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Message-ID: <d18a8c92-125e-cab4-ae74-8129fdf40da1@intel.com>
Date: Mon, 20 Jan 2020 14:32:13 +0200
From: Adrian Hunter <adrian.hunter@...el.com>
To: Faiz Abbas <faiz_abbas@...com>, linux-kernel@...r.kernel.org,
linux-mmc@...r.kernel.org, devicetree@...r.kernel.org
Cc: ulf.hansson@...aro.org, robh+dt@...nel.org
Subject: Re: [PATCH 3/3] mmc: sdhci_am654: Enable DLL only for some speed
modes
On 8/01/20 5:09 pm, Faiz Abbas wrote:
> Its recommended that DLL must only be enabled for SDR50, DDR50, DDR52,
> SDR104, HS200 and HS400 speed modes. Move DLL configuration to its own
> function and call it only in the above speed modes.
>
> Signed-off-by: Faiz Abbas <faiz_abbas@...com>
Acked-by: Adrian Hunter <adrian.hunter@...el.com>
> ---
> drivers/mmc/host/sdhci_am654.c | 128 +++++++++++++++++----------------
> 1 file changed, 68 insertions(+), 60 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
> index bb977de43f7d..575bbab1a6ed 100644
> --- a/drivers/mmc/host/sdhci_am654.c
> +++ b/drivers/mmc/host/sdhci_am654.c
> @@ -119,16 +119,80 @@ static const struct timing_data td[] = {
> [MMC_TIMING_MMC_HS400] = {"ti,otap-del-sel-hs400", MMC_CAP2_HS400},
> };
>
> +static void sdhci_am654_setup_dll(struct sdhci_host *host, unsigned int clock)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
> + int sel50, sel100, freqsel;
> + u32 mask, val;
> + int ret;
> +
> + if (sdhci_am654->flags & FREQSEL_2_BIT) {
> + switch (clock) {
> + case 200000000:
> + sel50 = 0;
> + sel100 = 0;
> + break;
> + case 100000000:
> + sel50 = 0;
> + sel100 = 1;
> + break;
> + default:
> + sel50 = 1;
> + sel100 = 0;
> + }
> +
> + /* Configure PHY DLL frequency */
> + mask = SEL50_MASK | SEL100_MASK;
> + val = (sel50 << SEL50_SHIFT) | (sel100 << SEL100_SHIFT);
> + regmap_update_bits(sdhci_am654->base, PHY_CTRL5, mask, val);
> +
> + } else {
> + switch (clock) {
> + case 200000000:
> + freqsel = 0x0;
> + break;
> + default:
> + freqsel = 0x4;
> + }
> +
> + regmap_update_bits(sdhci_am654->base, PHY_CTRL5, FREQSEL_MASK,
> + freqsel << FREQSEL_SHIFT);
> + }
> + /* Configure DLL TRIM */
> + mask = DLL_TRIM_ICP_MASK;
> + val = sdhci_am654->trm_icp << DLL_TRIM_ICP_SHIFT;
> +
> + /* Configure DLL driver strength */
> + mask |= DR_TY_MASK;
> + val |= sdhci_am654->drv_strength << DR_TY_SHIFT;
> + regmap_update_bits(sdhci_am654->base, PHY_CTRL1, mask, val);
> +
> + /* Enable DLL */
> + regmap_update_bits(sdhci_am654->base, PHY_CTRL1, ENDLL_MASK,
> + 0x1 << ENDLL_SHIFT);
> + /*
> + * Poll for DLL ready. Use a one second timeout.
> + * Works in all experiments done so far
> + */
> + ret = regmap_read_poll_timeout(sdhci_am654->base, PHY_STAT1, val,
> + val & DLLRDY_MASK, 1000, 1000000);
> + if (ret) {
> + dev_err(mmc_dev(host->mmc), "DLL failed to relock\n");
> + return;
> + }
> +
> + sdhci_am654->dll_on = true;
> +}
> +
> static void sdhci_am654_set_clock(struct sdhci_host *host, unsigned int clock)
> {
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct sdhci_am654_data *sdhci_am654 = sdhci_pltfm_priv(pltfm_host);
> unsigned char timing = host->mmc->ios.timing;
> - int sel50, sel100, freqsel;
> u32 otap_del_sel;
> u32 otap_del_ena;
> u32 mask, val;
> - int ret;
>
> if (sdhci_am654->dll_on) {
> regmap_update_bits(sdhci_am654->base, PHY_CTRL1, ENDLL_MASK, 0);
> @@ -163,64 +227,8 @@ static void sdhci_am654_set_clock(struct sdhci_host *host, unsigned int clock)
>
> regmap_update_bits(sdhci_am654->base, PHY_CTRL4, mask, val);
>
> - if (sdhci_am654->flags & FREQSEL_2_BIT) {
> - switch (clock) {
> - case 200000000:
> - sel50 = 0;
> - sel100 = 0;
> - break;
> - case 100000000:
> - sel50 = 0;
> - sel100 = 1;
> - break;
> - default:
> - sel50 = 1;
> - sel100 = 0;
> - }
> -
> - /* Configure PHY DLL frequency */
> - mask = SEL50_MASK | SEL100_MASK;
> - val = (sel50 << SEL50_SHIFT) | (sel100 << SEL100_SHIFT);
> - regmap_update_bits(sdhci_am654->base, PHY_CTRL5, mask,
> - val);
> - } else {
> - switch (clock) {
> - case 200000000:
> - freqsel = 0x0;
> - break;
> - default:
> - freqsel = 0x4;
> - }
> -
> - regmap_update_bits(sdhci_am654->base, PHY_CTRL5,
> - FREQSEL_MASK,
> - freqsel << FREQSEL_SHIFT);
> - }
> -
> - /* Configure DLL TRIM */
> - mask = DLL_TRIM_ICP_MASK;
> - val = sdhci_am654->trm_icp << DLL_TRIM_ICP_SHIFT;
> -
> - /* Configure DLL driver strength */
> - mask |= DR_TY_MASK;
> - val |= sdhci_am654->drv_strength << DR_TY_SHIFT;
> - regmap_update_bits(sdhci_am654->base, PHY_CTRL1, mask, val);
> - /* Enable DLL */
> - regmap_update_bits(sdhci_am654->base, PHY_CTRL1, ENDLL_MASK,
> - 0x1 << ENDLL_SHIFT);
> - /*
> - * Poll for DLL ready. Use a one second timeout.
> - * Works in all experiments done so far
> - */
> - ret = regmap_read_poll_timeout(sdhci_am654->base, PHY_STAT1,
> - val, val & DLLRDY_MASK, 1000,
> - 1000000);
> - if (ret) {
> - dev_err(mmc_dev(host->mmc), "DLL failed to relock\n");
> - return;
> - }
> -
> - sdhci_am654->dll_on = true;
> + if (timing > MMC_TIMING_UHS_SDR25)
> + sdhci_am654_setup_dll(host, clock);
> }
> }
>
>
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