Addy,
On Wed, Jul 9, 2014 at 8:31 PM, Addy Ke <addy.ke@xxxxxxxxxxxxxx> wrote:
> This patch focuses on clock setting for RK3288 mmc controller.
>
> In RK3288 mmc controller, CLKDIV register can only be set 0 or 1,
> and if DDR 8bit mode, CLKDIV register must be set 1.
>
> Signed-off-by: Addy Ke <addy.ke@xxxxxxxxxxxxxx>
> ---
> changes since v1:
> - dw_mci_rk3288_setup_clock: do not call clk_get_rate(), just use the
> host->bus_hz which is already called by dw_mmc.c, suggested by Jaehoon Chung
>
> .../devicetree/bindings/mmc/rockchip-dw-mshc.txt | 4 +-
> drivers/mmc/host/dw_mmc-pltfm.c | 50 +++++++++++++++++++++-
> 2 files changed, 51 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.txt
> index c559f3f..e3f95cd 100644
> --- a/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.txt
> +++ b/Documentation/devicetree/bindings/mmc/rockchip-dw-mshc.txt
> @@ -10,7 +10,9 @@ extensions to the Synopsys Designware Mobile Storage Host Controller.
> Required Properties:
>
> * compatible: should be
> - - "rockchip,rk2928-dw-mshc": for Rockchip RK2928 and following
> + - "rockchip,rk2928-dw-mshc": for Rockchip RK2928 and following,
> + before RK3288
> + - "rockchip,rk3288-dw-mshc": for Rockchip RK3288
>
> Example:
>
> diff --git a/drivers/mmc/host/dw_mmc-pltfm.c b/drivers/mmc/host/dw_mmc-pltfm.c
> index d4a47a9..809c28b 100644
> --- a/drivers/mmc/host/dw_mmc-pltfm.c
> +++ b/drivers/mmc/host/dw_mmc-pltfm.c
> @@ -21,17 +21,61 @@
> #include <linux/mmc/mmc.h>
> #include <linux/mmc/dw_mmc.h>
> #include <linux/of.h>
> +#include <linux/clk.h>
>
> #include "dw_mmc.h"
> #include "dw_mmc-pltfm.h"
>
> +#define RK3288_CLKGEN_DIV 2
Yup, this matches what I see in the TRM. It will always divide by 2
to allow for 4 phases (picking the phases not supported yet). Default
phase looks to be 180 degrees which is why we've (currently) got
USE_HOLD_REG hardcoded. :)
> +
> static void dw_mci_pltfm_prepare_command(struct dw_mci *host, u32 *cmdr)
> {
> *cmdr |= SDMMC_CMD_USE_HOLD_REG;
> }
>
> -static const struct dw_mci_drv_data rockchip_drv_data = {
> +static int dw_mci_rk3288_setup_clock(struct dw_mci *host)
> +{
> + host->bus_hz /= RK3288_CLKGEN_DIV;
> +
> + return 0;
> +}
> +
> +static void dw_mci_rk3288_set_ios(struct dw_mci *host, struct mmc_ios *ios)
> +{
> + int ret;
> + unsigned int cclkin;
> +
> + /*
> + * cclkin: source clock of mmc controller.
> + * bus_hz: card interface clock generated by CLKGEN.
> + * bus_hz = cclkin / RK3288_CLKGEN_DIV;
> + * ios->clock = (div == 0) ? bus_hz : (bus_hz / (2 * div))
> + *
> + * Note: div can only be 0 or 1
> + * if DDR50 8bit mode, div must be set 1
Makes sense. So this function is essentially reversing the logic in
dw_mmc and making sure that we'll get the right DIV (0 or 1) in
dw_mci_setup_bus().
> + */
> + if ((ios->bus_width == MMC_BUS_WIDTH_8) &&
> + (ios->timing == MMC_TIMING_UHS_DDR50 ||
Probably don't need UHS_DDR50 since (I think) you can't have an 8-bit
SD card--only MMC, right? ...but it doesn't hurt.
> + ios->timing == MMC_TIMING_MMC_DDR52))
> + cclkin = 2 * ios->clock * RK3288_CLKGEN_DIV;
> + else
> + cclkin = ios->clock * RK3288_CLKGEN_DIV;
> +
> + ret = clk_set_rate(host->ciu_clk, cclkin);
> + if (ret)
> + dev_warn(host->dev, "failed to set rate %uHz\n", ios->clock);
> +
> + host->bus_hz = clk_get_rate(host->ciu_clk) / RK3288_CLKGEN_DIV;
> +}
> +
> +static const struct dw_mci_drv_data rk2928_drv_data = {
> + .prepare_command = dw_mci_pltfm_prepare_command,
> +};
> +
> +static const struct dw_mci_drv_data rk3288_drv_data = {
> .prepare_command = dw_mci_pltfm_prepare_command,
> + .set_ios = dw_mci_rk3288_set_ios,
> + .setup_clock = dw_mci_rk3288_setup_clock,
> };
>
> static const struct dw_mci_drv_data socfpga_drv_data = {
> @@ -95,7 +139,9 @@ EXPORT_SYMBOL_GPL(dw_mci_pltfm_pmops);
> static const struct of_device_id dw_mci_pltfm_match[] = {
> { .compatible = "snps,dw-mshc", },
> { .compatible = "rockchip,rk2928-dw-mshc",
> - .data = &rockchip_drv_data },
> + .data = &rk2928_drv_data },
> + { .compatible = "rockchip,rk3288-dw-mshc",
> + .data = &rk3288_drv_data },
> { .compatible = "altr,socfpga-dw-mshc",
> .data = &socfpga_drv_data },
> {},
Reviewed-by: Doug Anderson <dianders@xxxxxxxxxxxx>
Tested-by: Doug Anderson <dianders@xxxxxxxxxxxx>
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