Re: [PATCH V0 4/7] usb: common: eud: Added the driver support for Embedded USB Debugger(EUD)
From: schowdhu
Date: Tue Oct 05 2021 - 08:54:15 EST
On 2021-10-04 17:01, Greg KH wrote:
On Mon, Oct 04, 2021 at 04:46:22PM +0530, Souradeep Chowdhury wrote:
Add support for control peripheral of EUD (Embedded USB Debugger) to
listen to events such as USB attach/detach, pet EUD to indicate
software
is functional.Reusing the platform device kobj, sysfs entry 'enable'
is
created to enable or disable EUD.
To enable the eud the following needs to be done
echo 1 > /sys/bus/platform/.../enable
To disable eud, following is the command
echo 0 > /sys/bus/platform/.../enable
Signed-off-by: Souradeep Chowdhury <schowdhu@xxxxxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-driver-eud | 7 +
drivers/usb/common/Kconfig | 9 +
drivers/usb/common/Makefile | 1 +
drivers/usb/common/qcom_eud.c | 256
+++++++++++++++++++++++++++++
4 files changed, 273 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-driver-eud
create mode 100644 drivers/usb/common/qcom_eud.c
diff --git a/Documentation/ABI/testing/sysfs-driver-eud
b/Documentation/ABI/testing/sysfs-driver-eud
new file mode 100644
index 0000000..14a02da
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-eud
@@ -0,0 +1,7 @@
+What: /sys/bus/platform/.../enable
Um, that's a _very_ generic regex, you just matched with any platform
device that might have a "enable" sysfs entry :(
Please use the dwc's name in here to help out with figuring this out.
Ack
+Date: October 2021
+Contact: Souradeep Chowdhury <schowdhu@xxxxxxxxxxxxxx>
No tabs?
+Description:
+ The Enable/Disable sysfs interface for Embedded
+ USB Debugger(EUD).This enables and disables the
+ EUD based on a 1 or a 0 value.
What does enabling or disabling actually do?
And please use a ' ' after a '.'.
Ack. On enabling, the debug mode is set for EUD. EUD is a mux, that sits
between the connector and the
controller, routing UTMI signals to an internal USB hub, which in-turn
has debug functions attached to
the hub. On disabling, this routing stops as EUD gets disabled.
diff --git a/drivers/usb/common/Kconfig b/drivers/usb/common/Kconfig
index 5e8a04e..669b3fe 100644
--- a/drivers/usb/common/Kconfig
+++ b/drivers/usb/common/Kconfig
@@ -50,3 +50,12 @@ config USB_CONN_GPIO
To compile the driver as a module, choose M here: the module will
be called usb-conn-gpio.ko
+
+config USB_QCOM_EUD
+ tristate "USB EUD Driver"
+ select USB_ROLE_SWITCH
+ help
+ This module enables support for Qualcomm Technologies, Inc.
+ Embedded USB Debugger (EUD). The EUD is a control peripheral
+ which reports VBUS attach/detach events and has USB-based
+ debug and trace capabilities.
What is the module name if this is built?
Ack. The module name for this is same as the driver name qcom_eud.ko,
will update the same here.
diff --git a/drivers/usb/common/Makefile b/drivers/usb/common/Makefile
index 8ac4d21..eb66045 100644
--- a/drivers/usb/common/Makefile
+++ b/drivers/usb/common/Makefile
@@ -11,3 +11,4 @@ usb-common-$(CONFIG_USB_LED_TRIG) += led.o
obj-$(CONFIG_USB_CONN_GPIO) += usb-conn-gpio.o
obj-$(CONFIG_USB_OTG_FSM) += usb-otg-fsm.o
obj-$(CONFIG_USB_ULPI_BUS) += ulpi.o
+obj-$(CONFIG_USB_QCOM_EUD) += qcom_eud.o
diff --git a/drivers/usb/common/qcom_eud.c
b/drivers/usb/common/qcom_eud.c
new file mode 100644
index 0000000..7a92fff
--- /dev/null
+++ b/drivers/usb/common/qcom_eud.c
@@ -0,0 +1,256 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2015-2021, The Linux Foundation. All rights
reserved.
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/usb/role.h>
+
+#define EUD_REG_INT1_EN_MASK 0x0024
+#define EUD_REG_INT_STATUS_1 0x0044
+#define EUD_REG_CTL_OUT_1 0x0074
+#define EUD_REG_VBUS_INT_CLR 0x0080
+#define EUD_REG_CSR_EUD_EN 0x1014
+#define EUD_REG_SW_ATTACH_DET 0x1018
+#define EUD_REG_EUD_EN2 0x0000
+
+#define EUD_ENABLE BIT(0)
+#define EUD_INT_PET_EUD BIT(0)
+#define EUD_INT_VBUS BIT(2)
+#define EUD_INT_SAFE_MODE BIT(4)
+#define EUD_INT_ALL (EUD_INT_VBUS|EUD_INT_SAFE_MODE)
+
+struct eud_chip {
+ struct device *dev;
+ struct usb_role_switch *role_sw;
+ void __iomem *eud_reg_base;
+ void __iomem *eud_mode_mgr2_phys_base;
+ unsigned int int_status;
+ int enable;
bool?
Ack.
+ int eud_irq;
+ bool usb_attach;
+
No need for a blank line.
Ack
+};
+
+static int enable_eud(struct eud_chip *priv)
+{
+ writel(EUD_ENABLE, priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+ writel(EUD_INT_VBUS | EUD_INT_SAFE_MODE,
+ priv->eud_reg_base + EUD_REG_INT1_EN_MASK);
+ writel(1, priv->eud_mode_mgr2_phys_base + EUD_REG_EUD_EN2);
+
+ return usb_role_switch_set_role(priv->role_sw, USB_ROLE_DEVICE);
+}
+
+static void disable_eud(struct eud_chip *priv)
+{
+ writel(0, priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+ writel(0, priv->eud_mode_mgr2_phys_base + EUD_REG_EUD_EN2);
+}
+
+static ssize_t enable_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct eud_chip *chip = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d", chip->enable);
sysfs_emit() please.
Ack
+}
+
+static ssize_t enable_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct eud_chip *chip = dev_get_drvdata(dev);
+ unsigned long enable;
+ int ret;
+
+ if (kstrtoul(buf, 16, &enable))
+ return -EINVAL;
Use the default sysfs function to parse 0/1/y/n/Y/N please.
Ack
+
+ if (enable == 1) {
+ ret = enable_eud(chip);
+ if (!ret)
+ chip->enable = enable;
+ } else if (enable == 0) {
+ disable_eud(chip);
+ } else {
+ return -EINVAL;
+ }
+
+ return count;
+}
+
+static DEVICE_ATTR_RW(enable);
+
+static const struct device_attribute *eud_attrs[] = {
+ &dev_attr_enable,
+ NULL,
+};
You create a list of attributes and then never use it?
Who reviewed this thing?
You were so close in getting this right, see below...
Ack
+
+static void usb_attach_detach(struct eud_chip *chip)
+{
+ u32 reg;
+
+ /* read ctl_out_1[4] to find USB attach or detach event */
+ reg = readl(chip->eud_reg_base + EUD_REG_CTL_OUT_1);
+ if (reg & EUD_INT_SAFE_MODE)
+ chip->usb_attach = true;
+ else
+ chip->usb_attach = false;
+
+ /* set and clear vbus_int_clr[0] to clear interrupt */
+ writel(BIT(0), chip->eud_reg_base + EUD_REG_VBUS_INT_CLR);
+ writel(0, chip->eud_reg_base + EUD_REG_VBUS_INT_CLR);
+}
+
+static void pet_eud(struct eud_chip *chip)
+{
+ u32 reg;
+ int ret;
+
+ /* read sw_attach_det[0] to find attach/detach event */
+ reg = readl(chip->eud_reg_base + EUD_REG_SW_ATTACH_DET);
+ if (reg & EUD_INT_PET_EUD) {
+ /* Detach & Attach pet for EUD */
+ writel(0, chip->eud_reg_base + EUD_REG_SW_ATTACH_DET);
+ /* Delay to make sure detach pet is done before attach pet */
+ ret = readl_poll_timeout(chip->eud_reg_base +
EUD_REG_SW_ATTACH_DET,
+ reg, (reg == 0), 1, 100);
+ if (ret) {
+ dev_err(chip->dev, "Detach pet failed\n");
+ return;
+ }
+
+ writel(EUD_INT_PET_EUD, chip->eud_reg_base +
+ EUD_REG_SW_ATTACH_DET);
+ } else {
+ /* Attach pet for EUD */
+ writel(EUD_INT_PET_EUD, chip->eud_reg_base +
+ EUD_REG_SW_ATTACH_DET);
+ }
+}
+
+static irqreturn_t handle_eud_irq(int irq, void *data)
+{
+ struct eud_chip *chip = data;
+ u32 reg;
+
+ /* read status register and find out which interrupt triggered */
+ reg = readl(chip->eud_reg_base + EUD_REG_INT_STATUS_1);
+ switch (reg & EUD_INT_ALL) {
+ case EUD_INT_VBUS:
+ chip->int_status = EUD_INT_VBUS;
+ usb_attach_detach(chip);
+ return IRQ_WAKE_THREAD;
+ case EUD_INT_SAFE_MODE:
+ pet_eud(chip);
+ break;
+ default:
+ return IRQ_NONE;
+ }
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t handle_eud_irq_thread(int irq, void *data)
+{
+ struct eud_chip *chip = data;
+ int ret;
+
+ if (chip->int_status == EUD_INT_VBUS) {
+ if (chip->usb_attach)
+ ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_DEVICE);
+ else
+ ret = usb_role_switch_set_role(chip->role_sw, USB_ROLE_HOST);
+ if (ret)
+ dev_err(chip->dev, "failed to set role switch\n");
+ }
+
+ return IRQ_HANDLED;
+}
+
+static int eud_probe(struct platform_device *pdev)
+{
+ struct eud_chip *chip;
+ int ret;
+
+ chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+ if (!chip)
+ return -ENOMEM;
+
+ chip->dev = &pdev->dev;
+
+ chip->role_sw = usb_role_switch_get(chip->dev);
+ if (IS_ERR(chip->role_sw)) {
+ if (PTR_ERR(chip->role_sw) != -EPROBE_DEFER)
+ dev_err(chip->dev, "failed to get role switch\n");
+
+ return PTR_ERR(chip->role_sw);
+ }
+
+ chip->eud_reg_base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(chip->eud_reg_base))
+ return PTR_ERR(chip->eud_reg_base);
+
+ chip->eud_mode_mgr2_phys_base = devm_platform_ioremap_resource(pdev,
1);
+ if (IS_ERR(chip->eud_mode_mgr2_phys_base))
+ return PTR_ERR(chip->eud_mode_mgr2_phys_base);
+
+ chip->eud_irq = platform_get_irq(pdev, 0);
+ ret = devm_request_threaded_irq(&pdev->dev, chip->eud_irq,
handle_eud_irq,
+ handle_eud_irq_thread, IRQF_ONESHOT, NULL, chip);
+ if (ret)
+ return ret;
+
+ device_init_wakeup(&pdev->dev, true);
+ enable_irq_wake(chip->eud_irq);
+
+ platform_set_drvdata(pdev, chip);
+
+ ret = device_create_file(&pdev->dev, eud_attrs[0]);
You raced with userspace and lost :(
Please properly attach the sysfs file to the platform driver to have
the
driver core register this correctly.
Ok.
+
+ return ret;
+}
+
+static int eud_remove(struct platform_device *pdev)
+{
+ struct eud_chip *chip = platform_get_drvdata(pdev);
+
+ if (chip->enable)
+ disable_eud(chip);
+
+ device_remove_file(&pdev->dev, eud_attrs[0]);
No need for this if you do the above correctly.
Ack.
+ device_init_wakeup(&pdev->dev, false);
Why is this needed?
This is already handled in device_unregister() path so will remove this.
thanks,
greg k-h