R-Car USB 2.0 controller can change the clock source from an oscillator to an external clock via a register. So, this patch adds support the clock source selector as a clock driver.
Signed-off-by: Yoshihiro Shimoda <[email protected]> --- This patch is based on the renesas-drivers.git / renesas-drivers-2017-06-27-v4.12-rc7 tag. Changes from v1: - Change this driver as a clock driver from a generic phy driver. https://patchwork.kernel.org/patch/9788697/ - Remove "RFC" tag. .../bindings/clock/renesas,rcar-usb2-clock-sel.txt | 54 ++++++ drivers/clk/renesas/Kconfig | 5 + drivers/clk/renesas/Makefile | 1 + drivers/clk/renesas/rcar-usb2-clock-sel.c | 205 +++++++++++++++++++++ 4 files changed, 265 insertions(+) create mode 100644 Documentation/devicetree/bindings/clock/renesas,rcar-usb2-clock-sel.txt create mode 100644 drivers/clk/renesas/rcar-usb2-clock-sel.c diff --git a/Documentation/devicetree/bindings/clock/renesas,rcar-usb2-clock-sel.txt b/Documentation/devicetree/bindings/clock/renesas,rcar-usb2-clock-sel.txt new file mode 100644 index 0000000..75ccafc --- /dev/null +++ b/Documentation/devicetree/bindings/clock/renesas,rcar-usb2-clock-sel.txt @@ -0,0 +1,54 @@ +* Renesas R-Car USB 2.0 clock selector + +This file provides information on what the device node for the R-Car USB 2.0 +clock selector. + +If you connect an external clock to the USB_EXTAL pin only, you should set +the clock rate to "usb_extal" node only. +If you connect an oscillator to both the USB_XTAL and USB_EXTAL, this module +is not needed because this is default setting. (Of course, you can set the +clock rates to both "usb_extal" and "usb_xtal" nodes. + +Case 1: An external clock connects to R-Car SoC + +----------+ +--- R-Car ---------------------+ + |External |---|USB_EXTAL ---> all usb channels| + |clock | |USB_XTAL | + +----------+ +-------------------------------+ +In this case, we need this driver with "usb_extal" clock. + +Case 2: An oscillator connects to R-Car SoC + +----------+ +--- R-Car ---------------------+ + |Oscillator|---|USB_EXTAL -+-> all usb channels| + | |---|USB_XTAL --+ | + +----------+ +-------------------------------+ +In this case, we don't need this selector. + +Required properties: +- compatible: "renesas,r8a7795-rcar-usb2-clock-sel" if the device is a part of + an R8A7795 SoC. + "renesas,r8a7796-rcar-usb2-clock-sel" if the device if a part of + an R8A7796 SoC. + "renesas,rcar-gen3-usb2-clock-sel" for a generic R-Car Gen3 + compatible device. + + When compatible with the generic version, nodes must list the + SoC-specific version corresponding to the platform first + followed by the generic version. + +- reg: offset and length of the USB 2.0 clock selector register block. +- clocks: A list of phandles and specifier pairs. +- clock-names: Name of the clocks. + - The functional clock must be "ehci_ohci" + - The USB_EXTAL clock pin must be "usb_extal" + - The USB_XTAL clock pin must be "usb_xtal" +- #clock-cells: Must be 0 + +Exxample (R-Car H3): + + usb2_clksel: clock-controller@e6590630 { + compatible = "renesas,r8a77950-rcar-usb2-clock-sel", + "renesas,rcar-gen3-usb2-clock-sel"; + reg = <0 0xe6590630 0 0x02>; + clocks = <&cpg CPG_MOD 703>, <&usb_extal>, <&usb_xtal>; + clock-names = "ehci_ohci", "usb_extal", "usb_xtal"; + }; diff --git a/drivers/clk/renesas/Kconfig b/drivers/clk/renesas/Kconfig index 78d1df9..094df5c 100644 --- a/drivers/clk/renesas/Kconfig +++ b/drivers/clk/renesas/Kconfig @@ -114,6 +114,11 @@ config CLK_RCAR_GEN3_CPG bool select CLK_RENESAS_CPG_MSSR +config CLK_RCAR_USB2_CLOCK_SEL + bool "Renesas R-Car USB2 clock selector support" + depends on ARCH_RENESAS || COMPILE_TEST + help + This is a driver for R-Car USB2 clock selector # Generic config CLK_RENESAS_CPG_MSSR diff --git a/drivers/clk/renesas/Makefile b/drivers/clk/renesas/Makefile index 02d0412..4eec85b 100644 --- a/drivers/clk/renesas/Makefile +++ b/drivers/clk/renesas/Makefile @@ -19,6 +19,7 @@ obj-$(CONFIG_CLK_SH73A0) += clk-sh73a0.o obj-$(CONFIG_CLK_RCAR_GEN2) += clk-rcar-gen2.o obj-$(CONFIG_CLK_RCAR_GEN2_CPG) += rcar-gen2-cpg.o obj-$(CONFIG_CLK_RCAR_GEN3_CPG) += rcar-gen3-cpg.o +obj-$(CONFIG_CLK_RCAR_USB2_CLOCK_SEL) += rcar-usb2-clock-sel.o # Generic obj-$(CONFIG_CLK_RENESAS_CPG_MSSR) += renesas-cpg-mssr.o diff --git a/drivers/clk/renesas/rcar-usb2-clock-sel.c b/drivers/clk/renesas/rcar-usb2-clock-sel.c new file mode 100644 index 0000000..b48b2fc --- /dev/null +++ b/drivers/clk/renesas/rcar-usb2-clock-sel.c @@ -0,0 +1,205 @@ +/* + * Renesas R-Car USB2.0 clock selector + * + * Copyright (C) 2017 Renesas Electronics Corp. + * + * Based on renesas-cpg-mssr.c + * + * Copyright (C) 2015 Glider bvba + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; version 2 of the License. + */ + +#include <linux/clk.h> +#include <linux/clk-provider.h> +#include <linux/device.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pm.h> +#include <linux/slab.h> + +#define USB20_CLKSET0 0x00 +#define CLKSET0_INTCLK_EN BIT(11) +#define CLKSET0_PRIVATE BIT(0) +#define CLKSET0_EXTAL_ONLY (CLKSET0_INTCLK_EN | CLKSET0_PRIVATE) + +struct usb2_clock_sel_priv { + void __iomem *base; + struct clk_hw hw; + struct clk *ehci_clk; + bool extal; + bool xtal; +}; +#define to_priv(_hw) container_of(_hw, struct usb2_clock_sel_priv, hw) + +static void usb2_clock_sel_enable_extal_only(struct usb2_clock_sel_priv *priv) +{ + u16 val = readw(priv->base + USB20_CLKSET0); + + pr_debug("%s: enter %d %d %x\n", __func__, + priv->extal, priv->xtal, val); + + if (priv->extal && !priv->xtal && val != CLKSET0_EXTAL_ONLY) + writew(CLKSET0_EXTAL_ONLY, priv->base + USB20_CLKSET0); +} + +static void usb2_clock_sel_disable_extal_only(struct usb2_clock_sel_priv *priv) +{ + if (priv->extal && !priv->xtal) + writew(CLKSET0_PRIVATE, priv->base + USB20_CLKSET0); +} + +static int usb2_clock_sel_enable(struct clk_hw *hw) +{ + usb2_clock_sel_enable_extal_only(to_priv(hw)); + + return 0; +} + +static void usb2_clock_sel_disable(struct clk_hw *hw) +{ + usb2_clock_sel_disable_extal_only(to_priv(hw)); +} + +/* + * This module seems a mux, but this driver assumes a gate because + * ehci/ohci platform drivers don't support clk_set_parent() for now. + * If this driver acts as a gate, ehci/ohci-platform drivers don't need + * any modification. + */ +static const struct clk_ops usb2_clock_sel_clock_ops = { + .enable = usb2_clock_sel_enable, + .disable = usb2_clock_sel_disable, +}; + +static const struct of_device_id rcar_usb2_clock_sel_match[] = { + { .compatible = "renesas,rcar-gen3-usb2-clock-sel" }, + { } +}; + +static int rcar_usb2_clock_sel_suspend(struct device *dev) +{ + struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev); + + usb2_clock_sel_disable_extal_only(priv); + clk_disable_unprepare(priv->ehci_clk); + + return 0; +} + +static int rcar_usb2_clock_sel_resume(struct device *dev) +{ + struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev); + int error; + + error = clk_prepare_enable(priv->ehci_clk); + if (error) + return error; + usb2_clock_sel_enable_extal_only(priv); + + return 0; +} + +static int rcar_usb2_clock_sel_remove(struct platform_device *pdev) +{ + struct usb2_clock_sel_priv *priv = platform_get_drvdata(pdev); + + clk_disable_unprepare(priv->ehci_clk); + of_clk_del_provider(pdev->dev.of_node); + clk_hw_unregister(&priv->hw); + + return 0; +} + +static int __init rcar_usb2_clock_sel_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct usb2_clock_sel_priv *priv; + struct resource *res; + struct clk *clk; + struct clk_init_data init; + int error; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + priv->base = devm_ioremap_resource(dev, res); + if (IS_ERR(priv->base)) + return PTR_ERR(priv->base); + + priv->ehci_clk = devm_clk_get(dev, "ehci_ohci"); + if (!IS_ERR(priv->ehci_clk)) { + error = clk_prepare_enable(priv->ehci_clk); + if (error) + return error; + } + + clk = devm_clk_get(dev, "usb_extal"); + if (!IS_ERR(clk) && !clk_prepare_enable(clk)) { + priv->extal = !!clk_get_rate(clk); + clk_disable_unprepare(clk); + } + clk = devm_clk_get(dev, "usb_xtal"); + if (!IS_ERR(clk) && !clk_prepare_enable(clk)) { + priv->xtal = !!clk_get_rate(clk); + clk_disable_unprepare(clk); + } + + if (!priv->extal && !priv->extal) { + dev_err(dev, "This driver needs usb_extal or usb_xtal\n"); + return -ENOENT; + } + + platform_set_drvdata(pdev, priv); + dev_set_drvdata(dev, priv); + + init.name = "rcar_usb2_clock_sel"; + init.ops = &usb2_clock_sel_clock_ops; + init.flags = CLK_IS_BASIC; + init.parent_names = NULL; + init.num_parents = 0; + priv->hw.init = &init; + + clk = clk_register(NULL, &priv->hw); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + error = of_clk_add_provider(np, of_clk_src_simple_get, clk); + if (error) + return error; + + return 0; +} + +static const struct dev_pm_ops rcar_usb2_clock_sel_pm_ops = { + .suspend = rcar_usb2_clock_sel_suspend, + .resume = rcar_usb2_clock_sel_resume, +}; + +static struct platform_driver rcar_usb2_clock_sel_driver = { + .driver = { + .name = "rcar-usb2-clock-sel", + .pm = &rcar_usb2_clock_sel_pm_ops, + .of_match_table = rcar_usb2_clock_sel_match, + }, + .remove = rcar_usb2_clock_sel_remove, +}; + +static int __init rcar_usb2_clock_sel_init(void) +{ + return platform_driver_probe(&rcar_usb2_clock_sel_driver, + rcar_usb2_clock_sel_probe); +} + +/* Since this driver needs other ccf drivers, this uses subsys_initcall_sync */ +subsys_initcall_sync(rcar_usb2_clock_sel_init); + +MODULE_DESCRIPTION("Renesas R-Car USB2 clock selector Driver"); +MODULE_LICENSE("GPL v2"); -- 1.9.1
