--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Intel Keem Bay eMMC PHY driver
+ * Copyright (C) 2020 Intel Corporation
+ */
+
+#include <linux/bitfield.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/phy/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+/* eMMC/SD/SDIO core/phy configuration registers */
+#define PHY_CFG_0 0x24
+#define SEL_DLY_TXCLK_MASK BIT(29)
+#define OTAP_DLY_ENA_MASK BIT(27)
+#define OTAP_DLY_SEL_MASK GENMASK(26, 23)
+#define DLL_EN_MASK BIT(10)
+#define PWR_DOWN_MASK BIT(0)
+
+#define PHY_CFG_2 0x2c
+#define SEL_FREQ_MASK GENMASK(12, 10)
+
+#define PHY_STAT 0x40
+#define CAL_DONE_MASK BIT(6)
+#define IS_CALDONE(x) ((x) & CAL_DONE_MASK)
+#define DLL_RDY_MASK BIT(5)
+#define IS_DLLRDY(x) ((x) & DLL_RDY_MASK)
+
+/* From ACS_eMMC51_16nFFC_RO1100_Userguide_v1p0.pdf p17 */
+#define FREQSEL_200M_170M 0x0
+#define FREQSEL_170M_140M 0x1
+#define FREQSEL_140M_110M 0x2
+#define FREQSEL_110M_80M 0x3
+#define FREQSEL_80M_50M 0x4
+
+struct keembay_emmc_phy {
+ struct regmap *syscfg;
+ struct clk *emmcclk;
+};
+
+static const struct regmap_config keembay_regmap_config = {
+ .reg_bits = 32,
+ .val_bits = 32,
+ .reg_stride = 4,
+};
+
+static int keembay_emmc_phy_power(struct phy *phy, bool on_off)
+{
+ struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
+ unsigned int caldone;
+ unsigned int dllrdy;
+ unsigned int freqsel;
+ unsigned int mhz;
+ int ret;
+
+ /*
+ * Keep phyctrl_pdb and phyctrl_endll low to allow
+ * initialization of CALIO state M/C DFFs
+ */
+ ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, PWR_DOWN_MASK,
+ FIELD_PREP(PWR_DOWN_MASK, 0));
+ if (ret) {
+ dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret);
+ return ret;
+ }
+
+ ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, DLL_EN_MASK,
+ FIELD_PREP(DLL_EN_MASK, 0));
+ if (ret) {
+ dev_err(&phy->dev, "turn off the dll failed: %d\n", ret);
+ return ret;
+ }
+
+ /* Already finish power off above */
+ if (!on_off)
+ return 0;
+
+ mhz = DIV_ROUND_CLOSEST(clk_get_rate(priv->emmcclk), 1000000);
+ if (mhz <= 200 && mhz >= 170)
+ freqsel = FREQSEL_200M_170M;
+ else if (mhz <= 170 && mhz >= 140)
+ freqsel = FREQSEL_170M_140M;
+ else if (mhz <= 140 && mhz >= 110)
+ freqsel = FREQSEL_140M_110M;
+ else if (mhz <= 110 && mhz >= 80)
+ freqsel = FREQSEL_110M_80M;
+ else if (mhz <= 80 && mhz >= 50)
+ freqsel = FREQSEL_80M_50M;
+ else
+ freqsel = 0x0;
+
+ if (mhz < 50 || mhz > 200)
+ dev_warn(&phy->dev, "Unsupported rate: %d MHz\n", mhz);
+
+ /*
+ * According to the user manual, calpad calibration
+ * cycle takes more than 2us without the minimal recommended
+ * value, so we may need a little margin here
+ */
+ udelay(5);
+
+ ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, PWR_DOWN_MASK,
+ FIELD_PREP(PWR_DOWN_MASK, 1));
+ if (ret) {
+ dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret);
+ return ret;
+ }
+
+ /*
+ * According to the user manual, it asks driver to wait 5us for
+ * calpad busy trimming. However it is documented that this value is
+ * PVT(A.K.A. process, voltage and temperature) relevant, so some
+ * failure cases are found which indicates we should be more tolerant
+ * to calpad busy trimming.
+ */
+ ret = regmap_read_poll_timeout(priv->syscfg, PHY_STAT,
+ caldone, IS_CALDONE(caldone),
+ 0, 50);
+ if (ret) {
+ dev_err(&phy->dev, "caldone failed, ret=%d\n", ret);
+ return ret;
+ }
+
+ /* Set the frequency of the DLL operation */
+ ret = regmap_update_bits(priv->syscfg, PHY_CFG_2, SEL_FREQ_MASK,
+ FIELD_PREP(SEL_FREQ_MASK, freqsel));
+ if (ret) {
+ dev_err(&phy->dev, "set the frequency of dll failed:%d\n", ret);
+ return ret;
+ }
+
+ /* Turn on the DLL */
+ ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, DLL_EN_MASK,
+ FIELD_PREP(DLL_EN_MASK, 1));
+ if (ret) {
+ dev_err(&phy->dev, "turn on the dll failed: %d\n", ret);
+ return ret;
+ }
+
+ /*
+ * We turned on the DLL even though the rate was 0 because we the
+ * clock might be turned on later. ...but we can't wait for the DLL
+ * to lock when the rate is 0 because it will never lock with no
+ * input clock.
+ *
+ * Technically we should be checking the lock later when the clock
+ * is turned on, but for now we won't.
+ */
+ if (mhz == 0)
+ return 0;
+
+ /*
+ * After enabling analog DLL circuits docs say that we need 10.2 us if
+ * our source clock is at 50 MHz and that lock time scales linearly
+ * with clock speed. If we are powering on the PHY and the card clock
+ * is super slow (like 100kHz) this could take as long as 5.1 ms as
+ * per the math: 10.2 us * (50000000 Hz / 100000 Hz) => 5.1 ms
+ * hopefully we won't be running at 100 kHz, but we should still make
+ * sure we wait long enough.
+ *
+ * NOTE: There appear to be corner cases where the DLL seems to take
+ * extra long to lock for reasons that aren't understood. In some
+ * extreme cases we've seen it take up to over 10ms (!). We'll be
+ * generous and give it 50ms.
+ */
+ ret = regmap_read_poll_timeout(priv->syscfg, PHY_STAT,
+ dllrdy, IS_DLLRDY(dllrdy),
+ 0, 50 * USEC_PER_MSEC);
+ if (ret)
+ dev_err(&phy->dev, "dllrdy failed, ret=%d\n", ret);
+
+ return ret;
+}
+
+static int keembay_emmc_phy_init(struct phy *phy)
+{
+ struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
+
+ /*
+ * We purposely get the clock here and not in probe to avoid the
+ * circular dependency problem. We expect:
+ * - PHY driver to probe
+ * - SDHCI driver to start probe
+ * - SDHCI driver to register it's clock
+ * - SDHCI driver to get the PHY
+ * - SDHCI driver to init the PHY
+ *
+ * The clock is optional, so upon any error just return it like
+ * any other error to user.
+ */
+ priv->emmcclk = clk_get_optional(&phy->dev, "emmcclk");
+
+ return PTR_ERR_OR_ZERO(priv->emmcclk);
+}
+
+static int keembay_emmc_phy_exit(struct phy *phy)
+{
+ struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
+
+ clk_put(priv->emmcclk);
+
+ return 0;
+};
+
+static int keembay_emmc_phy_power_on(struct phy *phy)
+{
+ struct keembay_emmc_phy *priv = phy_get_drvdata(phy);
+ int ret;
+
+ /* Delay chain based txclk: enable */
+ ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, SEL_DLY_TXCLK_MASK,
+ FIELD_PREP(SEL_DLY_TXCLK_MASK, 1));
+ if (ret) {
+ dev_err(&phy->dev, "ERROR: delay chain txclk set: %d\n", ret);
+ return ret;
+ }
+
+ /* Output tap delay: enable */
+ ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, OTAP_DLY_ENA_MASK,
+ FIELD_PREP(OTAP_DLY_ENA_MASK, 1));
+ if (ret) {
+ dev_err(&phy->dev, "ERROR: output tap delay set: %d\n", ret);
+ return ret;
+ }
+
+ /* Output tap delay */
+ ret = regmap_update_bits(priv->syscfg, PHY_CFG_0, OTAP_DLY_SEL_MASK,
+ FIELD_PREP(OTAP_DLY_SEL_MASK, 2));
+ if (ret) {
+ dev_err(&phy->dev, "ERROR: output tap delay select: %d\n", ret);
+ return ret;
+ }
+
+ /* Power up eMMC phy analog blocks */
+ return keembay_emmc_phy_power(phy, true);
+}
+
+static int keembay_emmc_phy_power_off(struct phy *phy)
+{
+ /* Power down eMMC phy analog blocks */
+ return keembay_emmc_phy_power(phy, false);
+}
+
+static const struct phy_ops ops = {
+ .init = keembay_emmc_phy_init,
+ .exit = keembay_emmc_phy_exit,
+ .power_on = keembay_emmc_phy_power_on,
+ .power_off = keembay_emmc_phy_power_off,
+ .owner = THIS_MODULE,
+};
+
+static int keembay_emmc_phy_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ struct keembay_emmc_phy *priv;
+ struct phy *generic_phy;
+ struct phy_provider *phy_provider;
+ void __iomem *base;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(base))
+ return PTR_ERR(base);
+
+ priv->syscfg = devm_regmap_init_mmio(dev, base, &keembay_regmap_config);
+ if (IS_ERR(priv->syscfg))
+ return PTR_ERR(priv->syscfg);
+
+ generic_phy = devm_phy_create(dev, np, &ops);
+ if (IS_ERR(generic_phy))
+ return dev_err_probe(dev, PTR_ERR(generic_phy),
+ "failed to create PHY\n");
+
+ phy_set_drvdata(generic_phy, priv);
+ phy_provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
+
+ return PTR_ERR_OR_ZERO(phy_provider);
+}
+
+static const struct of_device_id keembay_emmc_phy_dt_ids[] = {
+ { .compatible = "intel,keembay-emmc-phy" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, keembay_emmc_phy_dt_ids);
+
+static struct platform_driver keembay_emmc_phy_driver = {
+ .probe = keembay_emmc_phy_probe,
+ .driver = {
+ .name = "keembay-emmc-phy",
+ .of_match_table = keembay_emmc_phy_dt_ids,
+ },
+};
+module_platform_driver(keembay_emmc_phy_driver);
+
+MODULE_AUTHOR("Wan Ahmad Zainie <wan.ahmad.zainie.wan.mohamad@intel.com>");
+MODULE_DESCRIPTION("Intel Keem Bay eMMC PHY driver");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-starfive.git / commitdiff