clk: renesas: rcar-usb2-clock-sel: Add R-Car USB 2.0 clock selector PHY

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 <yoshihiro.shimoda.uh@renesas.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

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 (file)
index 0000000..e96e085
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/renesas,rcar-usb2-clock-sel.txt
@@ -0,0 +1,55 @@
+* 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
+
+Example (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";
+               #clock-cells = <0>;
+       };

diff --git a/drivers/clk/renesas/Kconfig b/drivers/clk/renesas/Kconfig
index eee076d..acbb381 100644 (file)
--- a/drivers/clk/renesas/Kconfig
+++ b/drivers/clk/renesas/Kconfig
@@ -119,6 +119,11 @@ config CLK_RCAR_GEN3_CPG
        bool "R-Car Gen3 CPG clock support" if COMPILE_TEST
        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 a3bb1fa..9bda3ec 100644 (file)
--- a/drivers/clk/renesas/Makefile
+++ b/drivers/clk/renesas/Makefile
@@ -20,6 +20,7 @@ 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 (file)
index 0000000..6cd030a
--- /dev/null
+++ b/drivers/clk/renesas/rcar-usb2-clock-sel.c
@@ -0,0 +1,188 @@
+/*
+ * 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/pm_runtime.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;
+       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);
+       pm_runtime_put(dev);
+
+       return 0;
+}
+
+static int rcar_usb2_clock_sel_resume(struct device *dev)
+{
+       struct usb2_clock_sel_priv *priv = dev_get_drvdata(dev);
+
+       pm_runtime_get_sync(dev);
+       usb2_clock_sel_enable_extal_only(priv);
+
+       return 0;
+}
+
+static int rcar_usb2_clock_sel_remove(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       struct usb2_clock_sel_priv *priv = platform_get_drvdata(pdev);
+
+       of_clk_del_provider(dev->of_node);
+       clk_hw_unregister(&priv->hw);
+       pm_runtime_put(dev);
+       pm_runtime_disable(dev);
+
+       return 0;
+}
+
+static int 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;
+
+       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);
+
+       pm_runtime_enable(dev);
+       pm_runtime_get_sync(dev);
+
+       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->xtal) {
+               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 = 0;
+       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);
+
+       return of_clk_add_hw_provider(np, of_clk_hw_simple_get, &priv->hw);
+}
+
+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",
+               .of_match_table = rcar_usb2_clock_sel_match,
+               .pm     = &rcar_usb2_clock_sel_pm_ops,
+       },
+       .probe          = rcar_usb2_clock_sel_probe,
+       .remove         = rcar_usb2_clock_sel_remove,
+};
+builtin_platform_driver(rcar_usb2_clock_sel_driver);
+
+MODULE_DESCRIPTION("Renesas R-Car USB2 clock selector Driver");
+MODULE_LICENSE("GPL v2");