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Subject[PATCH 2/4] usb: typec: ucsi: stm32g0: add support for stm32g0 i2c controller
Date
STM32G0 provides an integrated USB Type-C and power delivery interface.
It can be programmed with a firmware to handle UCSI protocol over I2C
interface. A GPIO is used as an interrupt line.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
---
drivers/usb/typec/ucsi/Kconfig | 10 ++
drivers/usb/typec/ucsi/Makefile | 1 +
drivers/usb/typec/ucsi/ucsi_stm32g0.c | 218 ++++++++++++++++++++++++++
3 files changed, 229 insertions(+)
create mode 100644 drivers/usb/typec/ucsi/ucsi_stm32g0.c

diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
index 5e9b37b3f25e1..8f9c4b9f31f79 100644
--- a/drivers/usb/typec/ucsi/Kconfig
+++ b/drivers/usb/typec/ucsi/Kconfig
@@ -48,4 +48,14 @@ config UCSI_ACPI
To compile the driver as a module, choose M here: the module will be
called ucsi_acpi

+config UCSI_STM32G0
+ tristate "UCSI Interface Driver for STM32G0"
+ depends on I2C
+ help
+ This driver enables UCSI support on platforms that expose a STM32G0
+ Type-C controller over I2C interface.
+
+ To compile the driver as a module, choose M here: the module will be
+ called ucsi_stm32g0.
+
endif
diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
index 8a8eb5cb8e0f0..480d533d762fe 100644
--- a/drivers/usb/typec/ucsi/Makefile
+++ b/drivers/usb/typec/ucsi/Makefile
@@ -17,3 +17,4 @@ endif

obj-$(CONFIG_UCSI_ACPI) += ucsi_acpi.o
obj-$(CONFIG_UCSI_CCG) += ucsi_ccg.o
+obj-$(CONFIG_UCSI_STM32G0) += ucsi_stm32g0.o
diff --git a/drivers/usb/typec/ucsi/ucsi_stm32g0.c b/drivers/usb/typec/ucsi/ucsi_stm32g0.c
new file mode 100644
index 0000000000000..d1f22cee8c6c9
--- /dev/null
+++ b/drivers/usb/typec/ucsi/ucsi_stm32g0.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * UCSI driver for STMicroelectronics STM32G0 Type-C controller
+ *
+ * Copyright (C) 2022, STMicroelectronics - All Rights Reserved
+ * Author: Fabrice Gasnier <fabrice.gasnier@foss.st.com>.
+ */
+
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+#include "ucsi.h"
+
+struct ucsi_stm32g0 {
+ struct i2c_client *client;
+ struct completion complete;
+ struct device *dev;
+ unsigned long flags;
+ struct ucsi *ucsi;
+};
+
+static int ucsi_stm32g0_read(struct ucsi *ucsi, unsigned int offset, void *val, size_t len)
+{
+ struct ucsi_stm32g0 *g0 = ucsi_get_drvdata(ucsi);
+ struct i2c_client *client = g0->client;
+ u8 reg = offset;
+ struct i2c_msg msg[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ .len = 1,
+ .buf = &reg,
+ },
+ {
+ .addr = client->addr,
+ .flags = I2C_M_RD,
+ .len = len,
+ .buf = val,
+ },
+ };
+ int ret;
+
+ ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+ if (ret != ARRAY_SIZE(msg)) {
+ dev_err(g0->dev, "i2c read %02x, %02x error: %d\n", client->addr, reg, ret);
+
+ return ret < 0 ? ret : -EIO;
+ }
+
+ return 0;
+}
+
+static int ucsi_stm32g0_async_write(struct ucsi *ucsi, unsigned int offset, const void *val,
+ size_t len)
+{
+ struct ucsi_stm32g0 *g0 = ucsi_get_drvdata(ucsi);
+ struct i2c_client *client = g0->client;
+ struct i2c_msg msg[] = {
+ {
+ .addr = client->addr,
+ .flags = 0,
+ }
+ };
+ unsigned char *buf;
+ int ret;
+
+ buf = kzalloc(len + 1, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ buf[0] = offset;
+ memcpy(&buf[1], val, len);
+ msg[0].len = len + 1;
+ msg[0].buf = buf;
+
+ ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+ kfree(buf);
+ if (ret != ARRAY_SIZE(msg)) {
+ dev_err(g0->dev, "i2c write %02x, %02x error: %d\n", client->addr, buf[0], ret);
+
+ return ret < 0 ? ret : -EIO;
+ }
+
+ return 0;
+}
+
+static int ucsi_stm32g0_sync_write(struct ucsi *ucsi, unsigned int offset, const void *val,
+ size_t len)
+{
+ struct ucsi_stm32g0 *g0 = ucsi_get_drvdata(ucsi);
+ int ret;
+
+ set_bit(COMMAND_PENDING, &g0->flags);
+
+ ret = ucsi_stm32g0_async_write(ucsi, offset, val, len);
+ if (ret)
+ goto out_clear_bit;
+
+ if (!wait_for_completion_timeout(&g0->complete, msecs_to_jiffies(5000)))
+ ret = -ETIMEDOUT;
+
+out_clear_bit:
+ clear_bit(COMMAND_PENDING, &g0->flags);
+
+ return ret;
+}
+
+static irqreturn_t ucsi_stm32g0_irq_handler(int irq, void *data)
+{
+ struct ucsi_stm32g0 *g0 = data;
+ u32 cci;
+ int ret;
+
+ ret = ucsi_stm32g0_read(g0->ucsi, UCSI_CCI, &cci, sizeof(cci));
+ if (ret)
+ return IRQ_NONE;
+
+ if (UCSI_CCI_CONNECTOR(cci))
+ ucsi_connector_change(g0->ucsi, UCSI_CCI_CONNECTOR(cci));
+
+ if (test_bit(COMMAND_PENDING, &g0->flags) &&
+ cci & (UCSI_CCI_ACK_COMPLETE | UCSI_CCI_COMMAND_COMPLETE))
+ complete(&g0->complete);
+
+ return IRQ_HANDLED;
+}
+
+static const struct ucsi_operations ucsi_stm32g0_ops = {
+ .read = ucsi_stm32g0_read,
+ .sync_write = ucsi_stm32g0_sync_write,
+ .async_write = ucsi_stm32g0_async_write,
+};
+
+static int ucsi_stm32g0_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+ struct device *dev = &client->dev;
+ struct ucsi_stm32g0 *g0;
+ int ret;
+
+ g0 = devm_kzalloc(dev, sizeof(*g0), GFP_KERNEL);
+ if (!g0)
+ return -ENOMEM;
+
+ g0->dev = dev;
+ g0->client = client;
+ init_completion(&g0->complete);
+ i2c_set_clientdata(client, g0);
+
+ g0->ucsi = ucsi_create(dev, &ucsi_stm32g0_ops);
+ if (IS_ERR(g0->ucsi))
+ return PTR_ERR(g0->ucsi);
+
+ ucsi_set_drvdata(g0->ucsi, g0);
+
+ /* Request alert interrupt */
+ ret = request_threaded_irq(client->irq, NULL, ucsi_stm32g0_irq_handler, IRQF_ONESHOT,
+ dev_name(&client->dev), g0);
+ if (ret) {
+ dev_err_probe(dev, ret, "request IRQ failed\n");
+ goto destroy;
+ }
+
+ ret = ucsi_register(g0->ucsi);
+ if (ret) {
+ dev_err_probe(dev, ret, "ucsi_register failed\n");
+ goto freeirq;
+ }
+
+ return 0;
+
+freeirq:
+ free_irq(client->irq, g0);
+destroy:
+ ucsi_destroy(g0->ucsi);
+
+ return ret;
+}
+
+static int ucsi_stm32g0_remove(struct i2c_client *client)
+{
+ struct ucsi_stm32g0 *g0 = i2c_get_clientdata(client);
+
+ ucsi_unregister(g0->ucsi);
+ free_irq(client->irq, g0);
+ ucsi_destroy(g0->ucsi);
+
+ return 0;
+}
+
+static const struct of_device_id __maybe_unused ucsi_stm32g0_typec_of_match[] = {
+ { .compatible = "st,stm32g0-typec" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, ucsi_stm32g0_typec_of_match);
+
+static const struct i2c_device_id ucsi_stm32g0_typec_i2c_devid[] = {
+ {"stm32g0-typec", 0},
+ {},
+};
+MODULE_DEVICE_TABLE(i2c, ucsi_stm32g0_typec_i2c_devid);
+
+static struct i2c_driver ucsi_stm32g0_i2c_driver = {
+ .driver = {
+ .name = "ucsi-stm32g0-i2c",
+ .of_match_table = of_match_ptr(ucsi_stm32g0_typec_of_match),
+ },
+ .probe = ucsi_stm32g0_probe,
+ .remove = ucsi_stm32g0_remove,
+ .id_table = ucsi_stm32g0_typec_i2c_devid
+};
+module_i2c_driver(ucsi_stm32g0_i2c_driver);
+
+MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@foss.st.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32G0 Type-C controller");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("platform:ucsi-stm32g0");
--
2.25.1
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