Re: [PATCH v3 4/4] clk: rockchip: rk3588: add GATE_GRF clocks for I2S MCLK output to IO

[Heiko Stuebner <heiko@sntech.de>]

Hi Daniele,

Am Freitag, 20. März 2026, 11:34:16 Mitteleuropäische Sommerzeit schrieb Daniele Briguglio:
> The I2S MCLK outputs on RK3588 are gated by bits in the SYS_GRF
> register SOC_CON6 (offset 0x318). These gates control whether the
> internal CRU MCLK signals reach the external IO pins connected to
> audio codecs.
> 
> The kernel should explicitly manage these gates so that audio
> functionality does not depend on bootloader register state. This is
> analogous to what was done for RK3576 SAI MCLK outputs [1].
> 
> Register the SYS_GRF as an auxiliary GRF with grf_type_sys in the
> early clock init, and add GATE_GRF entries for all four I2S MCLK
> output gates:
> 
>   - I2S0_8CH_MCLKOUT_TO_IO (bit 0)
>   - I2S1_8CH_MCLKOUT_TO_IO (bit 1)
>   - I2S2_2CH_MCLKOUT_TO_IO (bit 2)
>   - I2S3_2CH_MCLKOUT_TO_IO (bit 7)
> 
> Board DTS files that need MCLK on an IO pin can reference these
> clocks, e.g.:
> 
>     clocks = <&cru I2S0_8CH_MCLKOUT_TO_IO>;
> 
> Tested on the Youyeetoo YY3588 (RK3588) with an ES8388 codec on I2S0.
> 
> [1] https://lore.kernel.org/r/20250305-rk3576-sai-v1-2-64e6cf863e9a@collabora.com/
> 
> Reviewed-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
> Tested-by: Ricardo Pardini <ricardo@pardini.net>
> Signed-off-by: Daniele Briguglio <hello@superkali.me>
> ---
>  drivers/clk/rockchip/clk-rk3588.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
> 
> diff --git a/drivers/clk/rockchip/clk-rk3588.c b/drivers/clk/rockchip/clk-rk3588.c
> index 1694223f4f84..2cc85fb5b2cc 100644
> --- a/drivers/clk/rockchip/clk-rk3588.c
> +++ b/drivers/clk/rockchip/clk-rk3588.c
> @@ -5,11 +5,14 @@
>   */
>  
>  #include <linux/clk-provider.h>
> +#include <linux/mfd/syscon.h>
>  #include <linux/of.h>
> +#include <linux/slab.h>
>  #include <linux/of_address.h>
>  #include <linux/platform_device.h>
>  #include <linux/syscore_ops.h>
>  #include <dt-bindings/clock/rockchip,rk3588-cru.h>
> +#include <soc/rockchip/rk3588_grf.h>
>  #include "clk.h"
>  
>  #define RK3588_GRF_SOC_STATUS0		0x600
> @@ -892,6 +895,8 @@ static struct rockchip_clk_branch rk3588_early_clk_branches[] __initdata = {
>  			RK3588_CLKGATE_CON(8), 0, GFLAGS),
>  	MUX(I2S2_2CH_MCLKOUT, "i2s2_2ch_mclkout", i2s2_2ch_mclkout_p, CLK_SET_RATE_PARENT,
>  			RK3588_CLKSEL_CON(30), 2, 1, MFLAGS),
> +	GATE_GRF(I2S2_2CH_MCLKOUT_TO_IO, "i2s2_2ch_mclkout_to_io", "i2s2_2ch_mclkout",
> +			0, RK3588_SYSGRF_SOC_CON6, 2, GFLAGS, grf_type_sys),
>  
>  	COMPOSITE(CLK_I2S3_2CH_SRC, "clk_i2s3_2ch_src", gpll_aupll_p, 0,
>  			RK3588_CLKSEL_CON(30), 8, 1, MFLAGS, 3, 5, DFLAGS,
> @@ -907,6 +912,8 @@ static struct rockchip_clk_branch rk3588_early_clk_branches[] __initdata = {
>  			RK3588_CLKGATE_CON(8), 4, GFLAGS),
>  	MUX(I2S3_2CH_MCLKOUT, "i2s3_2ch_mclkout", i2s3_2ch_mclkout_p, CLK_SET_RATE_PARENT,
>  			RK3588_CLKSEL_CON(32), 2, 1, MFLAGS),
> +	GATE_GRF(I2S3_2CH_MCLKOUT_TO_IO, "i2s3_2ch_mclkout_to_io", "i2s3_2ch_mclkout",
> +			0, RK3588_SYSGRF_SOC_CON6, 7, GFLAGS, grf_type_sys),
>  	GATE(PCLK_ACDCDIG, "pclk_acdcdig", "pclk_audio_root", 0,
>  			RK3588_CLKGATE_CON(7), 11, GFLAGS),
>  	GATE(HCLK_I2S0_8CH, "hclk_i2s0_8ch", "hclk_audio_root", 0,
> @@ -935,6 +942,8 @@ static struct rockchip_clk_branch rk3588_early_clk_branches[] __initdata = {
>  			RK3588_CLKGATE_CON(7), 10, GFLAGS),
>  	MUX(I2S0_8CH_MCLKOUT, "i2s0_8ch_mclkout", i2s0_8ch_mclkout_p, CLK_SET_RATE_PARENT,
>  			RK3588_CLKSEL_CON(28), 2, 2, MFLAGS),
> +	GATE_GRF(I2S0_8CH_MCLKOUT_TO_IO, "i2s0_8ch_mclkout_to_io", "i2s0_8ch_mclkout",
> +			0, RK3588_SYSGRF_SOC_CON6, 0, GFLAGS, grf_type_sys),
>  
>  	GATE(HCLK_PDM1, "hclk_pdm1", "hclk_audio_root", 0,
>  			RK3588_CLKGATE_CON(9), 6, GFLAGS),
> @@ -2220,6 +2229,8 @@ static struct rockchip_clk_branch rk3588_early_clk_branches[] __initdata = {
>  			RK3588_PMU_CLKGATE_CON(2), 13, GFLAGS),
>  	MUX(I2S1_8CH_MCLKOUT, "i2s1_8ch_mclkout", i2s1_8ch_mclkout_p, CLK_SET_RATE_PARENT,
>  			RK3588_PMU_CLKSEL_CON(9), 2, 2, MFLAGS),
> +	GATE_GRF(I2S1_8CH_MCLKOUT_TO_IO, "i2s1_8ch_mclkout_to_io", "i2s1_8ch_mclkout",
> +			0, RK3588_SYSGRF_SOC_CON6, 1, GFLAGS, grf_type_sys),
>  	GATE(PCLK_PMU1, "pclk_pmu1", "pclk_pmu0_root", CLK_IS_CRITICAL,
>  			RK3588_PMU_CLKGATE_CON(1), 0, GFLAGS),
>  	GATE(CLK_DDR_FAIL_SAFE, "clk_ddr_fail_safe", "clk_pmu0", CLK_IGNORE_UNUSED,
> @@ -2439,6 +2450,8 @@ static struct rockchip_clk_branch rk3588_clk_branches[] = {
>  static void __init rk3588_clk_early_init(struct device_node *np)
>  {
>  	struct rockchip_clk_provider *ctx;
> +	struct rockchip_aux_grf *sys_grf_e;
> +	struct regmap *sys_grf;
>  	unsigned long clk_nr_clks, max_clk_id1, max_clk_id2;
>  	void __iomem *reg_base;
>  
> @@ -2479,6 +2492,17 @@ static void __init rk3588_clk_early_init(struct device_node *np)
>  			&rk3588_cpub1clk_data, rk3588_cpub1clk_rates,
>  			ARRAY_SIZE(rk3588_cpub1clk_rates));
>  
> +	/* Register SYS_GRF for I2S MCLK output to IO gate clocks */
> +	sys_grf = syscon_regmap_lookup_by_compatible("rockchip,rk3588-sys-grf");
> +	if (!IS_ERR(sys_grf)) {
> +		sys_grf_e = kzalloc_obj(*sys_grf_e);
> +		if (sys_grf_e) {
> +			sys_grf_e->grf = sys_grf;
> +			sys_grf_e->type = grf_type_sys;
> +			hash_add(ctx->aux_grf_table, &sys_grf_e->node, grf_type_sys);
> +		}
> +	}
> +

sorry, took me a bit to articulate, what "issue" I have with this, which
is only that it open-codes adding GRFs. I.e. over time this likely won't
be the only place this might happen, so I envision a more central
function in the rockchip clock code, aka something like:

(1)
rockchip_clk_add_grf(struct rockchip_clk_provider *ctx,
		struct regmap *grf, enum rockchip_grf_type type)


I'm still unsure, if we want the sycon lookup also in there, like:

(2)
rockchip_clk_add_grf(struct rockchip_clk_provider *ctx,
		const char *compat, enum rockchip_grf_type type)

but then we would end up having to also define if it's optional, so I
guess variant (1) is the nicer one, as it at least abstracts away all
the struct rockchip_aux_grf handling from the clock driver itself.


Heiko


>  	rockchip_clk_register_branches(ctx, rk3588_early_clk_branches,
>  				       ARRAY_SIZE(rk3588_early_clk_branches));
>  
> 
>