[PATCH v1 2/2] phy: intel-lgm-emmc: Add support for eMMC PHY

Ramuthevar,Vadivel MuruganX
2019-08-19T03:44:26Z

From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>

Adds support for eMMC PHY on Intel's Lightning Mountain SoC.

Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@linux.intel.com>
---
drivers/phy/Kconfig | 1 +
drivers/phy/Makefile | 1 +
drivers/phy/intel/Kconfig | 8 ++
drivers/phy/intel/Makefile | 2 +
drivers/phy/intel/phy-intel-emmc.c | 276 +++++++++++++++++++++++++++++++++++++
5 files changed, 288 insertions(+)
create mode 100644 drivers/phy/intel/Kconfig
create mode 100644 drivers/phy/intel/Makefile
create mode 100644 drivers/phy/intel/phy-intel-emmc.c

diff --git a/drivers/phy/Kconfig b/drivers/phy/Kconfig
index 0263db2ac874..b3ed94b98d9b 100644
--- a/drivers/phy/Kconfig
+++ b/drivers/phy/Kconfig
@@ -69,5 +69,6 @@ source "drivers/phy/socionext/Kconfig"
source "drivers/phy/st/Kconfig"
source "drivers/phy/tegra/Kconfig"
source "drivers/phy/ti/Kconfig"
+source "drivers/phy/intel/Kconfig"

endmenu
diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
index 0d9fddc498a6..3f1fc9efbbed 100644
--- a/drivers/phy/Makefile
+++ b/drivers/phy/Makefile
@@ -19,6 +19,7 @@ obj-y += broadcom/ \
cadence/ \
freescale/ \
hisilicon/ \
+ intel/ \
marvell/ \
motorola/ \
mscc/ \
diff --git a/drivers/phy/intel/Kconfig b/drivers/phy/intel/Kconfig
new file mode 100644
index 000000000000..aa34e0fa9824
--- /dev/null
+++ b/drivers/phy/intel/Kconfig
@@ -0,0 +1,8 @@
+#
+# Phy drivers for Intel X86 LGM platform
+#
+config PHY_INTEL_EMMC
+ tristate "Intel EMMC PHY driver"
+ select GENERIC_PHY
+ help
+ Enable this to support the Intel EMMC PHY
diff --git a/drivers/phy/intel/Makefile b/drivers/phy/intel/Makefile
new file mode 100644
index 000000000000..6b876a75599d
--- /dev/null
+++ b/drivers/phy/intel/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PHY_INTEL_EMMC) += phy-intel-emmc.o
diff --git a/drivers/phy/intel/phy-intel-emmc.c b/drivers/phy/intel/phy-intel-emmc.c
new file mode 100644
index 000000000000..2fd4e42f18f8
--- /dev/null
+++ b/drivers/phy/intel/phy-intel-emmc.c
@@ -0,0 +1,276 @@
+// 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_50OHM(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 1
+#define ENDLL_MASK BIT(7)
+#define ENDLL_VAL BIT(7)
+
+#define EMMC_PHYCTRL2_REG 0xb0
+#define FRQSEL_25M 0
+#define FRQSEL_150M 3
+#define FRQSEL_MASK GENMASK(24, 22)
+#define FRQSEL_SHIFT(x) ((x) << 22)
+
+#define EMMC_PHYSTAT_REG 0xbc
+#define CALDONE_MASK 1
+#define DLLRDY_MASK 1
+#define IS_CALDONE(x) ((((x) >> 9) & CALDONE_MASK) == 1)
+#define IS_DLLRDY(x) ((((x) >> 8) & DLLRDY_MASK) == 1)
+
+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 = 0;
+ 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 | ENDLL_MASK, 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
+ */
+ usleep_range(3, 6);
+ regmap_update_bits(priv->syscfg, EMMC_PHYCTRL1_REG, PDB_MASK, 1);
+
+ /*
+ * 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_VAL);
+ 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 we just set to NULL.
+ *
+ * NOTE: we don't do anything special for EPROBE_DEFER here. Given the
+ * above expected use case, EPROBE_DEFER isn't sensible to expect, so
+ * it's just like any other error.
+ */
+ priv->emmcclk = clk_get_optional(&phy->dev, "emmcclk");
+ if (IS_ERR(priv->emmcclk)) {
+ dev_warn(&phy->dev, "ERROR: getting emmcclk\n");
+ priv->emmcclk = NULL;
+ }
+
+ 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_50OHM(1));
+ 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,
+ 0x0);
+ 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 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(dev->of_node,
+ "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, dev->of_node, &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");
--
2.11.0