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Message-ID: <4acd00c6-8c0f-9478-ac4f-1ba0738fe90a@samsung.com>
Date: Fri, 9 Oct 2020 10:05:27 +0900
From: Chanwoo Choi <cw00.choi@...sung.com>
To: Michael Auchter <michael.auchter@...com>,
MyungJoo Ham <myungjoo.ham@...sung.com>
Cc: linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] extcon: add driver for TI TUSB320
Hi,
Almost looks good to me. I added some comments.
On 10/9/20 7:39 AM, Michael Auchter wrote:
> This patch adds an extcon driver for the TI TUSB320 USB Type-C device.
> This can be used to detect whether the port is configured as a
> downstream or upstream facing port.
>
> Signed-off-by: Michael Auchter <michael.auchter@...com>
> ---
> drivers/extcon/Kconfig | 7 ++
> drivers/extcon/Makefile | 1 +
> drivers/extcon/extcon-usbc-tusb320.c | 180 +++++++++++++++++++++++++++
> 3 files changed, 188 insertions(+)
> create mode 100644 drivers/extcon/extcon-usbc-tusb320.c
>
> diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
> index aac507bff135..241acaf8b882 100644
> --- a/drivers/extcon/Kconfig
> +++ b/drivers/extcon/Kconfig
> @@ -186,4 +186,11 @@ config EXTCON_USBC_CROS_EC
> Say Y here to enable USB Type C cable detection extcon support when
> using Chrome OS EC based USB Type-C ports.
>
> +config EXTCON_USBC_TUSB320
> + tristate "TI TUSB320 USB-C extcon support"
> + depends on GPIOLIB || COMPILE_TEST
> + help
> + Say Y here to enable support for USB Type C cable detection extcon
> + support using a TUSB320.
> +
> endif
> diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
> index 52096fd8a216..fe10a1b7d18b 100644
> --- a/drivers/extcon/Makefile
> +++ b/drivers/extcon/Makefile
> @@ -25,3 +25,4 @@ obj-$(CONFIG_EXTCON_RT8973A) += extcon-rt8973a.o
> obj-$(CONFIG_EXTCON_SM5502) += extcon-sm5502.o
> obj-$(CONFIG_EXTCON_USB_GPIO) += extcon-usb-gpio.o
> obj-$(CONFIG_EXTCON_USBC_CROS_EC) += extcon-usbc-cros-ec.o
> +obj-$(CONFIG_EXTCON_USBC_TUSB320) += extcon-usbc-tusb320.o
> diff --git a/drivers/extcon/extcon-usbc-tusb320.c b/drivers/extcon/extcon-usbc-tusb320.c
> new file mode 100644
> index 000000000000..217d6f416ff6
> --- /dev/null
> +++ b/drivers/extcon/extcon-usbc-tusb320.c
> @@ -0,0 +1,180 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/**
> + * drivers/extcon/extcon-tusb320.c - TUSB320 extcon driver
> + *
> + * Copyright (C) 2020 National Instruments Corporation
> + * Author: Michael Auchter <michael.auchter@...com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
You don't need to additional license info below 'author'
because you added '// SPDX-License-Identifier: GPL-2.0' at the first line.
> + */
> +
> +#include <linux/extcon-provider.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/i2c.h>
> +#include <linux/irq.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/workqueue.h>
> +
> +#define TUSB320_REG_9 0x9
> +#define TUSB320_REG_9_INTERRUPT_STATUS BIT(4)
> +#define TUSB320_REG_9_GET_ATTACHED_STATE(reg) (((reg) >> 6) & 0x3)
You need to define what is meaning of '6' and '0x3'.
#define TUSB30_xxx_SHIFT 6
#define TUSB30_xxx_MASK 0x3
> +#define TUSB320_REG_9_GET_CABLE_DIR(reg) (((reg) >> 5) & 1)
ditto.
#define TUSB30_xxx__SHIFT 5
#define TUSB30_xxx_MASK 0x1
> +#define TUSB320_ATTACHED_STATE_NONE 0x0
> +#define TUSB320_ATTACHED_STATE_DFP 0x1
> +#define TUSB320_ATTACHED_STATE_UFP 0x2
> +#define TUSB320_ATTACHED_STATE_ACC 0x3
> +
nitpick. For the indentation, how about editing as following:
#define TUSB320_REG_9 0x9
#define TUSB320_REG_9_INTERRUPT_STATUS BIT(4)
#define TUSB320_REG_9_GET_ATTACHED_STATE(reg) (((reg) >> 6) & 0x3)
#define TUSB320_REG_9_GET_CABLE_DIR(reg) (((reg) >> 5) & 1)
#define TUSB320_ATTACHED_STATE_NONE 0x0
#define TUSB320_ATTACHED_STATE_DFP 0x1
#define TUSB320_ATTACHED_STATE_UFP 0x2
#define TUSB320_ATTACHED_STATE_ACC 0x3
> +static const char * const tusb_attached_states[] = {
> + [TUSB320_ATTACHED_STATE_NONE] = "not attached",
> + [TUSB320_ATTACHED_STATE_DFP] = "downstream facing port",
> + [TUSB320_ATTACHED_STATE_UFP] = "upstream facing port",
> + [TUSB320_ATTACHED_STATE_ACC] = "accessory",
> +};
> +
> +static const unsigned int tusb320_extcon_cable[] = {
> + EXTCON_USB,
> + EXTCON_USB_HOST,
> + EXTCON_NONE,
> +};
> +
> +static int tusb320_check_signature(struct i2c_client *client)
> +{
> + static const char sig[] = { '\0', 'T', 'U', 'S', 'B', '3', '2', '0' };
> + int i, ret;
> +
> + for (i = 0; i < sizeof(sig); i++) {
> + ret = i2c_smbus_read_byte_data(client, sizeof(sig) - 1 - i);
> + if (ret < 0)
> + return ret;
> + if (ret != sig[i]) {
> + dev_err(&client->dev, "signature mismatch!\n");
> + return -ENODEV;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static irqreturn_t tusb320_irq_handler(int irq, void *dev_id)
> +{
> + struct i2c_client *client = dev_id;
> + struct extcon_dev *edev = i2c_get_clientdata(client);
> + int reg, state, polarity;
> +
> + reg = i2c_smbus_read_byte_data(client, TUSB320_REG_9);
> + if (reg < 0) {
> + dev_err(&client->dev, "error during i2c read: %d\n", reg);
> + return IRQ_NONE;
> + }
> +
> + if (!(reg & TUSB320_REG_9_INTERRUPT_STATUS))
> + return IRQ_NONE;
> +
> + state = TUSB320_REG_9_GET_ATTACHED_STATE(reg);
> + polarity = TUSB320_REG_9_GET_CABLE_DIR(reg);
> +
> + dev_dbg(&client->dev, "attached state: %s, polarity: %d\n",
> + tusb_attached_states[state], polarity);
> +
> + extcon_set_state(edev, EXTCON_USB,
> + state == TUSB320_ATTACHED_STATE_UFP);
> + extcon_set_state(edev, EXTCON_USB_HOST,
> + state == TUSB320_ATTACHED_STATE_DFP);
> + extcon_set_property(edev, EXTCON_USB,
> + EXTCON_PROP_USB_TYPEC_POLARITY,
> + (union extcon_property_value)polarity);
> + extcon_set_property(edev, EXTCON_USB_HOST,
> + EXTCON_PROP_USB_TYPEC_POLARITY,
> + (union extcon_property_value)polarity);
> + extcon_sync(edev, EXTCON_USB);
> + extcon_sync(edev, EXTCON_USB_HOST);
> +
> + i2c_smbus_write_byte_data(client, TUSB320_REG_9, reg);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int tusb320_extcon_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct extcon_dev *edev;
> + int ret;
I recommend that you better to use regmap_i2c with devm_regmap_init_i2c() function
instead of using i2c_smbus_*() function. You can refer regmap_i2c usage
on drivers/extcon/extcon-sm5502.c.
> +
> + ret = tusb320_check_signature(client);
> + if (ret)
> + return ret;
> +
> + edev = devm_extcon_dev_allocate(&client->dev, tusb320_extcon_cable);
> + if (IS_ERR(edev)) {
> + dev_err(&client->dev, "failed to allocate extcon device\n");
> + return -ENOMEM;
> + }
> + i2c_set_clientdata(client, edev);
> +
> + ret = devm_extcon_dev_register(&client->dev, edev);
> + if (ret < 0) {
> + dev_err(&client->dev, "failed to register extcon device\n");
> + return ret;
> + }
> +
> + extcon_set_property_capability(edev, EXTCON_USB,
> + EXTCON_PROP_USB_TYPEC_POLARITY);
> + extcon_set_property_capability(edev, EXTCON_USB_HOST,
> + EXTCON_PROP_USB_TYPEC_POLARITY);
> +
> + /* update initial state */
> + tusb320_irq_handler(client->irq, client);
> +
> + ret = devm_request_threaded_irq(&client->dev, client->irq,
> + NULL, tusb320_irq_handler,
> + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> + dev_name(&client->dev), client);
> +
> + return ret;
> +}
> +
> +static const struct of_device_id tusb320_extcon_dt_match[] = {
> + { .compatible = "ti,tusb320", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, tusb320_extcon_dt_match);
> +
> +static const struct i2c_device_id tusb320_i2c_id[] = {
> + { "tusb320", 0 },
> + { }
> +};
> +MODULE_DEVICE_TABLE(i2c, tusb320_i2c_id);
> +
> +static struct i2c_driver tusb320_extcon_driver = {
> + .probe = tusb320_extcon_probe,
> + .driver = {
> + .name = "extcon-tusb320",
> + .of_match_table = tusb320_extcon_dt_match,
> + },
> +};
> +
> +static int __init tusb320_init(void)
> +{
> + return i2c_add_driver(&tusb320_extcon_driver);
> +}
> +subsys_initcall(tusb320_init);
> +
> +static void __exit tusb320_exit(void)
> +{
> + i2c_del_driver(&tusb320_extcon_driver);
> +}
> +module_exit(tusb320_exit);
> +
> +MODULE_AUTHOR("Michael Auchter <michael.auchter@...com>");
> +MODULE_DESCRIPTION("TI TUSB320 extcon driver");
> +MODULE_LICENSE("GPL v2");
>
--
Best Regards,
Chanwoo Choi
Samsung Electronics
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