On Thu, Jul 04, 2013 at 03:25:32PM +0530, Kishon Vijay Abraham I wrote: > On Thursday 04 July 2013 02:51 PM, Patel, Satish wrote: > >Hi, > > > >>-----Original Message----- > >>From: Balbi, Felipe > >>Sent: Wednesday, July 03, 2013 6:51 PM > >>To: ABRAHAM, KISHON VIJAY > >>Cc: Patel, Satish; grant.lik...@linaro.org; t...@atomide.com; Balbi, > >>Felipe; a...@arndb.de; swar...@nvidia.com; > >>sylvester.nawro...@gmail.com; linux-ker...@vger.kernel.org; linux- > >>o...@vger.kernel.org; linux-arm-ker...@lists.infradead.org; linux- > >>u...@vger.kernel.org; gre...@linuxfoundation.org; akpm@linux- > >>foundation.org; rob.herr...@calxeda.com; r...@landley.net; > >>li...@arm.linux.org.uk; benoit.cous...@linaro.org; mche...@redhat.com; > >>ces...@cesarb.net; da...@davemloft.net; Nayak, Rajendra; > >>shawn....@linaro.org; Shilimkar, Santosh; devicetree- > >>disc...@lists.ozlabs.org; linux-...@vger.kernel.org; Nori, Sekhar; > >>Krishnamoorthy, Balaji T; Cherian, George > >>Subject: Re: [PATCH v9 0/8] Generic PHY Framework > >> > >>Hi, > >> > >>On Wed, Jul 03, 2013 at 03:35:39PM +0530, Kishon Vijay Abraham I > >>wrote: > >>>On Wednesday 03 July 2013 03:02 PM, Patel, Satish wrote: > >>>>Hi Kishon, > >>>> > >>>>>-----Original Message----- > >>>>>From: ABRAHAM, KISHON VIJAY > >>>>>Sent: Wednesday, June 26, 2013 5:17 PM > >>>>>To: grant.lik...@linaro.org; t...@atomide.com; Balbi, Felipe; > >>ABRAHAM, > >>>>>KISHON VIJAY; a...@arndb.de; swar...@nvidia.com; > >>>>>sylvester.nawro...@gmail.com; linux-ker...@vger.kernel.org; linux- > >>>>>o...@vger.kernel.org; linux-arm-ker...@lists.infradead.org; linux- > >>>>>u...@vger.kernel.org; gre...@linuxfoundation.org; akpm@linux- > >>>>>foundation.org > >>>>>Cc: rob.herr...@calxeda.com; r...@landley.net; > >>li...@arm.linux.org.uk; > >>>>>benoit.cous...@linaro.org; mche...@redhat.com; ces...@cesarb.net; > >>>>>da...@davemloft.net; Nayak, Rajendra; shawn....@linaro.org; > >>Shilimkar, > >>>>>Santosh; devicetree-discuss@lists.ozlabs.org; linux- > >>>>>d...@vger.kernel.org; Nori, Sekhar; Krishnamoorthy, Balaji T; > >>Cherian, > >>>>>George > >>>>>Subject: [PATCH v9 0/8] Generic PHY Framework > >>>>> > >>>>>Added a generic PHY framework that provides a set of APIs for the > >>PHY > >>>>>drivers > >>>>>to create/destroy a PHY and APIs for the PHY users to obtain a > >>>>>reference to > >>>>>the PHY with or without using phandle. > >>>>> > >>>>>This framework will be of use only to devices that uses external > >>PHY > >>>>>(PHY > >>>>>functionality is not embedded within the controller). > >>>>> > >>>>>The intention of creating this framework is to bring the phy > >>drivers > >>>>>spread > >>>>>all over the Linux kernel to drivers/phy to increase code re-use > >>and > >>>>>to > >>>>>increase code maintainability. > >>>> > >>>>I would like to use this framework for a smart-card controller > >>connected to a > >>>>smart-card phy. I have some questions and would like to get > >>feedback on the same. > >>> > >>>glad to know that :-) > >>>> > >>>>I am using “TDA8026" Smartcard PHY from NXP. Here is the link for > >>datasheet > >>>>and app note for the same. The smart card controller is inside the > >>TI SoC > >>>>I am working with. > >>>> > >>>>Datasheet : > >>>>www.nxp.com/documents/data_sheet/TDA8026.pdf? > >>>> > >>>>Appnote : > >>>>http://www.nxp.com/documents/application_note/AN10724.pdf > >>>> > >>>>The TI SoC details are not public (yet). I can provide details to > >>you offline. > >>>> > >>>>Brief about operation: > >>>>- The controller can work with and without a PHY > >>>>- When not using PHY, it is limited to talking to a single > >>>> smart card. There is also a need to put external de-activation > >>logic > >>>> on card removal for this case. > >>>>- With a PHY you can use more than one smart card. > >>>>- Phy has 5 slots : 1 for smart card (credit/debit/other card > >>with chip) > >>>> and others for SAM – SIM like modules > >>>>- Once the PHY is initialized, there are some operations that the > >>controller > >>>> can request of the PHY like: > >>>> - Card configurations - set voltage > >>>> - Activation of card > >>>> - ATR – Answer to reset > >>>> - Warm reset > >>>> - ADPU exchange > >>>> - Deactivation ( Normal/Emergency) > >>> > >>>hmm.. We should think about extending the phy_ops to include these > >>>operations (something like phy_smart_card_ops so that other > >>>smart_card PHYs will also be able to use it). > >> > >>let's try to avoid use-case specific additions. set_voltage sounds > >>like > >>a regulator thing, but the regulator is controlled through the PHY. I > >>guess it makes sense to have a generic phy_set_voltage() call since > >>even > >>USB can make use of that. > >> > >>For card activation, it sounds like phy_init()/phy_shutdown() would > >>cover it. > >> > >>For warm reset perhaps a phy_reset() callback ? Although that could, > >>easily, get abused. > >> > >>For deactivation, that's phy_shutdown(). > >> > >>ATR and ADPU needs more thought, I guess. > >> > >>>>- In the mode when smartcard controller talks directly to the > >>card without the need > >>>> for a PHY, all the above operations will be carried out by the > >>controller itself > >>>> > >>>>My current thought process is to make the controller driver provide > >>the user interface > >>>>and talk to the PHY using the generic PHY framework you proposed. > >>In the case where there > >>>>is no PHY, my idea is to create a "dummy" PHY which uses the > >>controller functionality itself. > >>> > >>>right. And in the case where you actually have a PHY, create a PHY > >>>driver and implement the phy_smart_card_ops and register with the > >>PHY > >>>framework. > >> > >>I would try to avoid that. Otherwise we will have phy_usb_ops, > >>phy_sata_ops, phy_network_ops, phy_pci_ops, etc etc etc. It would > >>easily > >>blow up. > >> > > > >- I do agree with you. Creating Phy specific ops will blow up whole > > concept of generic phy f/w. > >- Can we have interface like phy_setconfig - with parameter like > > phy_setconfig(int param, void *value) > > - Here param can be enum of available config parameters for > > specific phy. > >Phy can perform different operation/set internal state based on > >param selection and value passed by. > > > >e.x in case of smartcard > > enum set_config { > > SET_VOLATAGE, > > SET_ACTIVATE, > > SET_WARMRESET, > > SET_ATR, > > SET_DEACTIVE, > > .... > > }; > > hmm.. this looks similar to ioctl and can be abused easily IMO :s
+1 What we need is to come up with generic ways to model those, if we need set voltage, then add a phy_set_voltage() kinda thing, perhaps add capability flags to enable/disable support fort those (just like mmc does). But adding something which can handle "anything" like phy_set_config(), it's the same as adding use-case specific ops. -- balbi
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