On Wed, 28 Sept 2022 at 18:54, Dinh Nguyen <dinguyen@xxxxxxxxxx> wrote:
>
> The clock-phase settings for the SDMMC controller in the SoCFPGA
> Strarix10/Agilex/N5X platforms reside in a register in the System
> Manager. Add a method to access that register through the syscon
> interface.
>
> Signed-off-by: Dinh Nguyen <dinguyen@xxxxxxxxxx>
> ---
> v4: no change
> v3: add space before &socfpga_drv_data
> v2: simplify clk-phase calculations
> ---
> drivers/mmc/host/dw_mmc-pltfm.c | 41 ++++++++++++++++++++++++++++++++-
> 1 file changed, 40 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
> index 9901208be797..0f07fa6d0150 100644
> --- a/drivers/mmc/host/dw_mmc-pltfm.c
> +++ b/drivers/mmc/host/dw_mmc-pltfm.c
> @@ -17,10 +17,16 @@
> #include <linux/mmc/host.h>
> #include <linux/mmc/mmc.h>
> #include <linux/of.h>
> +#include <linux/mfd/altera-sysmgr.h>
> +#include <linux/regmap.h>
>
> #include "dw_mmc.h"
> #include "dw_mmc-pltfm.h"
>
> +#define SOCFPGA_DW_MMC_CLK_PHASE_STEP 45
> +#define SYSMGR_SDMMC_CTRL_SET(smplsel, drvsel) \
> + ((((smplsel) & 0x7) << 4) | (((drvsel) & 0x7) << 0))
> +
> int dw_mci_pltfm_register(struct platform_device *pdev,
> const struct dw_mci_drv_data *drv_data)
> {
> @@ -62,9 +68,42 @@ const struct dev_pm_ops dw_mci_pltfm_pmops = {
> };
> EXPORT_SYMBOL_GPL(dw_mci_pltfm_pmops);
>
> +static int dw_mci_socfpga_priv_init(struct dw_mci *host)
> +{
> + struct device_node *np = host->dev->of_node;
> + struct regmap *sys_mgr_base_addr;
> + u32 clk_phase[2] = {0}, reg_offset;
> + int i, rc, hs_timing;
> +
> + rc = of_property_read_variable_u32_array(np, "clk-phase-sd-hs", &clk_phase[0], 2, 0);
> + if (rc) {
This looks wrong, as rc may contain a negative error code,when there
is no clk-phase-sd-hs property found.
Instead, we probably want to check "if (rc < 0)" here instead, then
bail out, but without breaking backwards compatibility.
> + sys_mgr_base_addr =
> + altr_sysmgr_regmap_lookup_by_phandle(np, "altr,sysmgr-syscon");
> + if (IS_ERR(sys_mgr_base_addr)) {
> + pr_err("%s: failed to find altr,sys-mgr regmap!\n", __func__);
> + return 1;
> + }
> + } else
> + return 1;
> +
> + of_property_read_u32_index(np, "altr,sysmgr-syscon", 1, ®_offset);
> +
> + for (i = 0; i < ARRAY_SIZE(clk_phase); i++)
> + clk_phase[i] /= SOCFPGA_DW_MMC_CLK_PHASE_STEP;
> +
> + hs_timing = SYSMGR_SDMMC_CTRL_SET(clk_phase[0], clk_phase[1]);
> + regmap_write(sys_mgr_base_addr, reg_offset, hs_timing);
> +
> + return 0;
> +}
> +
> +static const struct dw_mci_drv_data socfpga_drv_data = {
> + .init = dw_mci_socfpga_priv_init,
> +};
> +
> static const struct of_device_id dw_mci_pltfm_match[] = {
> { .compatible = "snps,dw-mshc", },
> - { .compatible = "altr,socfpga-dw-mshc", },
> + { .compatible = "altr,socfpga-dw-mshc", .data = &socfpga_drv_data, },
> { .compatible = "img,pistachio-dw-mshc", },
> {},
> };
> --
> 2.25.1
>
Kind regards
Uffe
