--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * ON Semiconductor LC824206XA Micro USB Switch driver
+ *
+ * Copyright (c) 2024 Hans de Goede <hansg@kernel.org>
+ *
+ * ON Semiconductor has an "Advance Information" datasheet available
+ * (ENA2222-D.PDF), but no full datasheet. So there is no documentation
+ * available for the registers.
+ *
+ * This driver is based on the register info from the extcon-fsa9285.c driver,
+ * from the Lollipop Android sources for the Lenovo Yoga Tablet 2 (Pro)
+ * 830 / 1050 / 1380 models. Note despite the name this is actually a driver
+ * for the LC824206XA not the FSA9285. The Android sources can be downloaded
+ * from Lenovo's support page for these tablets, filename:
+ * yoga_tab_2_osc_android_to_lollipop_201505.rar.
+ */
+
+#include <linux/bits.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/extcon-provider.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/power_supply.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/workqueue.h>
+
+/*
+ * Register defines as mentioned above there is no datasheet with register
+ * info, so this may not be 100% accurate.
+ */
+#define REG00 0x00
+#define REG00_INIT_VALUE 0x01
+
+#define REG_STATUS 0x01
+#define STATUS_OVP BIT(0)
+#define STATUS_DATA_SHORT BIT(1)
+#define STATUS_VBUS_PRESENT BIT(2)
+#define STATUS_USB_ID GENMASK(7, 3)
+#define STATUS_USB_ID_GND 0x80
+#define STATUS_USB_ID_ACA 0xf0
+#define STATUS_USB_ID_FLOAT 0xf8
+
+/*
+ * This controls the DP/DM muxes + other switches,
+ * meaning of individual bits is unknown.
+ */
+#define REG_SWITCH_CONTROL 0x02
+#define SWITCH_STEREO_MIC 0xc8
+#define SWITCH_USB_HOST 0xec
+#define SWITCH_DISCONNECTED 0xf8
+#define SWITCH_USB_DEVICE 0xfc
+
+/* 5 bits? ADC 0x10 GND, 0x1a-0x1f ACA, 0x1f float */
+#define REG_ID_PIN_ADC_VALUE 0x03
+
+/* Masks for all 3 interrupt registers */
+#define INTR_ID_PIN_CHANGE BIT(0)
+#define INTR_VBUS_CHANGE BIT(1)
+/* Both of these get set after a continuous mode ADC conversion */
+#define INTR_ID_PIN_ADC_INT1 BIT(2)
+#define INTR_ID_PIN_ADC_INT2 BIT(3)
+/* Charger type available in reg 0x09 */
+#define INTR_CHARGER_DET_DONE BIT(4)
+#define INTR_OVP BIT(5)
+
+/* There are 7 interrupt sources, bit 6 use is unknown (OCP?) */
+#define INTR_ALL GENMASK(6, 0)
+
+/* Unmask interrupts this driver cares about */
+#define INTR_MASK \
+ (INTR_ALL & ~(INTR_ID_PIN_CHANGE | INTR_VBUS_CHANGE | INTR_CHARGER_DET_DONE))
+
+/* Active (event happened and not cleared yet) interrupts */
+#define REG_INTR_STATUS 0x04
+
+/*
+ * Writing a 1 to a bit here clears it in INTR_STATUS. These bits do NOT
+ * auto-reset to 0, so these must be set to 0 manually after clearing.
+ */
+#define REG_INTR_CLEAR 0x05
+
+/* Interrupts which bit is set to 1 here will not raise the HW IRQ */
+#define REG_INTR_MASK 0x06
+
+/* ID pin ADC control, meaning of individual bits is unknown */
+#define REG_ID_PIN_ADC_CTRL 0x07
+#define ID_PIN_ADC_AUTO 0x40
+#define ID_PIN_ADC_CONTINUOUS 0x44
+
+#define REG_CHARGER_DET 0x08
+#define CHARGER_DET_ON BIT(0)
+#define CHARGER_DET_CDP_ON BIT(1)
+#define CHARGER_DET_CDP_VAL BIT(2)
+
+#define REG_CHARGER_TYPE 0x09
+#define CHARGER_TYPE_UNKNOWN 0x00
+#define CHARGER_TYPE_DCP 0x01
+#define CHARGER_TYPE_SDP_OR_CDP 0x04
+#define CHARGER_TYPE_QC 0x06
+
+#define REG10 0x10
+#define REG10_INIT_VALUE 0x00
+
+struct lc824206xa_data {
+ struct work_struct work;
+ struct i2c_client *client;
+ struct extcon_dev *edev;
+ struct power_supply *psy;
+ struct regulator *vbus_boost;
+ unsigned int usb_type;
+ unsigned int cable;
+ unsigned int previous_cable;
+ u8 switch_control;
+ u8 previous_switch_control;
+ bool vbus_ok;
+ bool vbus_boost_enabled;
+ bool fastcharge_over_miclr;
+};
+
+static const unsigned int lc824206xa_cables[] = {
+ EXTCON_USB_HOST,
+ EXTCON_CHG_USB_SDP,
+ EXTCON_CHG_USB_CDP,
+ EXTCON_CHG_USB_DCP,
+ EXTCON_CHG_USB_ACA,
+ EXTCON_CHG_USB_FAST,
+ EXTCON_NONE,
+};
+
+/* read/write reg helpers to add error logging to smbus byte functions */
+static int lc824206xa_read_reg(struct lc824206xa_data *data, u8 reg)
+{
+ int ret;
+
+ ret = i2c_smbus_read_byte_data(data->client, reg);
+ if (ret < 0)
+ dev_err(&data->client->dev, "Error %d reading reg 0x%02x\n", ret, reg);
+
+ return ret;
+}
+
+static int lc824206xa_write_reg(struct lc824206xa_data *data, u8 reg, u8 val)
+{
+ int ret;
+
+ ret = i2c_smbus_write_byte_data(data->client, reg, val);
+ if (ret < 0)
+ dev_err(&data->client->dev, "Error %d writing reg 0x%02x\n", ret, reg);
+
+ return ret;
+}
+
+static int lc824206xa_get_id(struct lc824206xa_data *data)
+{
+ int ret;
+
+ ret = lc824206xa_write_reg(data, REG_ID_PIN_ADC_CTRL, ID_PIN_ADC_CONTINUOUS);
+ if (ret)
+ return ret;
+
+ ret = lc824206xa_read_reg(data, REG_ID_PIN_ADC_VALUE);
+
+ lc824206xa_write_reg(data, REG_ID_PIN_ADC_CTRL, ID_PIN_ADC_AUTO);
+
+ return ret;
+}
+
+static void lc824206xa_set_vbus_boost(struct lc824206xa_data *data, bool enable)
+{
+ int ret;
+
+ if (data->vbus_boost_enabled == enable)
+ return;
+
+ if (enable)
+ ret = regulator_enable(data->vbus_boost);
+ else
+ ret = regulator_disable(data->vbus_boost);
+
+ if (ret == 0)
+ data->vbus_boost_enabled = enable;
+ else
+ dev_err(&data->client->dev, "Error updating Vbus boost regulator: %d\n", ret);
+}
+
+static void lc824206xa_charger_detect(struct lc824206xa_data *data)
+{
+ int charger_type, ret;
+
+ charger_type = lc824206xa_read_reg(data, REG_CHARGER_TYPE);
+ if (charger_type < 0)
+ return;
+
+ dev_dbg(&data->client->dev, "charger type 0x%02x\n", charger_type);
+
+ switch (charger_type) {
+ case CHARGER_TYPE_UNKNOWN:
+ data->usb_type = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+ /* Treat as SDP */
+ data->cable = EXTCON_CHG_USB_SDP;
+ data->switch_control = SWITCH_USB_DEVICE;
+ break;
+ case CHARGER_TYPE_SDP_OR_CDP:
+ data->usb_type = POWER_SUPPLY_USB_TYPE_SDP;
+ data->cable = EXTCON_CHG_USB_SDP;
+ data->switch_control = SWITCH_USB_DEVICE;
+
+ ret = lc824206xa_write_reg(data, REG_CHARGER_DET,
+ CHARGER_DET_CDP_ON | CHARGER_DET_ON);
+ if (ret < 0)
+ break;
+
+ msleep(100);
+ ret = lc824206xa_read_reg(data, REG_CHARGER_DET);
+ if (ret >= 0 && (ret & CHARGER_DET_CDP_VAL)) {
+ data->usb_type = POWER_SUPPLY_USB_TYPE_CDP;
+ data->cable = EXTCON_CHG_USB_CDP;
+ }
+
+ lc824206xa_write_reg(data, REG_CHARGER_DET, CHARGER_DET_ON);
+ break;
+ case CHARGER_TYPE_DCP:
+ data->usb_type = POWER_SUPPLY_USB_TYPE_DCP;
+ data->cable = EXTCON_CHG_USB_DCP;
+ if (data->fastcharge_over_miclr)
+ data->switch_control = SWITCH_STEREO_MIC;
+ else
+ data->switch_control = SWITCH_DISCONNECTED;
+ break;
+ case CHARGER_TYPE_QC:
+ data->usb_type = POWER_SUPPLY_USB_TYPE_DCP;
+ data->cable = EXTCON_CHG_USB_DCP;
+ data->switch_control = SWITCH_DISCONNECTED;
+ break;
+ default:
+ dev_warn(&data->client->dev, "Unknown charger type: 0x%02x\n", charger_type);
+ break;
+ }
+}
+
+static void lc824206xa_work(struct work_struct *work)
+{
+ struct lc824206xa_data *data = container_of(work, struct lc824206xa_data, work);
+ bool vbus_boost_enable = false;
+ int status, id;
+
+ status = lc824206xa_read_reg(data, REG_STATUS);
+ if (status < 0)
+ return;
+
+ dev_dbg(&data->client->dev, "status 0x%02x\n", status);
+
+ data->vbus_ok = (status & (STATUS_VBUS_PRESENT | STATUS_OVP)) == STATUS_VBUS_PRESENT;
+
+ /* Read id pin ADC if necessary */
+ switch (status & STATUS_USB_ID) {
+ case STATUS_USB_ID_GND:
+ case STATUS_USB_ID_FLOAT:
+ break;
+ default:
+ /* Happens when the connector is inserted slowly, log at dbg level */
+ dev_dbg(&data->client->dev, "Unknown status 0x%02x\n", status);
+ fallthrough;
+ case STATUS_USB_ID_ACA:
+ id = lc824206xa_get_id(data);
+ dev_dbg(&data->client->dev, "RID 0x%02x\n", id);
+ switch (id) {
+ case 0x10:
+ status = STATUS_USB_ID_GND;
+ break;
+ case 0x18 ... 0x1e:
+ status = STATUS_USB_ID_ACA;
+ break;
+ case 0x1f:
+ status = STATUS_USB_ID_FLOAT;
+ break;
+ default:
+ dev_warn(&data->client->dev, "Unknown RID 0x%02x\n", id);
+ return;
+ }
+ }
+
+ /* Check for out of spec OTG charging hubs, treat as ACA */
+ if ((status & STATUS_USB_ID) == STATUS_USB_ID_GND &&
+ data->vbus_ok && !data->vbus_boost_enabled) {
+ dev_info(&data->client->dev, "Out of spec USB host adapter with Vbus present, not enabling 5V output\n");
+ status = STATUS_USB_ID_ACA;
+ }
+
+ switch (status & STATUS_USB_ID) {
+ case STATUS_USB_ID_ACA:
+ data->usb_type = POWER_SUPPLY_USB_TYPE_ACA;
+ data->cable = EXTCON_CHG_USB_ACA;
+ data->switch_control = SWITCH_USB_HOST;
+ break;
+ case STATUS_USB_ID_GND:
+ data->usb_type = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+ data->cable = EXTCON_USB_HOST;
+ data->switch_control = SWITCH_USB_HOST;
+ vbus_boost_enable = true;
+ break;
+ case STATUS_USB_ID_FLOAT:
+ /* When fast charging with Vbus > 5V, OVP will be set */
+ if (data->fastcharge_over_miclr &&
+ data->switch_control == SWITCH_STEREO_MIC &&
+ (status & STATUS_OVP)) {
+ data->cable = EXTCON_CHG_USB_FAST;
+ break;
+ }
+
+ if (data->vbus_ok) {
+ lc824206xa_charger_detect(data);
+ } else {
+ data->usb_type = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+ data->cable = EXTCON_NONE;
+ data->switch_control = SWITCH_DISCONNECTED;
+ }
+ break;
+ }
+
+ lc824206xa_set_vbus_boost(data, vbus_boost_enable);
+
+ if (data->switch_control != data->previous_switch_control) {
+ lc824206xa_write_reg(data, REG_SWITCH_CONTROL, data->switch_control);
+ data->previous_switch_control = data->switch_control;
+ }
+
+ if (data->cable != data->previous_cable) {
+ extcon_set_state_sync(data->edev, data->previous_cable, false);
+ extcon_set_state_sync(data->edev, data->cable, true);
+ data->previous_cable = data->cable;
+ }
+
+ power_supply_changed(data->psy);
+}
+
+static irqreturn_t lc824206xa_irq(int irq, void *_data)
+{
+ struct lc824206xa_data *data = _data;
+ int intr_status;
+
+ intr_status = lc824206xa_read_reg(data, REG_INTR_STATUS);
+ if (intr_status < 0)
+ intr_status = INTR_ALL; /* Should never happen, clear all */
+
+ dev_dbg(&data->client->dev, "interrupt 0x%02x\n", intr_status);
+
+ lc824206xa_write_reg(data, REG_INTR_CLEAR, intr_status);
+ lc824206xa_write_reg(data, REG_INTR_CLEAR, 0);
+
+ schedule_work(&data->work);
+ return IRQ_HANDLED;
+}
+
+/*
+ * Newer charger (power_supply) drivers expect the max input current to be
+ * provided by a parent power_supply device for the charger chip.
+ */
+static int lc824206xa_psy_get_prop(struct power_supply *psy,
+ enum power_supply_property psp,
+ union power_supply_propval *val)
+{
+ struct lc824206xa_data *data = power_supply_get_drvdata(psy);
+
+ switch (psp) {
+ case POWER_SUPPLY_PROP_ONLINE:
+ val->intval = data->vbus_ok && !data->vbus_boost_enabled;
+ break;
+ case POWER_SUPPLY_PROP_USB_TYPE:
+ val->intval = data->usb_type;
+ break;
+ case POWER_SUPPLY_PROP_CURRENT_MAX:
+ switch (data->usb_type) {
+ case POWER_SUPPLY_USB_TYPE_DCP:
+ case POWER_SUPPLY_USB_TYPE_ACA:
+ val->intval = 2000000;
+ break;
+ case POWER_SUPPLY_USB_TYPE_CDP:
+ val->intval = 1500000;
+ break;
+ default:
+ val->intval = 500000;
+ }
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static const enum power_supply_usb_type lc824206xa_psy_usb_types[] = {
+ POWER_SUPPLY_USB_TYPE_SDP,
+ POWER_SUPPLY_USB_TYPE_CDP,
+ POWER_SUPPLY_USB_TYPE_DCP,
+ POWER_SUPPLY_USB_TYPE_ACA,
+ POWER_SUPPLY_USB_TYPE_UNKNOWN,
+};
+
+static const enum power_supply_property lc824206xa_psy_props[] = {
+ POWER_SUPPLY_PROP_ONLINE,
+ POWER_SUPPLY_PROP_USB_TYPE,
+ POWER_SUPPLY_PROP_CURRENT_MAX,
+};
+
+static const struct power_supply_desc lc824206xa_psy_desc = {
+ .name = "lc824206xa-charger-detect",
+ .type = POWER_SUPPLY_TYPE_USB,
+ .usb_types = lc824206xa_psy_usb_types,
+ .num_usb_types = ARRAY_SIZE(lc824206xa_psy_usb_types),
+ .properties = lc824206xa_psy_props,
+ .num_properties = ARRAY_SIZE(lc824206xa_psy_props),
+ .get_property = lc824206xa_psy_get_prop,
+};
+
+static int lc824206xa_probe(struct i2c_client *client)
+{
+ struct power_supply_config psy_cfg = { };
+ struct device *dev = &client->dev;
+ struct lc824206xa_data *data;
+ int ret;
+
+ data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->client = client;
+ INIT_WORK(&data->work, lc824206xa_work);
+ data->cable = EXTCON_NONE;
+ data->previous_cable = EXTCON_NONE;
+ data->usb_type = POWER_SUPPLY_USB_TYPE_UNKNOWN;
+ /* Some designs use a custom fast-charge protocol over the mic L/R inputs */
+ data->fastcharge_over_miclr =
+ device_property_read_bool(dev, "onnn,enable-miclr-for-dcp");
+
+ data->vbus_boost = devm_regulator_get(dev, "vbus");
+ if (IS_ERR(data->vbus_boost))
+ return dev_err_probe(dev, PTR_ERR(data->vbus_boost),
+ "getting regulator\n");
+
+ /* Init */
+ ret = lc824206xa_write_reg(data, REG00, REG00_INIT_VALUE);
+ ret |= lc824206xa_write_reg(data, REG10, REG10_INIT_VALUE);
+ msleep(100);
+ ret |= lc824206xa_write_reg(data, REG_INTR_CLEAR, INTR_ALL);
+ ret |= lc824206xa_write_reg(data, REG_INTR_CLEAR, 0);
+ ret |= lc824206xa_write_reg(data, REG_INTR_MASK, INTR_MASK);
+ ret |= lc824206xa_write_reg(data, REG_ID_PIN_ADC_CTRL, ID_PIN_ADC_AUTO);
+ ret |= lc824206xa_write_reg(data, REG_CHARGER_DET, CHARGER_DET_ON);
+ if (ret)
+ return -EIO;
+
+ /* Initialize extcon device */
+ data->edev = devm_extcon_dev_allocate(dev, lc824206xa_cables);
+ if (IS_ERR(data->edev))
+ return PTR_ERR(data->edev);
+
+ ret = devm_extcon_dev_register(dev, data->edev);
+ if (ret)
+ return dev_err_probe(dev, ret, "registering extcon device\n");
+
+ psy_cfg.drv_data = data;
+ data->psy = devm_power_supply_register(dev, &lc824206xa_psy_desc, &psy_cfg);
+ if (IS_ERR(data->psy))
+ return dev_err_probe(dev, PTR_ERR(data->psy), "registering power supply\n");
+
+ ret = devm_request_threaded_irq(dev, client->irq, NULL, lc824206xa_irq,
+ IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+ KBUILD_MODNAME, data);
+ if (ret)
+ return dev_err_probe(dev, ret, "requesting IRQ\n");
+
+ /* Sync initial state */
+ schedule_work(&data->work);
+ return 0;
+}
+
+static const struct i2c_device_id lc824206xa_i2c_ids[] = {
+ { "lc824206xa" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, lc824206xa_i2c_ids);
+
+static struct i2c_driver lc824206xa_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ },
+ .probe = lc824206xa_probe,
+ .id_table = lc824206xa_i2c_ids,
+};
+
+module_i2c_driver(lc824206xa_driver);
+
+MODULE_AUTHOR("Hans de Goede <hansg@kernel.org>");
+MODULE_DESCRIPTION("LC824206XA Micro USB Switch driver");
+MODULE_LICENSE("GPL");
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