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Subject[PATCH v2 3/3] phy: stm32: add phy tuning support
Date
It can be necessary to adjust the phys settings to compensate parasitics.
This patch adds support of new optional properties to configure the tune
interface of the phys of stm32-usbphyc.
Properties are optional, that's why each property is skipped if not
found (-EINVAL).
Phy tuning is restored on resume because if deep low power state is
achieved, phy tuning configuration is reset.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
---
drivers/phy/st/phy-stm32-usbphyc.c | 191 +++++++++++++++++++++++++++++
1 file changed, 191 insertions(+)

diff --git a/drivers/phy/st/phy-stm32-usbphyc.c b/drivers/phy/st/phy-stm32-usbphyc.c
index 083593aea53a..238c4c8d4a15 100644
--- a/drivers/phy/st/phy-stm32-usbphyc.c
+++ b/drivers/phy/st/phy-stm32-usbphyc.c
@@ -20,6 +20,7 @@
#define STM32_USBPHYC_PLL 0x0
#define STM32_USBPHYC_MISC 0x8
#define STM32_USBPHYC_MONITOR(X) (0x108 + ((X) * 0x100))
+#define STM32_USBPHYC_TUNE(X) (0x10C + ((X) * 0x100))
#define STM32_USBPHYC_VERSION 0x3F4

/* STM32_USBPHYC_PLL bit fields */
@@ -41,6 +42,84 @@
#define STM32_USBPHYC_MON_SEL_LOCKP 0x1F
#define STM32_USBPHYC_MON_OUT_LOCKP BIT(3)

+/* STM32_USBPHYC_TUNE bit fields */
+#define INCURREN BIT(0)
+#define INCURRINT BIT(1)
+#define LFSCAPEN BIT(2)
+#define HSDRVSLEW BIT(3)
+#define HSDRVDCCUR BIT(4)
+#define HSDRVDCLEV BIT(5)
+#define HSDRVCURINCR BIT(6)
+#define FSDRVRFADJ BIT(7)
+#define HSDRVRFRED BIT(8)
+#define HSDRVCHKITRM GENMASK(12, 9)
+#define HSDRVCHKZTRM GENMASK(14, 13)
+#define OTPCOMP GENMASK(19, 15)
+#define SQLCHCTL GENMASK(21, 20)
+#define HDRXGNEQEN BIT(22)
+#define HSRXOFF GENMASK(24, 23)
+#define HSFALLPREEM BIT(25)
+#define SHTCCTCTLPROT BIT(26)
+#define STAGSEL BIT(27)
+
+enum boosting_vals {
+ BOOST_1_MA = 1,
+ BOOST_2_MA,
+ BOOST_MAX,
+};
+
+enum dc_level_vals {
+ DC_NOMINAL,
+ DC_PLUS_5_TO_7_MV,
+ DC_PLUS_10_TO_14_MV,
+ DC_MINUS_5_TO_7_MV,
+ DC_MAX,
+};
+
+enum current_trim {
+ CUR_NOMINAL,
+ CUR_PLUS_1_56_PCT,
+ CUR_PLUS_3_12_PCT,
+ CUR_PLUS_4_68_PCT,
+ CUR_PLUS_6_24_PCT,
+ CUR_PLUS_7_8_PCT,
+ CUR_PLUS_9_36_PCT,
+ CUR_PLUS_10_92_PCT,
+ CUR_PLUS_12_48_PCT,
+ CUR_PLUS_14_04_PCT,
+ CUR_PLUS_15_6_PCT,
+ CUR_PLUS_17_16_PCT,
+ CUR_PLUS_19_01_PCT,
+ CUR_PLUS_20_58_PCT,
+ CUR_PLUS_22_16_PCT,
+ CUR_PLUS_23_73_PCT,
+ CUR_MAX,
+};
+
+enum impedance_trim {
+ IMP_NOMINAL,
+ IMP_MINUS_2_OHMS,
+ IMP_MINUS_4_OMHS,
+ IMP_MINUS_6_OHMS,
+ IMP_MAX,
+};
+
+enum squelch_level {
+ SQLCH_NOMINAL,
+ SQLCH_PLUS_7_MV,
+ SQLCH_MINUS_5_MV,
+ SQLCH_PLUS_14_MV,
+ SQLCH_MAX,
+};
+
+enum rx_offset {
+ NO_RX_OFFSET,
+ RX_OFFSET_PLUS_5_MV,
+ RX_OFFSET_PLUS_10_MV,
+ RX_OFFSET_MINUS_5_MV,
+ RX_OFFSET_MAX,
+};
+
/* STM32_USBPHYC_VERSION bit fields */
#define MINREV GENMASK(3, 0)
#define MAJREV GENMASK(7, 4)
@@ -60,6 +139,7 @@ struct stm32_usbphyc_phy {
struct regulator *vbus;
u32 index;
bool active;
+ u32 tune;
};

struct stm32_usbphyc {
@@ -375,6 +455,107 @@ static int stm32_usbphyc_clk48_register(struct stm32_usbphyc *usbphyc)
return ret;
}

+static void stm32_usbphyc_phy_tuning(struct stm32_usbphyc *usbphyc,
+ struct device_node *np, u32 index)
+{
+ struct stm32_usbphyc_phy *usbphyc_phy = usbphyc->phys[index];
+ u32 reg = STM32_USBPHYC_TUNE(index);
+ u32 otpcomp, val;
+ int ret;
+
+ /* Backup OTP compensation code */
+ otpcomp = FIELD_GET(OTPCOMP, readl_relaxed(usbphyc->base + reg));
+
+ ret = of_property_read_u32(np, "st,current-boost-microamp", &val);
+ if (ret != -EINVAL) {
+ if (!ret && val < BOOST_MAX) {
+ val = (val == BOOST_2_MA) ? 1 : 0;
+ usbphyc_phy->tune |= INCURREN | FIELD_PREP(INCURRINT, val);
+ } else {
+ dev_warn(usbphyc->dev, "phy%d: invalid st,current-boost-microamp\n", index);
+ }
+ }
+
+ if (!of_property_read_bool(np, "st,no-lsfs-fb-cap"))
+ usbphyc_phy->tune |= LFSCAPEN;
+
+ if (of_property_read_bool(np, "st,slow-hs-slew-rate"))
+ usbphyc_phy->tune |= HSDRVSLEW;
+
+ ret = of_property_read_u32(np, "st,tune-hs-dc-level", &val);
+ if (ret != -EINVAL) {
+ if (!ret && val < DC_MAX) {
+ if (val == DC_MINUS_5_TO_7_MV) {/* Decreases HS driver DC level */
+ usbphyc_phy->tune |= HSDRVDCCUR;
+ } else if (val > 0) { /* Increases HS driver DC level */
+ val = (val == DC_PLUS_10_TO_14_MV) ? 1 : 0;
+ usbphyc_phy->tune |= HSDRVCURINCR | FIELD_PREP(HSDRVDCLEV, val);
+ }
+ } else {
+ dev_warn(usbphyc->dev, "phy%d: invalid st,tune-hs-dc-level\n", index);
+ }
+ }
+
+ if (of_property_read_bool(np, "st,enable-fs-rftime-tuning"))
+ usbphyc_phy->tune |= FSDRVRFADJ;
+
+ if (of_property_read_bool(np, "st,enable-hs-rftime-reduction"))
+ usbphyc_phy->tune |= HSDRVRFRED;
+
+ ret = of_property_read_u32(np, "st,trim-hs-current", &val);
+ if (ret != -EINVAL) {
+ if (!ret && val < CUR_MAX)
+ usbphyc_phy->tune |= FIELD_PREP(HSDRVCHKITRM, val);
+ else
+ dev_warn(usbphyc->dev, "phy%d: invalid st,trim-hs-current\n", index);
+ }
+
+ ret = of_property_read_u32(np, "st,trim-hs-impedance", &val);
+ if (ret != -EINVAL) {
+ if (!ret && val < IMP_MAX)
+ usbphyc_phy->tune |= FIELD_PREP(HSDRVCHKZTRM, val);
+ else
+ dev_warn(usbphyc->dev, "phy%d: invalid st,trim-hs-impedance\n", index);
+ }
+
+ ret = of_property_read_u32(np, "st,tune-squelch-level", &val);
+ if (ret != -EINVAL) {
+ if (!ret && val < SQLCH_MAX)
+ usbphyc_phy->tune |= FIELD_PREP(SQLCHCTL, val);
+ else
+ dev_warn(usbphyc->dev, "phy%d: invalid st,tune-squelch\n", index);
+ }
+
+ if (of_property_read_bool(np, "st,enable-hs-rx-gain-eq"))
+ usbphyc_phy->tune |= HDRXGNEQEN;
+
+ ret = of_property_read_u32(np, "st,tune-hs-rx-offset", &val);
+ if (ret != -EINVAL) {
+ if (!ret && val < RX_OFFSET_MAX)
+ usbphyc_phy->tune |= FIELD_PREP(HSRXOFF, val);
+ else
+ dev_warn(usbphyc->dev, "phy%d: invalid st,tune-hs-rx-offset\n", index);
+ }
+
+ if (of_property_read_bool(np, "st,no-hs-ftime-ctrl"))
+ usbphyc_phy->tune |= HSFALLPREEM;
+
+ if (!of_property_read_bool(np, "st,no-lsfs-sc"))
+ usbphyc_phy->tune |= SHTCCTCTLPROT;
+
+ if (of_property_read_bool(np, "st,enable-hs-tx-staggering"))
+ usbphyc_phy->tune |= STAGSEL;
+
+ /* Restore OTP compensation code */
+ usbphyc_phy->tune |= FIELD_PREP(OTPCOMP, otpcomp);
+
+ /*
+ * By default, if no st,xxx tuning property is used, usbphyc_phy->tune is equal to
+ * STM32_USBPHYC_TUNE reset value (LFSCAPEN | SHTCCTCTLPROT | OTPCOMP).
+ */
+ writel_relaxed(usbphyc_phy->tune, usbphyc->base + reg);
+}
+
static void stm32_usbphyc_switch_setup(struct stm32_usbphyc *usbphyc,
u32 utmi_switch)
{
@@ -550,6 +731,9 @@ static int stm32_usbphyc_probe(struct platform_device *pdev)
usbphyc->phys[port]->vbus = NULL;
}

+ /* Configure phy tuning */
+ stm32_usbphyc_phy_tuning(usbphyc, child, index);
+
port++;
}

@@ -601,10 +785,17 @@ static int stm32_usbphyc_remove(struct platform_device *pdev)
static int __maybe_unused stm32_usbphyc_resume(struct device *dev)
{
struct stm32_usbphyc *usbphyc = dev_get_drvdata(dev);
+ struct stm32_usbphyc_phy *usbphyc_phy;
+ int port;

if (usbphyc->switch_setup >= 0)
stm32_usbphyc_switch_setup(usbphyc, usbphyc->switch_setup);

+ for (port = 0; port < usbphyc->nphys; port++) {
+ usbphyc_phy = usbphyc->phys[port];
+ writel_relaxed(usbphyc_phy->tune, usbphyc->base + STM32_USBPHYC_TUNE(port));
+ }
+
return 0;
}

--
2.25.1
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