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path: root/drivers/nfc/st21nfca
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2014-12-02NFC: st21nfca: Report error returned by functions instead of -ENODEVChristophe Ricard
Report error returned by devm_gpio_request_one or st21nfca_hci_platform_init instead of -ENODEV. Reported-by: Dmitry Torokhov <dtor@chromium.org> Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-12-02NFC: st21nfca: Rework st21nfca_hci_event_received to route event to relevent ↵Christophe Ricard
gate. As many event with the same id can come from several gates, it will be easier to manage each of them by gate. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-12-02NFC: st21nfca: Remove gpio_irq field in static and dts configurationChristophe Ricard
- phy->gpio_irq is never done out of the request resources. - irq_of_parse_and_map is already done in the i2c core so client->irq is already set when entering in st21nfca_hci_i2c_of_request_resources - In case of static platform configuration client->irq can be set directly - It simplifies the code a bit. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-12-02NFC: st21nfca: Add of_st21nfca_i2c_match to MODULE_DEVICE_TABLEChristophe Ricard
When CONFIG_OF is define add of_st21nfca_i2c_match to MODULE_DEVICE_TABLE. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-11-28NFC: Don't include linux/unaligned/access_ok.hJohannes Berg
This is a specific implementation, <asm/unaligned.h> is the multiplexer that has the arch-specific knowledge of which of the implementations needs to be used, so include that. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-10-05Merge tag 'master-2014-10-02' of ↵David S. Miller
git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next John W. Linville says: ==================== pull request: wireless-next 2014-10-03 Please pull tihs batch of updates intended for the 3.18 stream! For the iwlwifi bits, Emmanuel says: "I have here a few things that depend on the latest mac80211's changes: RRM, TPC, Quiet Period etc... Eyal keeps improving our rate control and we have a new device ID. This last patch should probably have gone to wireless.git, but at that stage, I preferred to send it to -next and CC stable." For (most of) the Atheros bits, Kalle says: "The only new feature is testmode support from me. Ben added a new method to crash the firmware with an assert for debug purposes. As usual, we have lots of smaller fixes from Michal. Matteo fixed a Kconfig dependency with debugfs. I fixed some warnings recently added to checkpatch." For the NFC bits, Samuel says: "We've had major updates for TI and ST Microelectronics drivers, and a few NCI related changes. For TI's trf7970a driver: - Target mode support for trf7970a - Suspend/resume support for trf7970a - DT properties additions to handle different quirks - A bunch of fixes for smartphone IOP related issues For ST Microelectronics' ST21NFCA and ST21NFCB drivers: - ISO15693 support for st21nfcb - checkpatch and sparse related warning fixes - Code cleanups and a few minor fixes Finally, Marvell added ISO15693 support to the NCI stack, together with a couple of NCI fixes." For the Bluetooth bits, Johan says: "This 3.18 pull request replaces the one I did on Monday ("bluetooth-next 2014-09-22", which hasn't been pulled yet). The additions since the last request are: - SCO connection fix for devices not supporting eSCO - Cleanups regarding the SCO establishment logic - Remove unnecessary return value from logging functions - Header compression fix for 6lowpan - Cleanups to the ieee802154/mrf24j40 driver Here's a copy from previous request that this one replaces: ' Here are some more patches for 3.18. They include various fixes to the btusb HCI driver, a fix for LE SMP, as well as adding Jukka to the MAINTAINERS file for generic 6LoWPAN (as requested by Alexander Aring). I've held on to this pull request a bit since we were waiting for a SCO related fix to get sorted out first. However, since the merge window is getting closer I decided not to wait for it. If we do get the fix sorted out there'll probably be a second small pull request later this week. '" And, "Unless 3.17 gets delayed this will probably be our last -next pull request for 3.18. We've got: - New Marvell hardware supportr - Multicast support for 6lowpan - Several of 6lowpan fixes & cleanups - Fix for a (false-positive) lockdep warning in L2CAP - Minor btusb cleanup" On top of all that comes the usual sort of updates to ath5k, ath9k, ath10k, brcmfmac, mwifiex, and wil6210. This time around there are also a number of rtlwifi updates to enable some new hardware and to reconcile the in-kernel drivers with some newer releases of the Realtek vendor drivers. Also of note is some device tree work for the bcma bus. Please let me know if there are problems! ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-24NFC: st21nfca: Fix potential double kfree_skb errorChristophe Ricard
skb is already freed in st21nfca_tx_work and was freed also in st21nfca_im_send_psl_req. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-24NFC: st21nfca: ERR_PTR vs NULL fixChristophe Ricard
"skb" can be NULL here but it can't be an ERR_PTR: - IS_ERR(NULL) return false and skb migth be NULL. - skb cannot be a ERR_PTR as nfc_hci_send_cmd_async it never using such cast. !skb is more appropriate at those places. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-24NFC: st21nfca: Fix recursive fault when doing p2p in target mode.Christophe Ricard
This patch fix a previous patch introduce by commit 0a91e8ac240a12ac3a03581deb8cd531788c63d4 It is actually fixing a double free mistake in all st21nfca_tm_* function. We decide to return directly in case of successful execution because skb got already freed. In st21nfca_tm_recv_dep_req it got freed by nfc_tm_data_received. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-24NFC: st21nfca: Fix potential skb leaks in NFC-DEP codeChristophe Ricard
After a unsuccessful call to nfc_hci_send_event the skb was not freed and might lead to memory leak. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-24NFC: st21nfca: Fix few coding style issueChristophe Ricard
Fix few conding style issue such as useless line return or tab. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-08NFC: st21nfca: fix "WARNING: else is not generally useful after a break or ↵Christophe Ricard
return" scripts/checkpatch.pl -f drivers/nfc/st21nfca.c is throwing the following: WARNING: else is not generally useful after a break or return #866: FILE: drivers/nfc/st21nfca/st21nfca.c:866: + return 0; + } else { Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-08NFC: st21nfca: Clean up macros alignmentChristophe Ricard
Align every macros on the same column. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-08NFC: st21nfca: Clean up st21nfca.h macrosChristophe Ricard
Clean up st21nfca.h macros and move the one only used in st21nfca.c. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-08NFC: st21nfca: Add condition to make sure atr_req->length is valid.Christophe Ricard
gb_len in st21nfca_tm_send_atr_res can be negative. Not checking for that could lead to a potential kernel oops. We now make sure that atr_req->length > sizeof(struct st21nfca_atr_req) to avoid such situation. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-08NFC: st21nfca: Remove useless IS_ERR(skb) conditionsChristophe Ricard
skb is already verified to be not null from the below hci layer. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-08NFC: st21nfca: Remove useless err == 0 conditionChristophe Ricard
On top of st21nfca_im_recv_atr_res_cb and st21nfca_im_recv_dep_res_cb a condition if (err != 0) is present. Because err is never modified in the code err will always be 0 at the end. The condition can be removed. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-08NFC: st21nfca: Change nfcid3 generationChristophe Ricard
nfcid3 is based on sensf_res value. target->sensf is never NULL as it is a table. Check the sensf_res_len instead to make sure sensf_res is set or not. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07NFC: st21nfca: Remove useless new line in nfc_err callChristophe Ricard
Remove a useless new line in nfc_err call. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07NFC: st21nfca: Fix logic when setting session_idChristophe Ricard
If dev_num >= ST21NFCA_NUM_DEVICES, the driver was returning an incorrect success return code. Once dev_num is set, it was not stated as busy. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07NFC: st21nfca: Fix scripts/checkpatch.pl warnings "Missing a blank line ↵Christophe Ricard
after declarations" Fixing scripts/checkpatch.pl warning "Missing a blank line after declarations" in: - st21nfca.c: - check_presence after fwi variable declaration. - get_frame_size after len variable declaration. - st21nfca_hci_i2c_repack after "i, j, r, size" variable declaration. - st21nfca_dep.c st21nfca_tx_work after skb pointer declaration. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07NFC: st21nfca: Fix sparse: cast to restricted __be32Christophe Ricard
Fixing "sparse: cast to restricted __be32" message when building with make C=1 CF=-D__CHECK_ENDIAN__ Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07NFC: st21nfca: Convert to use devm_gpio_request_oneAxel Lin
This simplifies the code a bit. Acked-by: Christophe RICARD <christophe-h.ricard@st.com> Signed-off-by: Axel Lin <axel.lin@ingics.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07NFC: st21nfca: Remove double assignment of .owner in struct device_driverEmil Goode
The .owner member of struct device_driver is assigned THIS_MODULE twice. Introduced by: commit c44cb2edd01ca31471d9385f0895891b006ab904 ("NFC: dts: st21nfca: Add device-tree (Open Firmware) support to st21nfca") Acked-by: Christophe RICARD <christophe-h.ricard@st.com> Signed-off-by: Emil Goode <emilgoode@gmail.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-09-07NFC: st21nfca: Fix potential depmod dependency cycleChristophe Ricard
In the previous makefile 2 modules were generated for CONFIG_NFC_ST21NFCA (st21nfca.ko and st21nfca_dep.ko). Merge both of them into st21nfca_hci.ko and fix a potential depmod dependency cycle, similar to the one we saw on st21nfcb: depmod: WARNING: found 6 modules in dependency cycles! depmod: WARNING: /lib/modules/3.17.0-rc3-00002-g7505cea/kernel/drivers/nfc/st21nfcb/st21nfcb.ko in dependency cycle! depmod: WARNING: /lib/modules/3.17.0-rc3-00002-g7505cea/kernel/drivers/nfc/st21nfcb/ndlc.ko in dependency cycle! depmod: WARNING: /lib/modules/3.17.0-rc3-00002-g7505cea/kernel/net/rfkill/rfkill.ko in dependency cycle! depmod: WARNING: /lib/modules/3.17.0-rc3-00002-g7505cea/kernel/net/nfc/nfc.ko in dependency cycle! depmod: WARNING: /lib/modules/3.17.0-rc3-00002-g7505cea/kernel/net/nfc/nci/nci.ko in dependency cycle! depmod: WARNING: /lib/modules/3.17.0-rc3-00002-g7505cea/kernel/lib/crc-ccitt.ko in dependency cycle! ./scripts/depmod.sh: line 57: 23387 Segmentation fault (core dumped) "$DEPMOD" "$@" "$KERNELRELEASE" $SYMBOL_PREFIX make: *** [_modinst_post] Error 139 Reported-by: Daniel Wagner <wagi@monom.org> Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-07-23NFC: st21nfca: Adding P2P support to st21nfca in Initiator & Target modeChristophe Ricard
Support for Initiator and Target mode with ISO18092 commands support: - ATR_REQ/ATR_RES - PSL_REQ/PSL_RES - DEP_REQ/DEP_RES Work based on net/nfc/digital_dep.c. st21nfca is using: - Gate reader F for P2P in initiator mode. - Gate card F for P2P in target mode. Felica tag and p2p are differentiated with NFCID2. When starting with 01FE it is acting in p2p mode. On complete_target_discovered on ST21NFCA_RF_READER_F_GATE supported_protocols is set to NFC_PROTO_NFC_DEP_MASK for P2P. Tested against: Nexus S, Galaxy S2, Galaxy S3, Galaxy S3 Mini, Nexus 4 & Nexus 5. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-07-23NFC: st21nfca: Implement stop_poll HCI hookChristophe Ricard
Send DM_DISCONNECT command to disconnect Terminal Host from the HCI network. - The persistent states of the terminal host pipes, including registry values, are not modifies. Therefore, there is no NVRAM update to disconnect the terminal host. - The terminal host RF card gates are disabled which means that there will be no event related to card RF gates until communication has been restored. - The terminal host RF reader request is reset so the RF reader polling for terminal host is disabled. To restore the communication, the terminal host can send any HCI command or event. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-07-23NFC: st21nfca: Improve read length sequence for P2P mode.Christophe Ricard
A DEP_RES with a SUPERVISOR PDU can be up to 16 bytes long. In order to avoid useless read during p2p, extend first read sequence to 16 and reduce third sequence to 12 to keep same total on the full sequence. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-07-23NFC: st21nfca: Improved start of frame detectionChristophe Ricard
A start of frame is 7E 00 not only 7E. Make sure the first read sequence is starting with 7E 00. For example: 7E FF FF FF FF is as a correct crc but it is a bad frame. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-07-23NFC: st21nfca: Free buffer in case no data are retrieved.Christophe Ricard
In case no data are retrieve through i2c or one specific case is not handled. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-20NFC: st21nfca: Add ISO15693 Reader/Writer supportChristophe Ricard
Add support for ISO/IEC 15693 RF technology and Type 5 tags. ISO15963 is using proprietary gate 12. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-20NFC: st21nfca: Improve load_sessionChristophe Ricard
In case anybody uses previous patchset with the CLF, add a check to make sure missing pipe are created. st21nfca returns its pipe list in the creation order (most recent latest). Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-20NFC: dts: st21nfca: Add device-tree (Open Firmware) support to st21nfcaChristophe Ricard
Add functions to recover hardware resources from the device-tree when not provided by the platform data. Based on pn544 devicetree implementation Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-05NFC: st21nfca: Free buffer when a bad frame is detectedChristophe Ricard
When a bad frame is detected for a bad crc. We were reallocating and loosing the previous frame pointer. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-05NFC: st21nfca: Synchronize i2c Tx and Rx pathChristophe Ricard
Stabilize communication by using a mutex. This avoids running a write transaction during a read retry or a read transaction during a write retry. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-05NFC: st21nfca: Improved i2c Rx data correctness checkChristophe Ricard
A frame starts with ST21NFCA_SOF_EOF(0x7e) + 0x00. A frame ends with ST21NFCA_SOF_EOF(0x7e). It is possible that the i2c macrocell is stopped for other communication interfaces with highest priority(RF or SWP). This can be seen with some 0xFF data at the end of a received shdlc buffer. If this happen we need to discard the frame because the CLF will repeat it. In order to push accurate data to hci layer, we add the following fix: - Instead of looking for the first 0x7e in the frame, check that the last received byte is 0x7e. - Check that the first frame reception block start with start of frame(0x7e 0x00). If not, clear the buffer. - Check that the next frame reception block do not start with start of frame(0x7e). If so, clear the buffer. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-05NFC: st21nfca: Fix st21nfca_hci_remove_len_crc tail room handlingChristophe Ricard
There is no byte stuffing when data are stored in skb. TAILROOM is 2 byte crc + 1 byte eof. st21nfca_hci_remove_len_crc was doing an incorrect operation on the TAILROOM data. If shdlc timer T2 is triggered, it will request to send the same data. Before every hci data was lost after st21nfca_hci_remove_len_crc. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-05NFC: st21nfca: Fix incorrect byte stuffing revocationChristophe Ricard
Byte stuffing was not correctly removed after a i2c read operation. This was causing improper crc calculation when byte stuffing was applied to more than 1 byte. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-05-05NFC: st21nfca: Remove few useless includeChristophe Ricard
Remove unneeded includes from i2c.c Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: st21nfca: Improve st21nfca initialization by handling reboot properlyChristophe Ricard
Change in st21nfca_hci_platform_init in order to handle in a better way the internal reboot command. Once the reboot is completed, the driver expect to receive a 0x7e filled buffer. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: st21nfca: Reworked st21nfca_request_resourcesChristophe Ricard
Remove struct st21nfca_i2c_phy* as this parameter can be retrieve through i2c_get_clientdata(client) Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: st21nfca: st21nfca_hci_i2c_probe returns st21nfca_hci_probe result.Christophe Ricard
st21nfca_hci_probe return 0 in case of successful call and a different value in any other cases. There is no need to check for st21nfca_hci_probe return as this will be checked after st21nfca_hci_i2c_probe is completed. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: st21nfca: Add __packed to struct st21nfca_pipe_infoChristophe Ricard
Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: st21nfca: Remove sporadic wait_tab variable from functions.Christophe Ricard
wait_tab variable is already global and may create conflicts. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: st21nfca: Fix warning: array subscript is above array boundsChristophe Ricard
Fix "warning: array subscript is above array bounds" in load_session Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: st21nfca: Fix sparse: cast to restricted __be16Christophe Ricard
Fixing "sparse: cast to restricted __be16" message when building with make C=1 CF=-D__CHECK_ENDIAN__ Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: st21nfca: Implement load_session HCI hookChristophe Ricard
This implementation rely on the ST21NFCA_DEVICE_MGNT_GATE and ST21NFCA_DM_GETINFO proprietary gates commands. First we are retrieving a pipe list available on the CLF with the ST21NFCA_DM_GETINFO_PIPE_LIST parameter. A gate<->pipe table match is done with ST21NFCA_DM_GETINFO_PIPE_INFO for each pipe. If the pipe is created and open, we fill st21nfca_gates table. If the pipe is create but closed or is not created we keep the gate with NFC_HCI_INVALID_PIPE. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2014-04-22NFC: ST21NFCA: Add driver for STMicroelectronics ST21NFCA NFC ChipChristophe Ricard
Add driver for STMicroelectronics ST21NFCA NFC controller. ST21NFCA is using HCI protocol, shdlc as LLC layer & I2C as communication protocol. Adding support for Reader/Writer mode with Tag type 1/2/3/4 A & B. It is using proprietary gate 15 for ISO14443-3 such as type 1 & type 2 tags. It is using proprietary gate 14 for type F tags. ST21NFCA_DEVICE_MGNT_GATE gives access to proprietary CLF configuration. Standard gate for ISO14443-4 A (13) & B (11) are also used. ST21NFCA specific mecanism: One particular point to notice for the data handling is that frame does not contain any length value. Therefore the i2c part of this driver is managing the reception with a read length sequence until the end of frame (0x7e) is reached. In order to avoid conflict between sof & eof a mecanism called byte stuffing concist of an escape byte (0x7d) insertion before special byte (0x7e, 0x7d). The special byte is then xored with 0x20. In this driver, When data are available in the CLF, the interrupt gpio is driven to active state and triggered an interrupt. Once the i2c_master_recv start, the interrupt gpio is driven to idle state until its complete. If the frame is incomplete or data are still available, interrupts will be triggered again. Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>