Re: [PATCH v3 2/6] extcon: Add the support for extcon property according to extcon type

From: Chanwoo Choi
Date: Tue Aug 02 2016 - 04:09:13 EST


Hi,

On 2016ë 08ì 02ì 16:43, Roger Quadros wrote:
> +Felipe
>
> Hi,
>
> On 02/08/16 04:58, Chanwoo Choi wrote:
>> This patch support the extcon property for the external connector
>> because each external connector might have the property according to
>> the H/W design and the specific characteristics.
>>
>> - EXTCON_PROP_USB_[property name]
>> - EXTCON_PROP_CHG_[property name]
>> - EXTCON_PROP_JACK_[property name]
>> - EXTCON_PROP_DISP_[property name]
>>
>> Add the new extcon APIs to get/set the property value as following:
>> - int extcon_get_property(struct extcon_dev *edev, unsigned int id,
>> unsigned int prop,
>> union extcon_property_value *prop_val)
>> - int extcon_set_property(struct extcon_dev *edev, unsigned int id,
>> unsigned int prop,
>> union extcon_property_value prop_val)
>>
>> Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
>> Tested-by: Chris Zhong <zyw@xxxxxxxxxxxxxx>
>> Tested-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
>> Reviewed-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
>> ---
>> drivers/extcon/extcon.c | 201 +++++++++++++++++++++++++++++++++++++++++++++++-
>> include/linux/extcon.h | 86 +++++++++++++++++++++
>> 2 files changed, 286 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/extcon/extcon.c b/drivers/extcon/extcon.c
>> index 129afc87313e..bb6e99fe84c8 100644
>> --- a/drivers/extcon/extcon.c
>> +++ b/drivers/extcon/extcon.c
>> @@ -196,6 +196,11 @@ struct extcon_cable {
>> struct device_attribute attr_state;
>>
>> struct attribute *attrs[3]; /* to be fed to attr_g.attrs */
>> +
>> + union extcon_property_value usb_propval[EXTCON_PROP_USB_CNT];
>> + union extcon_property_value chg_propval[EXTCON_PROP_CHG_CNT];
>> + union extcon_property_value jack_propval[EXTCON_PROP_JACK_CNT];
>> + union extcon_property_value disp_propval[EXTCON_PROP_DISP_CNT];
>> };
>>
>> static struct class *extcon_class;
>> @@ -248,6 +253,27 @@ static int find_cable_index_by_id(struct extcon_dev *edev, const unsigned int id
>> return -EINVAL;
>> }
>>
>> +static int get_extcon_type(unsigned int prop)
>> +{
>> + switch (prop) {
>> + case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
>> + return EXTCON_TYPE_USB;
>> + case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
>> + return EXTCON_TYPE_CHG;
>> + case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
>> + return EXTCON_TYPE_JACK;
>> + case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
>> + return EXTCON_TYPE_DISP;
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
>> +static bool is_extcon_attached(struct extcon_dev *edev, unsigned int index)
>> +{
>> + return !!(edev->state & BIT(index));
>> +}
>> +
>> static bool is_extcon_changed(u32 prev, u32 new, int idx, bool *attached)
>> {
>> if (((prev >> idx) & 0x1) != ((new >> idx) & 0x1)) {
>> @@ -258,6 +284,34 @@ static bool is_extcon_changed(u32 prev, u32 new, int idx, bool *attached)
>> return false;
>> }
>>
>> +static bool is_extcon_property_supported(unsigned int id, unsigned int prop)
>> +{
>> + int type;
>> +
>> + /* Check whether the property is supported or not. */
>> + type = get_extcon_type(prop);
>> + if (type < 0)
>> + return false;
>> +
>> + /* Check whether a specific extcon id supports the property or not. */
>> + return !!(extcon_info[id].type & type);
>> +}
>> +
>> +static void init_property(struct extcon_dev *edev, unsigned int id, int index)
>> +{
>> + unsigned int type = extcon_info[id].type;
>> + struct extcon_cable *cable = &edev->cables[index];
>> +
>> + if (EXTCON_TYPE_USB & type)
>> + memset(cable->usb_propval, 0, sizeof(cable->usb_propval));
>> + if (EXTCON_TYPE_CHG & type)
>> + memset(cable->chg_propval, 0, sizeof(cable->chg_propval));
>> + if (EXTCON_TYPE_JACK & type)
>> + memset(cable->jack_propval, 0, sizeof(cable->jack_propval));
>> + if (EXTCON_TYPE_DISP & type)
>> + memset(cable->disp_propval, 0, sizeof(cable->disp_propval));
>> +}
>> +
>> static ssize_t state_show(struct device *dev, struct device_attribute *attr,
>> char *buf)
>> {
>> @@ -421,7 +475,7 @@ int extcon_get_cable_state_(struct extcon_dev *edev, const unsigned int id)
>> if (edev->max_supported && edev->max_supported <= index)
>> return -EINVAL;
>>
>> - return !!(edev->state & (1 << index));
>> + return is_extcon_attached(edev, index);
>> }
>> EXPORT_SYMBOL_GPL(extcon_get_cable_state_);
>>
>> @@ -449,12 +503,157 @@ int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
>> if (edev->max_supported && edev->max_supported <= index)
>> return -EINVAL;
>>
>> + /*
>> + * Initialize the value of extcon property before setting
>> + * the detached state for an external connector.
>> + */
>> + if (!cable_state)
>> + init_property(edev, id, index);
>> +
>
> I'm a bit concerned about this for USB case. See below why.
>
>> state = cable_state ? (1 << index) : 0;
>> return extcon_update_state(edev, 1 << index, state);
>> }
>> EXPORT_SYMBOL_GPL(extcon_set_cable_state_);
>>
>> /**
>> + * extcon_get_property() - Get the property value of a specific cable.
>> + * @edev: the extcon device that has the cable.
>> + * @id: the unique id of each external connector
>> + * in extcon enumeration.
>> + * @prop: the property id among enum extcon_property.
>> + * @prop_val: the pointer which store the value of property.
>> + *
>> + * When getting the property value of external connector, the external connector
>> + * should be attached. If detached state, function just return 0 without
>> + * property value. Also, the each property should be included in the list of
>> + * supported properties according to the type of external connectors.
>> + *
>> + * Returns 0 if success or error number if fail
>> + */
>> +int extcon_get_property(struct extcon_dev *edev, unsigned int id,
>> + unsigned int prop,
>> + union extcon_property_value *prop_val)
>> +{
>> + struct extcon_cable *cable;
>> + unsigned long flags;
>> + int index, ret = 0;
>> +
>> + *prop_val = (union extcon_property_value)(0);
>> +
>> + if (!edev)
>> + return -EINVAL;
>> +
>> + /* Check whether the property is supported or not */
>> + if (!is_extcon_property_supported(id, prop))
>> + return -EINVAL;
>> +
>> + /* Find the cable index of external connector by using id */
>> + index = find_cable_index_by_id(edev, id);
>> + if (index < 0)
>> + return index;
>> +
>> + spin_lock_irqsave(&edev->lock, flags);
>> +
>> + /*
>> + * Check whether the external connector is attached.
>> + * If external connector is detached, the user can not
>> + * get the property value.
>> + */
>
> How will this work for USB case? We need to know VBUS and ID states
> even if the USB cable is detached.

When USB is detached, extcon_get_property return the default value without any operation.
The default value of supported property are 0 (zero). If new property need the differnt default
value, I'll support it.

>
> Moreover there is no specific mechanism to detect if the USB cable is attached
> or not in the extcon-usb-gpio.c case.
> One solution could be to set EXTCON_USB as always attached on probe in extcon-usb-gpio.c.
>
> Is this acceptable?

No. the extcon have to detect the correct state. When USB cable is detached,
the extcon cannot set the attached state for EXTCON_USB.

>
>> + if (!is_extcon_attached(edev, index)) {
>> + spin_unlock_irqrestore(&edev->lock, flags);
>> + return 0;
>> + }
>> +
>> + cable = &edev->cables[index];
>> +
>> + /* Get the property value according to extcon type */
>> + switch (prop) {
>> + case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
>> + *prop_val = cable->usb_propval[prop - EXTCON_PROP_USB_MIN];
>> + break;
>> + case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
>> + *prop_val = cable->chg_propval[prop - EXTCON_PROP_CHG_MIN];
>> + break;
>> + case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
>> + *prop_val = cable->jack_propval[prop - EXTCON_PROP_JACK_MIN];
>> + break;
>> + case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
>> + *prop_val = cable->disp_propval[prop - EXTCON_PROP_DISP_MIN];
>> + break;
>
> All these should be simplified to
> *prop_val = cable->foo_propval[prop];
> see below why.

You mean that the macro?
I already used the macro. But, as comment, I don't use it.

>
>> + default:
>> + ret = -EINVAL;
>> + break;
>> + }
>> +
>> + spin_unlock_irqrestore(&edev->lock, flags);
>> +
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(extcon_get_property);
>> +
>> +/**
>> + * extcon_set_property() - Set the property value of a specific cable.
>> + * @edev: the extcon device that has the cable.
>> + * @id: the unique id of each external connector
>> + * in extcon enumeration.
>> + * @prop: the property id among enum extcon_property.
>> + * @prop_val: the pointer including the new value of property.
>> + *
>> + * The each property should be included in the list of supported properties
>> + * according to the type of external connectors.
>> + *
>> + * Returns 0 if success or error number if fail
>> + */
>> +int extcon_set_property(struct extcon_dev *edev, unsigned int id,
>> + unsigned int prop,
>> + union extcon_property_value prop_val)
>> +{
>> + struct extcon_cable *cable;
>> + unsigned long flags;
>> + int index, ret = 0;
>> +
>> + if (!edev)
>> + return -EINVAL;
>> +
>> + /* Check whether the property is supported or not */
>> + if (!is_extcon_property_supported(id, prop))
>> + return -EINVAL;
>> +
>> + /* Find the cable index of external connector by using id */
>> + index = find_cable_index_by_id(edev, id);
>> + if (index < 0)
>> + return index;
>> +
>> + spin_lock_irqsave(&edev->lock, flags);
>> +
>> + cable = &edev->cables[index];
>> +
>> + /* Set the property value according to extcon type */
>> + switch (prop) {
>> + case EXTCON_PROP_USB_MIN ... EXTCON_PROP_USB_MAX:
>> + cable->usb_propval[prop - EXTCON_PROP_USB_MIN] = prop_val;
>> + break;
>> + case EXTCON_PROP_CHG_MIN ... EXTCON_PROP_CHG_MAX:
>> + cable->chg_propval[prop - EXTCON_PROP_CHG_MIN] = prop_val;
>> + break;
>> + case EXTCON_PROP_JACK_MIN ... EXTCON_PROP_JACK_MAX:
>> + cable->jack_propval[prop - EXTCON_PROP_JACK_MIN] = prop_val;
>> + break;
>> + case EXTCON_PROP_DISP_MIN ... EXTCON_PROP_DISP_MAX:
>> + cable->disp_propval[prop - EXTCON_PROP_DISP_MIN] = prop_val;
>> + break;
>
> All these should be simplified to
> *prop_val = cable->foo_propval[prop];
> see below why.

ditto.

>
>> + default:
>> + ret = -EINVAL;
>> + break;
>> + }
>> +
>> + spin_unlock_irqrestore(&edev->lock, flags);
>> +
>> + return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(extcon_set_property);
>> +
>> +/**
>> * extcon_get_extcon_dev() - Get the extcon device instance from the name
>> * @extcon_name: The extcon name provided with extcon_dev_register()
>> */
>> diff --git a/include/linux/extcon.h b/include/linux/extcon.h
>> index 46d802892c82..fe583fca7732 100644
>> --- a/include/linux/extcon.h
>> +++ b/include/linux/extcon.h
>> @@ -77,6 +77,68 @@
>>
>> #define EXTCON_NUM 63
>>
>> +/*
>> + * Define the property of supported external connectors.
>> + *
>> + * When adding the new extcon property, they *must* have
>> + * the type/value/default information. Also, you *have to*
>> + * modify the EXTCON_PROP_[type]_START/END definitions
>> + * which mean the range of the supported properties
>> + * for each extcon type.
>> + *
>> + * The naming style of property
>> + * : EXTCON_PROP_[type]_[property name]
>> + *
>> + * EXTCON_PROP_USB_[property name] : USB property
>> + * EXTCON_PROP_CHG_[property name] : Charger property
>> + * EXTCON_PROP_JACK_[property name] : Jack property
>> + * EXTCON_PROP_DISP_[property name] : Display property
>> + */
>> +
>> +/*
>> + * Properties of EXTCON_TYPE_USB.
>> + *
>> + * - EXTCON_PROP_USB_ID
>> + * @type: integer (intval)
>> + * @value: 0 (low) or 1 (high)
>> + * @default: 0 (low)
>> + * - EXTCON_PROP_USB_VBUS
>> + * @type: integer (intval)
>> + * @value: 0 (low) or 1 (high)
>> + * @default: 0 (low)
>> + */
>> +#define EXTCON_PROP_USB_ID 0
>> +#define EXTCON_PROP_USB_VBUS 1
>> +
>> +#define EXTCON_PROP_USB_MIN 0
>> +#define EXTCON_PROP_USB_MAX 1
>> +#define EXTCON_PROP_USB_CNT (EXTCON_PROP_USB_MAX - EXTCON_PROP_USB_MIN + 1)
>
> As the properties themselves are separated by the cable type
> they can overlap.
>
> So MIN is not needed as it is always 0

Yes. Just adding the EXTCON_PROP_USB_MIN because remaining the
consistent expression for other types (EXTCON_PROP_[type]_MIN).

>
> #define EXTCON_PROP_USB_ID 0
> #define EXTCON_PROP_USB_VBUS 1
> #define EXTCON_PROP_USB_MAX 1
>
> #define EXTCON_PROP_CHG_MAX 1
> #define EXTCON_PROP_CHG_CNT (EXTCON_PROP_CHG_MAX + 1)
>
> and so on.
>
>> +
>> +/* Properties of EXTCON_TYPE_CHG. */
>> +#define EXTCON_PROP_CHG_MIN 50
>> +#define EXTCON_PROP_CHG_MAX 50
>> +#define EXTCON_PROP_CHG_CNT (EXTCON_PROP_CHG_MAX - EXTCON_PROP_CHG_MIN + 1)
>> +
>> +/* Properties of EXTCON_TYPE_JACK. */
>> +#define EXTCON_PROP_JACK_MIN 100
>> +#define EXTCON_PROP_JACK_MAX 100
>> +#define EXTCON_PROP_JACK_CNT (EXTCON_PROP_JACK_MAX - EXTCON_PROP_JACK_MIN + 1)
>> +
>> +/* Properties of EXTCON_TYPE_DISP. */
>> +#define EXTCON_PROP_DISP_MIN 150
>> +#define EXTCON_PROP_DISP_MAX 150
>> +#define EXTCON_PROP_DISP_CNT (EXTCON_PROP_DISP_MAX - EXTCON_PROP_DISP_MIN + 1)
>> +
>> +/*
>> + * Define the type of property's value.
>> + *
>> + * Define the property's value as union type. Because each property
>> + * would need the different data type to store it.
>> + */
>> +union extcon_property_value {
>> + int intval; /* type : integer (intval) */
>> +};
>> +
>
> Why is this a union? There is only one member.

No. The extcon support the various type of external connector.
This patch don't support the only USB type.

>
>> struct extcon_cable;
>>
>> /**
>> @@ -167,6 +229,17 @@ extern int extcon_set_cable_state_(struct extcon_dev *edev, unsigned int id,
>> bool cable_state);
>>
>> /*
>> + * get/set_property access the property value of each external connector.
>> + * They are used to access the property of each cable based on the property id.
>> + */
>> +extern int extcon_get_property(struct extcon_dev *edev, unsigned int id,
>> + unsigned int prop,
>> + union extcon_property_value *prop_val);
>> +extern int extcon_set_property(struct extcon_dev *edev, unsigned int id,
>> + unsigned int prop,
>> + union extcon_property_value prop_val);
>> +
>> +/*
>> * Following APIs are to monitor every action of a notifier.
>> * Registrar gets notified for every external port of a connection device.
>> * Probably this could be used to debug an action of notifier; however,
>> @@ -239,6 +312,19 @@ static inline int extcon_set_cable_state_(struct extcon_dev *edev,
>> return 0;
>> }
>>
>> +static inline int extcon_get_property(struct extcon_dev *edev, unsigned int id,
>> + unsigned int prop,
>> + union extcon_property_value *prop_val)
>> +{
>> + return 0;
>> +}
>> +static inline int extcon_set_property(struct extcon_dev *edev, unsigned int id,
>> + unsigned int prop,
>> + union extcon_property_value prop_val)
>> +{
>> + return 0;
>> +}
>> +
>> static inline struct extcon_dev *extcon_get_extcon_dev(const char *extcon_name)
>> {
>> return NULL;
>>
>

Thanks,
Chanwoo Choi