mmc: sdhci_omap: Add support to set IODELAY values

The data manual of J6/J6 Eco recommends to set different IODELAY values
depending on the mode in which the MMC/SD is enumerated in order to
ensure IO timings are met.

Add support to set the IODELAY values depending on the various MMC
modes using the pinctrl APIs.

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 148 insertions, 0 deletions

diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
index e24ae903f7ba..428849387992 100644
--- a/drivers/mmc/host/sdhci-omap.c
+++ b/drivers/mmc/host/sdhci-omap.c
@@ -25,6 +25,7 @@
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
+#include <linux/pinctrl/consumer.h>
 
 #include "sdhci-pltfm.h"
 
@@ -90,8 +91,12 @@
 
 #define MAX_PHASE_DELAY         0x7C
 
+/* sdhci-omap controller flags */
+#define SDHCI_OMAP_REQUIRE_IODELAY      BIT(0)
+
 struct sdhci_omap_data {
         u32 offset;
+        u8 flags;
 };
 
 struct sdhci_omap_host {
@@ -102,8 +107,16 @@ struct sdhci_omap_host {
         struct sdhci_host       *host;
         u8                      bus_mode;
         u8                      power_mode;
+        u8                      timing;
+        u8                      flags;
+
+        struct pinctrl          *pinctrl;
+        struct pinctrl_state    **pinctrl_state;
 };
 
+static void sdhci_omap_start_clock(struct sdhci_omap_host *omap_host);
+static void sdhci_omap_stop_clock(struct sdhci_omap_host *omap_host);
+
 static inline u32 sdhci_omap_readl(struct sdhci_omap_host *host,
                                    unsigned int offset)
 {
@@ -436,6 +449,31 @@ static int sdhci_omap_start_signal_voltage_switch(struct mmc_host *mmc,
         return 0;
 }
 
+static void sdhci_omap_set_timing(struct sdhci_omap_host *omap_host, u8 timing)
+{
+        int ret;
+        struct pinctrl_state *pinctrl_state;
+        struct device *dev = omap_host->dev;
+
+        if (!(omap_host->flags & SDHCI_OMAP_REQUIRE_IODELAY))
+                return;
+
+        if (omap_host->timing == timing)
+                return;
+
+        sdhci_omap_stop_clock(omap_host);
+
+        pinctrl_state = omap_host->pinctrl_state[timing];
+        ret = pinctrl_select_state(omap_host->pinctrl, pinctrl_state);
+        if (ret) {
+                dev_err(dev, "failed to select pinctrl state\n");
+                return;
+        }
+
+        sdhci_omap_start_clock(omap_host);
+        omap_host->timing = timing;
+}
+
 static void sdhci_omap_set_power_mode(struct sdhci_omap_host *omap_host,
                                       u8 power_mode)
 {
@@ -472,6 +510,7 @@ static void sdhci_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
         omap_host = sdhci_pltfm_priv(pltfm_host);
 
         sdhci_omap_set_bus_mode(omap_host, ios->bus_mode);
+        sdhci_omap_set_timing(omap_host, ios->timing);
         sdhci_set_ios(mmc, ios);
         sdhci_omap_set_power_mode(omap_host, ios->power_mode);
 }
@@ -680,6 +719,7 @@ static const struct sdhci_pltfm_data sdhci_omap_pdata = {
 
 static const struct sdhci_omap_data dra7_data = {
         .offset = 0x200,
+        .flags  = SDHCI_OMAP_REQUIRE_IODELAY,
 };
 
 static const struct of_device_id omap_sdhci_match[] = {
@@ -688,6 +728,108 @@ static const struct of_device_id omap_sdhci_match[] = {
 };
 MODULE_DEVICE_TABLE(of, omap_sdhci_match);
 
+static struct pinctrl_state
+*sdhci_omap_iodelay_pinctrl_state(struct sdhci_omap_host *omap_host, char *mode,
+                                  u32 *caps, u32 capmask)
+{
+        struct device *dev = omap_host->dev;
+        struct pinctrl_state *pinctrl_state = ERR_PTR(-ENODEV);
+
+        if (!(*caps & capmask))
+                goto ret;
+
+        pinctrl_state = pinctrl_lookup_state(omap_host->pinctrl, mode);
+        if (IS_ERR(pinctrl_state)) {
+                dev_err(dev, "no pinctrl state for %s mode", mode);
+                *caps &= ~capmask;
+        }
+
+ret:
+        return pinctrl_state;
+}
+
+static int sdhci_omap_config_iodelay_pinctrl_state(struct sdhci_omap_host
+                                                   *omap_host)
+{
+        struct device *dev = omap_host->dev;
+        struct sdhci_host *host = omap_host->host;
+        struct mmc_host *mmc = host->mmc;
+        u32 *caps = &mmc->caps;
+        u32 *caps2 = &mmc->caps2;
+        struct pinctrl_state *state;
+        struct pinctrl_state **pinctrl_state;
+
+        if (!(omap_host->flags & SDHCI_OMAP_REQUIRE_IODELAY))
+                return 0;
+
+        pinctrl_state = devm_kzalloc(dev, sizeof(*pinctrl_state) *
+                                     (MMC_TIMING_MMC_HS200 + 1), GFP_KERNEL);
+        if (!pinctrl_state)
+                return -ENOMEM;
+
+        omap_host->pinctrl = devm_pinctrl_get(omap_host->dev);
+        if (IS_ERR(omap_host->pinctrl)) {
+                dev_err(dev, "Cannot get pinctrl\n");
+                return PTR_ERR(omap_host->pinctrl);
+        }
+
+        state = pinctrl_lookup_state(omap_host->pinctrl, "default");
+        if (IS_ERR(state)) {
+                dev_err(dev, "no pinctrl state for default mode\n");
+                return PTR_ERR(state);
+        }
+        pinctrl_state[MMC_TIMING_LEGACY] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "sdr104", caps,
+                                                 MMC_CAP_UHS_SDR104);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_UHS_SDR104] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "ddr50", caps,
+                                                 MMC_CAP_UHS_DDR50);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_UHS_DDR50] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "sdr50", caps,
+                                                 MMC_CAP_UHS_SDR50);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_UHS_SDR50] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "sdr25", caps,
+                                                 MMC_CAP_UHS_SDR25);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_UHS_SDR25] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "sdr12", caps,
+                                                 MMC_CAP_UHS_SDR12);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_UHS_SDR12] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "ddr_1_8v", caps,
+                                                 MMC_CAP_1_8V_DDR);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_MMC_DDR52] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "hs", caps,
+                                                 MMC_CAP_SD_HIGHSPEED);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_SD_HS] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "hs", caps,
+                                                 MMC_CAP_MMC_HIGHSPEED);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_MMC_HS] = state;
+
+        state = sdhci_omap_iodelay_pinctrl_state(omap_host, "hs200_1_8v", caps2,
+                                                 MMC_CAP2_HS200_1_8V_SDR);
+        if (!IS_ERR(state))
+                pinctrl_state[MMC_TIMING_MMC_HS200] = state;
+
+        omap_host->pinctrl_state = pinctrl_state;
+
+        return 0;
+}
+
 static int sdhci_omap_probe(struct platform_device *pdev)
 {
         int ret;
@@ -724,6 +866,8 @@ static int sdhci_omap_probe(struct platform_device *pdev)
         omap_host->base = host->ioaddr;
         omap_host->dev = dev;
         omap_host->power_mode = MMC_POWER_UNDEFINED;
+        omap_host->timing = MMC_TIMING_LEGACY;
+        omap_host->flags = data->flags;
         host->ioaddr += offset;
 
         mmc = host->mmc;
@@ -772,6 +916,10 @@ static int sdhci_omap_probe(struct platform_device *pdev)
                 goto err_put_sync;
         }
 
+        ret = sdhci_omap_config_iodelay_pinctrl_state(omap_host);
+        if (ret)
+                goto err_put_sync;
+
         host->mmc_host_ops.get_ro = mmc_gpio_get_ro;
         host->mmc_host_ops.start_signal_voltage_switch =
                                         sdhci_omap_start_signal_voltage_switch;