全志R528 系统繁忙时触摸屏I2C报错问题。
最近调试项目时遇到一个奇怪的问题。
当linux 系统繁忙时（开机，关机或APP繁忙等情况），此时按下触摸屏后，
I2C总线就会报错，TP读数据失败，之后内存报错，重启。
root@TinaLinux:/# root@TinaLinux:/# root@TinaLinux:/# [ 199.777017] sunxi_i2c_drv_core_process()925 - [i2c2] Timeout when sending 9th SCL clk [ 200.847813] i2c_sunxi_drv_complete()1077 - [i2c2] incomplete xfer(status: 0x1, dev addr: 0x38) [ 200.857621] 0x02502a00: 01011001 00000001 00007100 00010021 [ 200.864177] 0x02502a10: 000080c0 00010004 01100010 00000001 [ 200.870703] hy46xx_ts 2-0038: fhy46xx_i2c_Read: i2c read error. [ 200.877463] hy46xx_ts 2-0038: hy46xx_read_Touchdata read touchdata failed. [ 200.885383] sunxi_i2c_drv_core_process()925 - [i2c2] Timeout when sending 9th SCL clk [ 201.967821] i2c_sunxi_drv_complete()1077 - [i2c2] incomplete xfer(status: 0x1, dev addr: 0x38) [ 201.977597] 0x02502a00: 01011001 00000001 00007100 00010021 [ 201.984129] 0x02502a10: 000080c0 00010004 01100010 00000001 [ 201.990648] hy46xx_ts 2-0038: fhy46xx_i2c_Read: i2c read error. [ 201.997400] hy46xx_ts 2-0038: hy46xx_read_Touchdata read touchdata failed. [ 202.005290] sunxi_i2c_drv_core_process()925 - [i2c2] Timeout when sending 9th SCL clk [ 203.087847] i2c_sunxi_drv_complete()1077 - [i2c2] incomplete xfer(status: 0x1, dev addr: 0x38) [ 203.097632] 0x02502a00: 01011001 00000001 00007100 00010021 [ 203.104146] 0x02502a10: 000080c0 00010004 01100010 00000001 [ 203.110665] hy46xx_ts 2-0038: fhy46xx_i2c_Read: i2c read error. [ 203.117391] hy46xx_ts 2-0038: hy46xx_read_Touchdata read touchdata failed. [ 207.567486] sunxi_i2c_drv_core_process()925 - [i2c2] Timeout when sending 9th SCL clk [ 208.607814] i2c_sunxi_drv_complete()1077 - [i2c2] incomplete xfer(status: 0x1, dev addr: 0x38) [ 208.617646] 0x02502a00: 01011001 00000001 00007100 00010021 [ 208.624170] 0x02502a10: 000080c0 00010004 01100010 00000001 [ 208.630683] hy46xx_ts 2-0038: fhy46xx_i2c_Read: i2c read error. [ 208.637404] hy46xx_ts 2-0038: hy46xx_read_Touchdata read touchdata failed. [ 208.645313] sunxi_i2c_drv_core_process()925 - [i2c2] Timeout when sending 9th SCL clk [ 209.727807] i2c_sunxi_drv_complete()1077 - [i2c2] incomplete xfer(status: 0x1, dev addr: 0x38) [ 209.737654] 0x02502a00: 01011001 00000001 00007100 00010021 [ 209.744190] 0x02502a10: 000080c0 00010004 01100010 00000001 [ 209.750683] hy46xx_ts 2-0038: fhy46xx_i2c_Read: i2c read error. [ 209.757424] hy46xx_ts 2-0038: hy46xx_read_Touchdata read touchdata failed. [ 221.624975] 8<--- cut here --- [ 221.628575] Unable to handle kernel paging request at virtual address 8201cb00 [ 221.636783] pgd = 4d9c9bba [ 221.640006] [8201cb00] *pgd=00000000 [ 221.644965] Internal error: Oops: 5 [#1] PREEMPT SMP ARM [ 221.650935] Modules linked in: mt7601Uap(O) esp8089(O) xt_time xt_multiport xt_mark xt_mac xt_limit xt_comment xt_TCPMSS xt_LOG iptable_filter ipt_REJECT fuse disp [last unloaded: mt7601Uap] [ 221.669992] CPU: 0 PID: 1822 Comm: APP Tainted: G O 5.4.61 #304 [ 221.678092] Hardware name: Generic DT based system [ 221.683474] PC is at __kmalloc+0x130/0x194 [ 221.688070] LR is at slab_pre_alloc_hook+0x18/0x2c [ 221.693444] pc : [<c01d0c74>] lr : [<c01ceea8>] psr: a00f0013 [ 221.700472] sp : c46e5d70 ip : e99b5807 fp : c2163a00 [ 221.706329] r10: 00009864 r9 : c46e5d70 r8 : c02434d8 [ 221.712189] r7 : 00000dc0 r6 : c46e4000 r5 : c7001e00 r4 : 8201cb00 [ 221.719510] r3 : 00000000 r2 : 06b73000 r1 : 00009864 r0 : c7001e00 [ 221.726829] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 221.734838] Control: 10c5387d Table: 4755806a DAC: 00000051 [ 221.741283] Process APP (pid: 1822, stack limit = 0xaac39cc5) [ 221.747729] Stack: (0xc46e5d70 to 0xc46e6000) [ 221.752617] 5d60: c42cb00c c6e1a708 06bf4962 c537fc40 [ 221.761796] 5d80: 90b73236 c46e5dd4 c42cb00c c02434d8 c42cb00c c6e1a708 c46e5e30 00000001 [ 221.770973] 5da0: c6e129c0 00000000 00000000 c026ca54 c46e5dd4 c6e129c0 c42cb000 00001000 [ 221.780150] 5dc0: 00000000 0000000c c2163a00 c42cbff8 00000064 c42cb014 00000002 6d8c1c09 [ 221.789328] 5de0: 00000018 00000000 c6e1a708 00000000 00000000 c2163a00 c6e1a708 c537fc60 [ 221.798505] 5e00: 00000000 c026d50c 00000000 00000000 c7508720 c02cc5c8 c0c05608 00000000 [ 221.807677] 5e20: 00000000 c01e14dc c71e4800 c0c05608 90b73236 06bf4962 00000004 c72c7894 [ 221.816857] 5e40: 00000000 00024800 00000000 c091c7aa 00000043 c7508ed8 000041ed c0c05608 [ 221.826032] 5e60: b02fe9a8 6d8c1c09 c0242d6c c46e5f68 c6e1a708 c2163a00 c537fc40 c6089400 [ 221.835209] 5e80: c6e1a708 00000000 00000000 c0242ee4 00000000 00000f65 000041ed 00000002 [ 221.844387] 5ea0: 00000000 00000000 00000000 00000000 00000000 00000000 00001000 00000000 [ 221.853565] 5ec0: 00001000 00000000 00000008 00000000 633112ff 35a4e903 6331138b 1017dfc6 [ 221.862743] 5ee0: 6331138b 6d8c1c09 00000f65 c2163a00 00000000 c6e1a708 00000001 c46e5f68 [ 221.871921] 5f00: c46e4000 000000d9 b02fefac c01e8bec c2163a00 c46e5f68 c2163900 00000000 [ 221.881099] 5f20: c4ba5ba8 00000000 c46e5f68 c46e4000 000000d9 c01e8bec c2163900 c46e5f68 [ 221.890276] 5f40: b1b00610 c0c05608 00008000 c2163900 c0101228 c46e4000 000000d9 c01e93ac [ 221.899452] 5f60: c2163900 00000003 c01e8ef8 00000000 00000000 00000000 b1b00610 00000000 [ 221.908629] 5f80: 00008000 00000000 00000008 6d8c1c09 000c8930 b1b005f0 b1b005f4 b02ff930 [ 221.917807] 5fa0: 000000d9 c0101000 b1b005f0 b1b005f4 0000001b b1b00610 00008000 00000000 [ 221.926987] 5fc0: b1b005f0 b1b005f4 b02ff930 000000d9 b1b00610 00000000 000d2af8 b02fefac [ 221.936165] 5fe0: 000f1324 b02fe9f0 b54c2878 b54c27d0 600f0010 0000001b 00000000 00000000 [ 221.945359] [<c01d0c74>] (__kmalloc) from [<c02434d8>] (ext4_htree_store_dirent+0x28/0xfc) [ 221.954642] [<c02434d8>] (ext4_htree_store_dirent) from [<c026ca54>] (htree_dirblock_to_tree+0x1bc/0x214) [ 221.965384] [<c026ca54>] (htree_dirblock_to_tree) from [<c026d50c>] (ext4_htree_fill_tree+0x104/0x2bc) [ 221.975835] [<c026d50c>] (ext4_htree_fill_tree) from [<c0242ee4>] (ext4_readdir+0x200/0x790) [ 221.985309] [<c0242ee4>] (ext4_readdir) from [<c01e8bec>] (iterate_dir+0x88/0x130) [ 221.993807] Code: eb154c75 e1a00004 e8bd87f0 e5953014 (e7940003) [ 222.000907] 8<--- cut here --- [ 222.004350] Unable to handle kernel paging request at virtual address 8201cb00 [ 222.012573] pgd = 4d9c9bba [ 222.015678] [8201cb00] *pgd=00000000 [ 222.019738] Internal error: Oops: 5 [#2] PREEMPT SMP ARM [ 222.025697] Modules linked in: mt7601Uap(O) esp8089(O) xt_time xt_multiport xt_mark xt_mac xt_limit xt_comment xt_TCPMSS xt_LOG iptable_filter ipt_REJECT fuse disp [last unloaded: mt7601Uap] [ 222.044748] CPU: 0 PID: 1822 Comm: APP Tainted: G D O 5.4.61 #304 [ 222.052848] Hardware name: Generic DT based system [ 222.058247] PC is at kmem_cache_alloc+0xfc/0x160 [ 222.063427] LR is at slab_pre_alloc_hook+0x18/0x2c [ 222.068799] pc : [<c01d0dd4>] lr : [<c01ceea8>] psr: a0000113 [ 222.075826] sp : c46e58c0 ip : 00000040 fp : 00000003 [ 222.081685] r10: 00009864 r9 : c46e58c0 r8 : c05b4428 [ 222.087544] r7 : 00000a20 r6 : c46e4000 r5 : c7001e00 r4 : 8201cb00 [ 222.094865] r3 : 00000000 r2 : 06b73000 r1 : 00009864 r0 : c7001e00 [ 222.102188] Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none [ 222.110192] Control: 10c5387d Table: 4755806a DAC: 00000051 [ 222.116640] Process APP (pid: 1822, stack limit = 0xaac39cc5) [ 222.123082] Stack: (0xc46e58c0 to 0xc46e6000) [ 222.127974] 58c0: c71a0910 c46e5998 c71a0680 c46e5994 c71e4780 c46e5a1c c46e59f8 c05b4428 [ 222.137151] 58e0: c71a0680 c71a0784 c71a0910 00000008 c46e59c0 c05e30b4 c46e59f8 c05b59a0 [ 222.146326] 5900: 00000001 c76c6dc0 c707d800 c707d780 c7384b00 c7384b80 c46e5998 c71a0680 [ 222.155504] 5920: c46e5994 c46e59c0 c46e59f8 0100007f c71a0680 c05e394c 00000047 00000008 [ 222.164682] 5940: c46e5998 c46e5994 00000040 c4532010 c5e07400 000000c0 c4532010 00000000 [ 222.173860] 5960: 00000003 c05e3d8c 000000c0 00000000 00000003 00000003 c46e59f8 c0c05608 [ 222.183037] 5980: c71a06f0 00000000 c5e0741c c0c05608 c68fc4c0 c71e4780 00000000 00000000 [ 222.192214] 59a0: 00000000 00000000 0100007f 00000000 c46e5a1c ffff0000 00000000 00000000 [ 222.201391] 59c0: 00000001 00000001 00000000 00010000 00000000 00000000 00000000 00000000 [ 222.210563] 59e0: 00000000 00000000 0100007f 0100007f 00000303 00000000 c5e07400 ffffffec [ 222.219742] 5a00: 0000003f 00000303 00000000 c7036cc0 c5e07400 c6a65b28 00000008 6d8c1c09 [ 222.228920] 5a20: c09335da 00000000 00000000 00000000 00000000 0000ecd9 00000000 00000000 [ 222.238098] 5a40: c5e07400 c05dce20 00000035 00000001 00000000 c73eb160 c5e07400 6d8c1c09 [ 222.247274] 5a60: c09335da c5e07400 c4532024 00000000 00000000 00000011 c0c41ac0 c0c085e0 [ 222.256453] 5a80: 0000002b c05e0238 c5e0741c 00000001 00000000 c0c085e0 c5e07400 c4080a90 [ 222.265630] 5aa0: c5e07400 c4080a80 c46e5ad8 6d8c1c09 0100007f c057e3b4 0100007f 00000001 [ 222.274808] 5ac0: c0c05608 6d8c1c09 c05b1118 c5e07400 c0c45c7c c0c41ac0 00000000 c0c08190 [ 222.283983] 5ae0: 00000000 00000040 00000040 c05b100c c0c41ac0 c5e07400 00000011 c5e07400 [ 222.293164] 5b00: c0c41ac0 c7031000 00000001 c76b86c8 00000000 c05b1178 c0c05608 c05b1210 [ 222.302339] 5b20: c7031000 c054441c c5e07400 c5e07400 c0c086a0 6d8c1c09 c76b8770 c5e07400 [ 222.311517] 5b40: 00000001 c054460c c76b86c0 c76b8770 c0b456c0 06b73000 00000001 c46e5b7c [ 222.320697] 5b60: c0c4aac9 c054559c 0000012c ffffe185 c0c05608 c0c02d00 c46e4000 c46e5b7c [ 222.329871] 5b80: c46e5b7c c46e5b84 c46e5b84 6d8c1c09 c09335da c46e4000 40000003 00000008 [ 222.339051] 5ba0: c46e5bb8 00000003 c0c02080 c0c0208c 00000100 c0102ae4 00000000 c76b142c [ 222.348222] 5bc0: 00400040 0000000a c0b44980 ffffe160 00000004 c0c02d00 00000000 c0b44980 [ 222.357400] 5be0: 00000003 00000000 c46e5c38 c090fcae c46e4000 c0c0abb0 00000005 c011da44 [ 222.366574] 5c00: 00000000 c010c5fc c8802000 c0c05960 c46e5c38 c8803000 c090fcae c036b854 [ 222.375755] 5c20: c010aa88 60000013 ffffffff c46e5c6c c090fcae c01021cc 00000000 c0c51428 [ 222.384931] 5c40: 00001080 60000013 c46e5d20 c0c5125c 0000000b c7387080 c090fcae ffffe000 [ 222.394108] 5c60: c0c0abb0 00000005 00000000 c46e5c88 c010aa54 c010aa88 60000013 ffffffff [ 222.403285] 5c80: 00000051 bf000000 c46e4210 0000000b c090fc32 60000013 00000000 8201cb00 [ 222.412461] 5ca0: c46e5d20 00000005 c609da00 c609da00 00000005 c609da40 00000000 c010f498 [ 222.421639] 5cc0: c7387080 c010f1d8 8201cb00 00010000 c46e5d20 00000005 c0c0ad24 8201cb00 [ 222.430815] 5ce0: c46e5d20 c02434d8 c46e4000 00009864 c2163a00 c010f330 c6e129c0 5a827999 [ 222.439993] 5d00: 6ed9eba1 c024f498 5b6af68f c01d0c74 a00f0013 ffffffff c46e5d54 c0102138 [ 222.449166] 5d20: c7001e00 00009864 06b73000 00000000 8201cb00 c7001e00 c46e4000 00000dc0 [ 222.458346] 5d40: c02434d8 c46e5d70 00009864 c2163a00 e99b5807 c46e5d70 c01ceea8 c01d0c74 [ 222.467521] 5d60: a00f0013 ffffffff 00000051 bf000000 c42cb00c c6e1a708 06bf4962 c537fc40 [ 222.476699] 5d80: 90b73236 c46e5dd4 c42cb00c c02434d8 c42cb00c c6e1a708 c46e5e30 00000001 [ 222.485877] 5da0: c6e129c0 00000000 00000000 c026ca54 c46e5dd4 c6e129c0 c42cb000 00001000 [ 222.495054] 5dc0: 00000000 0000000c c2163a00 c42cbff8 00000064 c42cb014 00000002 6d8c1c09 [ 222.504232] 5de0: 00000018 00000000 c6e1a708 00000000 00000000 c2163a00 c6e1a708 c537fc60 [ 222.513409] 5e00: 00000000 c026d50c 00000000 00000000 c7508720 c02cc5c8 c0c05608 00000000 [ 222.522582] 5e20: 00000000 c01e14dc c71e4800 c0c05608 90b73236 06bf4962 00000004 c72c7894 [ 222.531757] 5e40: 00000000 00024800 00000000 c091c7aa 00000043 c7508ed8 000041ed c0c05608 [ 222.540932] 5e60: b02fe9a8 6d8c1c09 c0242d6c c46e5f68 c6e1a708 c2163a00 c537fc40 c6089400 [ 222.550110] 5e80: c6e1a708 00000000 00000000 c0242ee4 00000000 00000f65 000041ed 00000002 [ 222.559287] 5ea0: 00000000 00000000 00000000 00000000 00000000 00000000 00001000 00000000 [ 222.568465] 5ec0: 00001000 00000000 00000008 00000000 633112ff 35a4e903 6331138b 1017dfc6 [ 222.577643] 5ee0: 6331138b 6d8c1c09 00000f65 c2163a00 00000000 c6e1a708 00000001 c46e5f68 [ 222.586821] 5f00: c46e4000 000000d9 b02fefac c01e8bec c2163a00 c46e5f68 c2163900 00000000 [ 222.595998] 5f20: c4ba5ba8 00000000 c46e5f68 c46e4000 000000d9 c01e8bec c2163900 c46e5f68 [ 222.605174] 5f40: b1b00610 c0c05608 00008000 c2163900 c0101228 c46e4000 000000d9 c01e93ac [ 222.614352] 5f60: c2163900 00000003 c01e8ef8 00000000 00000000 00000000 b1b00610 00000000 [ 222.623524] 5f80: 00008000 00000000 00000008 6d8c1c09 000c8930 b1b005f0 b1b005f4 b02ff930 [ 222.632702] 5fa0: 000000d9 c0101000 b1b005f0 b1b005f4 0000001b b1b00610 00008000 00000000 [ 222.641880] 5fc0: b1b005f0 b1b005f4 b02ff930 000000d9 b1b00610 00000000 000d2af8 b02fefac [ 222.651059] 5fe0: 000f1324 b02fe9f0 b54c2878 b54c27d0 600f0010 0000001b 00000000 00000000 [ 222.660253] [<c01d0dd4>] (kmem_cache_alloc) from [<c05b4428>] (ip_setup_cork+0x11c/0x144) [ 222.669437] [<c05b4428>] (ip_setup_cork) from [<c05b59a0>] (ip_append_data.part.11+0x44/0xac) [ 222.679010] [<c05b59a0>] (ip_append_data.part.11) from [<c05e394c>] (icmp_push_reply+0x4c/0x124) [ 222.688867] [<c05e394c>] (icmp_push_reply) from [<c05e3d8c>] (__icmp_send+0x330/0x3a8) [ 222.697753] [<c05e3d8c>] (__icmp_send) from [<c05e0238>] (__udp4_lib_rcv+0x60c/0x6d0) [ 222.706542] [<c05e0238>] (__udp4_lib_rcv) from [<c05b100c>] (ip_protocol_deliver_rcu+0xac/0x1b8) [ 222.716405] [<c05b100c>] (ip_protocol_deliver_rcu) from [<c05b1178>] (ip_local_deliver_finish+0x60/0x6c) [ 222.727052] [<c05b1178>] (ip_local_deliver_finish) from [<c054441c>] (__netif_receive_skb_one_core+0x4c/0x6c) [ 222.738183] [<c054441c>] (__netif_receive_skb_one_core) from [<c054460c>] (process_backlog+0x98/0x13c) [ 222.748629] [<c054460c>] (process_backlog) from [<c054559c>] (net_rx_action+0x11c/0x308) [ 222.757712] [<c054559c>] (net_rx_action) from [<c0102ae4>] (__do_softirq+0x1fc/0x278) [ 222.766503] [<c0102ae4>] (__do_softirq) from [<c011da44>] (irq_exit+0x78/0xd0) [ 222.774620] [<c011da44>] (irq_exit) from [<c010c5fc>] (handle_IPI+0x80/0x168) [ 222.782630] [<c010c5fc>] (handle_IPI) from [<c036b854>] (gic_handle_irq+0x70/0x78) [ 222.791131] [<c036b854>] (gic_handle_irq) from [<c01021cc>] (__irq_svc+0x6c/0xa8) [ 222.799525] Exception stack(0xc46e5c38 to 0xc46e5c80) [ 222.805190] 5c20: 00000000 c0c51428 [ 222.814369] 5c40: 00001080 60000013 c46e5d20 c0c5125c 0000000b c7387080 c090fcae ffffe000 [ 222.823547] 5c60: c0c0abb0 00000005 00000000 c46e5c88 c010aa54 c010aa88 60000013 ffffffff [ 222.832730] [<c01021cc>] (__irq_svc) from [<c010aa88>] (die+0x214/0x2f4) [ 222.840256] [<c010aa88>] (die) from [<c010f498>] (__do_kernel_fault.part.0+0x60/0x88) [ 222.849048] [<c010f498>] (__do_kernel_fault.part.0) from [<c010f1d8>] (do_page_fault+0x268/0x270) [ 222.859014] [<c010f1d8>] (do_page_fault) from [<c010f330>] (do_DataAbort+0x38/0xb8) [ 222.867605] [<c010f330>] (do_DataAbort) from [<c0102138>] (__dabt_svc+0x58/0x80) [ 222.875901] Exception stack(0xc46e5d20 to 0xc46e5d68) [ 222.881571] 5d20: c7001e00 00009864 06b73000 00000000 8201cb00 c7001e00 c46e4000 00000dc0 [ 222.890748] 5d40: c02434d8 c46e5d70 00009864 c2163a00 e99b5807 c46e5d70 c01ceea8 c01d0c74 [ 222.899921] 5d60: a00f0013 ffffffff [ 222.903843] [<c0102138>] (__dabt_svc) from [<c01d0c74>] (__kmalloc+0x130/0x194) [ 222.912052] [<c01d0c74>] (__kmalloc) from [<c02434d8>] (ext4_htree_store_dirent+0x28/0xfc) [ 222.921332] [<c02434d8>] (ext4_htree_store_dirent) from [<c026ca54>] (htree_dirblock_to_tree+0x1bc/0x214) [ 222.932073] [<c026ca54>] (htree_dirblock_to_tree) from [<c026d50c>] (ext4_htree_fill_tree+0x104/0x2bc) [ 222.942524] [<c026d50c>] (ext4_htree_fill_tree) from [<c0242ee4>] (ext4_readdir+0x200/0x790) [ 222.952000] [<c0242ee4>] (ext4_readdir) from [<c01e8bec>] (iterate_dir+0x88/0x130) [ 222.960499] Code: eb154c1d e1a00004 e8bd87f0 e5953014 (e7940003) [ 222.967497] ---[ end trace d24442ecf336d28e ]--- [ 222.972782] Kernel panic - not syncing: Fatal exception in interrupt [ 222.979931] CPU1: stopping [ 222.982980] CPU: 1 PID: 1319 Comm: logread Tainted: G D O 5.4.61 #304 [ 222.991469] Hardware name: Generic DT based system [ 222.996863] [<c010e248>] (unwind_backtrace) from [<c010a870>] (show_stack+0x10/0x14) [ 223.005558] [<c010a870>] (show_stack) from [<c0725220>] (dump_stack+0x7c/0x98) [ 223.013667] [<c0725220>] (dump_stack) from [<c010c648>] (handle_IPI+0xcc/0x168) [ 223.021874] [<c010c648>] (handle_IPI) from [<c036b854>] (gic_handle_irq+0x70/0x78) [ 223.030373] [<c036b854>] (gic_handle_irq) from [<c01025b0>] (__irq_usr+0x50/0x80) [ 223.038765] Exception stack(0xc4037fb0 to 0xc4037ff8) [ 223.044432] 7fa0: 0000000a b6e287e8 00000000 000000ff [ 223.053609] 7fc0: 00000000 ffff0000 00000000 0204c2c8 bebc0858 bebc0838 0045a12c 00000000 [ 223.062785] 7fe0: ffffffff bebc07b8 b6d92d58 b6d9305a 600e0430 ffffffff [ 223.070213] Rebooting in 3 seconds..
找了很长时间终于找到原因：
设备树中去掉dma 配置后正常，暂时怀疑可能是dma 和其他地方配置冲突导致的。
&twi2 {
clock-frequency = <200000>;
pinctrl-0 = <&twi2_pins_a>;
pinctrl-1 = <&twi2_pins_b>;
pinctrl-names = "default", "sleep";
// twi_drv_used = <1>;
// dmas = <&dma 45>, <&dma 45>;
// dma-names = "tx", "rx";
status = "okay";
