mmc: sdhci-of-dwcmshc: Add support for T-Head TH1520 99/307399/1
authorDrew Fustini <dfustini@baylibre.com>
Fri, 10 Nov 2023 05:41:13 +0000 (21:41 -0800)
committerJaehoon Chung <jh80.chung@samsung.com>
Fri, 8 Mar 2024 04:50:08 +0000 (13:50 +0900)
Add support for the mmc controller in the T-Head TH1520 with the new
compatible "thead,th1520-dwcmshc". Implement custom sdhci_ops for
set_uhs_signaling, reset, voltage_switch, and platform_execute_tuning.

Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Drew Fustini <dfustini@baylibre.com>
Link: https://lore.kernel.org/r/20231109-th1520-mmc-v5-3-018bd039cf17@baylibre.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
(cherry picked from commit 43658a542ebf13f1bb80cfaa8ae58f061d0d71b0)
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Change-Id: I01a0df403985333f3b9f5f9dd971af807c285be9

drivers/mmc/host/sdhci-of-dwcmshc.c

index 3a3bae6948a899e0f3375ab6a0d0462d8ccd626b..0eb72544c09ed5d26c32632c1c40f3c4fe740c87 100644 (file)
@@ -8,6 +8,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/iopoll.h>
 #define DWCMSHC_CARD_IS_EMMC           BIT(0)
 #define DWCMSHC_ENHANCED_STROBE                BIT(8)
 #define DWCMSHC_EMMC_ATCTRL            0x40
+/* Tuning and auto-tuning fields in AT_CTRL_R control register */
+#define AT_CTRL_AT_EN                  BIT(0) /* autotuning is enabled */
+#define AT_CTRL_CI_SEL                 BIT(1) /* interval to drive center phase select */
+#define AT_CTRL_SWIN_TH_EN             BIT(2) /* sampling window threshold enable */
+#define AT_CTRL_RPT_TUNE_ERR           BIT(3) /* enable reporting framing errors */
+#define AT_CTRL_SW_TUNE_EN             BIT(4) /* enable software managed tuning */
+#define AT_CTRL_WIN_EDGE_SEL_MASK      GENMASK(11, 8) /* bits [11:8] */
+#define AT_CTRL_WIN_EDGE_SEL           0xf /* sampling window edge select */
+#define AT_CTRL_TUNE_CLK_STOP_EN       BIT(16) /* clocks stopped during phase code change */
+#define AT_CTRL_PRE_CHANGE_DLY_MASK    GENMASK(18, 17) /* bits [18:17] */
+#define AT_CTRL_PRE_CHANGE_DLY         0x1  /* 2-cycle latency */
+#define AT_CTRL_POST_CHANGE_DLY_MASK   GENMASK(20, 19) /* bits [20:19] */
+#define AT_CTRL_POST_CHANGE_DLY                0x3  /* 4-cycle latency */
+#define AT_CTRL_SWIN_TH_VAL_MASK       GENMASK(31, 24) /* bits [31:24] */
+#define AT_CTRL_SWIN_TH_VAL            0x9  /* sampling window threshold */
 
 /* Rockchip specific Registers */
 #define DWCMSHC_EMMC_DLL_CTRL          0x800
        (((x) & DWCMSHC_EMMC_DLL_TIMEOUT) == 0))
 #define RK35xx_MAX_CLKS 3
 
+/* PHY register area pointer */
+#define DWC_MSHC_PTR_PHY_R     0x300
+
+/* PHY general configuration */
+#define PHY_CNFG_R             (DWC_MSHC_PTR_PHY_R + 0x00)
+#define PHY_CNFG_RSTN_DEASSERT 0x1  /* Deassert PHY reset */
+#define PHY_CNFG_PAD_SP_MASK   GENMASK(19, 16) /* bits [19:16] */
+#define PHY_CNFG_PAD_SP                0x0c /* PMOS TX drive strength */
+#define PHY_CNFG_PAD_SN_MASK   GENMASK(23, 20) /* bits [23:20] */
+#define PHY_CNFG_PAD_SN                0x0c /* NMOS TX drive strength */
+
+/* PHY command/response pad settings */
+#define PHY_CMDPAD_CNFG_R      (DWC_MSHC_PTR_PHY_R + 0x04)
+
+/* PHY data pad settings */
+#define PHY_DATAPAD_CNFG_R     (DWC_MSHC_PTR_PHY_R + 0x06)
+
+/* PHY clock pad settings */
+#define PHY_CLKPAD_CNFG_R      (DWC_MSHC_PTR_PHY_R + 0x08)
+
+/* PHY strobe pad settings */
+#define PHY_STBPAD_CNFG_R      (DWC_MSHC_PTR_PHY_R + 0x0a)
+
+/* PHY reset pad settings */
+#define PHY_RSTNPAD_CNFG_R     (DWC_MSHC_PTR_PHY_R + 0x0c)
+
+/* Bitfields are common for all pad settings */
+#define PHY_PAD_RXSEL_1V8              0x1 /* Receiver type select for 1.8V */
+#define PHY_PAD_RXSEL_3V3              0x2 /* Receiver type select for 3.3V */
+
+#define PHY_PAD_WEAKPULL_MASK          GENMASK(4, 3) /* bits [4:3] */
+#define PHY_PAD_WEAKPULL_PULLUP                0x1 /* Weak pull up enabled */
+#define PHY_PAD_WEAKPULL_PULLDOWN      0x2 /* Weak pull down enabled */
+
+#define PHY_PAD_TXSLEW_CTRL_P_MASK     GENMASK(8, 5) /* bits [8:5] */
+#define PHY_PAD_TXSLEW_CTRL_P          0x3 /* Slew control for P-Type pad TX */
+#define PHY_PAD_TXSLEW_CTRL_N_MASK     GENMASK(12, 9) /* bits [12:9] */
+#define PHY_PAD_TXSLEW_CTRL_N          0x3 /* Slew control for N-Type pad TX */
+
+/* PHY CLK delay line settings */
+#define PHY_SDCLKDL_CNFG_R             (DWC_MSHC_PTR_PHY_R + 0x1d)
+#define PHY_SDCLKDL_CNFG_UPDATE        BIT(4) /* set before writing to SDCLKDL_DC */
+
+/* PHY CLK delay line delay code */
+#define PHY_SDCLKDL_DC_R               (DWC_MSHC_PTR_PHY_R + 0x1e)
+#define PHY_SDCLKDL_DC_INITIAL         0x40 /* initial delay code */
+#define PHY_SDCLKDL_DC_DEFAULT         0x32 /* default delay code */
+#define PHY_SDCLKDL_DC_HS400           0x18 /* delay code for HS400 mode */
+
+/* PHY drift_cclk_rx delay line configuration setting */
+#define PHY_ATDL_CNFG_R                        (DWC_MSHC_PTR_PHY_R + 0x21)
+#define PHY_ATDL_CNFG_INPSEL_MASK      GENMASK(3, 2) /* bits [3:2] */
+#define PHY_ATDL_CNFG_INPSEL           0x3 /* delay line input source */
+
+/* PHY DLL control settings */
+#define PHY_DLL_CTRL_R                 (DWC_MSHC_PTR_PHY_R + 0x24)
+#define PHY_DLL_CTRL_DISABLE           0x0 /* PHY DLL is enabled */
+#define PHY_DLL_CTRL_ENABLE            0x1 /* PHY DLL is disabled */
+
+/* PHY DLL  configuration register 1 */
+#define PHY_DLL_CNFG1_R                        (DWC_MSHC_PTR_PHY_R + 0x25)
+#define PHY_DLL_CNFG1_SLVDLY_MASK      GENMASK(5, 4) /* bits [5:4] */
+#define PHY_DLL_CNFG1_SLVDLY           0x2 /* DLL slave update delay input */
+#define PHY_DLL_CNFG1_WAITCYCLE                0x5 /* DLL wait cycle input */
+
+/* PHY DLL configuration register 2 */
+#define PHY_DLL_CNFG2_R                        (DWC_MSHC_PTR_PHY_R + 0x26)
+#define PHY_DLL_CNFG2_JUMPSTEP         0xa /* DLL jump step input */
+
+/* PHY DLL master and slave delay line configuration settings */
+#define PHY_DLLDL_CNFG_R               (DWC_MSHC_PTR_PHY_R + 0x28)
+#define PHY_DLLDL_CNFG_SLV_INPSEL_MASK GENMASK(6, 5) /* bits [6:5] */
+#define PHY_DLLDL_CNFG_SLV_INPSEL      0x3 /* clock source select for slave DL */
+
+#define FLAG_IO_FIXED_1V8      BIT(0)
+
 #define BOUNDARY_OK(addr, len) \
        ((addr | (SZ_128M - 1)) == ((addr + len - 1) | (SZ_128M - 1)))
 
@@ -92,6 +184,8 @@ struct dwcmshc_priv {
        struct clk      *bus_clk;
        int vendor_specific_area1; /* P_VENDOR_SPECIFIC_AREA reg */
        void *priv; /* pointer to SoC private stuff */
+       u16 delay_line;
+       u16 flags;
 };
 
 /*
@@ -157,6 +251,127 @@ static void dwcmshc_request(struct mmc_host *mmc, struct mmc_request *mrq)
        sdhci_request(mmc, mrq);
 }
 
+static void dwcmshc_phy_1_8v_init(struct sdhci_host *host)
+{
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
+       u32 val;
+
+       /* deassert phy reset & set tx drive strength */
+       val = PHY_CNFG_RSTN_DEASSERT;
+       val |= FIELD_PREP(PHY_CNFG_PAD_SP_MASK, PHY_CNFG_PAD_SP);
+       val |= FIELD_PREP(PHY_CNFG_PAD_SN_MASK, PHY_CNFG_PAD_SN);
+       sdhci_writel(host, val, PHY_CNFG_R);
+
+       /* disable delay line */
+       sdhci_writeb(host, PHY_SDCLKDL_CNFG_UPDATE, PHY_SDCLKDL_CNFG_R);
+
+       /* set delay line */
+       sdhci_writeb(host, priv->delay_line, PHY_SDCLKDL_DC_R);
+       sdhci_writeb(host, PHY_DLL_CNFG2_JUMPSTEP, PHY_DLL_CNFG2_R);
+
+       /* enable delay lane */
+       val = sdhci_readb(host, PHY_SDCLKDL_CNFG_R);
+       val &= ~(PHY_SDCLKDL_CNFG_UPDATE);
+       sdhci_writeb(host, val, PHY_SDCLKDL_CNFG_R);
+
+       /* configure phy pads */
+       val = PHY_PAD_RXSEL_1V8;
+       val |= FIELD_PREP(PHY_PAD_WEAKPULL_MASK, PHY_PAD_WEAKPULL_PULLUP);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_P_MASK, PHY_PAD_TXSLEW_CTRL_P);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_N_MASK, PHY_PAD_TXSLEW_CTRL_N);
+       sdhci_writew(host, val, PHY_CMDPAD_CNFG_R);
+       sdhci_writew(host, val, PHY_DATAPAD_CNFG_R);
+       sdhci_writew(host, val, PHY_RSTNPAD_CNFG_R);
+
+       val = FIELD_PREP(PHY_PAD_TXSLEW_CTRL_P_MASK, PHY_PAD_TXSLEW_CTRL_P);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_N_MASK, PHY_PAD_TXSLEW_CTRL_N);
+       sdhci_writew(host, val, PHY_CLKPAD_CNFG_R);
+
+       val = PHY_PAD_RXSEL_1V8;
+       val |= FIELD_PREP(PHY_PAD_WEAKPULL_MASK, PHY_PAD_WEAKPULL_PULLDOWN);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_P_MASK, PHY_PAD_TXSLEW_CTRL_P);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_N_MASK, PHY_PAD_TXSLEW_CTRL_N);
+       sdhci_writew(host, val, PHY_STBPAD_CNFG_R);
+
+       /* enable data strobe mode */
+       sdhci_writeb(host, FIELD_PREP(PHY_DLLDL_CNFG_SLV_INPSEL_MASK, PHY_DLLDL_CNFG_SLV_INPSEL),
+                    PHY_DLLDL_CNFG_R);
+
+       /* enable phy dll */
+       sdhci_writeb(host, PHY_DLL_CTRL_ENABLE, PHY_DLL_CTRL_R);
+}
+
+static void dwcmshc_phy_3_3v_init(struct sdhci_host *host)
+{
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
+       u32 val;
+
+       /* deassert phy reset & set tx drive strength */
+       val = PHY_CNFG_RSTN_DEASSERT;
+       val |= FIELD_PREP(PHY_CNFG_PAD_SP_MASK, PHY_CNFG_PAD_SP);
+       val |= FIELD_PREP(PHY_CNFG_PAD_SN_MASK, PHY_CNFG_PAD_SN);
+       sdhci_writel(host, val, PHY_CNFG_R);
+
+       /* disable delay line */
+       sdhci_writeb(host, PHY_SDCLKDL_CNFG_UPDATE, PHY_SDCLKDL_CNFG_R);
+
+       /* set delay line */
+       sdhci_writeb(host, priv->delay_line, PHY_SDCLKDL_DC_R);
+       sdhci_writeb(host, PHY_DLL_CNFG2_JUMPSTEP, PHY_DLL_CNFG2_R);
+
+       /* enable delay lane */
+       val = sdhci_readb(host, PHY_SDCLKDL_CNFG_R);
+       val &= ~(PHY_SDCLKDL_CNFG_UPDATE);
+       sdhci_writeb(host, val, PHY_SDCLKDL_CNFG_R);
+
+       /* configure phy pads */
+       val = PHY_PAD_RXSEL_3V3;
+       val |= FIELD_PREP(PHY_PAD_WEAKPULL_MASK, PHY_PAD_WEAKPULL_PULLUP);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_P_MASK, PHY_PAD_TXSLEW_CTRL_P);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_N_MASK, PHY_PAD_TXSLEW_CTRL_N);
+       sdhci_writew(host, val, PHY_CMDPAD_CNFG_R);
+       sdhci_writew(host, val, PHY_DATAPAD_CNFG_R);
+       sdhci_writew(host, val, PHY_RSTNPAD_CNFG_R);
+
+       val = FIELD_PREP(PHY_PAD_TXSLEW_CTRL_P_MASK, PHY_PAD_TXSLEW_CTRL_P);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_N_MASK, PHY_PAD_TXSLEW_CTRL_N);
+       sdhci_writew(host, val, PHY_CLKPAD_CNFG_R);
+
+       val = PHY_PAD_RXSEL_3V3;
+       val |= FIELD_PREP(PHY_PAD_WEAKPULL_MASK, PHY_PAD_WEAKPULL_PULLDOWN);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_P_MASK, PHY_PAD_TXSLEW_CTRL_P);
+       val |= FIELD_PREP(PHY_PAD_TXSLEW_CTRL_N_MASK, PHY_PAD_TXSLEW_CTRL_N);
+       sdhci_writew(host, val, PHY_STBPAD_CNFG_R);
+
+       /* enable phy dll */
+       sdhci_writeb(host, PHY_DLL_CTRL_ENABLE, PHY_DLL_CTRL_R);
+}
+
+static void th1520_sdhci_set_phy(struct sdhci_host *host)
+{
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
+       u32 emmc_caps = MMC_CAP2_NO_SD | MMC_CAP2_NO_SDIO;
+       u16 emmc_ctrl;
+
+       /* Before power on, set PHY configs */
+       if (priv->flags & FLAG_IO_FIXED_1V8)
+               dwcmshc_phy_1_8v_init(host);
+       else
+               dwcmshc_phy_3_3v_init(host);
+
+       if ((host->mmc->caps2 & emmc_caps) == emmc_caps) {
+               emmc_ctrl = sdhci_readw(host, priv->vendor_specific_area1 + DWCMSHC_EMMC_CONTROL);
+               emmc_ctrl |= DWCMSHC_CARD_IS_EMMC;
+               sdhci_writew(host, emmc_ctrl, priv->vendor_specific_area1 + DWCMSHC_EMMC_CONTROL);
+       }
+
+       sdhci_writeb(host, FIELD_PREP(PHY_DLL_CNFG1_SLVDLY_MASK, PHY_DLL_CNFG1_SLVDLY) |
+                    PHY_DLL_CNFG1_WAITCYCLE, PHY_DLL_CNFG1_R);
+}
+
 static void dwcmshc_set_uhs_signaling(struct sdhci_host *host,
                                      unsigned int timing)
 {
@@ -189,9 +404,25 @@ static void dwcmshc_set_uhs_signaling(struct sdhci_host *host,
                ctrl_2 |= DWCMSHC_CTRL_HS400;
        }
 
+       if (priv->flags & FLAG_IO_FIXED_1V8)
+               ctrl_2 |= SDHCI_CTRL_VDD_180;
        sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
 }
 
+static void th1520_set_uhs_signaling(struct sdhci_host *host,
+                                    unsigned int timing)
+{
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
+
+       dwcmshc_set_uhs_signaling(host, timing);
+       if (timing == MMC_TIMING_MMC_HS400)
+               priv->delay_line = PHY_SDCLKDL_DC_HS400;
+       else
+               sdhci_writeb(host, 0, PHY_DLLDL_CNFG_R);
+       th1520_sdhci_set_phy(host);
+}
+
 static void dwcmshc_hs400_enhanced_strobe(struct mmc_host *mmc,
                                          struct mmc_ios *ios)
 {
@@ -338,6 +569,79 @@ static void rk35xx_sdhci_reset(struct sdhci_host *host, u8 mask)
        sdhci_reset(host, mask);
 }
 
+static int th1520_execute_tuning(struct sdhci_host *host, u32 opcode)
+{
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
+       u32 val = 0;
+
+       if (host->flags & SDHCI_HS400_TUNING)
+               return 0;
+
+       sdhci_writeb(host, FIELD_PREP(PHY_ATDL_CNFG_INPSEL_MASK, PHY_ATDL_CNFG_INPSEL),
+                    PHY_ATDL_CNFG_R);
+       val = sdhci_readl(host, priv->vendor_specific_area1 + DWCMSHC_EMMC_ATCTRL);
+
+       /*
+        * configure tuning settings:
+        *  - center phase select code driven in block gap interval
+        *  - disable reporting of framing errors
+        *  - disable software managed tuning
+        *  - disable user selection of sampling window edges,
+        *    instead tuning calculated edges are used
+        */
+       val &= ~(AT_CTRL_CI_SEL | AT_CTRL_RPT_TUNE_ERR | AT_CTRL_SW_TUNE_EN |
+                FIELD_PREP(AT_CTRL_WIN_EDGE_SEL_MASK, AT_CTRL_WIN_EDGE_SEL));
+
+       /*
+        * configure tuning settings:
+        *  - enable auto-tuning
+        *  - enable sampling window threshold
+        *  - stop clocks during phase code change
+        *  - set max latency in cycles between tx and rx clocks
+        *  - set max latency in cycles to switch output phase
+        *  - set max sampling window threshold value
+        */
+       val |= AT_CTRL_AT_EN | AT_CTRL_SWIN_TH_EN | AT_CTRL_TUNE_CLK_STOP_EN;
+       val |= FIELD_PREP(AT_CTRL_PRE_CHANGE_DLY_MASK, AT_CTRL_PRE_CHANGE_DLY);
+       val |= FIELD_PREP(AT_CTRL_POST_CHANGE_DLY_MASK, AT_CTRL_POST_CHANGE_DLY);
+       val |= FIELD_PREP(AT_CTRL_SWIN_TH_VAL_MASK, AT_CTRL_SWIN_TH_VAL);
+
+       sdhci_writel(host, val, priv->vendor_specific_area1 + DWCMSHC_EMMC_ATCTRL);
+       val = sdhci_readl(host, priv->vendor_specific_area1 + DWCMSHC_EMMC_ATCTRL);
+
+       /* perform tuning */
+       sdhci_start_tuning(host);
+       host->tuning_err = __sdhci_execute_tuning(host, opcode);
+       if (host->tuning_err) {
+               /* disable auto-tuning upon tuning error */
+               val &= ~AT_CTRL_AT_EN;
+               sdhci_writel(host, val, priv->vendor_specific_area1 + DWCMSHC_EMMC_ATCTRL);
+               dev_err(mmc_dev(host->mmc), "tuning failed: %d\n", host->tuning_err);
+               return -EIO;
+       }
+       sdhci_end_tuning(host);
+
+       return 0;
+}
+
+static void th1520_sdhci_reset(struct sdhci_host *host, u8 mask)
+{
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct dwcmshc_priv *priv = sdhci_pltfm_priv(pltfm_host);
+       u16 ctrl_2;
+
+       sdhci_reset(host, mask);
+
+       if (priv->flags & FLAG_IO_FIXED_1V8) {
+               ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+               if (!(ctrl_2 & SDHCI_CTRL_VDD_180)) {
+                       ctrl_2 |= SDHCI_CTRL_VDD_180;
+                       sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
+               }
+       }
+}
+
 static const struct sdhci_ops sdhci_dwcmshc_ops = {
        .set_clock              = sdhci_set_clock,
        .set_bus_width          = sdhci_set_bus_width,
@@ -356,6 +660,17 @@ static const struct sdhci_ops sdhci_dwcmshc_rk35xx_ops = {
        .adma_write_desc        = dwcmshc_adma_write_desc,
 };
 
+static const struct sdhci_ops sdhci_dwcmshc_th1520_ops = {
+       .set_clock              = sdhci_set_clock,
+       .set_bus_width          = sdhci_set_bus_width,
+       .set_uhs_signaling      = th1520_set_uhs_signaling,
+       .get_max_clock          = dwcmshc_get_max_clock,
+       .reset                  = th1520_sdhci_reset,
+       .adma_write_desc        = dwcmshc_adma_write_desc,
+       .voltage_switch         = dwcmshc_phy_1_8v_init,
+       .platform_execute_tuning = &th1520_execute_tuning,
+};
+
 static const struct sdhci_pltfm_data sdhci_dwcmshc_pdata = {
        .ops = &sdhci_dwcmshc_ops,
        .quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
@@ -379,6 +694,12 @@ static const struct sdhci_pltfm_data sdhci_dwcmshc_rk35xx_pdata = {
                   SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
 };
 
+static const struct sdhci_pltfm_data sdhci_dwcmshc_th1520_pdata = {
+       .ops = &sdhci_dwcmshc_th1520_ops,
+       .quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
+       .quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
+};
+
 static int dwcmshc_rk35xx_init(struct sdhci_host *host, struct dwcmshc_priv *dwc_priv)
 {
        int err;
@@ -447,6 +768,10 @@ static const struct of_device_id sdhci_dwcmshc_dt_ids[] = {
                .compatible = "snps,dwcmshc-sdhci",
                .data = &sdhci_dwcmshc_pdata,
        },
+       {
+               .compatible = "thead,th1520-dwcmshc",
+               .data = &sdhci_dwcmshc_th1520_pdata,
+       },
        {},
 };
 MODULE_DEVICE_TABLE(of, sdhci_dwcmshc_dt_ids);
@@ -542,6 +867,30 @@ static int dwcmshc_probe(struct platform_device *pdev)
                        goto err_clk;
        }
 
+       if (pltfm_data == &sdhci_dwcmshc_th1520_pdata) {
+               priv->delay_line = PHY_SDCLKDL_DC_DEFAULT;
+
+               if ((device_property_read_bool(dev, "mmc-ddr-1_8v")) |
+                   (device_property_read_bool(dev, "mmc-hs200-1_8v")) |
+                   (device_property_read_bool(dev, "mmc-hs400-1_8v")))
+                       priv->flags |= FLAG_IO_FIXED_1V8;
+               else
+                       priv->flags &= ~FLAG_IO_FIXED_1V8;
+
+               /*
+                * start_signal_voltage_switch() will try 3.3V first
+                * then 1.8V. Use SDHCI_SIGNALING_180 rather than
+                * SDHCI_SIGNALING_330 to avoid setting voltage to 3.3V
+                * in sdhci_start_signal_voltage_switch().
+                */
+               if (priv->flags & FLAG_IO_FIXED_1V8) {
+                       host->flags &= ~SDHCI_SIGNALING_330;
+                       host->flags |=  SDHCI_SIGNALING_180;
+               }
+
+               sdhci_enable_v4_mode(host);
+       }
+
 #ifdef CONFIG_ACPI
        if (pltfm_data == &sdhci_dwcmshc_bf3_pdata)
                sdhci_enable_v4_mode(host);