| Message ID | 20200831161436.134186-1-jagan@amarulasolutions.com (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Headers | show |
| Series | clk: rockchip: Fix overflow rate during fractional approximation | expand |
Quoting Jagan Teki (2020-08-31 09:14:36) > The current rockchip fractional approximation overflow the desired > rate if parent rate is lower than the (rate * 20) for few clocks like > dclk_vopb_frac. > > The overflow condition has observed in px30 for dclk_vopb_frac > clock with an input rate of 71.1MHz and parent rate of 24MHz is, > > [ 2.543280] rockchip-drm display-subsystem: bound ff460000.vop (ops vop_component_ops) Can you remove timestamps? > [ 2.557313] rockchip-drm display-subsystem: bound ff470000.vop (ops vop_component_ops) > [ 2.566356] rockchip-drm display-subsystem: bound ff140000.syscon:lvds (ops rockchip_lvds_component_ops) > [ 2.576999] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). > [ 2.592177] Unexpected kernel BRK exception at EL1 > [ 2.597551] Internal error: ptrace BRK handler: f20003e8 [#1] PREEMPT SMP > [ 2.605143] Modules linked in: > [ 2.608566] CPU: 1 PID: 31 Comm: kworker/1:1 Tainted: G U 5.8.0-rc1-15632-g97edd822b844 #30 > [ 2.619363] Hardware name: Engicam PX30.Core C.TOUCH 2.0 10.1" Open Frame (DT) > [ 2.627460] Workqueue: events deferred_probe_work_func > [ 2.633209] pstate: 20000005 (nzCv daif -PAN -UAO BTYPE=--) > [ 2.639445] pc : rational_best_approximation+0xc4/0xd0 > [ 2.645194] lr : rockchip_fractional_approximation+0xa8/0xe0 > [ 2.651520] sp : ffff800011ea31c0 > [ 2.655222] x29: ffff800011ea31c0 x28: ffff00007a4ecd50 > [ 2.661162] x27: ffff00007d042600 x26: 000000000439fca3 > [ 2.667102] x25: 0000000000000000 x24: ffff800011ac9948 > [ 2.673033] x23: ffff800011ea3308 x22: ffff00007d042418 > [ 2.678973] x21: ffff800011ea3240 x20: ffff800011ea3238 > [ 2.684904] x19: ea47000000000000 x18: 0000000000000000 > [ 2.690836] x17: 0000000000000500 x16: 0000000000000001 > [ 2.696775] x15: ffffffffffffffff x14: 0000000000000000 > [ 2.702707] x13: 0000000000000000 x12: 0000003c00000000 > [ 2.708647] x11: 0000000000000030 x10: 0101010101010101 > [ 2.714586] x9 : 0000032000000320 x8 : 7f7f7f7f7f7f7f7f > [ 2.720517] x7 : 000000a3c59050d3 x6 : 0000000000000030 > [ 2.726457] x5 : ffff800011ea3240 x4 : ffff800011ea3238 > [ 2.732397] x3 : 000000000000ffff x2 : 000000000000ffff > [ 2.738329] x1 : 00000000016e3600 x0 : 0000000001497e00 > [ 2.744269] Call trace: > [ 2.747005] rational_best_approximation+0xc4/0xd0 > [ 2.752365] clk_fd_round_rate+0x8c/0x110 > [ 2.756846] clk_composite_round_rate+0x30/0x40 > [ 2.761917] clk_core_determine_round_nolock.part.30+0x44/0x80 > [ 2.768442] clk_core_round_rate_nolock+0x78/0x80 > [ 2.773701] clk_mux_determine_rate_flags+0xd8/0x200 > [ 2.779253] clk_mux_determine_rate+0x10/0x20 > [ 2.784124] clk_core_determine_round_nolock.part.30+0x1c/0x80 > [ 2.790639] clk_core_round_rate_nolock+0x78/0x80 > [ 2.795900] clk_core_round_rate_nolock+0x5c/0x80 > [ 2.801159] clk_round_rate+0x64/0xf0 > [ 2.805254] vop_crtc_mode_fixup+0x2c/0x60 > [ 2.809828] drm_atomic_helper_check_modeset+0x95c/0xae0 > [ 2.815767] drm_atomic_helper_check+0x1c/0xa0 > [ 2.820738] drm_atomic_check_only+0x43c/0x760 > [ 2.825705] drm_atomic_commit+0x18/0x60 > [ 2.830095] drm_client_modeset_commit_atomic.isra.16+0x17c/0x250 > [ 2.836911] drm_client_modeset_commit_locked+0x58/0x1a0 > [ 2.842851] drm_client_modeset_commit+0x2c/0x50 > [ 2.848014] drm_fb_helper_restore_fbdev_mode_unlocked+0x70/0xd0 > [ 2.854730] drm_fb_helper_set_par+0x2c/0x60 > [ 2.859497] fbcon_init+0x3c0/0x540 > [ 2.863400] visual_init+0xac/0x100 > [ 2.867298] do_bind_con_driver+0x1e4/0x3a0 > [ 2.871973] do_take_over_console+0x140/0x200 > [ 2.876843] do_fbcon_takeover+0x6c/0xe0 > [ 2.881228] fbcon_fb_registered+0x10c/0x120 > [ 2.886005] register_framebuffer+0x1f0/0x340 > [ 2.890878] __drm_fb_helper_initial_config_and_unlock+0x318/0x4a0 > [ 2.897790] drm_fb_helper_initial_config+0x3c/0x50 > [ 2.903244] rockchip_drm_fbdev_init+0x5c/0xf0 > [ 2.908202] rockchip_drm_bind+0x194/0x1e0 > [ 2.912785] try_to_bring_up_master+0x164/0x1d0 > [ 2.917851] component_master_add_with_match+0xac/0xf0 > [ 2.923597] rockchip_drm_platform_probe+0x238/0x2e0 > [ 2.929150] platform_drv_probe+0x50/0xa0 > [ 2.933631] really_probe+0xd4/0x330 > [ 2.937628] driver_probe_device+0x54/0xb0 > [ 2.942207] __device_attach_driver+0x80/0xc0 > [ 2.947078] bus_for_each_drv+0x78/0xd0 > [ 2.951365] __device_attach+0xd4/0x130 > [ 2.955652] device_initial_probe+0x10/0x20 > [ 2.960328] bus_probe_device+0x90/0xa0 > [ 2.964616] deferred_probe_work_func+0x6c/0xa0 > [ 2.969685] process_one_work+0x1e4/0x360 > [ 2.974166] worker_thread+0x208/0x480 > [ 2.978358] kthread+0x150/0x160 > [ 2.981968] ret_from_fork+0x10/0x18 Wow this stack is huge. > [ 2.985970] Code: d65f03c0 d2800008 d2800027 17ffffe8 (d4207d00) > > This happened because the fractional divider does not apply if parent_rate > is lower than (rate * 20). > > So, this patch is trying to fix that overflow clock and switch to half-div > instead computing fractioanl approximation. > > Some part of the patch is referenced from below BSP commit: > > commit <88a5404a2277> ("clk: rockchip: fix up the > rockchip_fractional_approximation") > > commit <4186a0e4239b> ("clk: rockchip: Add supprot to limit input rate > for fractional divider") Not sure what these are. Do we need random commit hashes in the log that reference not-upstream patches? Seems like it could be left below the triple dash and anyone can reference the mailing list if they really care. > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> > Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com> > --- Any Fixes tag? > drivers/clk/rockchip/clk-px30.c | 12 ++++++------ > drivers/clk/rockchip/clk.c | 9 +++++++++ > 2 files changed, 15 insertions(+), 6 deletions(-) >
在 2020/9/1 上午12:14, Jagan Teki 写道: > The current rockchip fractional approximation overflow the desired > rate if parent rate is lower than the (rate * 20) for few clocks like > dclk_vopb_frac. > > The overflow condition has observed in px30 for dclk_vopb_frac > clock with an input rate of 71.1MHz and parent rate of 24MHz is, > > [ 2.543280] rockchip-drm display-subsystem: bound ff460000.vop (ops vop_component_ops) > [ 2.557313] rockchip-drm display-subsystem: bound ff470000.vop (ops vop_component_ops) > [ 2.566356] rockchip-drm display-subsystem: bound ff140000.syscon:lvds (ops rockchip_lvds_component_ops) > [ 2.576999] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). > [ 2.592177] Unexpected kernel BRK exception at EL1 > [ 2.597551] Internal error: ptrace BRK handler: f20003e8 [#1] PREEMPT SMP > [ 2.605143] Modules linked in: > [ 2.608566] CPU: 1 PID: 31 Comm: kworker/1:1 Tainted: G U 5.8.0-rc1-15632-g97edd822b844 #30 > [ 2.619363] Hardware name: Engicam PX30.Core C.TOUCH 2.0 10.1" Open Frame (DT) > [ 2.627460] Workqueue: events deferred_probe_work_func > [ 2.633209] pstate: 20000005 (nzCv daif -PAN -UAO BTYPE=--) > [ 2.639445] pc : rational_best_approximation+0xc4/0xd0 > [ 2.645194] lr : rockchip_fractional_approximation+0xa8/0xe0 > [ 2.651520] sp : ffff800011ea31c0 > [ 2.655222] x29: ffff800011ea31c0 x28: ffff00007a4ecd50 > [ 2.661162] x27: ffff00007d042600 x26: 000000000439fca3 > [ 2.667102] x25: 0000000000000000 x24: ffff800011ac9948 > [ 2.673033] x23: ffff800011ea3308 x22: ffff00007d042418 > [ 2.678973] x21: ffff800011ea3240 x20: ffff800011ea3238 > [ 2.684904] x19: ea47000000000000 x18: 0000000000000000 > [ 2.690836] x17: 0000000000000500 x16: 0000000000000001 > [ 2.696775] x15: ffffffffffffffff x14: 0000000000000000 > [ 2.702707] x13: 0000000000000000 x12: 0000003c00000000 > [ 2.708647] x11: 0000000000000030 x10: 0101010101010101 > [ 2.714586] x9 : 0000032000000320 x8 : 7f7f7f7f7f7f7f7f > [ 2.720517] x7 : 000000a3c59050d3 x6 : 0000000000000030 > [ 2.726457] x5 : ffff800011ea3240 x4 : ffff800011ea3238 > [ 2.732397] x3 : 000000000000ffff x2 : 000000000000ffff > [ 2.738329] x1 : 00000000016e3600 x0 : 0000000001497e00 > [ 2.744269] Call trace: > [ 2.747005] rational_best_approximation+0xc4/0xd0 > [ 2.752365] clk_fd_round_rate+0x8c/0x110 > [ 2.756846] clk_composite_round_rate+0x30/0x40 > [ 2.761917] clk_core_determine_round_nolock.part.30+0x44/0x80 > [ 2.768442] clk_core_round_rate_nolock+0x78/0x80 > [ 2.773701] clk_mux_determine_rate_flags+0xd8/0x200 > [ 2.779253] clk_mux_determine_rate+0x10/0x20 > [ 2.784124] clk_core_determine_round_nolock.part.30+0x1c/0x80 > [ 2.790639] clk_core_round_rate_nolock+0x78/0x80 > [ 2.795900] clk_core_round_rate_nolock+0x5c/0x80 > [ 2.801159] clk_round_rate+0x64/0xf0 > [ 2.805254] vop_crtc_mode_fixup+0x2c/0x60 > [ 2.809828] drm_atomic_helper_check_modeset+0x95c/0xae0 > [ 2.815767] drm_atomic_helper_check+0x1c/0xa0 > [ 2.820738] drm_atomic_check_only+0x43c/0x760 > [ 2.825705] drm_atomic_commit+0x18/0x60 > [ 2.830095] drm_client_modeset_commit_atomic.isra.16+0x17c/0x250 > [ 2.836911] drm_client_modeset_commit_locked+0x58/0x1a0 > [ 2.842851] drm_client_modeset_commit+0x2c/0x50 > [ 2.848014] drm_fb_helper_restore_fbdev_mode_unlocked+0x70/0xd0 > [ 2.854730] drm_fb_helper_set_par+0x2c/0x60 > [ 2.859497] fbcon_init+0x3c0/0x540 > [ 2.863400] visual_init+0xac/0x100 > [ 2.867298] do_bind_con_driver+0x1e4/0x3a0 > [ 2.871973] do_take_over_console+0x140/0x200 > [ 2.876843] do_fbcon_takeover+0x6c/0xe0 > [ 2.881228] fbcon_fb_registered+0x10c/0x120 > [ 2.886005] register_framebuffer+0x1f0/0x340 > [ 2.890878] __drm_fb_helper_initial_config_and_unlock+0x318/0x4a0 > [ 2.897790] drm_fb_helper_initial_config+0x3c/0x50 > [ 2.903244] rockchip_drm_fbdev_init+0x5c/0xf0 > [ 2.908202] rockchip_drm_bind+0x194/0x1e0 > [ 2.912785] try_to_bring_up_master+0x164/0x1d0 > [ 2.917851] component_master_add_with_match+0xac/0xf0 > [ 2.923597] rockchip_drm_platform_probe+0x238/0x2e0 > [ 2.929150] platform_drv_probe+0x50/0xa0 > [ 2.933631] really_probe+0xd4/0x330 > [ 2.937628] driver_probe_device+0x54/0xb0 > [ 2.942207] __device_attach_driver+0x80/0xc0 > [ 2.947078] bus_for_each_drv+0x78/0xd0 > [ 2.951365] __device_attach+0xd4/0x130 > [ 2.955652] device_initial_probe+0x10/0x20 > [ 2.960328] bus_probe_device+0x90/0xa0 > [ 2.964616] deferred_probe_work_func+0x6c/0xa0 > [ 2.969685] process_one_work+0x1e4/0x360 > [ 2.974166] worker_thread+0x208/0x480 > [ 2.978358] kthread+0x150/0x160 > [ 2.981968] ret_from_fork+0x10/0x18 > [ 2.985970] Code: d65f03c0 d2800008 d2800027 17ffffe8 (d4207d00) > > This happened because the fractional divider does not apply if parent_rate > is lower than (rate * 20). > > So, this patch is trying to fix that overflow clock and switch to half-div > instead computing fractioanl approximation. > > Some part of the patch is referenced from below BSP commit: > > commit <88a5404a2277> ("clk: rockchip: fix up the > rockchip_fractional_approximation") > > commit <4186a0e4239b> ("clk: rockchip: Add supprot to limit input rate > for fractional divider") > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> > Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com> > --- > drivers/clk/rockchip/clk-px30.c | 12 ++++++------ > drivers/clk/rockchip/clk.c | 9 +++++++++ > 2 files changed, 15 insertions(+), 6 deletions(-) > > diff --git a/drivers/clk/rockchip/clk-px30.c b/drivers/clk/rockchip/clk-px30.c > index 6fb9c98b7d24..06d3ff39d12f 100644 > --- a/drivers/clk/rockchip/clk-px30.c > +++ b/drivers/clk/rockchip/clk-px30.c > @@ -660,7 +660,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { > COMPOSITE(SCLK_UART1_SRC, "clk_uart1_src", mux_uart_src_p, CLK_SET_RATE_NO_REPARENT, > PX30_CLKSEL_CON(34), 14, 2, MFLAGS, 0, 5, DFLAGS, > PX30_CLKGATE_CON(10), 12, GFLAGS), > - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart1_np5", "clk_uart1_src", 0, > + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart1_np5", "clk_uart1_src", CLK_SET_RATE_PARENT, > PX30_CLKSEL_CON(35), 0, 5, DFLAGS, > PX30_CLKGATE_CON(10), 13, GFLAGS), > COMPOSITE_FRACMUX(0, "clk_uart1_frac", "clk_uart1_src", CLK_SET_RATE_PARENT, > @@ -673,7 +673,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { > COMPOSITE(SCLK_UART2_SRC, "clk_uart2_src", mux_uart_src_p, 0, > PX30_CLKSEL_CON(37), 14, 2, MFLAGS, 0, 5, DFLAGS, > PX30_CLKGATE_CON(11), 0, GFLAGS), > - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart2_np5", "clk_uart2_src", 0, > + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart2_np5", "clk_uart2_src", CLK_SET_RATE_PARENT, > PX30_CLKSEL_CON(38), 0, 5, DFLAGS, > PX30_CLKGATE_CON(11), 1, GFLAGS), > COMPOSITE_FRACMUX(0, "clk_uart2_frac", "clk_uart2_src", CLK_SET_RATE_PARENT, > @@ -686,7 +686,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { > COMPOSITE(0, "clk_uart3_src", mux_uart_src_p, 0, > PX30_CLKSEL_CON(40), 14, 2, MFLAGS, 0, 5, DFLAGS, > PX30_CLKGATE_CON(11), 4, GFLAGS), > - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart3_np5", "clk_uart3_src", 0, > + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart3_np5", "clk_uart3_src", CLK_SET_RATE_PARENT, > PX30_CLKSEL_CON(41), 0, 5, DFLAGS, > PX30_CLKGATE_CON(11), 5, GFLAGS), > COMPOSITE_FRACMUX(0, "clk_uart3_frac", "clk_uart3_src", CLK_SET_RATE_PARENT, > @@ -699,7 +699,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { > COMPOSITE(0, "clk_uart4_src", mux_uart_src_p, 0, > PX30_CLKSEL_CON(43), 14, 2, MFLAGS, 0, 5, DFLAGS, > PX30_CLKGATE_CON(11), 8, GFLAGS), > - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart4_np5", "clk_uart4_src", 0, > + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart4_np5", "clk_uart4_src", CLK_SET_RATE_PARENT, > PX30_CLKSEL_CON(44), 0, 5, DFLAGS, > PX30_CLKGATE_CON(11), 9, GFLAGS), > COMPOSITE_FRACMUX(0, "clk_uart4_frac", "clk_uart4_src", CLK_SET_RATE_PARENT, > @@ -712,7 +712,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { > COMPOSITE(0, "clk_uart5_src", mux_uart_src_p, 0, > PX30_CLKSEL_CON(46), 14, 2, MFLAGS, 0, 5, DFLAGS, > PX30_CLKGATE_CON(11), 12, GFLAGS), > - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart5_np5", "clk_uart5_src", 0, > + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart5_np5", "clk_uart5_src", CLK_SET_RATE_PARENT, > PX30_CLKSEL_CON(47), 0, 5, DFLAGS, > PX30_CLKGATE_CON(11), 13, GFLAGS), > COMPOSITE_FRACMUX(0, "clk_uart5_frac", "clk_uart5_src", CLK_SET_RATE_PARENT, > @@ -934,7 +934,7 @@ static struct rockchip_clk_branch px30_clk_pmu_branches[] __initdata = { > COMPOSITE(0, "clk_uart0_pmu_src", mux_uart_src_p, 0, > PX30_PMU_CLKSEL_CON(3), 14, 2, MFLAGS, 0, 5, DFLAGS, > PX30_PMU_CLKGATE_CON(1), 0, GFLAGS), > - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart0_np5", "clk_uart0_pmu_src", 0, > + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart0_np5", "clk_uart0_pmu_src", CLK_SET_RATE_PARENT, > PX30_PMU_CLKSEL_CON(4), 0, 5, DFLAGS, > PX30_PMU_CLKGATE_CON(1), 1, GFLAGS), > COMPOSITE_FRACMUX(0, "clk_uart0_frac", "clk_uart0_pmu_src", CLK_SET_RATE_PARENT, > diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c > index 546e810c3560..38d032faa05e 100644 > --- a/drivers/clk/rockchip/clk.c > +++ b/drivers/clk/rockchip/clk.c > @@ -190,6 +190,15 @@ static void rockchip_fractional_approximation(struct clk_hw *hw, > p_parent = clk_hw_get_parent(clk_hw_get_parent(hw)); > p_parent_rate = clk_hw_get_rate(p_parent); > *parent_rate = p_parent_rate; > + > + /* fractional divider not apply if parent_rate is lower than (rate * 20) */ > + if (*parent_rate < rate * 20) { > + pr_warn("%s: %s fractional div is not allowed, so use half-div\n", > + __func__, clk_hw_get_name(hw)); > + *m = 0; > + *n = 1; > + return; > + } This is a public file, please submit separately. And there are no half-div on some rockchip platforms. > } > > /*
hi, We have two submissions which I hope will be helpful to you. https://patchwork.kernel.org/patch/11272465/ https://patchwork.kernel.org/patch/11272471/ A few more notes: 1. DCLK does not recommend the use of fractional frequency divider. Generally, DCLK will monopolize a PLL, and the relationship between DCLK frequency and PLL frequency is 1:1. 2, half-div, not all SOC support, detailed need to see TRM. 在 2020/9/15 上午9:20, Finley Xiao 写道: > > 在 2020/9/1 上午12:14, Jagan Teki 写道: >> The current rockchip fractional approximation overflow the desired >> rate if parent rate is lower than the (rate * 20) for few clocks like >> dclk_vopb_frac. >> >> The overflow condition has observed in px30 for dclk_vopb_frac >> clock with an input rate of 71.1MHz and parent rate of 24MHz is, >> >> [ 2.543280] rockchip-drm display-subsystem: bound ff460000.vop >> (ops vop_component_ops) >> [ 2.557313] rockchip-drm display-subsystem: bound ff470000.vop >> (ops vop_component_ops) >> [ 2.566356] rockchip-drm display-subsystem: bound >> ff140000.syscon:lvds (ops rockchip_lvds_component_ops) >> [ 2.576999] [drm] Supports vblank timestamp caching Rev 2 >> (21.10.2013). >> [ 2.592177] Unexpected kernel BRK exception at EL1 >> [ 2.597551] Internal error: ptrace BRK handler: f20003e8 [#1] >> PREEMPT SMP >> [ 2.605143] Modules linked in: >> [ 2.608566] CPU: 1 PID: 31 Comm: kworker/1:1 Tainted: G >> U 5.8.0-rc1-15632-g97edd822b844 #30 >> [ 2.619363] Hardware name: Engicam PX30.Core C.TOUCH 2.0 10.1" >> Open Frame (DT) >> [ 2.627460] Workqueue: events deferred_probe_work_func >> [ 2.633209] pstate: 20000005 (nzCv daif -PAN -UAO BTYPE=--) >> [ 2.639445] pc : rational_best_approximation+0xc4/0xd0 >> [ 2.645194] lr : rockchip_fractional_approximation+0xa8/0xe0 >> [ 2.651520] sp : ffff800011ea31c0 >> [ 2.655222] x29: ffff800011ea31c0 x28: ffff00007a4ecd50 >> [ 2.661162] x27: ffff00007d042600 x26: 000000000439fca3 >> [ 2.667102] x25: 0000000000000000 x24: ffff800011ac9948 >> [ 2.673033] x23: ffff800011ea3308 x22: ffff00007d042418 >> [ 2.678973] x21: ffff800011ea3240 x20: ffff800011ea3238 >> [ 2.684904] x19: ea47000000000000 x18: 0000000000000000 >> [ 2.690836] x17: 0000000000000500 x16: 0000000000000001 >> [ 2.696775] x15: ffffffffffffffff x14: 0000000000000000 >> [ 2.702707] x13: 0000000000000000 x12: 0000003c00000000 >> [ 2.708647] x11: 0000000000000030 x10: 0101010101010101 >> [ 2.714586] x9 : 0000032000000320 x8 : 7f7f7f7f7f7f7f7f >> [ 2.720517] x7 : 000000a3c59050d3 x6 : 0000000000000030 >> [ 2.726457] x5 : ffff800011ea3240 x4 : ffff800011ea3238 >> [ 2.732397] x3 : 000000000000ffff x2 : 000000000000ffff >> [ 2.738329] x1 : 00000000016e3600 x0 : 0000000001497e00 >> [ 2.744269] Call trace: >> [ 2.747005] rational_best_approximation+0xc4/0xd0 >> [ 2.752365] clk_fd_round_rate+0x8c/0x110 >> [ 2.756846] clk_composite_round_rate+0x30/0x40 >> [ 2.761917] clk_core_determine_round_nolock.part.30+0x44/0x80 >> [ 2.768442] clk_core_round_rate_nolock+0x78/0x80 >> [ 2.773701] clk_mux_determine_rate_flags+0xd8/0x200 >> [ 2.779253] clk_mux_determine_rate+0x10/0x20 >> [ 2.784124] clk_core_determine_round_nolock.part.30+0x1c/0x80 >> [ 2.790639] clk_core_round_rate_nolock+0x78/0x80 >> [ 2.795900] clk_core_round_rate_nolock+0x5c/0x80 >> [ 2.801159] clk_round_rate+0x64/0xf0 >> [ 2.805254] vop_crtc_mode_fixup+0x2c/0x60 >> [ 2.809828] drm_atomic_helper_check_modeset+0x95c/0xae0 >> [ 2.815767] drm_atomic_helper_check+0x1c/0xa0 >> [ 2.820738] drm_atomic_check_only+0x43c/0x760 >> [ 2.825705] drm_atomic_commit+0x18/0x60 >> [ 2.830095] drm_client_modeset_commit_atomic.isra.16+0x17c/0x250 >> [ 2.836911] drm_client_modeset_commit_locked+0x58/0x1a0 >> [ 2.842851] drm_client_modeset_commit+0x2c/0x50 >> [ 2.848014] drm_fb_helper_restore_fbdev_mode_unlocked+0x70/0xd0 >> [ 2.854730] drm_fb_helper_set_par+0x2c/0x60 >> [ 2.859497] fbcon_init+0x3c0/0x540 >> [ 2.863400] visual_init+0xac/0x100 >> [ 2.867298] do_bind_con_driver+0x1e4/0x3a0 >> [ 2.871973] do_take_over_console+0x140/0x200 >> [ 2.876843] do_fbcon_takeover+0x6c/0xe0 >> [ 2.881228] fbcon_fb_registered+0x10c/0x120 >> [ 2.886005] register_framebuffer+0x1f0/0x340 >> [ 2.890878] __drm_fb_helper_initial_config_and_unlock+0x318/0x4a0 >> [ 2.897790] drm_fb_helper_initial_config+0x3c/0x50 >> [ 2.903244] rockchip_drm_fbdev_init+0x5c/0xf0 >> [ 2.908202] rockchip_drm_bind+0x194/0x1e0 >> [ 2.912785] try_to_bring_up_master+0x164/0x1d0 >> [ 2.917851] component_master_add_with_match+0xac/0xf0 >> [ 2.923597] rockchip_drm_platform_probe+0x238/0x2e0 >> [ 2.929150] platform_drv_probe+0x50/0xa0 >> [ 2.933631] really_probe+0xd4/0x330 >> [ 2.937628] driver_probe_device+0x54/0xb0 >> [ 2.942207] __device_attach_driver+0x80/0xc0 >> [ 2.947078] bus_for_each_drv+0x78/0xd0 >> [ 2.951365] __device_attach+0xd4/0x130 >> [ 2.955652] device_initial_probe+0x10/0x20 >> [ 2.960328] bus_probe_device+0x90/0xa0 >> [ 2.964616] deferred_probe_work_func+0x6c/0xa0 >> [ 2.969685] process_one_work+0x1e4/0x360 >> [ 2.974166] worker_thread+0x208/0x480 >> [ 2.978358] kthread+0x150/0x160 >> [ 2.981968] ret_from_fork+0x10/0x18 >> [ 2.985970] Code: d65f03c0 d2800008 d2800027 17ffffe8 (d4207d00) >> >> This happened because the fractional divider does not apply if >> parent_rate >> is lower than (rate * 20). >> >> So, this patch is trying to fix that overflow clock and switch to >> half-div >> instead computing fractioanl approximation. >> >> Some part of the patch is referenced from below BSP commit: >> >> commit <88a5404a2277> ("clk: rockchip: fix up the >> rockchip_fractional_approximation") >> >> commit <4186a0e4239b> ("clk: rockchip: Add supprot to limit input rate >> for fractional divider") >> >> Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> >> Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com> >> --- >> drivers/clk/rockchip/clk-px30.c | 12 ++++++------ >> drivers/clk/rockchip/clk.c | 9 +++++++++ >> 2 files changed, 15 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/clk/rockchip/clk-px30.c >> b/drivers/clk/rockchip/clk-px30.c >> index 6fb9c98b7d24..06d3ff39d12f 100644 >> --- a/drivers/clk/rockchip/clk-px30.c >> +++ b/drivers/clk/rockchip/clk-px30.c >> @@ -660,7 +660,7 @@ static struct rockchip_clk_branch >> px30_clk_branches[] __initdata = { >> COMPOSITE(SCLK_UART1_SRC, "clk_uart1_src", mux_uart_src_p, >> CLK_SET_RATE_NO_REPARENT, >> PX30_CLKSEL_CON(34), 14, 2, MFLAGS, 0, 5, DFLAGS, >> PX30_CLKGATE_CON(10), 12, GFLAGS), >> - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart1_np5", "clk_uart1_src", 0, >> + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart1_np5", "clk_uart1_src", >> CLK_SET_RATE_PARENT, >> PX30_CLKSEL_CON(35), 0, 5, DFLAGS, >> PX30_CLKGATE_CON(10), 13, GFLAGS), >> COMPOSITE_FRACMUX(0, "clk_uart1_frac", "clk_uart1_src", >> CLK_SET_RATE_PARENT, >> @@ -673,7 +673,7 @@ static struct rockchip_clk_branch >> px30_clk_branches[] __initdata = { >> COMPOSITE(SCLK_UART2_SRC, "clk_uart2_src", mux_uart_src_p, 0, >> PX30_CLKSEL_CON(37), 14, 2, MFLAGS, 0, 5, DFLAGS, >> PX30_CLKGATE_CON(11), 0, GFLAGS), >> - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart2_np5", "clk_uart2_src", 0, >> + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart2_np5", "clk_uart2_src", >> CLK_SET_RATE_PARENT, >> PX30_CLKSEL_CON(38), 0, 5, DFLAGS, >> PX30_CLKGATE_CON(11), 1, GFLAGS), >> COMPOSITE_FRACMUX(0, "clk_uart2_frac", "clk_uart2_src", >> CLK_SET_RATE_PARENT, >> @@ -686,7 +686,7 @@ static struct rockchip_clk_branch >> px30_clk_branches[] __initdata = { >> COMPOSITE(0, "clk_uart3_src", mux_uart_src_p, 0, >> PX30_CLKSEL_CON(40), 14, 2, MFLAGS, 0, 5, DFLAGS, >> PX30_CLKGATE_CON(11), 4, GFLAGS), >> - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart3_np5", "clk_uart3_src", 0, >> + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart3_np5", "clk_uart3_src", >> CLK_SET_RATE_PARENT, >> PX30_CLKSEL_CON(41), 0, 5, DFLAGS, >> PX30_CLKGATE_CON(11), 5, GFLAGS), >> COMPOSITE_FRACMUX(0, "clk_uart3_frac", "clk_uart3_src", >> CLK_SET_RATE_PARENT, >> @@ -699,7 +699,7 @@ static struct rockchip_clk_branch >> px30_clk_branches[] __initdata = { >> COMPOSITE(0, "clk_uart4_src", mux_uart_src_p, 0, >> PX30_CLKSEL_CON(43), 14, 2, MFLAGS, 0, 5, DFLAGS, >> PX30_CLKGATE_CON(11), 8, GFLAGS), >> - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart4_np5", "clk_uart4_src", 0, >> + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart4_np5", "clk_uart4_src", >> CLK_SET_RATE_PARENT, >> PX30_CLKSEL_CON(44), 0, 5, DFLAGS, >> PX30_CLKGATE_CON(11), 9, GFLAGS), >> COMPOSITE_FRACMUX(0, "clk_uart4_frac", "clk_uart4_src", >> CLK_SET_RATE_PARENT, >> @@ -712,7 +712,7 @@ static struct rockchip_clk_branch >> px30_clk_branches[] __initdata = { >> COMPOSITE(0, "clk_uart5_src", mux_uart_src_p, 0, >> PX30_CLKSEL_CON(46), 14, 2, MFLAGS, 0, 5, DFLAGS, >> PX30_CLKGATE_CON(11), 12, GFLAGS), >> - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart5_np5", "clk_uart5_src", 0, >> + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart5_np5", "clk_uart5_src", >> CLK_SET_RATE_PARENT, >> PX30_CLKSEL_CON(47), 0, 5, DFLAGS, >> PX30_CLKGATE_CON(11), 13, GFLAGS), >> COMPOSITE_FRACMUX(0, "clk_uart5_frac", "clk_uart5_src", >> CLK_SET_RATE_PARENT, >> @@ -934,7 +934,7 @@ static struct rockchip_clk_branch >> px30_clk_pmu_branches[] __initdata = { >> COMPOSITE(0, "clk_uart0_pmu_src", mux_uart_src_p, 0, >> PX30_PMU_CLKSEL_CON(3), 14, 2, MFLAGS, 0, 5, DFLAGS, >> PX30_PMU_CLKGATE_CON(1), 0, GFLAGS), >> - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart0_np5", "clk_uart0_pmu_src", 0, >> + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart0_np5", "clk_uart0_pmu_src", >> CLK_SET_RATE_PARENT, >> PX30_PMU_CLKSEL_CON(4), 0, 5, DFLAGS, >> PX30_PMU_CLKGATE_CON(1), 1, GFLAGS), >> COMPOSITE_FRACMUX(0, "clk_uart0_frac", "clk_uart0_pmu_src", >> CLK_SET_RATE_PARENT, >> diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c >> index 546e810c3560..38d032faa05e 100644 >> --- a/drivers/clk/rockchip/clk.c >> +++ b/drivers/clk/rockchip/clk.c >> @@ -190,6 +190,15 @@ static void >> rockchip_fractional_approximation(struct clk_hw *hw, >> p_parent = clk_hw_get_parent(clk_hw_get_parent(hw)); >> p_parent_rate = clk_hw_get_rate(p_parent); >> *parent_rate = p_parent_rate; >> + >> + /* fractional divider not apply if parent_rate is lower than >> (rate * 20) */ >> + if (*parent_rate < rate * 20) { >> + pr_warn("%s: %s fractional div is not allowed, so use >> half-div\n", >> + __func__, clk_hw_get_name(hw)); >> + *m = 0; >> + *n = 1; >> + return; >> + } > > This is a public file, please submit separately. > > And there are no half-div on some rockchip platforms. > >> } >> /* >
Hi, On Tue, Sep 15, 2020 at 7:10 AM elaine.zhang <zhangqing@rock-chips.com> wrote: > > hi, > > We have two submissions which I hope will be helpful to you. > > https://patchwork.kernel.org/patch/11272465/ > https://patchwork.kernel.org/patch/11272471/ I can see this, I have reconstructed the fractional divider handling for px30 instead of all rockchiip platforms, is it okay to send px30-alone fractional div handling support? > > > A few more notes: > 1. DCLK does not recommend the use of fractional frequency divider. > Generally, DCLK will monopolize a PLL, and the relationship between DCLK > frequency and PLL frequency is 1:1. > 2, half-div, not all SOC support, detailed need to see TRM. Can you point me the Page number on TRM? Jagan.
diff --git a/drivers/clk/rockchip/clk-px30.c b/drivers/clk/rockchip/clk-px30.c index 6fb9c98b7d24..06d3ff39d12f 100644 --- a/drivers/clk/rockchip/clk-px30.c +++ b/drivers/clk/rockchip/clk-px30.c @@ -660,7 +660,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { COMPOSITE(SCLK_UART1_SRC, "clk_uart1_src", mux_uart_src_p, CLK_SET_RATE_NO_REPARENT, PX30_CLKSEL_CON(34), 14, 2, MFLAGS, 0, 5, DFLAGS, PX30_CLKGATE_CON(10), 12, GFLAGS), - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart1_np5", "clk_uart1_src", 0, + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart1_np5", "clk_uart1_src", CLK_SET_RATE_PARENT, PX30_CLKSEL_CON(35), 0, 5, DFLAGS, PX30_CLKGATE_CON(10), 13, GFLAGS), COMPOSITE_FRACMUX(0, "clk_uart1_frac", "clk_uart1_src", CLK_SET_RATE_PARENT, @@ -673,7 +673,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { COMPOSITE(SCLK_UART2_SRC, "clk_uart2_src", mux_uart_src_p, 0, PX30_CLKSEL_CON(37), 14, 2, MFLAGS, 0, 5, DFLAGS, PX30_CLKGATE_CON(11), 0, GFLAGS), - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart2_np5", "clk_uart2_src", 0, + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart2_np5", "clk_uart2_src", CLK_SET_RATE_PARENT, PX30_CLKSEL_CON(38), 0, 5, DFLAGS, PX30_CLKGATE_CON(11), 1, GFLAGS), COMPOSITE_FRACMUX(0, "clk_uart2_frac", "clk_uart2_src", CLK_SET_RATE_PARENT, @@ -686,7 +686,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { COMPOSITE(0, "clk_uart3_src", mux_uart_src_p, 0, PX30_CLKSEL_CON(40), 14, 2, MFLAGS, 0, 5, DFLAGS, PX30_CLKGATE_CON(11), 4, GFLAGS), - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart3_np5", "clk_uart3_src", 0, + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart3_np5", "clk_uart3_src", CLK_SET_RATE_PARENT, PX30_CLKSEL_CON(41), 0, 5, DFLAGS, PX30_CLKGATE_CON(11), 5, GFLAGS), COMPOSITE_FRACMUX(0, "clk_uart3_frac", "clk_uart3_src", CLK_SET_RATE_PARENT, @@ -699,7 +699,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { COMPOSITE(0, "clk_uart4_src", mux_uart_src_p, 0, PX30_CLKSEL_CON(43), 14, 2, MFLAGS, 0, 5, DFLAGS, PX30_CLKGATE_CON(11), 8, GFLAGS), - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart4_np5", "clk_uart4_src", 0, + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart4_np5", "clk_uart4_src", CLK_SET_RATE_PARENT, PX30_CLKSEL_CON(44), 0, 5, DFLAGS, PX30_CLKGATE_CON(11), 9, GFLAGS), COMPOSITE_FRACMUX(0, "clk_uart4_frac", "clk_uart4_src", CLK_SET_RATE_PARENT, @@ -712,7 +712,7 @@ static struct rockchip_clk_branch px30_clk_branches[] __initdata = { COMPOSITE(0, "clk_uart5_src", mux_uart_src_p, 0, PX30_CLKSEL_CON(46), 14, 2, MFLAGS, 0, 5, DFLAGS, PX30_CLKGATE_CON(11), 12, GFLAGS), - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart5_np5", "clk_uart5_src", 0, + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart5_np5", "clk_uart5_src", CLK_SET_RATE_PARENT, PX30_CLKSEL_CON(47), 0, 5, DFLAGS, PX30_CLKGATE_CON(11), 13, GFLAGS), COMPOSITE_FRACMUX(0, "clk_uart5_frac", "clk_uart5_src", CLK_SET_RATE_PARENT, @@ -934,7 +934,7 @@ static struct rockchip_clk_branch px30_clk_pmu_branches[] __initdata = { COMPOSITE(0, "clk_uart0_pmu_src", mux_uart_src_p, 0, PX30_PMU_CLKSEL_CON(3), 14, 2, MFLAGS, 0, 5, DFLAGS, PX30_PMU_CLKGATE_CON(1), 0, GFLAGS), - COMPOSITE_NOMUX_HALFDIV(0, "clk_uart0_np5", "clk_uart0_pmu_src", 0, + COMPOSITE_NOMUX_HALFDIV(0, "clk_uart0_np5", "clk_uart0_pmu_src", CLK_SET_RATE_PARENT, PX30_PMU_CLKSEL_CON(4), 0, 5, DFLAGS, PX30_PMU_CLKGATE_CON(1), 1, GFLAGS), COMPOSITE_FRACMUX(0, "clk_uart0_frac", "clk_uart0_pmu_src", CLK_SET_RATE_PARENT, diff --git a/drivers/clk/rockchip/clk.c b/drivers/clk/rockchip/clk.c index 546e810c3560..38d032faa05e 100644 --- a/drivers/clk/rockchip/clk.c +++ b/drivers/clk/rockchip/clk.c @@ -190,6 +190,15 @@ static void rockchip_fractional_approximation(struct clk_hw *hw, p_parent = clk_hw_get_parent(clk_hw_get_parent(hw)); p_parent_rate = clk_hw_get_rate(p_parent); *parent_rate = p_parent_rate; + + /* fractional divider not apply if parent_rate is lower than (rate * 20) */ + if (*parent_rate < rate * 20) { + pr_warn("%s: %s fractional div is not allowed, so use half-div\n", + __func__, clk_hw_get_name(hw)); + *m = 0; + *n = 1; + return; + } } /*
The current rockchip fractional approximation overflow the desired rate if parent rate is lower than the (rate * 20) for few clocks like dclk_vopb_frac. The overflow condition has observed in px30 for dclk_vopb_frac clock with an input rate of 71.1MHz and parent rate of 24MHz is, [ 2.543280] rockchip-drm display-subsystem: bound ff460000.vop (ops vop_component_ops) [ 2.557313] rockchip-drm display-subsystem: bound ff470000.vop (ops vop_component_ops) [ 2.566356] rockchip-drm display-subsystem: bound ff140000.syscon:lvds (ops rockchip_lvds_component_ops) [ 2.576999] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 2.592177] Unexpected kernel BRK exception at EL1 [ 2.597551] Internal error: ptrace BRK handler: f20003e8 [#1] PREEMPT SMP [ 2.605143] Modules linked in: [ 2.608566] CPU: 1 PID: 31 Comm: kworker/1:1 Tainted: G U 5.8.0-rc1-15632-g97edd822b844 #30 [ 2.619363] Hardware name: Engicam PX30.Core C.TOUCH 2.0 10.1" Open Frame (DT) [ 2.627460] Workqueue: events deferred_probe_work_func [ 2.633209] pstate: 20000005 (nzCv daif -PAN -UAO BTYPE=--) [ 2.639445] pc : rational_best_approximation+0xc4/0xd0 [ 2.645194] lr : rockchip_fractional_approximation+0xa8/0xe0 [ 2.651520] sp : ffff800011ea31c0 [ 2.655222] x29: ffff800011ea31c0 x28: ffff00007a4ecd50 [ 2.661162] x27: ffff00007d042600 x26: 000000000439fca3 [ 2.667102] x25: 0000000000000000 x24: ffff800011ac9948 [ 2.673033] x23: ffff800011ea3308 x22: ffff00007d042418 [ 2.678973] x21: ffff800011ea3240 x20: ffff800011ea3238 [ 2.684904] x19: ea47000000000000 x18: 0000000000000000 [ 2.690836] x17: 0000000000000500 x16: 0000000000000001 [ 2.696775] x15: ffffffffffffffff x14: 0000000000000000 [ 2.702707] x13: 0000000000000000 x12: 0000003c00000000 [ 2.708647] x11: 0000000000000030 x10: 0101010101010101 [ 2.714586] x9 : 0000032000000320 x8 : 7f7f7f7f7f7f7f7f [ 2.720517] x7 : 000000a3c59050d3 x6 : 0000000000000030 [ 2.726457] x5 : ffff800011ea3240 x4 : ffff800011ea3238 [ 2.732397] x3 : 000000000000ffff x2 : 000000000000ffff [ 2.738329] x1 : 00000000016e3600 x0 : 0000000001497e00 [ 2.744269] Call trace: [ 2.747005] rational_best_approximation+0xc4/0xd0 [ 2.752365] clk_fd_round_rate+0x8c/0x110 [ 2.756846] clk_composite_round_rate+0x30/0x40 [ 2.761917] clk_core_determine_round_nolock.part.30+0x44/0x80 [ 2.768442] clk_core_round_rate_nolock+0x78/0x80 [ 2.773701] clk_mux_determine_rate_flags+0xd8/0x200 [ 2.779253] clk_mux_determine_rate+0x10/0x20 [ 2.784124] clk_core_determine_round_nolock.part.30+0x1c/0x80 [ 2.790639] clk_core_round_rate_nolock+0x78/0x80 [ 2.795900] clk_core_round_rate_nolock+0x5c/0x80 [ 2.801159] clk_round_rate+0x64/0xf0 [ 2.805254] vop_crtc_mode_fixup+0x2c/0x60 [ 2.809828] drm_atomic_helper_check_modeset+0x95c/0xae0 [ 2.815767] drm_atomic_helper_check+0x1c/0xa0 [ 2.820738] drm_atomic_check_only+0x43c/0x760 [ 2.825705] drm_atomic_commit+0x18/0x60 [ 2.830095] drm_client_modeset_commit_atomic.isra.16+0x17c/0x250 [ 2.836911] drm_client_modeset_commit_locked+0x58/0x1a0 [ 2.842851] drm_client_modeset_commit+0x2c/0x50 [ 2.848014] drm_fb_helper_restore_fbdev_mode_unlocked+0x70/0xd0 [ 2.854730] drm_fb_helper_set_par+0x2c/0x60 [ 2.859497] fbcon_init+0x3c0/0x540 [ 2.863400] visual_init+0xac/0x100 [ 2.867298] do_bind_con_driver+0x1e4/0x3a0 [ 2.871973] do_take_over_console+0x140/0x200 [ 2.876843] do_fbcon_takeover+0x6c/0xe0 [ 2.881228] fbcon_fb_registered+0x10c/0x120 [ 2.886005] register_framebuffer+0x1f0/0x340 [ 2.890878] __drm_fb_helper_initial_config_and_unlock+0x318/0x4a0 [ 2.897790] drm_fb_helper_initial_config+0x3c/0x50 [ 2.903244] rockchip_drm_fbdev_init+0x5c/0xf0 [ 2.908202] rockchip_drm_bind+0x194/0x1e0 [ 2.912785] try_to_bring_up_master+0x164/0x1d0 [ 2.917851] component_master_add_with_match+0xac/0xf0 [ 2.923597] rockchip_drm_platform_probe+0x238/0x2e0 [ 2.929150] platform_drv_probe+0x50/0xa0 [ 2.933631] really_probe+0xd4/0x330 [ 2.937628] driver_probe_device+0x54/0xb0 [ 2.942207] __device_attach_driver+0x80/0xc0 [ 2.947078] bus_for_each_drv+0x78/0xd0 [ 2.951365] __device_attach+0xd4/0x130 [ 2.955652] device_initial_probe+0x10/0x20 [ 2.960328] bus_probe_device+0x90/0xa0 [ 2.964616] deferred_probe_work_func+0x6c/0xa0 [ 2.969685] process_one_work+0x1e4/0x360 [ 2.974166] worker_thread+0x208/0x480 [ 2.978358] kthread+0x150/0x160 [ 2.981968] ret_from_fork+0x10/0x18 [ 2.985970] Code: d65f03c0 d2800008 d2800027 17ffffe8 (d4207d00) This happened because the fractional divider does not apply if parent_rate is lower than (rate * 20). So, this patch is trying to fix that overflow clock and switch to half-div instead computing fractioanl approximation. Some part of the patch is referenced from below BSP commit: commit <88a5404a2277> ("clk: rockchip: fix up the rockchip_fractional_approximation") commit <4186a0e4239b> ("clk: rockchip: Add supprot to limit input rate for fractional divider") Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com> --- drivers/clk/rockchip/clk-px30.c | 12 ++++++------ drivers/clk/rockchip/clk.c | 9 +++++++++ 2 files changed, 15 insertions(+), 6 deletions(-)