[PATCH v3 2/2] extcon-axp288: Add axp288 extcon driver support

[Ramakrishna Pallala]

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.pallala@xxxxxxxxx>
---
 drivers/extcon/Kconfig         |    7 +
 drivers/extcon/Makefile        |    1 +
 drivers/extcon/extcon-axp288.c |  462 ++++++++++++++++++++++++++++++++++++++++
 include/linux/mfd/axp20x.h     |    5 +
 4 files changed, 475 insertions(+)
 create mode 100644 drivers/extcon/extcon-axp288.c

diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index 6a1f7de..f6e8b2a 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 0370b42..5429377 100644
--- a/drivers/extcon/Makefile
+++ b/drivers/extcon/Makefile
@@ -5,6 +5,7 @@
 obj-$(CONFIG_EXTCON)		+= extcon-class.o
 obj-$(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..363552c
--- /dev/null
+++ b/drivers/extcon/extcon-axp288.c
@@ -0,0 +1,462 @@
+/*
+ * extcon-axp288.c - X-Power AXP288 PMIC extcon cable detection driver
+ *
+ * Copyright (C) 2015 Intel Corporation
+ * Author: Ramakrishna Pallala <ramakrishna.pallala@xxxxxxxxx>
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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,
+};
+
+#define AXP288_DRV_NAME			"axp288_extcon"
+
+#define AXP288_EXTCON_CABLE_SDP		"Slow-charger"
+#define AXP288_EXTCON_CABLE_CDP		"Charge-downstream"
+#define AXP288_EXTCON_CABLE_DCP		"Fast-charger"
+
+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_CABLE_SDP,
+	AXP288_EXTCON_CABLE_CDP,
+	AXP288_EXTCON_CABLE_DCP,
+	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 usb_phy *otg;
+	struct notifier_block extcon_nb;
+	struct extcon_specific_cable_nb cable;
+	/* detect OTG or ID events */
+	bool usb_id_short;
+};
+
+/* 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 **pwrsrc_rsi_info, int reg)
+{
+	char **rsi;
+	unsigned int val, i, clear_mask = 0;
+	int ret;
+
+	ret = regmap_read(info->regmap, reg, &val);
+	for (i = 0, rsi = pwrsrc_rsi_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, 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) && !info->usb_id_short;
+	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_CABLE_SDP;
+	} else if (chrg_type == DET_STAT_CDP) {
+		dev_dbg(info->dev, "cdp cable connecetd\n");
+		notify_otg = true;
+		notify_charger = true;
+		cable = AXP288_EXTCON_CABLE_CDP;
+	} else if (chrg_type == DET_STAT_DCP) {
+		dev_dbg(info->dev, "dcp cable connecetd\n");
+		notify_charger = true;
+		cable = AXP288_EXTCON_CABLE_DCP;
+	} 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 != NULL)
+			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 int axp288_handle_extcon_event(struct notifier_block *nb,
+				   unsigned long event, void *param)
+{
+	struct axp288_extcon_info *info =
+	    container_of(nb, struct axp288_extcon_info, extcon_nb);
+	struct extcon_dev *edev = param;
+	int usb_host = extcon_get_cable_state(edev, "USB-Host");
+
+	dev_dbg(info->dev, "external connector USB-Host is %s\n",
+				usb_host ? "attached" : "detached");
+
+	/*
+	 * Set usb_id_short flag to avoid running charger detection logic
+	 * in case usb host.
+	 */
+	info->usb_id_short = usb_host;
+
+	/*
+	 * Connect the USB mux to SOC in case of usb host else connect
+	 * it to PMIC.
+	 */
+	if (info->pdata->gpio_mux_cntl != NULL) {
+		if (info->usb_id_short)
+			gpiod_set_value(info->pdata->gpio_mux_cntl,
+					EXTCON_GPIO_MUX_SEL_SOC);
+		else
+			gpiod_set_value(info->pdata->gpio_mux_cntl,
+					EXTCON_GPIO_MUX_SEL_PMIC);
+	}
+
+	return NOTIFY_OK;
+}
+
+static int axp288_init_gpio_mux_cntl(struct axp288_extcon_info *info)
+{
+	int ret;
+
+	ret = gpio_request(desc_to_gpio(info->pdata->gpio_mux_cntl), "USB_MUX");
+	if (ret < 0) {
+		dev_err(info->dev, "Failed to request the gpio=%d\n",
+			desc_to_gpio(info->pdata->gpio_mux_cntl));
+		return ret;
+	}
+	gpiod_direction_output(info->pdata->gpio_mux_cntl,
+					EXTCON_GPIO_MUX_SEL_PMIC);
+
+	info->extcon_nb.notifier_call = axp288_handle_extcon_event;
+	ret = extcon_register_interest(&info->cable, NULL,
+				"USB-Host", &info->extcon_nb);
+	if (ret) {
+		dev_err(info->dev, "failed to register extcon notifier\n");
+		return ret;
+	}
+
+	if (info->cable.edev)
+		info->usb_id_short =
+			extcon_get_cable_state(info->cable.edev, "USB-Host");
+
+	if (info->usb_id_short)
+		gpiod_set_value(info->pdata->gpio_mux_cntl,
+					EXTCON_GPIO_MUX_SEL_SOC);
+
+	return 0;
+}
+
+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;
+
+	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, axp288_pwr_up_down_info,
+				AXP288_PS_BOOT_REASON_REG);
+
+	/* 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");
+		return -ENOMEM;
+	}
+
+	/* Register extcon device */
+	info->edev->name = dev_name(&pdev->dev);
+	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;
+	}
+
+	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;
+		}
+	}
+
+	/* Set up gpio control for USB Mux */
+	if (info->pdata->gpio_mux_cntl != NULL) {
+		ret = axp288_init_gpio_mux_cntl(info);
+		if (ret < 0)
+			goto intr_reg_failed;
+	}
+
+	/* 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);
+
+	return 0;
+
+intr_reg_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.pallala@xxxxxxxxx>");
+MODULE_DESCRIPTION("X-Powers AXP288 extcon driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/mfd/axp20x.h b/include/linux/mfd/axp20x.h
index dfabd6d..4ed8071 100644
--- a/include/linux/mfd/axp20x.h
+++ b/include/linux/mfd/axp20x.h
@@ -275,4 +275,9 @@ struct axp20x_fg_pdata {
 	int thermistor_curve[MAX_THERM_CURVE_SIZE][2];
 };
 
+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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