Add support for control peripheral of EUD (Embedded USB Debugger) to
listen to events such as USB attach/detach, charger enable/disable, pet
EUD to indicate software is functional.

Signed-off-by: Satya Durga Srinivasu Prabhala <sat...@codeaurora.org>
Signed-off-by: Prakruthi Deepak Heragu <pher...@codeaurora.org>
---
 drivers/soc/qcom/Kconfig  |  12 ++
 drivers/soc/qcom/Makefile |   1 +
 drivers/soc/qcom/eud.c    | 338 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 351 insertions(+)
 create mode 100644 drivers/soc/qcom/eud.c

diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 5856e79..12669ec 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -136,4 +136,16 @@ config QCOM_APR
           application processor and QDSP6. APR is
           used by audio driver to configure QDSP6
           ASM, ADM and AFE modules.
+
+config QCOM_EUD
+       tristate "QTI Embedded USB Debugger (EUD)"
+       depends on ARCH_QCOM
+       help
+         The Embedded USB Debugger (EUD) driver is a driver for the
+         control peripheral which waits on events like USB attach/detach
+         and charger enable/disable. The control peripheral further helps
+         support the USB-based debug and trace capabilities.
+         This module enables support for Qualcomm Technologies, Inc.
+         Embedded USB Debugger (EUD).
+         If unsure, say N.
 endmenu
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 19dcf95..dd4701b 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_QCOM_SMP2P)      += smp2p.o
 obj-$(CONFIG_QCOM_SMSM)        += smsm.o
 obj-$(CONFIG_QCOM_WCNSS_CTRL) += wcnss_ctrl.o
 obj-$(CONFIG_QCOM_APR) += apr.o
+obj-$(CONFIG_QCOM_EUD) += eud.o
diff --git a/drivers/soc/qcom/eud.c b/drivers/soc/qcom/eud.c
new file mode 100644
index 0000000..16a0e7b
--- /dev/null
+++ b/drivers/soc/qcom/eud.c
@@ -0,0 +1,338 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2016-2018, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/extcon.h>
+#include <linux/delay.h>
+#include <linux/sysfs.h>
+#include <linux/io.h>
+#include <linux/bitops.h>
+#include <linux/workqueue.h>
+#include <linux/power_supply.h>
+
+#define EUD_ENABLE_CMD 1
+#define EUD_DISABLE_CMD 0
+
+#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_CHGR_INT_CLR   0x0084
+#define EUD_REG_CSR_EUD_EN     0x1014
+#define EUD_REG_SW_ATTACH_DET  0x1018
+
+#define EUD_INT_VBUS           BIT(2)
+#define EUD_INT_CHGR           BIT(3)
+#define EUD_INT_SAFE_MODE      BIT(4)
+
+struct eud_chip {
+       struct device                   *dev;
+       int                             eud_irq;
+       unsigned int                    extcon_id;
+       unsigned int                    int_status;
+       bool                            usb_attach;
+       bool                            chgr_enable;
+       void __iomem                    *eud_reg_base;
+       struct extcon_dev               *extcon;
+       struct work_struct              eud_work;
+};
+
+static const unsigned int eud_extcon_cable[] = {
+       EXTCON_USB,
+       EXTCON_CHG_USB_SDP,
+       EXTCON_NONE,
+};
+
+/*
+ * On the kernel command line specify eud.enable=1 to enable EUD.
+ * EUD is disabled by default.
+ */
+static int enable;
+static bool eud_ready;
+static struct eud_chip *eud_private;
+
+static void enable_eud(struct eud_chip *priv)
+{
+       struct power_supply *usb_psy = NULL;
+       union power_supply_propval pval = {0};
+       union power_supply_propval tval = {0};
+       int ret;
+
+       usb_psy = power_supply_get_by_name("usb");
+       if (!usb_psy)
+               return;
+
+       ret = power_supply_get_property(usb_psy,
+                       POWER_SUPPLY_PROP_PRESENT, &pval);
+       if (ret)
+               return;
+
+       ret = power_supply_get_property(usb_psy,
+                       POWER_SUPPLY_PROP_REAL_TYPE, &tval);
+       if (ret)
+               return;
+
+       if (pval.intval && (tval.intval == POWER_SUPPLY_TYPE_USB ||
+           tval.intval == POWER_SUPPLY_TYPE_USB_CDP)) {
+               /* write into CSR to enable EUD */
+               writel_relaxed(BIT(0), priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+               /* Enable vbus, chgr & safe mode warning interrupts */
+               writel_relaxed(EUD_INT_VBUS | EUD_INT_CHGR | EUD_INT_SAFE_MODE,
+                               priv->eud_reg_base + EUD_REG_INT1_EN_MASK);
+
+               /* Ensure Register Writes Complete */
+               wmb();
+
+               /*
+                * Set the default cable state to usb connect and charger
+                * enable
+                */
+               ret = extcon_set_state_sync(priv->extcon, EXTCON_USB, true);
+               if (ret)
+                       return;
+               ret = extcon_set_state_sync(priv->extcon,
+                               EXTCON_CHG_USB_SDP, true);
+               if (ret)
+                       return;
+       } else {
+               return;
+       }
+
+}
+
+static void disable_eud(struct eud_chip *priv)
+{
+       /* write into CSR to disable EUD */
+       writel_relaxed(0, priv->eud_reg_base + EUD_REG_CSR_EUD_EN);
+}
+
+static int param_eud_set(const char *val, const struct kernel_param *kp)
+{
+       int enable = 0;
+
+       if (sscanf(val, "%du", &enable) != 1)
+               return -EINVAL;
+
+       if (enable != EUD_ENABLE_CMD && enable != EUD_DISABLE_CMD)
+               return -EINVAL;
+
+       *((uint *)kp->arg) = enable;
+       if (!eud_ready)
+               return 0;
+
+       if (enable == EUD_ENABLE_CMD)
+               enable_eud(eud_private);
+       else if (enable == EUD_DISABLE_CMD)
+               disable_eud(eud_private);
+
+       return 0;
+}
+
+static const struct kernel_param_ops eud_param_ops = {
+       .set = param_eud_set,
+       .get = param_get_int,
+};
+
+module_param_cb(enable, &eud_param_ops, &enable, 0644);
+
+static void eud_event_notifier(struct work_struct *eud_work)
+{
+       struct eud_chip *chip = container_of(eud_work, struct eud_chip,
+                                       eud_work);
+       int ret;
+
+       if (chip->int_status == EUD_INT_VBUS) {
+               ret = extcon_set_state_sync(chip->extcon, chip->extcon_id,
+                                       chip->usb_attach);
+               if (ret)
+                       return;
+       } else if (chip->int_status == EUD_INT_CHGR) {
+               ret = extcon_set_state_sync(chip->extcon, chip->extcon_id,
+                                       chip->chgr_enable);
+               if (ret)
+                       return;
+       }
+}
+
+static void usb_attach_detach(struct eud_chip *chip)
+{
+       u32 reg;
+
+       chip->extcon_id = EXTCON_USB;
+       /* read ctl_out_1[4] to find USB attach or detach event */
+       reg = readl_relaxed(chip->eud_reg_base + EUD_REG_CTL_OUT_1);
+       if (reg & BIT(4))
+               chip->usb_attach = true;
+       else
+               chip->usb_attach = false;
+
+       schedule_work(&chip->eud_work);
+
+       /* set and clear vbus_int_clr[0] to clear interrupt */
+       writel_relaxed(BIT(0), chip->eud_reg_base + EUD_REG_VBUS_INT_CLR);
+       /* Ensure Register Writes Complete */
+       wmb();
+       writel_relaxed(0, chip->eud_reg_base + EUD_REG_VBUS_INT_CLR);
+}
+
+static void chgr_enable_disable(struct eud_chip *chip)
+{
+       u32 reg;
+
+       chip->extcon_id = EXTCON_CHG_USB_SDP;
+       /* read ctl_out_1[6] to find charger enable or disable event */
+       reg = readl_relaxed(chip->eud_reg_base + EUD_REG_CTL_OUT_1);
+       if (reg & BIT(6))
+               chip->chgr_enable = true;
+       else
+               chip->chgr_enable = false;
+
+       schedule_work(&chip->eud_work);
+
+       /* set and clear chgr_int_clr[0] to clear interrupt */
+       writel_relaxed(BIT(0), chip->eud_reg_base + EUD_REG_CHGR_INT_CLR);
+       /* Ensure Register Writes Complete */
+       wmb();
+       writel_relaxed(0, chip->eud_reg_base + EUD_REG_CHGR_INT_CLR);
+}
+
+static void pet_eud(struct eud_chip *chip)
+{
+       u32 reg;
+
+       /* read sw_attach_det[0] to find attach/detach event */
+       reg = readl_relaxed(chip->eud_reg_base + EUD_REG_SW_ATTACH_DET);
+       if (reg & BIT(0)) {
+               /* Detach & Attach pet for EUD */
+               writel_relaxed(0, chip->eud_reg_base + EUD_REG_SW_ATTACH_DET);
+               /* Ensure Register Writes Complete */
+               wmb();
+               /* Delay to make sure detach pet is done before attach pet */
+               udelay(100);
+               writel_relaxed(BIT(0), chip->eud_reg_base +
+                                       EUD_REG_SW_ATTACH_DET);
+               /* Ensure Register Writes Complete */
+               wmb();
+       } else {
+               /* Attach pet for EUD */
+               writel_relaxed(BIT(0), chip->eud_reg_base +
+                                       EUD_REG_SW_ATTACH_DET);
+               /* Ensure Register Writes Complete */
+               wmb();
+       }
+}
+
+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_relaxed(chip->eud_reg_base + EUD_REG_INT_STATUS_1);
+       if (reg & EUD_INT_VBUS) {
+               chip->int_status = EUD_INT_VBUS;
+               usb_attach_detach(chip);
+       } else if (reg & EUD_INT_CHGR) {
+               chip->int_status = EUD_INT_CHGR;
+               chgr_enable_disable(chip);
+       } else if (reg & EUD_INT_SAFE_MODE) {
+               pet_eud(chip);
+       } else {
+               return IRQ_NONE;
+       }
+
+       return IRQ_HANDLED;
+}
+
+static int msm_eud_probe(struct platform_device *pdev)
+{
+       struct eud_chip *chip;
+       struct resource *res;
+       int ret;
+
+       chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
+       if (!chip) {
+               ret = -ENOMEM;
+               return ret;
+       }
+
+       platform_set_drvdata(pdev, chip);
+
+       chip->extcon = devm_extcon_dev_allocate(&pdev->dev, eud_extcon_cable);
+       if (IS_ERR(chip->extcon))
+               return PTR_ERR(chip->extcon);
+
+       ret = devm_extcon_dev_register(&pdev->dev, chip->extcon);
+       if (ret)
+               return ret;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res) {
+               ret = -ENOMEM;
+               return ret;
+       }
+
+       chip->eud_reg_base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(chip->eud_reg_base))
+               return PTR_ERR(chip->eud_reg_base);
+
+       chip->eud_irq = platform_get_irq(pdev, 0);
+
+       ret = devm_request_irq(&pdev->dev, chip->eud_irq, handle_eud_irq,
+                               IRQF_TRIGGER_HIGH, NULL, chip);
+       if (ret)
+               return ret;
+
+       device_init_wakeup(&pdev->dev, true);
+       enable_irq_wake(chip->eud_irq);
+
+       INIT_WORK(&chip->eud_work, eud_event_notifier);
+
+       eud_private = chip;
+       eud_ready = true;
+
+       /* Enable EUD */
+       if (enable)
+               enable_eud(eud_private);
+
+       return 0;
+}
+
+static int msm_eud_remove(struct platform_device *pdev)
+{
+       struct eud_chip *chip = platform_get_drvdata(pdev);
+
+       if (enable)
+               disable_eud(eud_private);
+       device_init_wakeup(&pdev->dev, false);
+       disable_irq_wake(chip->eud_irq);
+       platform_set_drvdata(pdev, NULL);
+
+       return 0;
+}
+
+static const struct of_device_id msm_eud_dt_match[] = {
+       {.compatible = "qcom,msm-eud"},
+       {},
+};
+MODULE_DEVICE_TABLE(of, msm_eud_dt_match);
+
+static struct platform_driver msm_eud_driver = {
+       .probe          = msm_eud_probe,
+       .remove         = msm_eud_remove,
+       .driver         = {
+               .name           = "msm-eud",
+               .of_match_table = msm_eud_dt_match,
+       },
+};
+module_platform_driver(msm_eud_driver);
+
+MODULE_DESCRIPTION("QTI EUD driver");
+MODULE_LICENSE("GPL v2");
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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