This patch adds the extcon support for AXP288 PMIC which
has the BC1.2 charger detection capability. Additionally
it also adds the USB mux switching support b/w SOC and PMIC
based on GPIO control.

Signed-off-by: Ramakrishna Pallala <ramakrishna.pall...@intel.com>
---
 drivers/extcon/Kconfig         |    7 +
 drivers/extcon/Makefile        |    1 +
 drivers/extcon/extcon-axp288.c |  399 ++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/axp20x.h     |    9 +
 4 files changed, 416 insertions(+)
 create mode 100644 drivers/extcon/extcon-axp288.c

diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index fdc0bf0..2305edc 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -28,6 +28,13 @@ config EXTCON_ARIZONA
          with Wolfson Arizona devices. These are audio CODECs with
          advanced audio accessory detection support.
 
+config EXTCON_AXP288
+       tristate "X-Power AXP288 EXTCON support"
+       depends on MFD_AXP20X && USB_PHY
+       help
+         Say Y here to enable support for USB peripheral detection
+         and USB MUX switching by X-Power AXP288 PMIC.
+
 config EXTCON_GPIO
        tristate "GPIO extcon support"
        depends on GPIOLIB
diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
index 9204114..ba787d0 100644
--- a/drivers/extcon/Makefile
+++ b/drivers/extcon/Makefile
@@ -5,6 +5,7 @@
 obj-$(CONFIG_EXTCON)           += extcon.o
 obj-$(CONFIG_EXTCON_ADC_JACK)  += extcon-adc-jack.o
 obj-$(CONFIG_EXTCON_ARIZONA)   += extcon-arizona.o
+obj-$(CONFIG_EXTCON_AXP288)    += extcon-axp288.o
 obj-$(CONFIG_EXTCON_GPIO)      += extcon-gpio.o
 obj-$(CONFIG_EXTCON_MAX14577)  += extcon-max14577.o
 obj-$(CONFIG_EXTCON_MAX77693)  += extcon-max77693.o
diff --git a/drivers/extcon/extcon-axp288.c b/drivers/extcon/extcon-axp288.c
new file mode 100644
index 0000000..9e69d21
--- /dev/null
+++ b/drivers/extcon/extcon-axp288.c
@@ -0,0 +1,399 @@
+/*
+ * extcon-axp288.c - X-Power AXP288 PMIC extcon cable detection driver
+ *
+ * Copyright (C) 2014 Intel Corporation
+ * Author: Ramakrishna Pallala <ramakrishna.pall...@intel.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; 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/kernel.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/usb/phy.h>
+#include <linux/notifier.h>
+#include <linux/extcon.h>
+#include <linux/regmap.h>
+#include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
+#include <linux/mfd/axp20x.h>
+
+/* Power source status register */
+#define PS_STAT_VBUS_TRIGGER           BIT(0)
+#define PS_STAT_BAT_CHRG_DIR           BIT(2)
+#define PS_STAT_VBUS_ABOVE_VHOLD       BIT(3)
+#define PS_STAT_VBUS_VALID             BIT(4)
+#define PS_STAT_VBUS_PRESENT           BIT(5)
+
+/* BC module global register */
+#define BC_GLOBAL_RUN                  BIT(0)
+#define BC_GLOBAL_DET_STAT             BIT(2)
+#define BC_GLOBAL_DBP_TOUT             BIT(3)
+#define BC_GLOBAL_VLGC_COM_SEL         BIT(4)
+#define BC_GLOBAL_DCD_TOUT_MASK                (BIT(6)|BIT(5))
+#define BC_GLOBAL_DCD_TOUT_300MS       0
+#define BC_GLOBAL_DCD_TOUT_100MS       1
+#define BC_GLOBAL_DCD_TOUT_500MS       2
+#define BC_GLOBAL_DCD_TOUT_900MS       3
+#define BC_GLOBAL_DCD_DET_SEL          BIT(7)
+
+/* BC module vbus control and status register */
+#define VBUS_CNTL_DPDM_PD_EN           BIT(4)
+#define VBUS_CNTL_DPDM_FD_EN           BIT(5)
+#define VBUS_CNTL_FIRST_PO_STAT                BIT(6)
+
+/* BC USB status register */
+#define USB_STAT_BUS_STAT_MASK         (BIT(3)|BIT(2)|BIT(1)|BIT(0))
+#define USB_STAT_BUS_STAT_SHIFT                0
+#define USB_STAT_BUS_STAT_ATHD         0
+#define USB_STAT_BUS_STAT_CONN         1
+#define USB_STAT_BUS_STAT_SUSP         2
+#define USB_STAT_BUS_STAT_CONF         3
+#define USB_STAT_USB_SS_MODE           BIT(4)
+#define USB_STAT_DEAD_BAT_DET          BIT(6)
+#define USB_STAT_DBP_UNCFG             BIT(7)
+
+/* BC detect status register */
+#define DET_STAT_MASK                  (BIT(7)|BIT(6)|BIT(5))
+#define DET_STAT_SHIFT                 5
+#define DET_STAT_SDP                   1
+#define DET_STAT_CDP                   2
+#define DET_STAT_DCP                   3
+
+/* IRQ enable-1 register */
+#define PWRSRC_IRQ_CFG_MASK            (BIT(4)|BIT(3)|BIT(2))
+
+/* IRQ enable-6 register */
+#define BC12_IRQ_CFG_MASK              BIT(1)
+
+enum axp288_extcon_reg {
+       AXP288_PS_STAT_REG              = 0x00,
+       AXP288_PS_BOOT_REASON_REG       = 0x02,
+       AXP288_BC_GLOBAL_REG            = 0x2c,
+       AXP288_BC_VBUS_CNTL_REG         = 0x2d,
+       AXP288_BC_USB_STAT_REG          = 0x2e,
+       AXP288_BC_DET_STAT_REG          = 0x2f,
+       AXP288_PWRSRC_IRQ_CFG_REG       = 0x40,
+       AXP288_BC12_IRQ_CFG_REG         = 0x45,
+};
+
+enum axp288_mux_select {
+       EXTCON_GPIO_MUX_SEL_PMIC = 0,
+       EXTCON_GPIO_MUX_SEL_SOC,
+};
+
+enum axp288_extcon_irq {
+       VBUS_FALLING_IRQ = 0,
+       VBUS_RISING_IRQ,
+       MV_CHNG_IRQ,
+       BC_USB_CHNG_IRQ,
+       EXTCON_IRQ_END,
+};
+
+static const char *axp288_extcon_cables[] = {
+       AXP288_EXTCON_SLOW_CHARGER,
+       AXP288_EXTCON_DOWNSTREAM_CHARGER,
+       AXP288_EXTCON_FAST_CHARGER,
+       NULL,
+};
+
+struct axp288_extcon_info {
+       struct device *dev;
+       struct regmap *regmap;
+       struct regmap_irq_chip_data *regmap_irqc;
+       struct axp288_extcon_pdata *pdata;
+       int irq[EXTCON_IRQ_END];
+       struct extcon_dev *edev;
+       struct notifier_block extcon_nb;
+       struct usb_phy *otg;
+};
+
+/* Power up/down reason string array */
+static char *axp288_pwr_up_down_info[] = {
+       "Last wake caused by user pressing the power button",
+       "Last wake caused by a charger insertion",
+       "Last wake caused by a battery insertion",
+       "Last wake caused by SOC initiated global reset",
+       "Last wake caused by cold reset",
+       "Last shutdown caused by PMIC UVLO threshold",
+       "Last shutdown caused by SOC initiated cold off",
+       "Last shutdown caused by user pressing the power button",
+       NULL,
+};
+
+/*
+ * Decode and log the given "reset source indicator" (rsi)
+ * register and then clear it.
+ */
+static void axp288_extcon_log_rsi(struct axp288_extcon_info *info)
+{
+       char **rsi;
+       unsigned int val, i, clear_mask = 0;
+       int ret;
+
+       ret = regmap_read(info->regmap, AXP288_PS_BOOT_REASON_REG, &val);
+       for (i = 0, rsi = axp288_pwr_up_down_info; *rsi; rsi++, i++) {
+               if (val & BIT(i)) {
+                       dev_dbg(info->dev, "%s\n", *rsi);
+                       clear_mask |= BIT(i);
+               }
+       }
+
+       /* Clear the register value for next reboot (write 1 to clear bit) */
+       regmap_write(info->regmap, AXP288_PS_BOOT_REASON_REG, clear_mask);
+}
+
+static int handle_chrg_det_event(struct axp288_extcon_info *info)
+{
+       static bool notify_otg, notify_charger;
+       static char *cable;
+       int ret, stat, cfg, pwr_stat;
+       u8 chrg_type;
+       bool vbus_attach = false;
+
+       ret = regmap_read(info->regmap, AXP288_PS_STAT_REG, &pwr_stat);
+       if (ret < 0) {
+               dev_err(info->dev, "vbus status read error\n");
+               return ret;
+       }
+
+       vbus_attach = (pwr_stat & PS_STAT_VBUS_PRESENT);
+       if (vbus_attach) {
+               dev_dbg(info->dev, "vbus present\n");
+       } else {
+               dev_dbg(info->dev, "vbus not present\n");
+               goto notify_otg;
+       }
+
+       /* Check charger detection completion status */
+       ret = regmap_read(info->regmap, AXP288_BC_GLOBAL_REG, &cfg);
+       if (ret < 0)
+               goto dev_det_ret;
+       if (cfg & BC_GLOBAL_DET_STAT) {
+               dev_dbg(info->dev, "charger detection not complete!!\n");
+               goto dev_det_ret;
+       }
+
+       ret = regmap_read(info->regmap, AXP288_BC_DET_STAT_REG, &stat);
+       if (ret < 0)
+               goto dev_det_ret;
+       dev_dbg(info->dev, "stat:%x, cfg:%x\n", stat, cfg);
+
+       chrg_type = (stat & DET_STAT_MASK) >> DET_STAT_SHIFT;
+
+       if (chrg_type == DET_STAT_SDP) {
+               dev_dbg(info->dev, "sdp cable connecetd\n");
+               notify_otg = true;
+               notify_charger = true;
+               cable = AXP288_EXTCON_SLOW_CHARGER;
+       } else if (chrg_type == DET_STAT_CDP) {
+               dev_dbg(info->dev, "cdp cable connecetd\n");
+               notify_otg = true;
+               notify_charger = true;
+               cable = AXP288_EXTCON_DOWNSTREAM_CHARGER;
+       } else if (chrg_type == DET_STAT_DCP) {
+               dev_dbg(info->dev, "dcp cable connecetd\n");
+               notify_charger = true;
+               cable = AXP288_EXTCON_FAST_CHARGER;
+       } else {
+               dev_warn(info->dev,
+                       "disconnect or unknown or ID event\n");
+       }
+
+notify_otg:
+       if (notify_otg) {
+               /*
+                * If VBUS is absent Connect D+/D- lines to PMIC for BC
+                * detection. Else connect them to SOC for USB communication.
+                */
+               if (info->pdata->gpio_mux_cntl)
+                       gpiod_set_value(info->pdata->gpio_mux_cntl,
+                               vbus_attach ? EXTCON_GPIO_MUX_SEL_SOC
+                                               : EXTCON_GPIO_MUX_SEL_PMIC);
+
+               atomic_notifier_call_chain(&info->otg->notifier,
+                       vbus_attach ? USB_EVENT_VBUS : USB_EVENT_NONE, NULL);
+       }
+
+       if (notify_charger)
+               extcon_set_cable_state(info->edev, cable, vbus_attach);
+
+       /* Clear the flags on disconnect event */
+       if (!vbus_attach) {
+               notify_otg = false;
+               notify_charger = false;
+       }
+
+       return 0;
+
+dev_det_ret:
+       if (ret < 0)
+               dev_warn(info->dev, "BC Mod detection error\n");
+
+       return ret;
+}
+
+static irqreturn_t axp288_extcon_isr(int irq, void *data)
+{
+       struct axp288_extcon_info *info = data;
+       unsigned int i;
+       int ret;
+
+       for (i = 0; i < EXTCON_IRQ_END; i++) {
+               if (info->irq[i] == irq)
+                       break;
+       }
+
+       if (i == EXTCON_IRQ_END) {
+               dev_warn(info->dev, "spurious interrupt!!\n");
+               return IRQ_NONE;
+       }
+
+       ret = handle_chrg_det_event(info);
+       if (ret < 0)
+               dev_warn(info->dev, "error in PWRSRC INT handling\n");
+
+       return IRQ_HANDLED;
+}
+
+static void axp288_extcon_enable_irq(struct axp288_extcon_info *info)
+{
+       /* Unmask VBUS interrupt */
+       regmap_write(info->regmap, AXP288_PWRSRC_IRQ_CFG_REG,
+                                               PWRSRC_IRQ_CFG_MASK);
+       regmap_update_bits(info->regmap, AXP288_BC_GLOBAL_REG,
+                                               BC_GLOBAL_RUN, 0);
+       /* Unmask the BC1.2 complte interrupts */
+       regmap_write(info->regmap, AXP288_BC12_IRQ_CFG_REG, BC12_IRQ_CFG_MASK);
+       /* Enable the charger detection logic */
+       regmap_update_bits(info->regmap, AXP288_BC_GLOBAL_REG,
+                                       BC_GLOBAL_RUN, BC_GLOBAL_RUN);
+}
+
+static int axp288_extcon_probe(struct platform_device *pdev)
+{
+       struct axp288_extcon_info *info;
+       struct axp20x_dev *axp20x = dev_get_drvdata(pdev->dev.parent);
+       int ret, i, pirq, gpio;
+
+       info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
+       if (!info)
+               return -ENOMEM;
+
+       info->dev = &pdev->dev;
+       info->regmap = axp20x->regmap;
+       info->regmap_irqc = axp20x->regmap_irqc;
+       info->pdata = pdev->dev.platform_data;
+
+       if (!info->pdata) {
+               /* TODO: Try ACPI provided pdata via device properties */
+               if (!device_property_present(&pdev->dev,
+                                       "axp288_extcon_data\n"))
+                       dev_err(&pdev->dev, "no platform data\n");
+               return -ENODEV;
+       }
+       platform_set_drvdata(pdev, info);
+
+       axp288_extcon_log_rsi(info);
+
+       /* Initialize extcon device */
+       info->edev = devm_extcon_dev_allocate(&pdev->dev,
+                                             axp288_extcon_cables);
+       if (IS_ERR(info->edev)) {
+               dev_err(&pdev->dev, "failed to allocate memory for extcon\n");
+               ret = PTR_ERR(info->edev);
+               return ret;
+       }
+
+       /* Register extcon device */
+       ret = devm_extcon_dev_register(&pdev->dev, info->edev);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to register extcon device\n");
+               return ret;
+       }
+
+       /* Get otg transceiver phy */
+       info->otg = usb_get_phy(USB_PHY_TYPE_USB2);
+       if (IS_ERR(info->otg)) {
+               dev_warn(&pdev->dev, "failed to get otg transceiver\n");
+               ret = PTR_ERR(info->otg);
+               return ret;
+       }
+
+       /* Set up gpio control for USB Mux */
+       if (info->pdata->gpio_mux_cntl) {
+               gpio = desc_to_gpio(info->pdata->gpio_mux_cntl);
+               ret = gpio_request(gpio, "USB_MUX");
+               if (ret < 0) {
+                       dev_err(&pdev->dev,
+                               "failed to request the gpio=%d\n", gpio);
+                       goto gpio_req_failed;
+               }
+               gpiod_direction_output(info->pdata->gpio_mux_cntl,
+                                               EXTCON_GPIO_MUX_SEL_PMIC);
+       }
+
+       for (i = 0; i < EXTCON_IRQ_END; i++) {
+               pirq = platform_get_irq(pdev, i);
+               info->irq[i] = regmap_irq_get_virq(info->regmap_irqc, pirq);
+               if (info->irq[i] < 0) {
+                       dev_warn(&pdev->dev,
+                               "regmap_irq get virq failed for IRQ %d: %d\n",
+                               pirq, info->irq[i]);
+                       info->irq[i] = -1;
+                       goto intr_reg_failed;
+               }
+
+               ret = devm_request_threaded_irq(&pdev->dev, info->irq[i],
+                               NULL, axp288_extcon_isr,
+                               IRQF_ONESHOT | IRQF_NO_SUSPEND,
+                               pdev->name, info);
+               if (ret) {
+                       dev_err(&pdev->dev, "request_irq fail :%d err:%d\n",
+                                                       info->irq[i], ret);
+                       goto intr_reg_failed;
+               }
+       }
+
+       /* Enable interrupts */
+       axp288_extcon_enable_irq(info);
+
+       return 0;
+
+intr_reg_failed:
+gpio_req_failed:
+       usb_put_phy(info->otg);
+       return ret;
+}
+
+static int axp288_extcon_remove(struct platform_device *pdev)
+{
+       struct axp288_extcon_info *info = platform_get_drvdata(pdev);
+
+       usb_put_phy(info->otg);
+       return 0;
+}
+
+static struct platform_driver axp288_extcon_driver = {
+       .probe = axp288_extcon_probe,
+       .remove = axp288_extcon_remove,
+       .driver = {
+               .name = "axp288_extcon",
+       },
+};
+module_platform_driver(axp288_extcon_driver);
+
+MODULE_AUTHOR("Ramakrishna Pallala <ramakrishna.pall...@intel.com>");
+MODULE_DESCRIPTION("X-Powers AXP288 extcon driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/mfd/axp20x.h b/include/linux/mfd/axp20x.h
index dfabd6d..38653e0 100644
--- a/include/linux/mfd/axp20x.h
+++ b/include/linux/mfd/axp20x.h
@@ -275,4 +275,13 @@ struct axp20x_fg_pdata {
        int thermistor_curve[MAX_THERM_CURVE_SIZE][2];
 };
 
+#define AXP288_EXTCON_SLOW_CHARGER             "SLOW-CHARGER"
+#define AXP288_EXTCON_DOWNSTREAM_CHARGER       "CHARGE-DOWNSTREAM"
+#define AXP288_EXTCON_FAST_CHARGER             "FAST-CHARGER"
+
+struct axp288_extcon_pdata {
+       /* GPIO pin control to switch D+/D- lines b/w PMIC and SOC */
+       struct gpio_desc *gpio_mux_cntl;
+};
+
 #endif /* __LINUX_MFD_AXP20X_H */
-- 
1.7.9.5

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