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>

3 files changed, 292 insertions, 0 deletions

diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index 540e8cd16ee6..1ed4b45536c7 100644
--- a/drivers/extcon/Kconfig
+++ b/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
diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
index 261ce4cfe209..d3941a735df3 100644
--- a/drivers/extcon/Makefile
+++ b/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
diff --git a/drivers/extcon/extcon-intel-mrfld.c b/drivers/extcon/extcon-intel-mrfld.c
new file mode 100644
index 000000000000..f47016fb28a8
--- /dev/null
+++ b/drivers/extcon/extcon-intel-mrfld.c
@@ -0,0 +1,284 @@
+// 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");