diff options
Diffstat (limited to 'drivers/phy/intel/phy-intel-keembay-emmc.c')
| -rw-r--r-- | drivers/phy/intel/phy-intel-keembay-emmc.c | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/drivers/phy/intel/phy-intel-keembay-emmc.c b/drivers/phy/intel/phy-intel-keembay-emmc.c new file mode 100644 index 0000000000..0eb11ac7c2 --- /dev/null +++ b/drivers/phy/intel/phy-intel-keembay-emmc.c @@ -0,0 +1,308 @@ +// 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; + + /* Check for EMMC clock rate*/ + if (mhz > 175) + 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"); |