Re: [PATCH v2] phy: Add a driver for dm816x USB PHY
From: Kishon Vijay Abraham I
Date: Wed Mar 18 2015 - 11:08:13 EST
Hi Tony,
On Wednesday 18 March 2015 05:42 AM, Tony Lindgren wrote:
Add a minimal driver for dm816x USB. This makes USB work on dm816x
without any other changes needed as it can use the existing musb_dsps
glue layer for the USB controller.
Note that this phy is different from dm814x and am335x.
Cc: Bin Liu <binmlist@xxxxxxxxx>
Cc: Brian Hutchinson <b.hutchman@xxxxxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Matthijs van Duin <matthijsvanduin@xxxxxxxxx>
Cc: Paul Bolle <pebolle@xxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
---
.../devicetree/bindings/phy/dm816x-phy.txt | 24 ++
drivers/phy/Kconfig | 7 +
drivers/phy/Makefile | 1 +
drivers/phy/phy-dm816x-usb.c | 304 +++++++++++++++++++++
4 files changed, 336 insertions(+)
create mode 100644 Documentation/devicetree/bindings/phy/dm816x-phy.txt
create mode 100644 drivers/phy/phy-dm816x-usb.c
diff --git a/Documentation/devicetree/bindings/phy/dm816x-phy.txt b/Documentation/devicetree/bindings/phy/dm816x-phy.txt
new file mode 100644
index 0000000..2fe3d11
--- /dev/null
+++ b/Documentation/devicetree/bindings/phy/dm816x-phy.txt
@@ -0,0 +1,24 @@
+Device tree binding documentation for am816x USB PHY
+=========================
+
+Required properties:
+- compatible : should be "ti,dm816x-usb-phy"
+- reg : offset and length of the PHY register set.
+- reg-names : name for the phy registers
+- clocks : phandle to the clock
+- clock-names : name of the clock
+- syscon: phandle for the syscon node to access misc registers
+- #phy-cells : from the generic PHY bindings, must be 1
^^^^
should be '0'
+- syscon: phandle for the syscon node to access misc registers
+
+Example:
+
+usb_phy0: usb-phy@20 {
+ compatible = "ti,dm8168-usb-phy";
+ reg = <0x20 0x8>;
+ reg-names = "phy";
+ clocks = <&main_fapll 6>;
+ clock-names = "refclk";
+ #phy-cells = <0>;
+ syscon = <&scm_conf>;
+};
diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index 2962de2..c858c2b 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -35,6 +35,13 @@ config ARMADA375_USBCLUSTER_PHY
depends on OF
select GENERIC_PHY
+config PHY_DM816X_USB
+ tristate "TI dm816x USB PHY driver"
+ depends on ARCH_OMAP2PLUS
+ select GENERIC_PHY
+ help
+ Enable this for dm81xx USB to work."
+
config PHY_EXYNOS_MIPI_VIDEO
tristate "S5P/EXYNOS SoC series MIPI CSI-2/DSI PHY driver"
depends on HAS_IOMEM
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index f080e1b..dab6665 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -5,6 +5,7 @@
obj-$(CONFIG_GENERIC_PHY) += phy-core.o
obj-$(CONFIG_PHY_BERLIN_USB) += phy-berlin-usb.o
obj-$(CONFIG_PHY_BERLIN_SATA) += phy-berlin-sata.o
+obj-$(CONFIG_PHY_DM816X_USB) += phy-dm816x-usb.o
obj-$(CONFIG_ARMADA375_USBCLUSTER_PHY) += phy-armada375-usb2.o
obj-$(CONFIG_BCM_KONA_USB2_PHY) += phy-bcm-kona-usb2.o
obj-$(CONFIG_PHY_EXYNOS_DP_VIDEO) += phy-exynos-dp-video.o
diff --git a/drivers/phy/phy-dm816x-usb.c b/drivers/phy/phy-dm816x-usb.c
new file mode 100644
index 0000000..2fc276d
--- /dev/null
+++ b/drivers/phy/phy-dm816x-usb.c
@@ -0,0 +1,304 @@
+/*
+ * 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.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/io.h>
+#include <linux/usb/phy_companion.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/pm_runtime.h>
+#include <linux/delay.h>
+#include <linux/phy/phy.h>
+#include <linux/of_platform.h>
+
+#include <linux/mfd/syscon.h>
+
+/*
+ * TRM has two sets of USB_CTRL registers.. The correct register bits
+ * are in TRM section 24.9.8.2 USB_CTRL Register. The TRM documents the
+ * phy as being SR70LX Synopsys USB 2.0 OTG nanoPHY. It also seems at
+ * least dm816x rev c ignores writes to USB_CTRL register, but the TI
+ * kernel is writing to those so it's possible that later revisions
+ * have worknig USB_CTRL register.
+ *
+ * Also note that At least USB_CTRL register seems to be dm816x specific
+ * according to the TRM. It's possible that USBPHY_CTRL is more generic,
+ * but that would have to be checked against the SR70LX documentation
+ * which does not seem to be publicly available.
+ *
+ * Finally, the phy on dm814x and am335x is different from dm816x.
+ */
+#define DM816X_USB_CTRL_PHYCLKSRC BIT(8) /* 1 = PLL ref clock */
+#define DM816X_USB_CTRL_PHYSLEEP1 BIT(1) /* Enable the first phy */
+#define DM816X_USB_CTRL_PHYSLEEP0 BIT(0) /* Enable the second phy */
+
+#define DM816X_USBPHY_CTRL_TXRISETUNE 1
+#define DM816X_USBPHY_CTRL_TXVREFTUNE 0xc
+#define DM816X_USBPHY_CTRL_TXPREEMTUNE 0x2
+
+struct dm816x_usb_phy {
+ struct regmap *syscon;
+ struct device *dev;
+ unsigned int instance;
+ struct clk *refclk;
+ struct usb_phy phy;
+ unsigned int usb_ctrl; /* Shared between phy0 and phy1 */
+ unsigned int usbphy_ctrl;
+};
+
+static int dm816x_usb_phy_set_host(struct usb_otg *otg, struct usb_bus *host)
+{
+ otg->host = host;
+ if (!host)
+ otg->state = OTG_STATE_UNDEFINED;
+
+ return 0;
+}
+
+static int dm816x_usb_phy_set_peripheral(struct usb_otg *otg,
+ struct usb_gadget *gadget)
+{
+ otg->gadget = gadget;
+ if (!gadget)
+ otg->state = OTG_STATE_UNDEFINED;
+
+ return 0;
+}
+
+/*
+ * We have phy-core.c handle pm_runtime calls for us. We implement
+ * these functions for phy-core.c to keep track of power_count.
+ * Note that we may want to remove these eventually and rely only
+ * on the usecounting done by PM runtime.
irrespective of whether the phy drivers implement power_off/power_on callbacks
or not, the phy core maintains it's usecount. So the following two functions
shouldn't be needed at all.
+ */
+static int dm816x_usb_phy_power_off(struct phy *x)
+{
+ return 0;
+}
+
+static int dm816x_usb_phy_power_on(struct phy *x)
+{
+ return 0;
+}
+
+static int dm816x_usb_phy_init(struct phy *x)
+{
+ struct dm816x_usb_phy *phy = phy_get_drvdata(x);
+ unsigned int val;
+ int error;
+
+ if (clk_get_rate(phy->refclk) != 24000000)
+ dev_warn(phy->dev, "nonstandard phy refclk\n");
+
+ /* Set PLL ref clock and put phys to sleep */
+ error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
+ DM816X_USB_CTRL_PHYCLKSRC |
+ DM816X_USB_CTRL_PHYSLEEP1 |
+ DM816X_USB_CTRL_PHYSLEEP0,
+ 0);
+ regmap_read(phy->syscon, phy->usb_ctrl, &val);
+
+ /*
+ * TI kernel sets these values for "symmetrical eye diagram and
+ * better signal quality" so let's assume somebody checked the
+ * values with a scope and set them here too.
+ */
+ regmap_read(phy->syscon, phy->usbphy_ctrl, &val);
+ val |= DM816X_USBPHY_CTRL_TXRISETUNE |
+ DM816X_USBPHY_CTRL_TXVREFTUNE |
+ DM816X_USBPHY_CTRL_TXPREEMTUNE;
+ regmap_write(phy->syscon, phy->usbphy_ctrl, val);
+
+ return 0;
+}
+
+static struct phy_ops ops = {
+ .init = dm816x_usb_phy_init,
+ .power_on = dm816x_usb_phy_power_on,
+ .power_off = dm816x_usb_phy_power_off,
+ .owner = THIS_MODULE,
+};
+
+static int dm816x_usb_phy_runtime_suspend(struct device *dev)
+{
+ struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
+ unsigned int mask, val;
+ int error = 0;
+
+ mask = BIT(phy->instance);
+ val = ~BIT(phy->instance);
+ error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
+ mask, val);
Shouldn't this be protected since both the PHYs can access the same register?
Thanks
Kishon
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