[PATCH v1 2/2] extcon: Add basic support for Maxim MAX14526 MUIC

From: Svyatoslav Ryhel
Date: Wed Feb 19 2025 - 03:48:48 EST

The MAX14526 is designed to simplify interface requirements on
portable devices by multiplexing common inputs (USB, UART,
Microphone, Stereo Audio and Composite Video) on a single
micro/mini USB connector. The USB input supports Hi-Speed USB
and the audio/video inputs feature negative rail signal
operation allowing simple DC coupled accessories. These device
allow a single micro/mini USB port to support all the common
interfaces on Cellular phones and portable media players over
the same external lines.

Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
---
drivers/extcon/Kconfig | 12 ++
drivers/extcon/Makefile | 1 +
drivers/extcon/extcon-max14526.c | 308 +++++++++++++++++++++++++++++++
3 files changed, 321 insertions(+)
create mode 100644 drivers/extcon/extcon-max14526.c

diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index a6f6d467aacf..1096afc0b5bb 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -134,6 +134,18 @@ config EXTCON_MAX8997
Maxim MAX8997 PMIC. The MAX8997 MUIC is a USB port accessory
detector and switch.

+config EXTCON_MAX14526
+ tristate "Maxim MAX14526 EXTCON Support"
+ select IRQ_DOMAIN
+ select REGMAP_I2C
+ help
+ If you say yes here you get support for the Maxim MAX14526
+ MUIC device. The MAX14526 MUIC is a USB port accessory
+ detector and switch. The MAX14526 is designed to simplify
+ interface requirements on portable devices by multiplexing
+ common inputs (USB, UART, Microphone, Stereo Audio and
+ Composite Video) on a single micro/mini USB connector.
+
config EXTCON_PALMAS
tristate "Palmas USB EXTCON support"
depends on MFD_PALMAS
diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
index 0d6d23faf748..6482f2bfd661 100644
--- a/drivers/extcon/Makefile
+++ b/drivers/extcon/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_EXTCON_MAX3355) += extcon-max3355.o
obj-$(CONFIG_EXTCON_MAX77693) += extcon-max77693.o
obj-$(CONFIG_EXTCON_MAX77843) += extcon-max77843.o
obj-$(CONFIG_EXTCON_MAX8997) += extcon-max8997.o
+obj-$(CONFIG_EXTCON_MAX14526) += extcon-max14526.o
obj-$(CONFIG_EXTCON_PALMAS) += extcon-palmas.o
obj-$(CONFIG_EXTCON_PTN5150) += extcon-ptn5150.o
obj-$(CONFIG_EXTCON_QCOM_SPMI_MISC) += extcon-qcom-spmi-misc.o
diff --git a/drivers/extcon/extcon-max14526.c b/drivers/extcon/extcon-max14526.c
new file mode 100644
index 000000000000..5a406eb5994a
--- /dev/null
+++ b/drivers/extcon/extcon-max14526.c
@@ -0,0 +1,308 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MAX14526 extcon driver to support MUIC
+ */
+
+#include <linux/device.h>
+#include <linux/devm-helpers.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/extcon-provider.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/regmap.h>
+
+/* I2C addresses of MUIC internal registers */
+#define MAX14526_DEVICE_ID 0x00
+#define MAX14526_ID 0x02
+
+/* CONTROL_1 register masks */
+#define MAX14526_CONTROL_1 0x01
+#define ID_2P2 BIT(6)
+#define ID_620 BIT(5)
+#define ID_200 BIT(4)
+#define VLDO BIT(3)
+#define SEMREN BIT(2)
+#define ADC_EN BIT(1)
+#define CP_EN BIT(0)
+
+/* CONTROL_2 register masks */
+#define MAX14526_CONTROL_2 0x02
+#define INTPOL BIT(7)
+#define INT_EN BIT(6)
+#define MIC_LP BIT(5)
+#define CP_AUD BIT(4)
+#define CHG_TYPE BIT(1)
+#define USB_DET_DIS BIT(0)
+
+/* SW_CONTROL register masks */
+#define MAX14526_SW_CONTROL 0x03
+#define SW_DATA 0x00
+#define SW_UART 0x01
+#define SW_AUDIO 0x02
+#define SW_OPEN 0x07
+
+/* INT_STATUS register masks */
+#define MAX14526_INT_STAT 0x04
+#define CHGDET BIT(7)
+#define MR_COMP BIT(6)
+#define SENDEND BIT(5)
+#define V_VBUS BIT(4)
+
+/* STATUS register masks */
+#define MAX14526_STATUS 0x05
+#define DCPORT BIT(7)
+#define CHPORT BIT(6)
+#define C1COMP BIT(0)
+
+enum max14526_idno_resistance {
+ MAX14526_GND,
+ MAX14526_24KOHM,
+ MAX14526_56KOHM,
+ MAX14526_100KOHM,
+ MAX14526_130KOHM,
+ MAX14526_180KOHM,
+ MAX14526_240KOHM,
+ MAX14526_330KOHM,
+ MAX14526_430KOHM,
+ MAX14526_620KOHM,
+ MAX14526_910KOHM,
+ MAX14526_OPEN
+};
+
+enum max14526_field_idx {
+ VENDOR_ID, CHIP_REV, /* DEVID */
+ DM, DP, /* SW_CONTROL */
+ MAX14526_N_REGMAP_FIELDS
+};
+
+static const struct reg_field max14526_reg_field[MAX14526_N_REGMAP_FIELDS] = {
+ [VENDOR_ID] = REG_FIELD(MAX14526_DEVICE_ID, 4, 7),
+ [CHIP_REV] = REG_FIELD(MAX14526_DEVICE_ID, 0, 3),
+ [DM] = REG_FIELD(MAX14526_SW_CONTROL, 0, 2),
+ [DP] = REG_FIELD(MAX14526_SW_CONTROL, 3, 5),
+};
+
+struct max14526_data {
+ struct i2c_client *client;
+ struct extcon_dev *edev;
+
+ struct regmap *regmap;
+ struct regmap_field *rfield[MAX14526_N_REGMAP_FIELDS];
+
+ struct gpio_desc *usif_gpio;
+ struct gpio_desc *dp2t_gpio;
+
+ int last_state;
+ int cable;
+};
+
+enum max14526_muic_modes {
+ MAX14526_OTG = MAX14526_GND, /* no power */
+ MAX14526_MHL = MAX14526_56KOHM, /* no power */
+ MAX14526_OTG_Y = MAX14526_GND | V_VBUS,
+ MAX14526_MHL_CHG = MAX14526_GND | V_VBUS | CHGDET,
+ MAX14526_NONE = MAX14526_OPEN,
+ MAX14526_USB = MAX14526_OPEN | V_VBUS,
+ MAX14526_CHG = MAX14526_OPEN | V_VBUS | CHGDET,
+};
+
+static const unsigned int max14526_extcon_cable[] = {
+ EXTCON_USB,
+ EXTCON_USB_HOST,
+ EXTCON_CHG_USB_FAST,
+ EXTCON_DISP_MHL,
+ EXTCON_NONE,
+};
+
+static int max14526_ap_usb_mode(struct max14526_data *priv)
+{
+ struct device *dev = &priv->client->dev;
+ int ret;
+
+ /* Enable USB Path */
+ ret = regmap_field_write(priv->rfield[DM], SW_DATA);
+ if (ret)
+ return ret;
+
+ ret = regmap_field_write(priv->rfield[DP], SW_DATA);
+ if (ret)
+ return ret;
+
+ /* Enable 200K, Charger Pump and ADC */
+ ret = regmap_write(priv->regmap, MAX14526_CONTROL_1,
+ ID_200 | ADC_EN | CP_EN);
+ if (ret)
+ return ret;
+
+ dev_dbg(dev, "AP USB mode set\n");
+
+ return 0;
+}
+
+static irqreturn_t max14526_interrupt(int irq, void *dev_id)
+{
+ struct max14526_data *priv = dev_id;
+ struct device *dev = &priv->client->dev;
+ int state, ret;
+
+ /*
+ * Upon an MUIC IRQ (MUIC_INT_N falls), wait at least 70ms
+ * before reading INT_STAT and STATUS. After the reads,
+ * MUIC_INT_N returns to high (but the INT_STAT and STATUS
+ * contents will be held).
+ */
+ msleep(100);
+
+ ret = regmap_read(priv->regmap, MAX14526_INT_STAT, &state);
+ if (ret)
+ dev_err(dev, "failed to read MUIC state %d\n", ret);
+
+ if (state == priv->last_state)
+ return IRQ_HANDLED;
+
+ /* Detach previous device */
+ extcon_set_state_sync(priv->edev, priv->cable, false);
+
+ switch (state) {
+ case MAX14526_USB:
+ priv->cable = EXTCON_USB;
+ break;
+
+ case MAX14526_CHG:
+ priv->cable = EXTCON_CHG_USB_FAST;
+ break;
+
+ case MAX14526_OTG:
+ case MAX14526_OTG_Y:
+ priv->cable = EXTCON_USB_HOST;
+ break;
+
+ case MAX14526_MHL:
+ case MAX14526_MHL_CHG:
+ priv->cable = EXTCON_DISP_MHL;
+ break;
+
+ case MAX14526_NONE:
+ default:
+ priv->cable = EXTCON_NONE;
+ break;
+ }
+
+ extcon_set_state_sync(priv->edev, priv->cable, true);
+
+ priv->last_state = state;
+
+ return IRQ_HANDLED;
+}
+
+static const struct regmap_config max14526_regmap_config = {
+ .reg_bits = 8,
+ .val_bits = 8,
+ .max_register = MAX14526_STATUS,
+};
+
+static int max14526_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct max14526_data *priv;
+ int ret, dev_id, rev, i;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->client = client;
+ i2c_set_clientdata(client, priv);
+
+ priv->regmap = devm_regmap_init_i2c(client, &max14526_regmap_config);
+ if (IS_ERR(priv->regmap))
+ return dev_err_probe(dev, PTR_ERR(priv->regmap), "cannot allocate regmap\n");
+
+ for (i = 0; i < MAX14526_N_REGMAP_FIELDS; i++) {
+ priv->rfield[i] = devm_regmap_field_alloc(dev, priv->regmap,
+ max14526_reg_field[i]);
+ if (IS_ERR(priv->rfield[i]))
+ return dev_err_probe(dev, PTR_ERR(priv->rfield[i]),
+ "cannot allocate regmap field\n");
+ }
+
+ /* Detect if MUIC version is supported */
+ ret = regmap_field_read(priv->rfield[VENDOR_ID], &dev_id);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to read MUIC ID\n");
+
+ regmap_field_read(priv->rfield[CHIP_REV], &rev);
+
+ if (dev_id == MAX14526_ID)
+ dev_info(dev, "detected MAX14526 MUIC with id 0x%x, rev 0x%x\n", dev_id, rev);
+ else
+ dev_err_probe(dev, -EINVAL, "MUIC vendor id 0x%X is not recognized\n", dev_id);
+
+ priv->edev = devm_extcon_dev_allocate(dev, max14526_extcon_cable);
+ if (IS_ERR(priv->edev))
+ return dev_err_probe(dev, (IS_ERR(priv->edev)),
+ "failed to allocate extcon device\n");
+
+ ret = devm_extcon_dev_register(dev, priv->edev);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "failed to register extcon device\n");
+
+ ret = max14526_ap_usb_mode(priv);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "failed to set AP USB mode\n");
+
+ regmap_write_bits(priv->regmap, MAX14526_CONTROL_2, INT_EN, INT_EN);
+ regmap_write_bits(priv->regmap, MAX14526_CONTROL_2, USB_DET_DIS, ~USB_DET_DIS);
+
+ ret = devm_request_threaded_irq(dev, client->irq, NULL, &max14526_interrupt,
+ IRQF_ONESHOT | IRQF_SHARED, client->name, priv);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to register IRQ\n");
+
+ irq_wake_thread(client->irq, priv);
+
+ return 0;
+}
+
+static int max14526_resume(struct device *dev)
+{
+ struct i2c_client *client = to_i2c_client(dev);
+ struct max14526_data *priv = i2c_get_clientdata(client);
+
+ irq_wake_thread(client->irq, priv);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(max14526_pm_ops, NULL, max14526_resume);
+
+static const struct of_device_id max14526_match[] = {
+ { .compatible = "maxim,max14526-muic" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, max14526_match);
+
+static const struct i2c_device_id max14526_id[] = {
+ { "max14526_muic" },
+ { }
+};
+MODULE_DEVICE_TABLE(i2c, max14526_id);
+
+static struct i2c_driver max14526_driver = {
+ .driver = {
+ .name = "max14526-muic",
+ .of_match_table = max14526_match,
+ .pm = &max14526_pm_ops,
+ },
+ .probe = max14526_probe,
+ .id_table = max14526_id,
+};
+module_i2c_driver(max14526_driver);
+
+MODULE_AUTHOR("Svyatoslav Ryhel <clamor95@xxxxxxxxx>");
+MODULE_DESCRIPTION("MAX14526 extcon driver to support MUIC");
+MODULE_LICENSE("GPL");
--
2.43.0