From 0370395d45ca6dd53bb931978f0e91ac8dd6f1c5 Mon Sep 17 00:00:00 2001 From: Michal Wilczynski Date: Mon, 23 Jun 2025 20:08:53 +0200 Subject: [PATCH 1/2] clk: thead: Mark essential bus clocks as CLK_IGNORE_UNUSED Probing peripherals in the AON and PERI domains, such as the PVT thermal sensor and the PWM controller, can lead to boot hangs or unresponsive devices on the LPi4A board. The root cause is that their parent bus clocks ('CLK_CPU2AON_X2H' and the 'CLK_PERISYS_APB' clocks) are automatically gated by the kernel's power-saving mechanisms when the bus is perceived as idle. Alternative solutions were investigated, including modeling the parent bus in the Device Tree with 'simple-pm-bus' or refactoring the clock driver's parentage. The 'simple-pm-bus' approach is not viable due to the lack of defined bus address ranges in the hardware manual and its creation of improper dependencies on the 'pm_runtime' API for consumer drivers. Therefore, applying the'`CLK_IGNORE_UNUSED' flag directly to the essential bus clocks is the most direct and targeted fix. This prevents the kernel from auto-gating these buses and ensures peripherals remain accessible. This change fixes the boot hang associated with the PVT sensor and resolves the functional issues with the PWM controller. Link: https://lore.kernel.org/all/9e8a12db-236d-474c-b110-b3be96edf057@samsung.com/ [1] Reviewed-by: Drew Fustini Acked-by: Stephen Boyd Signed-off-by: Michal Wilczynski Signed-off-by: Drew Fustini --- drivers/clk/thead/clk-th1520-ap.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c index ebfb1d59401d..cf7f6bd428a0 100644 --- a/drivers/clk/thead/clk-th1520-ap.c +++ b/drivers/clk/thead/clk-th1520-ap.c @@ -792,11 +792,12 @@ static CCU_GATE(CLK_AON2CPU_A2X, aon2cpu_a2x_clk, "aon2cpu-a2x", axi4_cpusys2_ac 0x134, BIT(8), 0); static CCU_GATE(CLK_X2X_CPUSYS, x2x_cpusys_clk, "x2x-cpusys", axi4_cpusys2_aclk_pd, 0x134, BIT(7), 0); -static CCU_GATE(CLK_CPU2AON_X2H, cpu2aon_x2h_clk, "cpu2aon-x2h", axi_aclk_pd, 0x138, BIT(8), 0); +static CCU_GATE(CLK_CPU2AON_X2H, cpu2aon_x2h_clk, "cpu2aon-x2h", axi_aclk_pd, + 0x138, BIT(8), CLK_IGNORE_UNUSED); static CCU_GATE(CLK_CPU2PERI_X2H, cpu2peri_x2h_clk, "cpu2peri-x2h", axi4_cpusys2_aclk_pd, 0x140, BIT(9), CLK_IGNORE_UNUSED); static CCU_GATE(CLK_PERISYS_APB1_HCLK, perisys_apb1_hclk, "perisys-apb1-hclk", perisys_ahb_hclk_pd, - 0x150, BIT(9), 0); + 0x150, BIT(9), CLK_IGNORE_UNUSED); static CCU_GATE(CLK_PERISYS_APB2_HCLK, perisys_apb2_hclk, "perisys-apb2-hclk", perisys_ahb_hclk_pd, 0x150, BIT(10), CLK_IGNORE_UNUSED); static CCU_GATE(CLK_PERISYS_APB3_HCLK, perisys_apb3_hclk, "perisys-apb3-hclk", perisys_ahb_hclk_pd, From d274c77ffa202b70ad01d579f33b73b4de123375 Mon Sep 17 00:00:00 2001 From: Yao Zi Date: Thu, 10 Jul 2025 09:21:34 +0000 Subject: [PATCH 2/2] clk: thead: th1520-ap: Correctly refer the parent of osc_12m The "osc_12m" fixed factor clock refers the external oscillator by setting clk_parent_data.fw_name to osc_24m, which is obviously wrong since no clock-names property is allowed for compatible thead,th1520-clk-ap. Refer the oscillator as parent by index instead. Fixes: ae81b69fd2b1 ("clk: thead: Add support for T-Head TH1520 AP_SUBSYS clocks") Signed-off-by: Yao Zi Reviewed-by: Drew Fustini Signed-off-by: Drew Fustini --- drivers/clk/thead/clk-th1520-ap.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/clk/thead/clk-th1520-ap.c b/drivers/clk/thead/clk-th1520-ap.c index cf7f6bd428a0..5a102beb6ac1 100644 --- a/drivers/clk/thead/clk-th1520-ap.c +++ b/drivers/clk/thead/clk-th1520-ap.c @@ -582,7 +582,14 @@ static const struct clk_parent_data peri2sys_apb_pclk_pd[] = { { .hw = &peri2sys_apb_pclk.common.hw } }; -static CLK_FIXED_FACTOR_FW_NAME(osc12m_clk, "osc_12m", "osc_24m", 2, 1, 0); +static struct clk_fixed_factor osc12m_clk = { + .div = 2, + .mult = 1, + .hw.init = CLK_HW_INIT_PARENTS_DATA("osc_12m", + osc_24m_clk, + &clk_fixed_factor_ops, + 0), +}; static const char * const out_parents[] = { "osc_24m", "osc_12m" };