/fantasyhujian/article/details/38943639?utm_source=tuicool
前些天在调试一组高通msm8926上的摄像头，之前ov5648+imx135已正常的点亮了，但是后续需要一个mini配置版本的方案，需要兼容ov2685+ov8865,于是先做好调试的前期准备，跟摄像头模组厂要模组spec和芯片的datasheet,先仔细阅读一下ic的datasheet,并仔细查看模组的打样图纸和模组spec，首先要确认的是ic的各路电压是可以正常的供出，一般需要注意的就是DVDD，IOVDD，AVDD，还有STANDBY和RESET,这些管脚的连接要和主板上兼容，确保在硬件上主板可以正常的兼容摄像头模组，我就开始被模组厂忽悠了，有一组DVDD电压说是可以不用去供电，ic也可以正常工作，我阅读ic的datasheet就发现不对，但是既然是模组厂已确认是可以兼容的，我开始居然天真的被相信了！冋阿，善良程序猿的悲哀，太容易相信别人了，！
模组厂提供了基本的ic驱动代码之后，首先需要在kernel中兼容这组摄像头，展讯去配置Camera的Kconfig和Makefile，以及sensorcfg就可以基本完成对新Camera senssor的兼容，高通上处理就有些不一样，由于目前高通平台引入了设备树dts来配置内核信息，关于设备树，各位童鞋可以查看我的相关博客-点击打开链接去了解更多相关知识，首先是在设备树中配置Camera ic的i2c从地址芯片和各个控制管脚的gpio和e2prom的配置信息，这个地方需要注意的是，模组手册对这个从设备地址没有统一的写法，有的给出8位地址，有的给出7位地址，一开始容易混淆。如果给出的是8位地址，那第8位是指Write-0或者Read-1，实际的I2C芯片地址是7位的，内核中配置的地址是真实地址，这个需要格外的注意，不然就会造成i2c不通，导致摄像头驱动加载失败。
配置完相关信息，开机进入摄像头测试，发现摄像头已停止，无法连接到设备，抓取相关的内核log,发现是match id失败，导致驱动加载不成功，这个我最开始怀疑的就是相关的电压没能正常起来，用电压表，测起，发现电压貌似正常，然后我再次怀疑是设备的从地址有问题，跟模组厂再三确认，他们依旧说这个从地址是没问题的，唉，这货简直是睁着眼睛说瞎话，众所周知，ov的FAE非常难请来现场调试，所以只能抄示波器自己先看看，果然示波器抓取驱动加载时的各路电压貌似出了问题，虽然驱动上电这个过程非常的短暂，但是还是在数次的抓取中，终于成功抓到了这个开机加载驱动转瞬即逝的上电时序波形，我再次分析一下这个加载驱动的log,log如下：
[html]view plaincopy<6>[4.582687]synaptics_rmi4_i2c5-0020:fwu_read_f34_queriesperm:1,bl:1,display:0 <3>[4.594144]msm_camera_power_uptype2 <3>[4.599995]msm_camera_power_upindex1 <3>[4.602787]msm_camera_power_uptype2 <3>[4.608830]msm_camera_power_upindex2 <3>[4.611622]msm_camera_power_uptype2 <3>[4.617866]msm_camera_power_upindex3 <3>[4.620658]msm_camera_power_uptype2 <3>[4.630691]msm_camera_power_upindex4 <3>[4.633482]msm_camera_power_uptype1 <3>[4.637215]msm_camera_power_upindex5 <3>[4.641060]msm_camera_power_uptype1 <3>[4.644768]msm_camera_power_up:1023gpiosetval37 <3>[4.655759]msm_camera_power_upindex6 <3>[4.658573]msm_camera_power_uptype1 <3>[4.662282]msm_camera_power_upindex7 <3>[4.666102]msm_camera_power_uptype1 <3>[4.669857]msm_camera_power_upindex8 <3>[4.673654]msm_camera_power_uptype1 <3>[4.677408]msm_camera_power_up:1023gpiosetval37 <3>[4.693360]msm_camera_power_upindex9 <3>[4.696151]msm_camera_power_uptype1 <3>[4.699907]msm_camera_power_upindex10 <3>[4.703790]msm_camera_power_uptype0 <3>[4.718602]msm_camera_power_upindex11 <3>[4.721480]msm_camera_power_uptype3 <3>[4.725312]msm_camera_power_upexit <3>[4.728945]msm_cci_irq:852MASTER_0error10000000 <3>[4.733666]msm_cci_i2c_read:426read_words=0,expwords=1 <3>[4.739474]msm_cci_i2c_read_bytes:504failedrc-22 <3>[4.744398]msm_camera_cci_i2c_read:line53rc=-22 <3>[4.749454]msm_sensor_match_id:ov8865_q8v18a:readidfailed <3>[4.755249]msm_sensor_check_id:1055matchidfailedrc-22 <3>[4.760824]msm_camera_power_down:1154 <3>[4.764581]msm_camera_power_downindex0 <3>[4.768552]msm_camera_power_downtype3 <3>[4.772434]msm_camera_power_downindex1 <3>[4.776427]msm_camera_power_downtype0 <3>[4.791392]msm_camera_power_downindex2 <3>[4.794358]msm_camera_power_downtype1 <3>[4.798288]msm_camera_power_downindex3 <3>[4.802256]msm_camera_power_downtype1 <3>[4.817189]msm_camera_power_downindex4 <3>[4.83]msm_camera_power_downtype1 <3>[4.824060]msm_camera_power_downindex5 <3>[4.828076]msm_camera_power_downtype1 <3>[4.831959]msm_camera_power_downindex6 <3>[4.835951]msm_camera_power_downtype1 <3>[4.845902]msm_camera_power_downindex7 <3>[4.848890]msm_camera_power_downtype1 <3>[4.852773]msm_camera_power_downindex8 <3>[4.856766]msm_camera_power_downtype2 <3>[4.866952]msm_camera_power_downindex9 <3>[4.869942]msm_camera_power_downtype2 <3>[4.876452]msm_camera_power_downindex10 <3>[4.879527]msm_camera_power_downtype2 <3>[4.885664]msm_camera_power_downindex11 <3>[4.888740]msm_camera_power_downtype2 <3>[4.894707]msm_camera_power_downexit <3>[4.897436]msm_sensor_platform_probeov8865_q8v18apowerupfailed <4>[4.903675]ovti,ov8865:probeof20.qcom,camerafailedwitherror-22 <3>[4.910245]ov8865_init_module:158rc-19 <3>[4.915152]msm_sensor_platform_probecalleddatac0e98778 <3>[4.919663]msm_sensor_platform_probepdevname(null) <3>[4.924760]msm_sensor_get_dt_dataqcom,sensor-nameov2685,rc0 <3>[4.930771]msm_sensor_get_dt_dataqcom,cci-master0,rc0 <3>[4.936217]msm_sensor_get_sub_module_index:125src_nodeNULL <3>[4.941968]msm_sensor_get_sub_module_index:141eepromsrc_nodeNULL <3>[4.948305]msm_sensor_get_sub_module_index:169src_nodeNULL <3>[4.954014]msm_sensor_get_sub_module_indexcsiphy_core[0]=1 <3>[4.959851]msm_sensor_get_sub_module_indexcsid_core[0]=1 <3>[4.965469]msm_sensor_get_dt_dataqcom,mount-angle90,rc0 <3>[4.971135]msm_sensor_get_dt_dataqcom,sensor-position1,rc0 <3>[4.977014]msm_sensor_get_dt_dataqcom,sensor-mode1,rc0 <3>[4.982594]msm_sensor_get_dt_csi_dataqcom,csi-lane-assign4320,rc0 <3>[4.989102]msm_sensor_get_dt_csi_dataqcom,csi-lane-mask3,rc0 <3>[4.995157]msm_camera_get_dt_vreg_dataqcom,cam-vreg-namecount3 <3>[5.001343]msm_camera_get_dt_vreg_datareg_name[0]=cam_vdig <3>[5.007136]msm_camera_get_dt_vreg_datareg_name[1]=cam_vio <3>[5.012892]msm_camera_get_dt_vreg_datareg_name[2]=cam_vana <3>[5.018704]msm_camera_get_dt_vreg_datacam_vreg[0].type=0 <3>[5.024322]msm_camera_get_dt_vreg_datacam_vreg[1].type=1 <3>[5.029987]msm_camera_get_dt_vreg_datacam_vreg[2].type=0 <3>[5.035608]msm_camera_get_dt_vreg_datacam_vreg[0].min_voltage=2050000 <3>[5.042399]msm_camera_get_dt_vreg_datacam_vreg[1].min_voltage=2800000 <3>[5.049196]msm_camera_get_dt_vreg_datacam_vreg[2].min_voltage=2850000 <3>[5.055921]msm_camera_get_dt_vreg_datacam_vreg[0].max_voltage=2050000 <3>[5.062713]msm_camera_get_dt_vreg_datacam_vreg[1].max_voltage=2800000 <3>[5.069519]msm_camera_get_dt_vreg_datacam_vreg[2].max_voltage=2850000 <3>[5.076233]msm_camera_get_dt_vreg_datacam_vreg[0].op_mode=200000 <3>[5.082592]msm_camera_get_dt_vreg_datacam_vreg[1].op_mode=0 <3>[5.088493]msm_camera_get_dt_vreg_datacam_vreg[2].op_mode=80000 <3>[5.094724]msm_camera_get_dt_power_setting_dataqcom,cam-power-seq-typecount-22 <3>[5.102345]msm_sensor_get_dt_datagpiocount2 <3>[5.106795]msm_sensor_get_dt_datagpio_array[0]=26 <3>[5.111860]msm_sensor_get_dt_datagpio_array[1]=35 <3>[5.116863]msm_camera_get_dt_gpio_req_tblcam_gpio_req_tbl[0].gpio=26 <3>[5.123565]msm_camera_get_dt_gpio_req_tblcam_gpio_req_tbl[1].gpio=35 <3>[5.130249]msm_camera_get_dt_gpio_req_tblcam_gpio_req_tbl[0].flags=1 <3>[5.136909]msm_camera_get_dt_gpio_req_tblcam_gpio_req_tbl[1].flags=0 <3>[5.143617]msm_camera_get_dt_gpio_req_tblcam_gpio_req_tbl[0].label=CAMIF_MCLK <3>[5.151082]msm_camera_get_dt_gpio_req_tblcam_gpio_req_tbl[1].label=CAM_STANDBY <3>[5.158640]msm_camera_get_dt_gpio_set_tblcam_gpio_set_tbl[0].gpio=35 <3>[5.165295]msm_camera_get_dt_gpio_set_tblcam_gpio_set_tbl[1].gpio=35 <3>[5.17]msm_camera_get_dt_gpio_set_tblcam_gpio_set_tbl[0].flags=0 <3>[5.178684]msm_camera_get_dt_gpio_set_tblcam_gpio_set_tbl[1].flags=2 <3>[5.185349]msm_camera_get_dt_gpio_set_tblcam_gpio_set_tbl[0].delay=1000 <3>[5.192312]msm_camera_get_dt_gpio_set_tblcam_gpio_set_tbl[1].delay=4000 <3>[5.199265]msm_camera_init_gpio_pin_tblqcom,gpio-reset35 <3>[5.204797]msm_sensor_get_dt_actuator_dataqcom,actuator-cam-name0,rc-22 <3>[5.211848]msm_sensor_get_dt_data:291slaveaddr78sensorreg300aid2685 <3>[5.218878]msm_sensor_get_dt_dataqcom,misc_regulator(null),rc-22 <3>[5.225280]msm_camera_power_up:959 <3>[5.228782]msm_camera_power_upindex0 <3>[5.232568]msm_camera_power_uptype2 <3>[5.240940]msm_camera_power_upindex1 <3>[5.243731]msm_camera_power_uptype2 <3>[5.250775]msm_camera_power_upindex2 <3>[5.253566]msm_camera_power_uptype2 <3>[5.263427]msm_camera_power_upindex3 <3>[5.266218]msm_camera_power_uptype1 <3>[5.269976]msm_camera_power_up:1023gpiosetval35 <3>[5.280925]msm_camera_power_upindex4 <3>[5.283716]msm_camera_power_uptype1 <3>[5.287473]msm_camera_power_up:1023gpiosetval35 <3>[5.298422]msm_camera_power_upindex5 <3>[5.301212]msm_camera_power_uptype0 <3>[5.325996]msm_camera_power_upindex6 <3>[5.328812]msm_camera_power_uptype3 <3>[5.332624]msm_camera_power_upexit <3>[5.427310]msm_cci_i2c_read:wait_for_completion_interruptible_timeout410 <3>[5.527309]msm_cci_flush_queue:106waittimeout <3>[5.530899]msm_cci_i2c_read_bytes:504failedrc-110 <3>[5.535916]msm_camera_cci_i2c_read:line53rc=-110 <3>[5.541063]msm_sensor_match_id:ov2685:readidfailed <3>[5.546247]msm_sensor_check_id:1055matchidfailedrc-110 <3>[5.551911]msm_camera_power_down:1154 <3>[5.555665]msm_camera_power_downindex0 <3>[5.559638]msm_camera_power_downtype3 <3>[5.563521]msm_camera_power_downindex1 <3>[5.567571]msm_camera_power_downtype0 <3>[5.592458]msm_camera_power_downindex2 <3>[5.595424]msm_camera_power_downtype1 <5>[5.599370]fwu_start_reflash:Startofreflashprocess 仔细分析log，发现i2c地址应该是有问题，报着试试的态度，对地址进行了移位，转换成认为的真实地址，编译代码发现，还是无法打开设备，仔细检查原理图和打样图纸，让硬件把dvdd将上拉电阻接到一个PMIC的控制脚上，我想按照datasheet的上电时序再来一遍，编译烧写文件，怀着忐忑的心情打开摄像头，居然亮了，着实激动了一把，我擦，坑爹的模组厂，差点害我放弃点亮这颗摄像头了！
后摄还是无法打开摄像头,参考上电时序和电路原理图，将STANDBYf飞线到主板上一个不用gpio，我按照上电时序修改poweron代码，也正常点亮了--至此，已基本完成了在高通msm8926上对ov2685+ov8865的兼容！
得出的调试经验给大家分享一下：
1 Camera驱动加载失败的原因大部分就是i2c和电压不对，请确保这些是正常配置的。
2.仔细分析内核的调试log，在关键的地方加调试信息，善用示波器和电压表等辅助调试设备，分析失败的根本原因
3 严格按照spec和datasheet，当然要确保你的资料是正确的，不要轻易的相信别人的信息，特别是调试出现问题的时候，你需要逐步去排除各种可能的错误
希望这些能帮到那些正在痛苦调试的程序猿，大家共勉！
