linux-kernel - Re: [PATCH 4/4] usb: typec: tcpci: add support to set connector orientation

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Message-ID: <8cffdf64-d0ee-4e20-8c43-d3010ddf9839@roeck-us.net>
Date: Mon, 5 Feb 2024 09:11:46 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Marco Felsch <m.felsch@...gutronix.de>,
 "Dr. David Alan Gilbert" <linux@...blig.org>
Cc: gregkh@...uxfoundation.org, robh+dt@...nel.org,
 krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
 heikki.krogerus@...ux.intel.com, linux-usb@...r.kernel.org,
 devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
 kernel@...gutronix.de
Subject: Re: [PATCH 4/4] usb: typec: tcpci: add support to set connector
 orientation

On 2/5/24 08:54, Marco Felsch wrote:
> Hi David,
> 
> On 24-02-05, Dr. David Alan Gilbert wrote:
>> * Marco Felsch (m.felsch@...gutronix.de) wrote:
>>> This add the support to set the optional connector orientation bit which
>>> is part of the optional CONFIG_STANDARD_OUTPUT register 0x18 [1]. This
>>> allows system designers to connect the tcpc orientation pin directly to
>>> the 2:1 ss-mux.
>>>
>>> [1] https://www.usb.org/sites/default/files/documents/usb-port_controller_specification_rev2.0_v1.0_0.pdf
>>>
>>> Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
>>> ---
>>>   drivers/usb/typec/tcpm/tcpci.c | 43 ++++++++++++++++++++++++++++++++++
>>>   include/linux/usb/tcpci.h      |  8 +++++++
>>>   2 files changed, 51 insertions(+)
>>>
>>> diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
>>> index 7118551827f6..7ce9d4923bc7 100644
>>> --- a/drivers/usb/typec/tcpm/tcpci.c
>>> +++ b/drivers/usb/typec/tcpm/tcpci.c
>>> @@ -67,6 +67,18 @@ static int tcpci_write16(struct tcpci *tcpci, unsigned int reg, u16 val)
>>>   	return regmap_raw_write(tcpci->regmap, reg, &val, sizeof(u16));
>>>   }
>>>   
>>> +static bool tcpci_check_std_output_cap(struct regmap *regmap, u8 mask)
>>> +{
>>> +	unsigned int reg;
>>> +	int ret;
>>> +
>>> +	ret = regmap_read(regmap, TCPC_STD_OUTPUT_CAP, &reg);
>>> +	if (ret < 0)
>>> +		return ret;
>>> +
>>> +	return (reg & mask) == mask;
>>> +}
>>> +
>>>   static int tcpci_set_cc(struct tcpc_dev *tcpc, enum typec_cc_status cc)
>>>   {
>>>   	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
>>> @@ -301,6 +313,27 @@ static int tcpci_set_polarity(struct tcpc_dev *tcpc,
>>>   			   TCPC_TCPC_CTRL_ORIENTATION : 0);
>>>   }
>>>   
>>> +static int tcpci_set_orientation(struct tcpc_dev *tcpc,
>>> +				 enum typec_orientation orientation)
>>> +{
>>> +	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
>>> +	unsigned int reg;
>>> +
>>> +	switch (orientation) {
>>> +	case TYPEC_ORIENTATION_NONE:
>>> +		/* We can't put a single output into high impedance */
>>
>> Is that intended to be a fallthrough? If so I guess it needs
>> marking as such with a
>>                  fallthrough;
> 
> You need to add it if there is code in between. Since there is no code,
> just this comment, it shouldn't be necessary.
> 

Still, I think it would be desirable here to clarify that this
is not a lost return but intentionally sets
TCPC_CONFIG_STD_OUTPUT_ORIENTATION_NORMAL.

Guenter

> Regards,
>    Marco
> 
>>
>> Dave
>>
>>> +	case TYPEC_ORIENTATION_NORMAL:
>>> +		reg = TCPC_CONFIG_STD_OUTPUT_ORIENTATION_NORMAL;
>>> +		break;
>>> +	case TYPEC_ORIENTATION_REVERSE:
>>> +		reg = TCPC_CONFIG_STD_OUTPUT_ORIENTATION_FLIPPED;
>>> +		break;
>>> +	}
>>> +
>>> +	return regmap_update_bits(tcpci->regmap, TCPC_CONFIG_STD_OUTPUT,
>>> +				  TCPC_CONFIG_STD_OUTPUT_ORIENTATION_MASK, reg);
>>> +}
>>> +
>>>   static void tcpci_set_partner_usb_comm_capable(struct tcpc_dev *tcpc, bool capable)
>>>   {
>>>   	struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
>>> @@ -808,6 +841,9 @@ struct tcpci *tcpci_register_port(struct device *dev, struct tcpci_data *data)
>>>   	if (tcpci->data->vbus_vsafe0v)
>>>   		tcpci->tcpc.is_vbus_vsafe0v = tcpci_is_vbus_vsafe0v;
>>>   
>>> +	if (tcpci->data->set_orientation)
>>> +		tcpci->tcpc.set_orientation = tcpci_set_orientation;
>>> +
>>>   	err = tcpci_parse_config(tcpci);
>>>   	if (err < 0)
>>>   		return ERR_PTR(err);
>>> @@ -851,6 +887,13 @@ static int tcpci_probe(struct i2c_client *client)
>>>   	if (err < 0)
>>>   		return err;
>>>   
>>> +	err = tcpci_check_std_output_cap(chip->data.regmap,
>>> +					 TCPC_STD_OUTPUT_CAP_ORIENTATION);
>>> +	if (err < 0)
>>> +		return err;
>>> +
>>> +	chip->data.set_orientation = err;
>>> +
>>>   	chip->tcpci = tcpci_register_port(&client->dev, &chip->data);
>>>   	if (IS_ERR(chip->tcpci))
>>>   		return PTR_ERR(chip->tcpci);
>>> diff --git a/include/linux/usb/tcpci.h b/include/linux/usb/tcpci.h
>>> index 467e8045e9f8..f2bfb4250366 100644
>>> --- a/include/linux/usb/tcpci.h
>>> +++ b/include/linux/usb/tcpci.h
>>> @@ -47,6 +47,9 @@
>>>   #define TCPC_SINK_FAST_ROLE_SWAP	BIT(0)
>>>   
>>>   #define TCPC_CONFIG_STD_OUTPUT		0x18
>>> +#define TCPC_CONFIG_STD_OUTPUT_ORIENTATION_MASK		BIT(0)
>>> +#define TCPC_CONFIG_STD_OUTPUT_ORIENTATION_NORMAL	0
>>> +#define TCPC_CONFIG_STD_OUTPUT_ORIENTATION_FLIPPED	1
>>>   
>>>   #define TCPC_TCPC_CTRL			0x19
>>>   #define TCPC_TCPC_CTRL_ORIENTATION	BIT(0)
>>> @@ -127,6 +130,7 @@
>>>   #define TCPC_DEV_CAP_2			0x26
>>>   #define TCPC_STD_INPUT_CAP		0x28
>>>   #define TCPC_STD_OUTPUT_CAP		0x29
>>> +#define TCPC_STD_OUTPUT_CAP_ORIENTATION	BIT(0)
>>>   
>>>   #define TCPC_MSG_HDR_INFO		0x2e
>>>   #define TCPC_MSG_HDR_INFO_DATA_ROLE	BIT(3)
>>> @@ -198,12 +202,16 @@ struct tcpci;
>>>    *		Chip level drivers are expected to check for contaminant and call
>>>    *		tcpm_clean_port when the port is clean to put the port back into
>>>    *		toggling state.
>>> + * @set_orientation:
>>> + *		Optional; Enable setting the connector orientation
>>> + *		CONFIG_STANDARD_OUTPUT (0x18) bit0.
>>>    */
>>>   struct tcpci_data {
>>>   	struct regmap *regmap;
>>>   	unsigned char TX_BUF_BYTE_x_hidden:1;
>>>   	unsigned char auto_discharge_disconnect:1;
>>>   	unsigned char vbus_vsafe0v:1;
>>> +	unsigned char set_orientation:1;
>>>   
>>>   	int (*init)(struct tcpci *tcpci, struct tcpci_data *data);
>>>   	int (*set_vconn)(struct tcpci *tcpci, struct tcpci_data *data,
>>> -- 
>>> 2.39.2
>>>
>>>
>> -- 
>>   -----Open up your eyes, open up your mind, open up your code -------
>> / Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \
>> \        dave @ treblig.org |                               | In Hex /
>>   \ _________________________|_____ http://www.treblig.org   |_______/
>>