extcon: mrfld: Introduce extcon driver for Basin Cove PMIC

On Intel Merrifield the Basin Cove PMIC provides a feature to detect
the USB connection type. This driver utilizes the feature in order
to support the USB dual role detection.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>

drivers/extcon/Kconfig

@@ -60,6 +60,13 @@ config EXTCON_INTEL_CHT_WC
 	  Say Y here to enable extcon support for charger detection / control
 	  on the Intel Cherrytrail Whiskey Cove PMIC.
 
+config EXTCON_INTEL_MRFLD
+	tristate "Intel Merrifield Basin Cove PMIC extcon driver"
+	depends on INTEL_SOC_PMIC_MRFLD
+	help
+	  Say Y here to enable extcon support for charger detection / control
+	  on the Intel Merrifield Basin Cove PMIC.
+
 config EXTCON_MAX14577
 	tristate "Maxim MAX14577/77836 EXTCON Support"
 	depends on MFD_MAX14577

drivers/extcon/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_EXTCON_AXP288)	+= extcon-axp288.o
 obj-$(CONFIG_EXTCON_GPIO)	+= extcon-gpio.o
 obj-$(CONFIG_EXTCON_INTEL_INT3496) += extcon-intel-int3496.o
 obj-$(CONFIG_EXTCON_INTEL_CHT_WC) += extcon-intel-cht-wc.o
+obj-$(CONFIG_EXTCON_INTEL_MRFLD) += extcon-intel-mrfld.o
 obj-$(CONFIG_EXTCON_MAX14577)	+= extcon-max14577.o
 obj-$(CONFIG_EXTCON_MAX3355)	+= extcon-max3355.o
 obj-$(CONFIG_EXTCON_MAX77693)	+= extcon-max77693.o

drivers/extcon/extcon-intel-mrfld.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * extcon driver for Basin Cove PMIC
+ *
+ * Copyright (c) 2019, Intel Corporation.
+ * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ */
+
+#include <linux/extcon-provider.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/intel_soc_pmic.h>
+#include <linux/mfd/intel_soc_pmic_mrfld.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+#include "extcon-intel.h"
+
+#define BCOVE_USBIDCTRL			0x19
+#define BCOVE_USBIDCTRL_ID		BIT(0)
+#define BCOVE_USBIDCTRL_ACA		BIT(1)
+#define BCOVE_USBIDCTRL_ALL	(BCOVE_USBIDCTRL_ID | BCOVE_USBIDCTRL_ACA)
+
+#define BCOVE_USBIDSTS			0x1a
+#define BCOVE_USBIDSTS_GND		BIT(0)
+#define BCOVE_USBIDSTS_RARBRC_MASK	GENMASK(2, 1)
+#define BCOVE_USBIDSTS_RARBRC_SHIFT	1
+#define BCOVE_USBIDSTS_NO_ACA		0
+#define BCOVE_USBIDSTS_R_ID_A		1
+#define BCOVE_USBIDSTS_R_ID_B		2
+#define BCOVE_USBIDSTS_R_ID_C		3
+#define BCOVE_USBIDSTS_FLOAT		BIT(3)
+#define BCOVE_USBIDSTS_SHORT		BIT(4)
+
+#define BCOVE_CHGRIRQ_ALL	(BCOVE_CHGRIRQ_VBUSDET | BCOVE_CHGRIRQ_DCDET | \
+				 BCOVE_CHGRIRQ_BATTDET | BCOVE_CHGRIRQ_USBIDDET)
+
+#define BCOVE_CHGRCTRL0			0x4b
+#define BCOVE_CHGRCTRL0_CHGRRESET	BIT(0)
+#define BCOVE_CHGRCTRL0_EMRGCHREN	BIT(1)
+#define BCOVE_CHGRCTRL0_EXTCHRDIS	BIT(2)
+#define BCOVE_CHGRCTRL0_SWCONTROL	BIT(3)
+#define BCOVE_CHGRCTRL0_TTLCK		BIT(4)
+#define BCOVE_CHGRCTRL0_BIT_5		BIT(5)
+#define BCOVE_CHGRCTRL0_BIT_6		BIT(6)
+#define BCOVE_CHGRCTRL0_CHR_WDT_NOKICK	BIT(7)
+
+struct mrfld_extcon_data {
+	struct device *dev;
+	struct regmap *regmap;
+	struct extcon_dev *edev;
+	unsigned int status;
+	unsigned int id;
+};
+
+static const unsigned int mrfld_extcon_cable[] = {
+	EXTCON_USB,
+	EXTCON_USB_HOST,
+	EXTCON_CHG_USB_SDP,
+	EXTCON_CHG_USB_CDP,
+	EXTCON_CHG_USB_DCP,
+	EXTCON_CHG_USB_ACA,
+	EXTCON_NONE,
+};
+
+static int mrfld_extcon_clear(struct mrfld_extcon_data *data, unsigned int reg,
+			      unsigned int mask)
+{
+	return regmap_update_bits(data->regmap, reg, mask, 0x00);
+}
+
+static int mrfld_extcon_set(struct mrfld_extcon_data *data, unsigned int reg,
+			    unsigned int mask)
+{
+	return regmap_update_bits(data->regmap, reg, mask, 0xff);
+}
+
+static int mrfld_extcon_sw_control(struct mrfld_extcon_data *data, bool enable)
+{
+	unsigned int mask = BCOVE_CHGRCTRL0_SWCONTROL;
+	struct device *dev = data->dev;
+	int ret;
+
+	if (enable)
+		ret = mrfld_extcon_set(data, BCOVE_CHGRCTRL0, mask);
+	else
+		ret = mrfld_extcon_clear(data, BCOVE_CHGRCTRL0, mask);
+	if (ret)
+		dev_err(dev, "can't set SW control: %d\n", ret);
+	return ret;
+}
+
+static int mrfld_extcon_get_id(struct mrfld_extcon_data *data)
+{
+	struct regmap *regmap = data->regmap;
+	unsigned int id;
+	bool ground;
+	int ret;
+
+	ret = regmap_read(regmap, BCOVE_USBIDSTS, &id);
+	if (ret)
+		return ret;
+
+	if (id & BCOVE_USBIDSTS_FLOAT)
+		return INTEL_USB_ID_FLOAT;
+
+	switch ((id & BCOVE_USBIDSTS_RARBRC_MASK) >> BCOVE_USBIDSTS_RARBRC_SHIFT) {
+	case BCOVE_USBIDSTS_R_ID_A:
+		return INTEL_USB_RID_A;
+	case BCOVE_USBIDSTS_R_ID_B:
+		return INTEL_USB_RID_B;
+	case BCOVE_USBIDSTS_R_ID_C:
+		return INTEL_USB_RID_C;
+	}
+
+	/*
+	 * PMIC A0 reports USBIDSTS_GND = 1 for ID_GND,
+	 * but PMIC B0 reports USBIDSTS_GND = 0 for ID_GND.
+	 * Thus we must check this bit at last.
+	 */
+	ground = id & BCOVE_USBIDSTS_GND;
+	switch ('A' + BCOVE_MAJOR(data->id)) {
+	case 'A':
+		return ground ? INTEL_USB_ID_GND : INTEL_USB_ID_FLOAT;
+	case 'B':
+		return ground ? INTEL_USB_ID_FLOAT : INTEL_USB_ID_GND;
+	}
+
+	/* Unknown or unsupported type */
+	return INTEL_USB_ID_FLOAT;
+}
+
+static int mrfld_extcon_role_detect(struct mrfld_extcon_data *data)
+{
+	unsigned int id;
+	bool usb_host;
+	int ret;
+
+	ret = mrfld_extcon_get_id(data);
+	if (ret < 0)
+		return ret;
+
+	id = ret;
+
+	usb_host = (id == INTEL_USB_ID_GND) || (id == INTEL_USB_RID_A);
+	extcon_set_state_sync(data->edev, EXTCON_USB_HOST, usb_host);
+
+	return 0;
+}
+
+static int mrfld_extcon_cable_detect(struct mrfld_extcon_data *data)
+{
+	struct regmap *regmap = data->regmap;
+	unsigned int status, change;
+	int ret;
+
+	/*
+	 * It seems SCU firmware clears the content of BCOVE_CHGRIRQ1
+	 * and makes it useless for OS. Instead we compare a previously
+	 * stored status to the current one, provided by BCOVE_SCHGRIRQ1.
+	 */
+	ret = regmap_read(regmap, BCOVE_SCHGRIRQ1, &status);
+	if (ret)
+		return ret;
+
+	change = status ^ data->status;
+	if (!change)
+		return -ENODATA;
+
+	if (change & BCOVE_CHGRIRQ_USBIDDET) {
+		ret = mrfld_extcon_role_detect(data);
+		if (ret)
+			return ret;
+	}
+
+	data->status = status;
+
+	return 0;
+}
+
+static irqreturn_t mrfld_extcon_interrupt(int irq, void *dev_id)
+{
+	struct mrfld_extcon_data *data = dev_id;
+	int ret;
+
+	ret = mrfld_extcon_cable_detect(data);
+
+	mrfld_extcon_clear(data, BCOVE_MIRQLVL1, BCOVE_LVL1_CHGR);
+
+	return ret ? IRQ_NONE: IRQ_HANDLED;
+}
+
+static int mrfld_extcon_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct intel_soc_pmic *pmic = dev_get_drvdata(dev->parent);
+	struct regmap *regmap = pmic->regmap;
+	struct mrfld_extcon_data *data;
+	unsigned int id;
+	int irq, ret;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->dev = dev;
+	data->regmap = regmap;
+
+	data->edev = devm_extcon_dev_allocate(dev, mrfld_extcon_cable);
+	if (IS_ERR(data->edev))
+		return -ENOMEM;
+
+	ret = devm_extcon_dev_register(dev, data->edev);
+	if (ret < 0) {
+		dev_err(dev, "can't register extcon device: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_request_threaded_irq(dev, irq, NULL, mrfld_extcon_interrupt,
+					IRQF_ONESHOT | IRQF_SHARED, pdev->name,
+					data);
+	if (ret) {
+		dev_err(dev, "can't register IRQ handler: %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_read(regmap, BCOVE_ID, &id);
+	if (ret) {
+		dev_err(dev, "can't read PMIC ID: %d\n", ret);
+		return ret;
+	}
+
+	data->id = id;
+
+	ret = mrfld_extcon_sw_control(data, true);
+	if (ret)
+		return ret;
+
+	/* Get initial state */
+	mrfld_extcon_role_detect(data);
+
+	mrfld_extcon_clear(data, BCOVE_MIRQLVL1, BCOVE_LVL1_CHGR);
+	mrfld_extcon_clear(data, BCOVE_MCHGRIRQ1, BCOVE_CHGRIRQ_ALL);
+
+	mrfld_extcon_set(data, BCOVE_USBIDCTRL, BCOVE_USBIDCTRL_ALL);
+
+	platform_set_drvdata(pdev, data);
+
+	return 0;
+}
+
+static int mrfld_extcon_remove(struct platform_device *pdev)
+{
+	struct mrfld_extcon_data *data = platform_get_drvdata(pdev);
+
+	mrfld_extcon_sw_control(data, false);
+
+	return 0;
+}
+
+static const struct platform_device_id mrfld_extcon_id_table[] = {
+	{ .name = "mrfld_bcove_pwrsrc" },
+	{}
+};
+MODULE_DEVICE_TABLE(platform, mrfld_extcon_id_table);
+
+static struct platform_driver mrfld_extcon_driver = {
+	.driver = {
+		.name	= "mrfld_bcove_pwrsrc",
+	},
+	.probe		= mrfld_extcon_probe,
+	.remove		= mrfld_extcon_remove,
+	.id_table	= mrfld_extcon_id_table,
+};
+module_platform_driver(mrfld_extcon_driver);
+
+MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
+MODULE_DESCRIPTION("extcon driver for Intel Merrifield Basin Cove PMIC");
+MODULE_LICENSE("GPL v2");