[PATCH 2/7] mmc: tegra: Reconfigure pad voltages during voltage switching

[Aapo Vienamo]

Parse the pinctrl states from the device tree and implement pad voltage
state reconfiguration in the mmc start_signal_voltage_switch() callback.
This is done in the mmc callback because the order of pad
reconfiguration and sdhci voltage switch depend on the voltage to which
the transition occurs.

Add NVQUIRK_NEEDS_PAD_CONTROL and add set it for Tegra210 and Tegra186.

Signed-off-by: Aapo Vienamo <avienamo@xxxxxxxxxx>
---
 drivers/mmc/host/sdhci-tegra.c | 91 +++++++++++++++++++++++++++++++++++++++---
 1 file changed, 85 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index ddf00166..f108c48 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -21,6 +21,7 @@
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/reset.h>
 #include <linux/mmc/card.h>
 #include <linux/mmc/host.h>
@@ -55,6 +56,7 @@
 #define NVQUIRK_ENABLE_SDR104		BIT(4)
 #define NVQUIRK_ENABLE_DDR50		BIT(5)
 #define NVQUIRK_HAS_PADCALIB		BIT(6)
+#define NVQUIRK_NEEDS_PAD_CONTROL	BIT(7)
 
 struct sdhci_tegra_soc_data {
 	const struct sdhci_pltfm_data *pdata;
@@ -66,8 +68,12 @@ struct sdhci_tegra {
 	struct gpio_desc *power_gpio;
 	bool ddr_signaling;
 	bool pad_calib_required;
+	bool pad_control_required;
 
 	struct reset_control *rst;
+	struct pinctrl *pinctrl_sdmmc;
+	struct pinctrl_state *pinctrl_state_3v3;
+	struct pinctrl_state *pinctrl_state_1v8;
 };
 
 static u16 tegra_sdhci_readw(struct sdhci_host *host, int reg)
@@ -286,14 +292,80 @@ static int tegra_sdhci_execute_tuning(struct sdhci_host *host, u32 opcode)
 	return mmc_send_tuning(host->mmc, opcode, NULL);
 }
 
-static void tegra_sdhci_voltage_switch(struct sdhci_host *host)
+static int tegra_sdhci_set_padctrl(struct sdhci_host *host, int voltage)
 {
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
-	const struct sdhci_tegra_soc_data *soc_data = tegra_host->soc_data;
+	int ret;
+
+	if (!tegra_host->pad_control_required)
+		return 0;
+
+	if (voltage == MMC_SIGNAL_VOLTAGE_180) {
+		ret = pinctrl_select_state(tegra_host->pinctrl_sdmmc,
+					   tegra_host->pinctrl_state_1v8);
+		if (ret < 0)
+			dev_err(mmc_dev(host->mmc),
+				"setting 1.8V failed, ret: %d\n", ret);
+	} else {
+		ret = pinctrl_select_state(tegra_host->pinctrl_sdmmc,
+					   tegra_host->pinctrl_state_3v3);
+		if (ret < 0)
+			dev_err(mmc_dev(host->mmc),
+				"setting 3.3V failed, ret: %d\n", ret);
+	}
 
-	if (soc_data->nvquirks & NVQUIRK_HAS_PADCALIB)
-		tegra_host->pad_calib_required = true;
+	return ret;
+}
+
+static int sdhci_tegra_start_signal_voltage_switch(struct mmc_host *mmc,
+						   struct mmc_ios *ios)
+{
+	struct sdhci_host *host = mmc_priv(mmc);
+	int ret = 0;
+
+	if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330) {
+		ret = tegra_sdhci_set_padctrl(host, ios->signal_voltage);
+		if (ret < 0)
+			return ret;
+		ret = sdhci_start_signal_voltage_switch(mmc, ios);
+	} else if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
+		ret = sdhci_start_signal_voltage_switch(mmc, ios);
+		if (ret < 0)
+			return ret;
+		ret = tegra_sdhci_set_padctrl(host, ios->signal_voltage);
+	}
+
+	return ret;
+}
+
+static void tegra_sdhci_init_pinctrl_info(struct device *dev,
+					  struct sdhci_tegra *tegra_host)
+{
+	tegra_host->pinctrl_sdmmc = devm_pinctrl_get(dev);
+	if (IS_ERR_OR_NULL(tegra_host->pinctrl_sdmmc)) {
+		dev_dbg(dev, "No pinctrl info, err: %ld\n",
+			PTR_ERR(tegra_host->pinctrl_sdmmc));
+		return;
+	}
+
+	tegra_host->pinctrl_state_3v3 =
+		pinctrl_lookup_state(tegra_host->pinctrl_sdmmc, "sdmmc-3v3");
+	if (IS_ERR_OR_NULL(tegra_host->pinctrl_state_3v3)) {
+		dev_err(dev, "Missing 3.3V pad state, err: %ld\n",
+			PTR_ERR(tegra_host->pinctrl_state_3v3));
+		return;
+	}
+
+	tegra_host->pinctrl_state_1v8 =
+		pinctrl_lookup_state(tegra_host->pinctrl_sdmmc, "sdmmc-1v8");
+	if (IS_ERR_OR_NULL(tegra_host->pinctrl_state_1v8)) {
+		dev_err(dev, "Missing 1.8V pad state, err: %ld\n",
+			  PTR_ERR(tegra_host->pinctrl_state_3v3));
+		return;
+	}
+
+	tegra_host->pad_control_required = true;
 }
 
 static const struct sdhci_ops tegra_sdhci_ops = {
@@ -305,7 +377,6 @@ static const struct sdhci_ops tegra_sdhci_ops = {
 	.reset      = tegra_sdhci_reset,
 	.platform_execute_tuning = tegra_sdhci_execute_tuning,
 	.set_uhs_signaling = tegra_sdhci_set_uhs_signaling,
-	.voltage_switch = tegra_sdhci_voltage_switch,
 	.get_max_clock = tegra_sdhci_get_max_clock,
 };
 
@@ -362,7 +433,6 @@ static const struct sdhci_ops tegra114_sdhci_ops = {
 	.reset      = tegra_sdhci_reset,
 	.platform_execute_tuning = tegra_sdhci_execute_tuning,
 	.set_uhs_signaling = tegra_sdhci_set_uhs_signaling,
-	.voltage_switch = tegra_sdhci_voltage_switch,
 	.get_max_clock = tegra_sdhci_get_max_clock,
 };
 
@@ -419,6 +489,7 @@ static const struct sdhci_pltfm_data sdhci_tegra210_pdata = {
 
 static const struct sdhci_tegra_soc_data soc_data_tegra210 = {
 	.pdata = &sdhci_tegra210_pdata,
+	.nvquirks = NVQUIRK_NEEDS_PAD_CONTROL,
 };
 
 static const struct sdhci_pltfm_data sdhci_tegra186_pdata = {
@@ -442,6 +513,7 @@ static const struct sdhci_pltfm_data sdhci_tegra186_pdata = {
 
 static const struct sdhci_tegra_soc_data soc_data_tegra186 = {
 	.pdata = &sdhci_tegra186_pdata,
+	.nvquirks = NVQUIRK_NEEDS_PAD_CONTROL,
 };
 
 static const struct of_device_id sdhci_tegra_dt_match[] = {
@@ -478,8 +550,15 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
 	tegra_host = sdhci_pltfm_priv(pltfm_host);
 	tegra_host->ddr_signaling = false;
 	tegra_host->pad_calib_required = false;
+	tegra_host->pad_control_required = false;
 	tegra_host->soc_data = soc_data;
 
+	if (soc_data->nvquirks & NVQUIRK_NEEDS_PAD_CONTROL) {
+		host->mmc_host_ops.start_signal_voltage_switch =
+			sdhci_tegra_start_signal_voltage_switch;
+		tegra_sdhci_init_pinctrl_info(&pdev->dev, tegra_host);
+	}
+
 	rc = mmc_of_parse(host->mmc);
 	if (rc)
 		goto err_parse_dt;
-- 
2.7.4