Subject: Re: [PATCH 06/11] mux: Add Pericom PI3USB30532 Type-C mux driver
To: Hans de Goede <hdegoede@redhat.com>,
        MyungJoo Ham <myungjoo.ham@samsung.com>,
        Chanwoo Choi <cw00.choi@samsung.com>,
        Guenter Roeck <linux@roeck-us.net>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        Darren Hart <dvhart@infradead.org>,
        Andy Shevchenko <andy@infradead.org>,
        Mathias Nyman <mathias.nyman@intel.com>
Cc: platform-driver-x86@vger.kernel.org, devel@driverdev.osuosl.org,
        Kuppuswamy Sathyanarayanan 
        <sathyanarayanan.kuppuswamy@linux.intel.com>,
        Sathyanarayanan Kuppuswamy Natarajan <sathyaosid@gmail.com>,
        linux-kernel@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        linux-usb@vger.kernel.org
References: <20170901214845.7153-1-hdegoede@redhat.com>
 <20170901214845.7153-7-hdegoede@redhat.com>
From: Peter Rosin <peda@axentia.se>
Organization: Axentia Technologies AB
Message-ID: <600628b1-5555-1b96-743f-0593af5a6069@axentia.se>
Date: Mon, 4 Sep 2017 13:19:48 +0200
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Hi!

One comment inline...

On 2017-09-01 23:48, Hans de Goede wrote:
> Add a driver for the Pericom PI3USB30532 Type-C cross switch /
> mux chip found on some devices with a Type-C port.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/mux/Kconfig       | 10 +++++
>  drivers/mux/Makefile      |  2 +
>  drivers/mux/pi3usb30532.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 109 insertions(+)
>  create mode 100644 drivers/mux/pi3usb30532.c
> 
> diff --git a/drivers/mux/Kconfig b/drivers/mux/Kconfig
> index 17938918bf93..19a3065c34e6 100644
> --- a/drivers/mux/Kconfig
> +++ b/drivers/mux/Kconfig
> @@ -58,4 +58,14 @@ config MUX_MMIO
>  	  To compile the driver as a module, choose M here: the module will
>  	  be called mux-mmio.
>  
> +config MUX_PI3USB30532
> +	tristate "Pericom PI3USB30532 Type-C cross switch driver"
> +	depends on I2C
> +	help
> +	  This driver adds support for the Pericom PI3USB30532 Type-C cross
> +	  switch / mux chip found on some devices with a Type-C port.
> +
> +	  To compile the driver as a module, choose M here: the module will
> +	  be called mux-pi3usb30532.
> +
>  endmenu
> diff --git a/drivers/mux/Makefile b/drivers/mux/Makefile
> index a12e812c7966..7563dbf04593 100644
> --- a/drivers/mux/Makefile
> +++ b/drivers/mux/Makefile
> @@ -7,9 +7,11 @@ mux-adg792a-objs		:= adg792a.o
>  mux-gpio-objs			:= gpio.o
>  mux-mmio-objs			:= mmio.o
>  mux-intel_cht_usb_mux-objs	:= intel_cht_usb_mux.o
> +mux-pi3usb30532-objs		:= pi3usb30532.o
>  
>  obj-$(CONFIG_MULTIPLEXER)	+= mux-core.o
>  obj-$(CONFIG_MUX_ADG792A)	+= mux-adg792a.o
>  obj-$(CONFIG_MUX_GPIO)		+= mux-gpio.o
>  obj-$(CONFIG_MUX_MMIO)		+= mux-mmio.o
>  obj-$(CONFIG_MUX_CHT_USB_MUX)	+= mux-intel_cht_usb_mux.o
> +obj-$(CONFIG_MUX_PI3USB30532)	+= mux-pi3usb30532.o
> diff --git a/drivers/mux/pi3usb30532.c b/drivers/mux/pi3usb30532.c
> new file mode 100644
> index 000000000000..fa8abd851520
> --- /dev/null
> +++ b/drivers/mux/pi3usb30532.c
> @@ -0,0 +1,97 @@
> +/*
> + * Pericom PI3USB30532 Type-C cross switch / mux driver
> + *
> + * Copyright (c) 2017 Hans de Goede <hdegoede@redhat.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, or (at your option)
> + * any later version.
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/mux/consumer.h> /* For the MUX_USB_* defines */
> +#include <linux/mux/driver.h>
> +
> +#define PI3USB30532_CONF			0x00
> +
> +#define PI3USB30532_CONF_OPEN			0x00
> +#define PI3USB30532_CONF_SWAP			0x01
> +#define PI3USB30532_CONF_4LANE_DP		0x02
> +#define PI3USB30532_CONF_USB3			0x04
> +#define PI3USB30532_CONF_USB3_AND_2LANE_DP	0x06
> +
> +struct pi3usb30532_mux {
> +	struct i2c_client *client;
> +};
> +
> +static int pi3usb30532_mux_set_mux(struct mux_control *mux_ctrl, int state)
> +{
> +	struct pi3usb30532_mux *mux = mux_chip_priv(mux_ctrl->chip);

The "mux" variable name is used for the mux_control in other drivers, and
I don't think the private data is needed. Like so:

static int pi3usb30532_mux_set_mux(struct mux_control *mux, int state)
{
	struct i2c_client *i2c = to_i2c_client(mux->chip->dev.parent);

...

Cheers,
Peter

> +	u8 conf = PI3USB30532_CONF_OPEN;
> +
> +	switch (state & ~MUX_USB_POLARITY_INV) {
> +	case MUX_USB_NONE:
> +		conf = PI3USB30532_CONF_OPEN;
> +		break;
> +	case MUX_USB_DEVICE:
> +	case MUX_USB_HOST:
> +		conf = PI3USB30532_CONF_USB3;
> +		break;
> +	case MUX_USB_HOST_AND_DP_SRC:
> +		conf = PI3USB30532_CONF_USB3_AND_2LANE_DP;
> +		break;
> +	case MUX_USB_DP_SRC:
> +		conf = PI3USB30532_CONF_4LANE_DP;
> +		break;
> +	}
> +
> +	if (state & MUX_USB_POLARITY_INV)
> +		conf |= PI3USB30532_CONF_SWAP;
> +
> +	return i2c_smbus_write_byte_data(mux->client, PI3USB30532_CONF, conf);
> +}
> +
> +static const struct mux_control_ops pi3usb30532_mux_ops = {
> +	.set = pi3usb30532_mux_set_mux,
> +};
> +
> +static int pi3usb30532_mux_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct pi3usb30532_mux *mux;
> +	struct mux_chip *mux_chip;
> +
> +	mux_chip = devm_mux_chip_alloc(dev, 1, sizeof(*mux));
> +	if (IS_ERR(mux_chip))
> +		return PTR_ERR(mux_chip);
> +
> +	mux_chip->ops = &pi3usb30532_mux_ops;
> +	mux_chip->mux[0].states = MUX_USB_STATES;
> +	mux = mux_chip_priv(mux_chip);
> +	mux->client = client;
> +
> +	return devm_mux_chip_register(dev, mux_chip);
> +}
> +
> +static const struct i2c_device_id pi3usb30532_mux_table[] = {
> +	{ "pi3usb30532" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, pi3usb30532_mux_table);
> +
> +static struct i2c_driver pi3usb30532_mux_driver = {
> +	.driver = {
> +		.name = "pi3usb30532",
> +	},
> +	.probe_new = pi3usb30532_mux_probe,
> +	.id_table = pi3usb30532_mux_table,
> +};
> +
> +module_i2c_driver(pi3usb30532_mux_driver);
> +
> +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
> +MODULE_DESCRIPTION("Pericom PI3USB30532 Type-C mux driver");
> +MODULE_LICENSE("GPL");
>