigned int	reg_offset;

	struct regmap	*reg_base;

	struct clk	*emmcclk;

	unsigned int drive_impedance;

};



static int rockchip_emmc_phy_power(struct phy *phy, bool on_off)
@@ -281,10 +282,10 @@ static int rockchip_emmc_phy_power_on(struct phy *phy) 
{

	struct rockchip_emmc_phy *rk_phy = phy_get_drvdata(phy);



	/* Drive impedance: 50 Ohm */

	/* Drive impedance: from DTS */

	regmap_write(rk_phy->reg_base,

		     rk_phy->reg_offset + GRF_EMMCPHY_CON6,

		     HIWORD_UPDATE(PHYCTRL_DR_50OHM,

		     HIWORD_UPDATE(rk_phy->drive_impedance,

				   PHYCTRL_DR_MASK,

				   PHYCTRL_DR_SHIFT));
@@ -314,6 +315,26 @@ static const struct phy_ops ops = { 
	.owner		= THIS_MODULE,

};



static u32 convert_drive_impedance_ohm(struct platform_device *pdev, u32 dr_ohm)

{

	switch (dr_ohm) {

	case 100:

		return PHYCTRL_DR_100OHM;

	case 66:

		return PHYCTRL_DR_66OHM;

	case 50:

		return PHYCTRL_DR_50OHM;

	case 40:

		return PHYCTRL_DR_40OHM;

	case 33:

		return PHYCTRL_DR_33OHM;

	}



	dev_warn(&pdev->dev, "Invalid value %u for drive-impedance-ohm.\n",

		 dr_ohm);

	return PHYCTRL_DR_50OHM;

}



static int rockchip_emmc_phy_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;
@@ -322,6 +343,7 @@ static int rockchip_emmc_phy_probe(struct platform_device *pdev) 
	struct phy_provider *phy_provider;

	struct regmap *grf;

	unsigned int reg_offset;

	u32 val;



	if (!dev->parent || !dev->parent->of_node)

		return -ENODEV;
@@ -344,6 +366,10 @@ static int rockchip_emmc_phy_probe(struct platform_device *pdev) 


	rk_phy->reg_offset = reg_offset;

	rk_phy->reg_base = grf;

	rk_phy->drive_impedance = PHYCTRL_DR_50OHM;



	if (!of_property_read_u32(dev->of_node, "drive-impedance-ohm", &val))

		rk_phy->drive_impedance = convert_drive_impedance_ohm(pdev, val);



	generic_phy = devm_phy_create(dev, dev->of_node, &ops);

	if (IS_ERR(generic_phy)) {

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