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@xxxxxxxxxxx>
---
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
