Vaibhav Hiremath <vaibhav.hiremath@xxxxxxxxxx> writes: >> So, I applied patches 1-6 to for-next to make some progress. >> >> The others need more thought because of the bindings which shall be >> discussed replying to the patches in question. >> >> Thanks for the updated work with lots of proper references. >> > > OK, Thanks and no issues. > > Lets discuss more on the bindings. I made a simple try on my reference platform with the whole patchset. It oopses on a NULL dereference. The stack is in [1]. I think it boils down to : - i2c_pxa_do_sclk_adj() - reg_ilcr = readl(_ILCR(i2c)); I also think the faulty patch is : - i2c: pxa: Add ILCR (tLow & tHigh) configuration support My case, an I2C master case, I'd like you to find the issue and fix it. Cheers. -- Robert [1] Stack &Unable to handle kernel NULL pointer dereference at virtual address 00000000 &pgd = c0004000 "[00000000] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT ARM Modules linked in: CPU: 0 PID: 1 Comm: swapper Not tainted 4.2.0-rc2-next-20150713+ #705 Hardware name: MIO A701 task: c3856bc0 ti: c3858000 task.ti: c3858000 PC is at i2c_pxa_reset+0x114/0x1cc LR is at i2c_pxa_probe+0x35c/0x428 pc : [<c02ee4b0>] lr : [<c02ef080>] psr: 68000053 sp : c3859d50 ip : c3859d70 fp : c3859d6c r10: c38f75ac r9 : c06c7668 r8 : 00000000 r7 : c394a300 r6 : c06c42f0 r5 : c38f7410 r4 : 00000002 r3 : 000087a0 r2 : f2301690 r1 : 00000000 r0 : 00000000 Flags: nZCv IRQs on FIQs off Mode SVC_32 ISA ARM Segment kernel Control: 0000397f Table: a0004000 DAC: 00000017 Process swapper (pid: 1, stack limit = 0xc3858198) Stack: (0xc3859d50 to 0xc385a000) 9d40: 00004080 c38f7410 c06c42e0 c06c42f0 9d60: c3859dbc c3859d70 c02ef080 c02ee3a8 00004080 c38d7b40 c38f7410 c3859d88 9d80: c014eb08 c04d1878 00000001 00000000 00000000 c06c42f0 c06c42f0 c06f10c8 9da0: fffffdfb 00000000 c0678550 00000000 c3859ddc c3859dc0 c0280b18 c02eed30 9dc0: c06c42f0 c0731330 c0705098 c06f10c8 c3859e0c c3859de0 c027e850 c0280ad0 9de0: c3859e0c c3859df0 c06c42f0 c06f10c8 c06c4324 00000000 c0704fc0 c0678550 9e00: c3859e2c c3859e10 c027eb64 c027e6c8 00000000 00000000 c06f10c8 c027eaec 9e20: c3859e54 c3859e30 c027c5c4 c027eaf8 c389b96c c38dc6d0 c3940c78 c06f10c8 9e40: c39408e0 c06ec778 c3859e64 c3859e58 c027e228 c027c56c c3859e94 c3859e68 9e60: c027dbc8 c027e20c c05803d0 c394a3e0 c3859e94 c06f10c8 c06c2380 c394a3e0 9e80: c069a888 00000000 c3859eac c3859e98 c027f6d4 c027dac0 c06c2380 c06c2380 9ea0: c3859ebc c3859eb0 c0280a38 c027f630 c3859ecc c3859ec0 c069a8a0 c02809ec 9ec0: c3859f4c c3859ed0 c000975c c069a894 c3859efc c3859ee0 c3859efc c3859ee8 9ee0: c00389e0 c0201e98 00000000 c3ffcbe1 c3859f4c c3859f00 c0038c00 c00389cc 9f00: c004710c c003eea8 00000000 00000004 00000004 c3ffcbfd c0615b48 c057cd28 9f20: 00000000 00000004 c070f7a0 00000004 c070f7a0 c06bd020 c070f7a0 c06a64b0 9f40: c3859f94 c3859f50 c0678e3c c000963c 00000004 00000004 00000000 c0678550 9f60: c0497ffc 00000085 00000000 00000000 c0497ffc 00000000 00000000 00000000 9f80: 00000000 00000000 c3859fac c3859f98 c0498014 c0678d44 c3858000 00000000 9fa0: 00000000 c3859fb0 c000a5f0 c0498008 00000000 00000000 00000000 00000000 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 b3ff8c5d 4cc3d76f [<c02ee4b0>] (i2c_pxa_reset) from [<c02ef080>] (i2c_pxa_probe+0x35c/0x428) [<c02ef080>] (i2c_pxa_probe) from [<c0280b18>] (platform_drv_probe+0x54/0xb0) [<c0280b18>] (platform_drv_probe) from [<c027e850>] (driver_probe_device+0x194/0x430) [<c027e850>] (driver_probe_device) from [<c027eb64>] (__driver_attach+0x78/0x9c) [<c027eb64>] (__driver_attach) from [<c027c5c4>] (bus_for_each_dev+0x64/0xb4) [<c027c5c4>] (bus_for_each_dev) from [<c027e228>] (driver_attach+0x28/0x30) [<c027e228>] (driver_attach) from [<c027dbc8>] (bus_add_driver+0x114/0x274) [<c027dbc8>] (bus_add_driver) from [<c027f6d4>] (driver_register+0xb0/0xf8) [<c027f6d4>] (driver_register) from [<c0280a38>] (__platform_driver_register+0x58/0x6c) [<c0280a38>] (__platform_driver_register) from [<c069a8a0>] (i2c_adap_pxa_init+0x18/0x20) [<c069a8a0>] (i2c_adap_pxa_init) from [<c000975c>] (do_one_initcall+0x12c/0x220) [<c000975c>] (do_one_initcall) from [<c0678e3c>] (kernel_init_freeable+0x104/0x1d8) [<c0678e3c>] (kernel_init_freeable) from [<c0498014>] (kernel_init+0x18/0xfc) [<c0498014>] (kernel_init) from [<c000a5f0>] (ret_from_fork+0x14/0x24) Code: 03a00000 e1803003 e5823000 e5950318 (e5903000) ---[ end trace 76138ae455db32c0 ]--- [2] Disassembly of the i2c_pxa_reset() and its inlined i2c_pxa_do_sclk_adj() 512 513 static void i2c_pxa_do_sclk_adj(struct pxa_i2c *i2c) 514 { 515 unsigned int reg_ilcr; 516 517 reg_ilcr = readl(_ILCR(i2c)); 0xc02ee4ac <+272>: ldr r0, [r5, #792] ; 0x318 518 519 /* For standard/fast mode tlow and thigh counters are same */ 520 if (i2c->sclk_tlow_load_cnt) { 0xc02ee4b4 <+280>: ldr r12, [r5, #828] ; 0x33c 0xc02ee4b8 <+284>: cmp r12, #0 0xc02ee4bc <+288>: beq 0xc02ee4fc <i2c_pxa_reset+352> -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html