[PATCH/RFC] phy: renesas: rcar-gen3-usb2-clksel: Add R-Car Gen3 USB 2.0 clock selector PHY

From: Yoshihiro Shimoda
Date: Thu Jun 15 2017 - 07:37:18 EST

USB 2.0 PHY of R-Car Gen3 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 generic PHY driver.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
This patch is based on the latest linux-phy.git / next branch
(commit id = 787f24543c4a599e5d9d311a3fce839ce87bbff0)

I'm not sure this driver ss OK or not as a generic phy driver.
So, I send this patch as RFC.

.../bindings/phy/rcar-gen3-phy-usb2-clksel.txt | 58 +++++++++
drivers/phy/renesas/Kconfig | 8 ++
drivers/phy/renesas/Makefile | 1 +
drivers/phy/renesas/phy-rcar-gen3-usb2-clksel.c | 129 +++++++++++++++++++++
4 files changed, 196 insertions(+)
create mode 100644 Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2-clksel.txt
create mode 100644 drivers/phy/renesas/phy-rcar-gen3-usb2-clksel.c

diff --git a/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2-clksel.txt b/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2-clksel.txt
new file mode 100644
index 0000000..71b2f1b
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2-clksel.txt
@@ -0,0 +1,58 @@
+* Renesas R-Car generation 3 USB 2.0 clock selector PHY
+
+This file provides information on what the device node for the R-Car generation
+3 USB 2.0 clock selector PHY contains.
+
+If you connect an external clock to the USB_EXTAL pin, you can use the
+"renesas,usb_extal_only" property for it.
+If you connect an oscillator to both the USB_XTAL and USB_EXTAL, this module
+is not needed because this is default setting.
+
+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-only" property.
+
+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-usb2-clksel-phy" if the device is a part of an
+ R8A7795 SoC.
+ "renesas,r8a7796-usb2-clksel-phy" if the device is a part of an
+ R8A7796 SoC.
+
+ 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: clock phandle and specifier pair(s).
+- #phy-cells: see phy-bindings.txt in the same directory, must be <0>.
+
+Optional properties:
+- renesas,usb-extal-only: to connect a clock generator to USB_EXTAL pin.
+
+Example (R-Car H3):
+
+ usb2_clksel_phy: usb-phy@e6590630 {
+ compatible = "renesas,r8a7795-usb2-clksel-phy",
+ "renesas,rcar-gen3-usb2-clksel-phy";
+ reg = <0 0xe6590630 0 0x02>;
+ clocks = <&cpg CPG_MOD 703>;
+ renesas,usb-extal-only;
+ };
+
+ &ehci0 {
+ /* We should set usb2_clksel_phy into the first phys prop */
+ phys = <&usb2_clksel_phy>, <&usb2_phy0>;
+ phy-names = "usb_clk", "usb";
+
+ status = "okay";
+ };
diff --git a/drivers/phy/renesas/Kconfig b/drivers/phy/renesas/Kconfig
index cb09245..a3b511b 100644
--- a/drivers/phy/renesas/Kconfig
+++ b/drivers/phy/renesas/Kconfig
@@ -16,6 +16,14 @@ config PHY_RCAR_GEN3_USB2
help
Support for USB 2.0 PHY found on Renesas R-Car generation 3 SoCs.

+config PHY_RCAR_GEN3_USB2_CLKSEL
+ tristate "Renesas R-Car generation 3 USB 2.0 clock selector PHY driver"
+ depends on ARCH_RENESAS
+ select GENERIC_PHY
+ help
+ Support for USB 2.0 clock selector PHY found on Renesas R-Car
+ generation 3 SoCs.
+
config PHY_RCAR_GEN3_USB3
tristate "Renesas R-Car generation 3 USB 3.0 PHY driver"
depends on ARCH_RENESAS || COMPILE_TEST
diff --git a/drivers/phy/renesas/Makefile b/drivers/phy/renesas/Makefile
index 8b60259..26175b7 100644
--- a/drivers/phy/renesas/Makefile
+++ b/drivers/phy/renesas/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_PHY_RCAR_GEN2) += phy-rcar-gen2.o
obj-$(CONFIG_PHY_RCAR_GEN3_USB2) += phy-rcar-gen3-usb2.o
+obj-$(CONFIG_PHY_RCAR_GEN3_USB2_CLKSEL) += phy-rcar-gen3-usb2-clksel.o
obj-$(CONFIG_PHY_RCAR_GEN3_USB3) += phy-rcar-gen3-usb3.o
diff --git a/drivers/phy/renesas/phy-rcar-gen3-usb2-clksel.c b/drivers/phy/renesas/phy-rcar-gen3-usb2-clksel.c
new file mode 100644
index 0000000..e0e41c9
--- /dev/null
+++ b/drivers/phy/renesas/phy-rcar-gen3-usb2-clksel.c
@@ -0,0 +1,129 @@
+/*
+ * Renesas R-Car Gen3 for USB2.0 clock selector PHY driver
+ *
+ * Copyright (C) 2017 Renesas Electronics Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.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 rcar_gen3_usb2_clksel {
+ void __iomem *base;
+ struct phy *phy;
+ bool usb_extal_only;
+};
+
+static int rcar_gen3_usb2_clksel_init(struct phy *p)
+{
+ struct rcar_gen3_usb2_clksel *r = phy_get_drvdata(p);
+ u16 val = readw(r->base + USB20_CLKSET0);
+
+ dev_vdbg(&r->phy->dev, "%s: %d, %04x\n", __func__, r->usb_extal_only,
+ val);
+
+ if (r->usb_extal_only && val != CLKSET0_EXTAL_ONLY)
+ writew(CLKSET0_EXTAL_ONLY, r->base + USB20_CLKSET0);
+
+ return 0;
+}
+
+static const struct phy_ops rcar_gen3_usb2_clksel_ops = {
+ .init = rcar_gen3_usb2_clksel_init,
+ .owner = THIS_MODULE,
+};
+
+static const struct of_device_id rcar_gen3_usb2_clksel_match_table[] = {
+ { .compatible = "renesas,rcar-gen3-usb2-clksel-phy" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, rcar_gen3_usb2_clksel_match_table);
+
+static int rcar_gen3_usb2_clksel_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct rcar_gen3_usb2_clksel *r;
+ struct phy_provider *provider;
+ struct resource *res;
+ int ret = 0;
+
+ if (!dev->of_node) {
+ dev_err(dev, "This driver needs device tree\n");
+ return -EINVAL;
+ }
+
+ r = devm_kzalloc(dev, sizeof(*r), GFP_KERNEL);
+ if (!r)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ r->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(r->base))
+ return PTR_ERR(r->base);
+
+ /*
+ * devm_phy_create() will call pm_runtime_enable(&phy->dev);
+ * And then, phy-core will manage runtime pm for this device.
+ */
+ pm_runtime_enable(dev);
+
+ r->phy = devm_phy_create(dev, NULL, &rcar_gen3_usb2_clksel_ops);
+ if (IS_ERR(r->phy)) {
+ dev_err(dev, "Failed to create USB 2.0 clock selector PHY\n");
+ ret = PTR_ERR(r->phy);
+ goto error;
+ }
+
+ r->usb_extal_only = of_property_read_bool(dev->of_node,
+ "renesas,usb-extal-only");
+
+ platform_set_drvdata(pdev, r);
+ phy_set_drvdata(r->phy, r);
+
+ provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+ if (IS_ERR(provider)) {
+ dev_err(dev, "Failed to register PHY provider\n");
+ ret = PTR_ERR(provider);
+ goto error;
+ }
+
+ return 0;
+
+error:
+ pm_runtime_disable(dev);
+
+ return ret;
+}
+
+static int rcar_gen3_usb2_clksel_remove(struct platform_device *pdev)
+{
+ pm_runtime_disable(&pdev->dev);
+
+ return 0;
+};
+
+static struct platform_driver rcar_gen3_usb2_clksel_driver = {
+ .driver = {
+ .name = "phy_rcar_gen3_usb2_clksel",
+ .of_match_table = rcar_gen3_usb2_clksel_match_table,
+ },
+ .probe = rcar_gen3_usb2_clksel_probe,
+ .remove = rcar_gen3_usb2_clksel_remove,
+};
+module_platform_driver(rcar_gen3_usb2_clksel_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Renesas R-Car Gen3 USB 2.0 clock selector PHY");
+MODULE_AUTHOR("Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>");
--
1.9.1