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Message-ID: <20201015134017.GB239257@xaphan>
Date: Thu, 15 Oct 2020 08:40:17 -0500
From: Michael Auchter <michael.auchter@...com>
To: Chanwoo Choi <cw00.choi@...sung.com>
Cc: MyungJoo Ham <myungjoo.ham@...sung.com>,
linux-kernel@...r.kernel.org
Subject: Re: Re: [PATCH v2 1/2] extcon: add driver for TI TUSB320
On Wed, Oct 14, 2020 at 12:51:26PM +0900, Chanwoo Choi wrote:
> Hi,
>
> Looks good to me. I add some comment. Please check them.
Thanks for the prompt review! I'll address these and send out a v3.
Cheers,
Michael
> On 10/12/20 11:47 PM, 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>
> > ---
> > Changes since v1:
> > - Drop license text that's redundant with SPDX tag
> > - Cleanup, sort list of includes
> > - Add additional register defines
> > - Switch to use regmap API
> > - Fix Kconfig to depend on I2C, not GPIOLIB
> >
> > drivers/extcon/Kconfig | 8 ++
> > drivers/extcon/Makefile | 1 +
> > drivers/extcon/extcon-usbc-tusb320.c | 191 +++++++++++++++++++++++++++
> > 3 files changed, 200 insertions(+)
> > create mode 100644 drivers/extcon/extcon-usbc-tusb320.c
> >
> > diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
> > index aac507bff135..af58ebca2bf6 100644
> > --- a/drivers/extcon/Kconfig
> > +++ b/drivers/extcon/Kconfig
> > @@ -186,4 +186,12 @@ 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 I2C
> > + select REGMAP_I2C
> > + 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..93f1843ca89b
> > --- /dev/null
> > +++ b/drivers/extcon/extcon-usbc-tusb320.c
> > @@ -0,0 +1,191 @@
> > +// 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>
> > + */
> > +
> > +#include <linux/extcon-provider.h>
> > +#include <linux/i2c.h>
> > +#include <linux/init.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
>
> irq.h doesn't be needed. Better to remove irq.h.
>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/regmap.h>
> > +
> > +#define TUSB320_REG9 0x9
> > +#define TUSB320_REG9_ATTACHED_STATE_SHIFT 6
> > +#define TUSB320_REG9_ATTACHED_STATE_MASK 0x3
> > +#define TUSB320_REG9_CABLE_DIRECTION BIT(5)
> > +#define TUSB320_REG9_INTERRUPT_STATUS BIT(4)
> > +#define TUSB320_ATTACHED_STATE_NONE 0x0
> > +#define TUSB320_ATTACHED_STATE_DFP 0x1
> > +#define TUSB320_ATTACHED_STATE_UFP 0x2
> > +#define TUSB320_ATTACHED_STATE_ACC 0x3
>
> Above definition contain the 'space' for indentation.
> Please edit it as following:
>
>
> -#define TUSB320_ATTACHED_STATE_DFP 0x1
> -#define TUSB320_ATTACHED_STATE_UFP 0x2
> -#define TUSB320_ATTACHED_STATE_ACC 0x3
> +#define TUSB320_ATTACHED_STATE_DFP 0x1
> +#define TUSB320_ATTACHED_STATE_UFP 0x2
> +#define TUSB320_ATTACHED_STATE_ACC 0x3
>
>
> > +
> > +struct tusb320_priv {
> > + struct device *dev;
> > + struct regmap *regmap;
> > + struct extcon_dev *edev;
> > +};
> > +
> > +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 tusb320_priv *priv)
> > +{
> > + static const char sig[] = { '\0', 'T', 'U', 'S', 'B', '3', '2', '0' };
> > + unsigned val;
> > + int i, ret;
> > +
> > + for (i = 0; i < sizeof(sig); i++) {
> > + ret = regmap_read(priv->regmap, sizeof(sig) - 1 - i, &val);
> > + if (ret < 0)
> > + return ret;
> > + if (val != sig[i]) {
> > + dev_err(priv->dev, "signature mismatch!\n");
> > + return -ENODEV;
> > + }
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +static irqreturn_t tusb320_irq_handler(int irq, void *dev_id)
> > +{
> > + struct tusb320_priv *priv = dev_id;
> > + int state, polarity;
> > + unsigned reg;
> > +
> > + if (regmap_read(priv->regmap, TUSB320_REG9, ®)) {
> > + dev_err(priv->dev, "error during i2c read!\n");
> > + return IRQ_NONE;
> > + }
> > +
> > + if (!(reg & TUSB320_REG9_INTERRUPT_STATUS))
> > + return IRQ_NONE;
> > +
> > + state = (reg >> TUSB320_REG9_ATTACHED_STATE_SHIFT) &
> > + TUSB320_REG9_ATTACHED_STATE_MASK;
> > + polarity = !!(reg & TUSB320_REG9_CABLE_DIRECTION);
> > +
> > + dev_dbg(priv->dev, "attached state: %s, polarity: %d\n",
> > + tusb_attached_states[state], polarity);
> > +
> > + extcon_set_state(priv->edev, EXTCON_USB,
> > + state == TUSB320_ATTACHED_STATE_UFP);
> > + extcon_set_state(priv->edev, EXTCON_USB_HOST,
> > + state == TUSB320_ATTACHED_STATE_DFP);
> > + extcon_set_property(priv->edev, EXTCON_USB,
> > + EXTCON_PROP_USB_TYPEC_POLARITY,
> > + (union extcon_property_value)polarity);
> > + extcon_set_property(priv->edev, EXTCON_USB_HOST,
> > + EXTCON_PROP_USB_TYPEC_POLARITY,
> > + (union extcon_property_value)polarity);
> > + extcon_sync(priv->edev, EXTCON_USB);
> > + extcon_sync(priv->edev, EXTCON_USB_HOST);
> > +
> > + regmap_write(priv->regmap, TUSB320_REG9, reg);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > +static const struct regmap_config tusb320_regmap_config = {
> > + .reg_bits = 8,
> > + .val_bits = 8,
> > +};
> > +
> > +static int tusb320_extcon_probe(struct i2c_client *client,
> > + const struct i2c_device_id *id)
> > +{
> > + struct tusb320_priv *priv;
> > + int ret;
> > +
> > + priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > + priv->dev = &client->dev;
> > +
> > + priv->regmap = devm_regmap_init_i2c(client, &tusb320_regmap_config);
> > + if (IS_ERR(priv->regmap))
> > + return PTR_ERR(priv->regmap);
> > +
> > + ret = tusb320_check_signature(priv);
> > + if (ret)
> > + return ret;
> > +
> > + priv->edev = devm_extcon_dev_allocate(priv->dev, tusb320_extcon_cable);
> > + if (IS_ERR(priv->edev)) {
> > + dev_err(priv->dev, "failed to allocate extcon device\n");
> > + return -ENOMEM;
>
> Use 'return PTR_ERR(priv->edev)' instead of '-ENOMEM'.
>
> > + }
> > +
> > + ret = devm_extcon_dev_register(priv->dev, priv->edev);
> > + if (ret < 0) {
> > + dev_err(priv->dev, "failed to register extcon device\n");
> > + return ret;
> > + }
> > +
> > + extcon_set_property_capability(priv->edev, EXTCON_USB,
> > + EXTCON_PROP_USB_TYPEC_POLARITY);
> > + extcon_set_property_capability(priv->edev, EXTCON_USB_HOST,
> > + EXTCON_PROP_USB_TYPEC_POLARITY);
> > +
> > + /* update initial state */
> > + tusb320_irq_handler(client->irq, priv);
> > +
> > + ret = devm_request_threaded_irq(priv->dev, client->irq, NULL,
> > + tusb320_irq_handler,
> > + IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
> > + dev_name(priv->dev), priv);
> > +
> > + 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);
>
> tusb320_i2c_id is not used on this driver.
>
> > +
> > +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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