From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?Q?Christoph_M=C3=BCllner?= Subject: Re: [PATCH 1/3] phy: rockchip-emmc: Allow to set drive impedance via DTS. Date: Fri, 1 Mar 2019 17:21:36 +0100 Message-ID: <32D33089-37C4-4086-88B1-5408A0782917@theobroma-systems.com> References: <20190301153348.29870-1-christoph.muellner@theobroma-systems.com> <2706069.0FZLJLT2V8@phil> Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <2706069.0FZLJLT2V8@phil> Sender: linux-kernel-owner@vger.kernel.org To: Heiko Stuebner Cc: robh+dt@kernel.org, mark.rutland@arm.com, shawn.lin@rock-chips.com, Philipp Tomsich , Kishon Vijay Abraham I , Enric Balletbo i Serra , Klaus Goger , Douglas Anderson , Viresh Kumar , Matthias Brugger , Emil Renner Berthing , Tony Xie , Randy Li , Vicente Bergas , Ezequiel Garcia , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org Hi Heiko, > On 01.03.2019, at 16:59, Heiko Stuebner wrote: > > Hi Christoph, > > Am Freitag, 1. März 2019, 16:33:43 CET schrieb Christoph Muellner: >> 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: Christoph Muellner >> Signed-off-by: Philipp Tomsich >> --- >> drivers/phy/rockchip/phy-rockchip-emmc.c | 38 ++++++++++++++++++++++++++++++-- > > looks good on first glance, but is missing an addition to the emmc-phy > devicetree binding in > Documentation/devicetree/bindings/phy/rockchip-emmc-phy.txt you are right. I've just sent that in a separate patch (DT doc changes need to be in a separate commit anyways). Thanks, Christoph > > > Heiko > >> 1 file changed, 36 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/phy/rockchip/phy-rockchip-emmc.c b/drivers/phy/rockchip/phy-rockchip-emmc.c >> index 19bf84f0bc67..5413fa73dd45 100644 >> --- a/drivers/phy/rockchip/phy-rockchip-emmc.c >> +++ b/drivers/phy/rockchip/phy-rockchip-emmc.c >> @@ -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 +315,28 @@ 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. " >> + "Falling back to 50 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 +345,7 @@ 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; >> @@ -345,6 +369,16 @@ static int rockchip_emmc_phy_probe(struct platform_device *pdev) >> rk_phy->reg_offset = reg_offset; >> rk_phy->reg_base = grf; >> >> + if (of_property_read_u32(dev->of_node, "drive-impedance-ohm", &val)) { >> + dev_info(dev, >> + "Missing drive-impedance-ohm property in node %s " >> + "Falling back to 50 Ohm.\n", >> + dev->of_node->name); >> + rk_phy->drive_impedance = PHYCTRL_DR_50OHM; >> + } else { >> + 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)) { >> dev_err(dev, "failed to create PHY\n"); >> > > > >