[PATCH 2/5] phy: stm32-usphyc: sync with Linux v6.3-rc5
Ahmad Fatoum
a.fatoum at pengutronix.de
Fri Apr 21 03:06:39 PDT 2023
DT binding changed in the meantime and the PHY is now clock provider
to the EHCI. Sync the driver to enable use of the EHCI.
Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
---
drivers/phy/phy-stm32-usbphyc.c | 321 +++++++++++++++++++++++++++++---
include/linux/units.h | 111 +++++++++++
2 files changed, 406 insertions(+), 26 deletions(-)
create mode 100644 include/linux/units.h
diff --git a/drivers/phy/phy-stm32-usbphyc.c b/drivers/phy/phy-stm32-usbphyc.c
index 3ccbc7b9027a..ac82b019f44c 100644
--- a/drivers/phy/phy-stm32-usbphyc.c
+++ b/drivers/phy/phy-stm32-usbphyc.c
@@ -14,11 +14,14 @@
#include <linux/phy/phy.h>
#include <linux/reset.h>
#include <linux/math64.h>
+#include <asm-generic/atomic.h>
#include <linux/usb/phy.h>
+#include <linux/units.h>
#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 */
@@ -40,6 +43,83 @@
#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_1000_UA = 1000,
+ BOOST_2000_UA = 2000,
+};
+
+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)
@@ -47,7 +127,6 @@
#define PLL_FVCO_MHZ 2880
#define PLL_INFF_MIN_RATE_HZ 19200000
#define PLL_INFF_MAX_RATE_HZ 38400000
-#define HZ_PER_MHZ 1000000L
struct pll_params {
u8 ndiv;
@@ -57,30 +136,34 @@ struct pll_params {
struct stm32_usbphyc_phy {
struct phy *phy;
struct stm32_usbphyc *usbphyc;
+ struct regulator *vbus;
u32 index;
bool active;
+ u32 tune;
};
struct stm32_usbphyc {
struct device *dev;
void __iomem *base;
struct clk *clk;
+ struct reset_control *rst;
struct stm32_usbphyc_phy **phys;
int nphys;
struct regulator *vdda1v1;
struct regulator *vdda1v8;
- int n_pll_cons;
+ atomic_t n_pll_cons;
+ struct clk_hw clk48_hw;
int switch_setup;
};
static inline void stm32_usbphyc_set_bits(void __iomem *reg, u32 bits)
{
- writel(readl(reg) | bits, reg);
+ writel_relaxed(readl_relaxed(reg) | bits, reg);
}
static inline void stm32_usbphyc_clr_bits(void __iomem *reg, u32 bits)
{
- writel(readl(reg) & ~bits, reg);
+ writel_relaxed(readl_relaxed(reg) & ~bits, reg);
}
static int stm32_usbphyc_regulators_enable(struct stm32_usbphyc *usbphyc)
@@ -168,7 +251,7 @@ static int stm32_usbphyc_pll_init(struct stm32_usbphyc *usbphyc)
if (pll_params.frac)
usbphyc_pll |= PLLFRACCTL | frac;
- writel(usbphyc_pll, usbphyc->base + STM32_USBPHYC_PLL);
+ writel_relaxed(usbphyc_pll, usbphyc->base + STM32_USBPHYC_PLL);
dev_dbg(usbphyc->dev, "input clk freq=%dHz, ndiv=%lu, frac=%lu\n",
clk_rate, FIELD_GET(PLLNDIV, usbphyc_pll),
@@ -185,7 +268,7 @@ static int __stm32_usbphyc_pll_disable(struct stm32_usbphyc *usbphyc)
stm32_usbphyc_clr_bits(pll_reg, PLLEN);
/* Wait for minimum width of powerdown pulse (ENABLE = Low) */
- if (readl_poll_timeout(pll_reg, pllen, !(pllen & PLLEN), 50))
+ if (readl_relaxed_poll_timeout(pll_reg, pllen, !(pllen & PLLEN), 50))
dev_err(usbphyc->dev, "PLL not reset\n");
return stm32_usbphyc_regulators_disable(usbphyc);
@@ -194,7 +277,7 @@ static int __stm32_usbphyc_pll_disable(struct stm32_usbphyc *usbphyc)
static int stm32_usbphyc_pll_disable(struct stm32_usbphyc *usbphyc)
{
/* Check if a phy port is still active or clk48 in use */
- if (--usbphyc->n_pll_cons > 0)
+ if (atomic_dec_return(&usbphyc->n_pll_cons) > 0)
return 0;
return __stm32_usbphyc_pll_disable(usbphyc);
@@ -203,14 +286,14 @@ static int stm32_usbphyc_pll_disable(struct stm32_usbphyc *usbphyc)
static int stm32_usbphyc_pll_enable(struct stm32_usbphyc *usbphyc)
{
void __iomem *pll_reg = usbphyc->base + STM32_USBPHYC_PLL;
- bool pllen = readl(pll_reg) & PLLEN;
+ bool pllen = readl_relaxed(pll_reg) & PLLEN;
int ret;
/*
* Check if a phy port or clk48 prepare has configured the pll
* and ensure the PLL is enabled
*/
- if (++usbphyc->n_pll_cons > 1 && pllen)
+ if (atomic_inc_return(&usbphyc->n_pll_cons) > 1 && pllen)
return 0;
if (pllen) {
@@ -222,7 +305,7 @@ static int stm32_usbphyc_pll_enable(struct stm32_usbphyc *usbphyc)
ret = __stm32_usbphyc_pll_disable(usbphyc);
if (ret)
- return ret;
+ goto dec_n_pll_cons;
}
ret = stm32_usbphyc_regulators_enable(usbphyc);
@@ -241,7 +324,7 @@ reg_disable:
stm32_usbphyc_regulators_disable(usbphyc);
dec_n_pll_cons:
- usbphyc->n_pll_cons--;
+ atomic_dec(&usbphyc->n_pll_cons);
return ret;
}
@@ -261,10 +344,10 @@ static int stm32_usbphyc_phy_init(struct phy *phy)
return ret;
/* Check that PLL Lock input to PHY is High */
- writel(monsel, usbphyc->base + reg_mon);
- ret = readl_poll_timeout(usbphyc->base + reg_mon, monout,
- (monout & STM32_USBPHYC_MON_OUT_LOCKP),
- 1000);
+ writel_relaxed(monsel, usbphyc->base + reg_mon);
+ ret = readl_relaxed_poll_timeout(usbphyc->base + reg_mon, monout,
+ (monout & STM32_USBPHYC_MON_OUT_LOCKP),
+ 1000);
if (ret) {
dev_err(usbphyc->dev, "PLL Lock input to PHY is Low (val=%x)\n",
(u32)(monout & STM32_USBPHYC_MON_OUT));
@@ -285,7 +368,9 @@ static int stm32_usbphyc_phy_init(struct phy *phy)
return 0;
pll_disable:
- return stm32_usbphyc_pll_disable(usbphyc);
+ stm32_usbphyc_pll_disable(usbphyc);
+
+ return ret;
}
static int stm32_usbphyc_phy_exit(struct phy *phy)
@@ -298,11 +383,177 @@ static int stm32_usbphyc_phy_exit(struct phy *phy)
return stm32_usbphyc_pll_disable(usbphyc);
}
+static int stm32_usbphyc_phy_power_on(struct phy *phy)
+{
+ struct stm32_usbphyc_phy *usbphyc_phy = phy_get_drvdata(phy);
+
+ if (usbphyc_phy->vbus)
+ return regulator_enable(usbphyc_phy->vbus);
+
+ return 0;
+}
+
+static int stm32_usbphyc_phy_power_off(struct phy *phy)
+{
+ struct stm32_usbphyc_phy *usbphyc_phy = phy_get_drvdata(phy);
+
+ if (usbphyc_phy->vbus)
+ return regulator_disable(usbphyc_phy->vbus);
+
+ return 0;
+}
+
static const struct phy_ops stm32_usbphyc_phy_ops = {
.init = stm32_usbphyc_phy_init,
.exit = stm32_usbphyc_phy_exit,
+ .power_on = stm32_usbphyc_phy_power_on,
+ .power_off = stm32_usbphyc_phy_power_off,
};
+static int stm32_usbphyc_clk48_prepare(struct clk_hw *hw)
+{
+ struct stm32_usbphyc *usbphyc = container_of(hw, struct stm32_usbphyc, clk48_hw);
+
+ return stm32_usbphyc_pll_enable(usbphyc);
+}
+
+static void stm32_usbphyc_clk48_unprepare(struct clk_hw *hw)
+{
+ struct stm32_usbphyc *usbphyc = container_of(hw, struct stm32_usbphyc, clk48_hw);
+
+ stm32_usbphyc_pll_disable(usbphyc);
+}
+
+static unsigned long stm32_usbphyc_clk48_recalc_rate(struct clk_hw *hw, unsigned long parent_rate)
+{
+ return 48000000;
+}
+
+static const struct clk_ops usbphyc_clk48_ops = {
+ .enable = stm32_usbphyc_clk48_prepare,
+ .disable = stm32_usbphyc_clk48_unprepare,
+ .recalc_rate = stm32_usbphyc_clk48_recalc_rate,
+};
+
+static int stm32_usbphyc_clk48_register(struct stm32_usbphyc *usbphyc)
+{
+ struct device_node *node = usbphyc->dev->of_node;
+ struct clk_init_data init = { };
+ int ret = 0;
+
+ init.name = "ck_usbo_48m";
+ init.ops = &usbphyc_clk48_ops;
+
+ usbphyc->clk48_hw.init = &init;
+
+ ret = clk_hw_register(usbphyc->dev, &usbphyc->clk48_hw);
+ if (ret)
+ return ret;
+
+ return of_clk_add_hw_provider(node, of_clk_hw_simple_get, &usbphyc->clk48_hw);
+}
+
+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_1000_UA || val == BOOST_2000_UA)) {
+ val = (val == BOOST_2000_UA) ? 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,decrease-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)
{
@@ -399,8 +650,8 @@ static int stm32_usbphyc_probe(struct device *dev)
* Wait for minimum width of powerdown pulse (ENABLE = Low):
* we have to ensure the PLL is disabled before phys initialization.
*/
- if (readl_poll_timeout(usbphyc->base + STM32_USBPHYC_PLL,
- pllen, !(pllen & PLLEN), 50)) {
+ if (readl_relaxed_poll_timeout(usbphyc->base + STM32_USBPHYC_PLL,
+ pllen, !(pllen & PLLEN), 50)) {
dev_warn(usbphyc->dev, "PLL not reset\n");
ret = -EPROBE_DEFER;
goto clk_disable;
@@ -416,17 +667,15 @@ static int stm32_usbphyc_probe(struct device *dev)
usbphyc->vdda1v1 = regulator_get(dev, "vdda1v1");
if (IS_ERR(usbphyc->vdda1v1)) {
- ret = PTR_ERR(usbphyc->vdda1v1);
- if (ret != -EPROBE_DEFER)
- dev_err(dev, "failed to get vdda1v1 supply: %d\n", ret);
+ ret = dev_err_probe(dev, PTR_ERR(usbphyc->vdda1v1),
+ "failed to get vdda1v1 supply\n");
goto clk_disable;
}
usbphyc->vdda1v8 = regulator_get(dev, "vdda1v8");
if (IS_ERR(usbphyc->vdda1v8)) {
- ret = PTR_ERR(usbphyc->vdda1v8);
- if (ret != -EPROBE_DEFER)
- dev_err(dev, "failed to get vdda1v8 supply: %d\n", ret);
+ ret = dev_err_probe(dev, PTR_ERR(usbphyc->vdda1v8),
+ "failed to get vdda1v8 supply\n");
goto clk_disable;
}
@@ -456,6 +705,8 @@ static int stm32_usbphyc_probe(struct device *dev)
ret = of_property_read_u32(child, "reg", &index);
if (ret || index > usbphyc->nphys) {
dev_err(&phy->dev, "invalid reg property: %d\n", ret);
+ if (!ret)
+ ret = -EINVAL;
goto clk_disable;
}
@@ -468,6 +719,17 @@ static int stm32_usbphyc_probe(struct device *dev)
usbphyc->phys[port]->index = index;
usbphyc->phys[port]->active = false;
+ usbphyc->phys[port]->vbus = regulator_get(&phy->dev, "vbus");
+ if (IS_ERR(usbphyc->phys[port]->vbus)) {
+ ret = PTR_ERR(usbphyc->phys[port]->vbus);
+ if (ret == -EPROBE_DEFER)
+ goto clk_disable;
+ usbphyc->phys[port]->vbus = NULL;
+ }
+
+ /* Configure phy tuning */
+ stm32_usbphyc_phy_tuning(usbphyc, child, index);
+
port++;
}
@@ -478,8 +740,14 @@ static int stm32_usbphyc_probe(struct device *dev)
goto clk_disable;
}
- version = readl(usbphyc->base + STM32_USBPHYC_VERSION);
- dev_info(dev, "registered rev: %lu.%lu\n",
+ ret = stm32_usbphyc_clk48_register(usbphyc);
+ if (ret) {
+ dev_err(dev, "failed to register ck_usbo_48m clock: %d\n", ret);
+ goto clk_disable;
+ }
+
+ version = readl_relaxed(usbphyc->base + STM32_USBPHYC_VERSION);
+ dev_info(dev, "registered rev:%lu.%lu\n",
FIELD_GET(MAJREV, version), FIELD_GET(MINREV, version));
return 0;
@@ -512,6 +780,7 @@ static const struct of_device_id stm32_usbphyc_of_match[] = {
{ .compatible = "st,stm32mp1-usbphyc", },
{ /* sentinel */ },
};
+MODULE_DEVICE_TABLE(of, stm32_usbphyc_of_match);
static struct driver stm32_usbphyc_driver = {
.name = "stm32-usbphyc",
diff --git a/include/linux/units.h b/include/linux/units.h
new file mode 100644
index 000000000000..120a2fc87b13
--- /dev/null
+++ b/include/linux/units.h
@@ -0,0 +1,111 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_UNITS_H
+#define _LINUX_UNITS_H
+
+#include <linux/kernel.h>
+
+/* Metric prefixes in accordance with Système international (d'unités) */
+#define PETA 1000000000000000ULL
+#define TERA 1000000000000ULL
+#define GIGA 1000000000UL
+#define MEGA 1000000UL
+#define KILO 1000UL
+#define HECTO 100UL
+#define DECA 10UL
+#define DECI 10UL
+#define CENTI 100UL
+#define MILLI 1000UL
+#define MICRO 1000000UL
+#define NANO 1000000000UL
+#define PICO 1000000000000ULL
+#define FEMTO 1000000000000000ULL
+
+#define NANOHZ_PER_HZ 1000000000UL
+#define MICROHZ_PER_HZ 1000000UL
+#define MILLIHZ_PER_HZ 1000UL
+#define HZ_PER_KHZ 1000UL
+#define KHZ_PER_MHZ 1000UL
+#define HZ_PER_MHZ 1000000UL
+
+#define MILLIWATT_PER_WATT 1000UL
+#define MICROWATT_PER_MILLIWATT 1000UL
+#define MICROWATT_PER_WATT 1000000UL
+
+#define ABSOLUTE_ZERO_MILLICELSIUS -273150
+
+static inline long milli_kelvin_to_millicelsius(long t)
+{
+ return t + ABSOLUTE_ZERO_MILLICELSIUS;
+}
+
+static inline long millicelsius_to_milli_kelvin(long t)
+{
+ return t - ABSOLUTE_ZERO_MILLICELSIUS;
+}
+
+#define MILLIDEGREE_PER_DEGREE 1000
+#define MILLIDEGREE_PER_DECIDEGREE 100
+
+static inline long kelvin_to_millicelsius(long t)
+{
+ return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DEGREE);
+}
+
+static inline long millicelsius_to_kelvin(long t)
+{
+ t = millicelsius_to_milli_kelvin(t);
+
+ return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE);
+}
+
+static inline long deci_kelvin_to_celsius(long t)
+{
+ t = milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE);
+
+ return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DEGREE);
+}
+
+static inline long celsius_to_deci_kelvin(long t)
+{
+ t = millicelsius_to_milli_kelvin(t * MILLIDEGREE_PER_DEGREE);
+
+ return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE);
+}
+
+/**
+ * deci_kelvin_to_millicelsius_with_offset - convert Kelvin to Celsius
+ * @t: temperature value in decidegrees Kelvin
+ * @offset: difference between Kelvin and Celsius in millidegrees
+ *
+ * Return: temperature value in millidegrees Celsius
+ */
+static inline long deci_kelvin_to_millicelsius_with_offset(long t, long offset)
+{
+ return t * MILLIDEGREE_PER_DECIDEGREE - offset;
+}
+
+static inline long deci_kelvin_to_millicelsius(long t)
+{
+ return milli_kelvin_to_millicelsius(t * MILLIDEGREE_PER_DECIDEGREE);
+}
+
+static inline long millicelsius_to_deci_kelvin(long t)
+{
+ t = millicelsius_to_milli_kelvin(t);
+
+ return DIV_ROUND_CLOSEST(t, MILLIDEGREE_PER_DECIDEGREE);
+}
+
+static inline long kelvin_to_celsius(long t)
+{
+ return t + DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
+ MILLIDEGREE_PER_DEGREE);
+}
+
+static inline long celsius_to_kelvin(long t)
+{
+ return t - DIV_ROUND_CLOSEST(ABSOLUTE_ZERO_MILLICELSIUS,
+ MILLIDEGREE_PER_DEGREE);
+}
+
+#endif /* _LINUX_UNITS_H */
--
2.39.2
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