diff options
Diffstat (limited to 'drivers/phy/intel/phy-intel-emmc.c')
| -rw-r--r-- | drivers/phy/intel/phy-intel-emmc.c | 283 |
1 files changed, 283 insertions, 0 deletions
diff --git a/drivers/phy/intel/phy-intel-emmc.c b/drivers/phy/intel/phy-intel-emmc.c new file mode 100644 index 000000000000..1a358e7fd236 --- /dev/null +++ b/drivers/phy/intel/phy-intel-emmc.c @@ -0,0 +1,283 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Intel eMMC PHY driver + * Copyright (C) 2019 Intel, Corp. + */ + +#include <linux/bits.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 phy register definitions */ +#define EMMC_PHYCTRL0_REG 0xa8 +#define DR_TY_MASK GENMASK(30, 28) +#define DR_TY_SHIFT(x) (((x) << 28) & DR_TY_MASK) +#define OTAPDLYENA BIT(14) +#define OTAPDLYSEL_MASK GENMASK(13, 10) +#define OTAPDLYSEL_SHIFT(x) (((x) << 10) & OTAPDLYSEL_MASK) + +#define EMMC_PHYCTRL1_REG 0xac +#define PDB_MASK BIT(0) +#define PDB_SHIFT(x) (((x) << 0) & PDB_MASK) +#define ENDLL_MASK BIT(7) +#define ENDLL_SHIFT(x) (((x) << 7) & ENDLL_MASK) + +#define EMMC_PHYCTRL2_REG 0xb0 +#define FRQSEL_25M 0 +#define FRQSEL_50M 1 +#define FRQSEL_100M 2 +#define FRQSEL_150M 3 +#define FRQSEL_MASK GENMASK(24, 22) +#define FRQSEL_SHIFT(x) (((x) << 22) & FRQSEL_MASK) + +#define EMMC_PHYSTAT_REG 0xbc +#define CALDONE_MASK BIT(9) +#define DLLRDY_MASK BIT(8) +#define IS_CALDONE(x) ((x) & CALDONE_MASK) +#define IS_DLLRDY(x) ((x) & DLLRDY_MASK) + +struct intel_emmc_phy { + struct regmap *syscfg; + struct clk *emmcclk; +}; + +static int intel_emmc_phy_power(struct phy *phy, bool on_off) +{ + struct intel_emmc_phy *priv = phy_get_drvdata(phy); + unsigned int caldone; + unsigned int dllrdy; + unsigned int freqsel; + unsigned long rate; + int ret, quot; + + /* + * Keep phyctrl_pdb and phyctrl_endll low to allow + * initialization of CALIO state M/C DFFs + */ + ret = regmap_update_bits(priv->syscfg, EMMC_PHYCTRL1_REG, PDB_MASK, + PDB_SHIFT(0)); + if (ret) { + dev_err(&phy->dev, "CALIO power down bar failed: %d\n", ret); + return ret; + } + + /* Already finish power_off above */ + if (!on_off) + return 0; + + rate = clk_get_rate(priv->emmcclk); + quot = DIV_ROUND_CLOSEST(rate, 50000000); + if (quot > FRQSEL_150M) + dev_warn(&phy->dev, "Unsupported rate: %lu\n", rate); + freqsel = clamp_t(int, quot, FRQSEL_25M, FRQSEL_150M); + + /* + * 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, EMMC_PHYCTRL1_REG, PDB_MASK, + PDB_SHIFT(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, EMMC_PHYSTAT_REG, + 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, EMMC_PHYCTRL2_REG, FRQSEL_MASK, + FRQSEL_SHIFT(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, EMMC_PHYCTRL1_REG, ENDLL_MASK, + ENDLL_SHIFT(1)); + if (ret) { + dev_err(&phy->dev, "turn on the dll failed: %d\n", ret); + return ret; + } + + /* + * 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 100 kHZ) 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, + EMMC_PHYSTAT_REG, + dllrdy, IS_DLLRDY(dllrdy), + 0, 50 * USEC_PER_MSEC); + if (ret) { + dev_err(&phy->dev, "dllrdy failed. ret=%d\n", ret); + return ret; + } + + return 0; +} + +static int intel_emmc_phy_init(struct phy *phy) +{ + struct intel_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"); + if (IS_ERR(priv->emmcclk)) { + dev_err(&phy->dev, "ERROR: getting emmcclk\n"); + return PTR_ERR(priv->emmcclk); + } + + return 0; +} + +static int intel_emmc_phy_exit(struct phy *phy) +{ + struct intel_emmc_phy *priv = phy_get_drvdata(phy); + + clk_put(priv->emmcclk); + + return 0; +} + +static int intel_emmc_phy_power_on(struct phy *phy) +{ + struct intel_emmc_phy *priv = phy_get_drvdata(phy); + int ret; + + /* Drive impedance: 50 Ohm */ + ret = regmap_update_bits(priv->syscfg, EMMC_PHYCTRL0_REG, DR_TY_MASK, + DR_TY_SHIFT(6)); + if (ret) { + dev_err(&phy->dev, "ERROR set drive-impednce-50ohm: %d\n", ret); + return ret; + } + + /* Output tap delay: disable */ + ret = regmap_update_bits(priv->syscfg, EMMC_PHYCTRL0_REG, OTAPDLYENA, + 0); + if (ret) { + dev_err(&phy->dev, "ERROR Set output tap delay : %d\n", ret); + return ret; + } + + /* Output tap delay */ + ret = regmap_update_bits(priv->syscfg, EMMC_PHYCTRL0_REG, + OTAPDLYSEL_MASK, OTAPDLYSEL_SHIFT(4)); + if (ret) { + dev_err(&phy->dev, "ERROR: output tap dly select: %d\n", ret); + return ret; + } + + /* Power up eMMC phy analog blocks */ + return intel_emmc_phy_power(phy, true); +} + +static int intel_emmc_phy_power_off(struct phy *phy) +{ + /* Power down eMMC phy analog blocks */ + return intel_emmc_phy_power(phy, false); +} + +static const struct phy_ops ops = { + .init = intel_emmc_phy_init, + .exit = intel_emmc_phy_exit, + .power_on = intel_emmc_phy_power_on, + .power_off = intel_emmc_phy_power_off, + .owner = THIS_MODULE, +}; + +static int intel_emmc_phy_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *np = dev->of_node; + struct intel_emmc_phy *priv; + struct phy *generic_phy; + struct phy_provider *phy_provider; + + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + /* Get eMMC phy (accessed via chiptop) regmap */ + priv->syscfg = syscon_regmap_lookup_by_phandle(np, "intel,syscon"); + if (IS_ERR(priv->syscfg)) { + dev_err(dev, "failed to find syscon\n"); + return PTR_ERR(priv->syscfg); + } + + generic_phy = devm_phy_create(dev, np, &ops); + if (IS_ERR(generic_phy)) { + dev_err(dev, "failed to create PHY\n"); + return PTR_ERR(generic_phy); + } + + 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 intel_emmc_phy_dt_ids[] = { + { .compatible = "intel,lgm-emmc-phy" }, + {} +}; + +MODULE_DEVICE_TABLE(of, intel_emmc_phy_dt_ids); + +static struct platform_driver intel_emmc_driver = { + .probe = intel_emmc_phy_probe, + .driver = { + .name = "intel-emmc-phy", + .of_match_table = intel_emmc_phy_dt_ids, + }, +}; + +module_platform_driver(intel_emmc_driver); + +MODULE_AUTHOR("Peter Harliman Liem <peter.harliman.liem@intel.com>"); +MODULE_DESCRIPTION("Intel eMMC PHY driver"); |