Re: [PATCH] mmc: sdhci-of-arasan: Use standard mmc_clk_phase_map infrastructure
From: Sai Krishna Potthuri
Date: Mon Mar 23 2026 - 05:27:44 EST
-----Original Message-----
From: Simek, Michal <michal.simek@xxxxxxx>
Sent: Thursday, March 19, 2026 3:39 PM
To: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>; Ulf Hansson
<ulf.hansson@xxxxxxxxxx>; Potthuri, Sai Krishna
<sai.krishna.potthuri@xxxxxxx>
Cc: linux-mmc@xxxxxxxxxxxxxxx; Adrian Hunter <adrian.hunter@xxxxxxxxx>;
linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH] mmc: sdhci-of-arasan: Use standard
mmc_clk_phase_map infrastructure
+Sai,
On 3/17/26 03:17, Shawn Lin wrote:
> Convert the Arasan SDHCI driver to use the mainline standard
> mmc_clk_phase_map infrastructure instead of custom clk_phase_in/out
> arrays as well as arasan_dt_read_clk_phase().
>
> The phase values for ZynqMP, Versal, and Versal-NET platforms are
> still initialized from the predefined tables, but now follow the
> standard phase_map format with valid flag.
>
> Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> ---
>
> drivers/mmc/host/sdhci-of-arasan.c | 79 +++++++++-----------------------------
> 1 file changed, 18 insertions(+), 61 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c
> b/drivers/mmc/host/sdhci-of-arasan.c
> index caf9723..b97d27c 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -152,8 +152,7 @@ struct sdhci_arasan_clk_ops {
> * @sdcardclk: Pointer to normal 'struct clock' for
sdcardclk_hw.
> * @sampleclk_hw: Struct for the clock we might provide to a PHY.
> * @sampleclk: Pointer to normal 'struct clock' for
sampleclk_hw.
> - * @clk_phase_in: Array of Input Clock Phase Delays for all speed modes
> - * @clk_phase_out: Array of Output Clock Phase Delays for all speed
modes
> + * @phase_map: Struct for mmc_clk_phase_map provided.
> * @set_clk_delays: Function pointer for setting Clock Delays
> * @clk_of_data: Platform specific runtime clock data storage pointer
> */
> @@ -162,8 +161,7 @@ struct sdhci_arasan_clk_data {
> struct clk *sdcardclk;
> struct clk_hw sampleclk_hw;
> struct clk *sampleclk;
> - int clk_phase_in[MMC_TIMING_MMC_HS400 + 1];
> - int clk_phase_out[MMC_TIMING_MMC_HS400 + 1];
> + struct mmc_clk_phase_map phase_map;
> void (*set_clk_delays)(struct sdhci_host *host);
> void *clk_of_data;
> };
> @@ -1248,37 +1246,13 @@ static void sdhci_arasan_set_clk_delays(struct
sdhci_host *host)
> struct sdhci_arasan_data *sdhci_arasan =
sdhci_pltfm_priv(pltfm_host);
> struct sdhci_arasan_clk_data *clk_data = &sdhci_arasan->clk_data;
>
> - clk_set_phase(clk_data->sampleclk,
> - clk_data->clk_phase_in[host->timing]);
> - clk_set_phase(clk_data->sdcardclk,
> - clk_data->clk_phase_out[host->timing]);
> -}
> -
> -static void arasan_dt_read_clk_phase(struct device *dev,
> - struct sdhci_arasan_clk_data *clk_data,
> - unsigned int timing, const char *prop)
> -{
> - struct device_node *np = dev->of_node;
> -
> - u32 clk_phase[2] = {0};
> - int ret;
> -
> - /*
> - * Read Tap Delay values from DT, if the DT does not contain the
> - * Tap Values then use the pre-defined values.
> - */
> - ret = of_property_read_variable_u32_array(np, prop, &clk_phase[0],
> - 2, 0);
> - if (ret < 0) {
> - dev_dbg(dev, "Using predefined clock phase for %s = %d
%d\n",
> - prop, clk_data->clk_phase_in[timing],
> - clk_data->clk_phase_out[timing]);
> + if (!clk_data->phase_map.phase[host->timing].valid)
> return;
This check breaks platforms relying on default phase values. When DT
properties are absent, mmc_of_parse_timing_phase() sets valid=false,
which causes sdhci_arasan_set_clk_delays() to skip phase configuration.
Regards
Sai Krishna
> - }
>
> - /* The values read are Input and Output Clock Delays in order */
> - clk_data->clk_phase_in[timing] = clk_phase[0];
> - clk_data->clk_phase_out[timing] = clk_phase[1];
> + clk_set_phase(clk_data->sampleclk,
> + clk_data->phase_map.phase[host->timing].in_deg);
> + clk_set_phase(clk_data->sdcardclk,
> + clk_data->phase_map.phase[host->timing].out_deg);
> }
>
> /**
> @@ -1315,8 +1289,9 @@ static void arasan_dt_parse_clk_phases(struct
device *dev,
> }
>
> for (i = 0; i <= MMC_TIMING_MMC_HS400; i++) {
> - clk_data->clk_phase_in[i] = zynqmp_iclk_phase[i];
> - clk_data->clk_phase_out[i] = zynqmp_oclk_phase[i];
> + clk_data->phase_map.phase[i].in_deg =
zynqmp_iclk_phase[i];
> + clk_data->phase_map.phase[i].out_deg =
zynqmp_oclk_phase[i];
> + clk_data->phase_map.phase[i].valid = true;
> }
> }
>
> @@ -1327,8 +1302,9 @@ static void arasan_dt_parse_clk_phases(struct
device *dev,
> VERSAL_OCLK_PHASE;
>
> for (i = 0; i <= MMC_TIMING_MMC_HS400; i++) {
> - clk_data->clk_phase_in[i] = versal_iclk_phase[i];
> - clk_data->clk_phase_out[i] = versal_oclk_phase[i];
> + clk_data->phase_map.phase[i].in_deg =
versal_iclk_phase[i];
> + clk_data->phase_map.phase[i].out_deg =
versal_oclk_phase[i];
> + clk_data->phase_map.phase[i].valid = true;
> }
> }
> if (of_device_is_compatible(dev->of_node, "xlnx,versal-net-emmc"))
> { @@ -1338,32 +1314,13 @@ static void arasan_dt_parse_clk_phases(struct
device *dev,
> VERSAL_NET_EMMC_OCLK_PHASE;
>
> for (i = 0; i <= MMC_TIMING_MMC_HS400; i++) {
> - clk_data->clk_phase_in[i] = versal_net_iclk_phase[i];
> - clk_data->clk_phase_out[i] =
versal_net_oclk_phase[i];
> + clk_data->phase_map.phase[i].in_deg =
versal_net_iclk_phase[i];
> + clk_data->phase_map.phase[i].out_deg =
versal_net_oclk_phase[i];
> + clk_data->phase_map.phase[i].valid = true;
> }
> }
> - arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_LEGACY,
> - "clk-phase-legacy");
> - arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_MMC_HS,
> - "clk-phase-mmc-hs");
> - arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_SD_HS,
> - "clk-phase-sd-hs");
> - arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_UHS_SDR12,
> - "clk-phase-uhs-sdr12");
> - arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_UHS_SDR25,
> - "clk-phase-uhs-sdr25");
> - arasan_dt_read_clk_phase(dev, clk_data, MMC_TIMING_UHS_SDR50,
> - "clk-phase-uhs-sdr50");
> - arasan_dt_read_clk_phase(dev, clk_data,
MMC_TIMING_UHS_SDR104,
> - "clk-phase-uhs-sdr104");
> - arasan_dt_read_clk_phase(dev, clk_data,
MMC_TIMING_UHS_DDR50,
> - "clk-phase-uhs-ddr50");
> - arasan_dt_read_clk_phase(dev, clk_data,
MMC_TIMING_MMC_DDR52,
> - "clk-phase-mmc-ddr52");
> - arasan_dt_read_clk_phase(dev, clk_data,
MMC_TIMING_MMC_HS200,
> - "clk-phase-mmc-hs200");
> - arasan_dt_read_clk_phase(dev, clk_data,
MMC_TIMING_MMC_HS400,
> - "clk-phase-mmc-hs400");
> +
> + mmc_of_parse_clk_phase(dev, &clk_data->phase_map);
> }
>
> static const struct sdhci_pltfm_data sdhci_arasan_pdata = {
please take a look at this patch.
I was talking to him yesterday and he needs to finish two things before he has
time to look at it. That's why please give him some time.
Thanks,
Michal