Re: [PATCH v6 4/5] mmc: sdhci-msm: Add Device tree parsing logic for DLL settings

Bjorn Andersson
2025-12-18T13:32:42Z

On Mon, Dec 15, 2025 at 05:30:08PM +0530, Ram Prakash Gupta wrote:
> From: Sachin Gupta <quic_sachgupt@quicinc.com>
>
> This update introduces the capability to configure HS200
> and HS400 DLL settings via the device tree and parsing it.

No it doesn't, it merely reads a bunch of integers from DeviceTree and
does nothing with them.

Please write your commit message in imperative mood (avoid "This
update") and please include a reasoning for why this commit exists, or
as
https://docs.kernel.org/process/submitting-patches.html#describe-your-changes
says "Describe your problem.".

>
> Signed-off-by: Sachin Gupta <quic_sachgupt@quicinc.com>
> Signed-off-by: Ram Prakash Gupta <quic_rampraka@quicinc.com>
> ---
> drivers/mmc/host/sdhci-msm.c | 41 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 41 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index dc79f828522b..1fcd92158bee 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -266,6 +266,19 @@ struct sdhci_msm_variant_info {
> const struct sdhci_msm_offset *offset;
> };
>
> +/*
> + * DLL registers which needs be programmed with HSR settings.
> + * Add any new register only at the end and don't change the
> + * sequence.

/* You have to only add entries at the end, but I'm not going to tell you why... */

> + */
> +struct sdhci_msm_dll {
> + u32 dll_config;
> + u32 dll_config_2;
> + u32 dll_config_3;
> + u32 dll_usr_ctl;
> + u32 ddr_config;
> +};
> +
> struct sdhci_msm_host {
> struct platform_device *pdev;
> void __iomem *core_mem; /* MSM SDCC mapped address */
> @@ -274,6 +287,7 @@ struct sdhci_msm_host {
> struct clk *xo_clk; /* TCXO clk needed for FLL feature of cm_dll*/
> /* core, iface, cal and sleep clocks */
> struct clk_bulk_data bulk_clks[4];
> + struct sdhci_msm_dll dll[2];
> #ifdef CONFIG_MMC_CRYPTO
> struct qcom_ice *ice;
> #endif
> @@ -302,6 +316,7 @@ struct sdhci_msm_host {
> u32 dll_config;
> u32 ddr_config;

So this dll_config/ddr_config pair is no longer supposed to be used? Or
are there now two sets of dll and ddr configurations to be provided?

Regards,
Bjorn

> bool vqmmc_enabled;
> + bool artanis_dll;
> };
>
> static const struct sdhci_msm_offset *sdhci_priv_msm_offset(struct sdhci_host *host)
> @@ -2534,6 +2549,23 @@ static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
> return ret;
> }
>
> +#define DLL_SIZE 10
> +static int sdhci_msm_dt_parse_dll_info(struct device *dev, struct sdhci_msm_host *msm_host)
> +{
> + u32 *dll_table = &msm_host->dll[0].dll_config;
> + int ret;
> +
> + msm_host->artanis_dll = false;
> +
> + ret = of_property_read_variable_u32_array(dev->of_node,
> + "qcom,dll-presets",
> + dll_table, DLL_SIZE, DLL_SIZE);
> + if (ret == DLL_SIZE)
> + msm_host->artanis_dll = true;
> +
> + return ret;
> +}
> +
> static int sdhci_msm_probe(struct platform_device *pdev)
> {
> struct sdhci_host *host;
> @@ -2580,6 +2612,15 @@ static int sdhci_msm_probe(struct platform_device *pdev)
>
> msm_host->saved_tuning_phase = INVALID_TUNING_PHASE;
>
> + /*
> + * Parse HSR dll only when property is present in DT.
> + */
> + ret = sdhci_msm_dt_parse_dll_info(&pdev->dev, msm_host);
> + if (ret == -ENODATA || ret == -EOVERFLOW) {
> + dev_err(&pdev->dev, "Bad DLL in dt (%d)\n", ret);
> + return ret;
> + }
> +
> ret = sdhci_msm_gcc_reset(&pdev->dev, host);
> if (ret)
> return ret;
> --
> 2.34.1
>