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Message-Id: <20250408-rk3576-pwm-v1-4-a49286c2ca8e@collabora.com>
Date: Tue, 08 Apr 2025 14:32:16 +0200
From: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
To: Linus Walleij <linus.walleij@...aro.org>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>, Heiko Stuebner <heiko@...ech.de>,
Uwe Kleine-König <ukleinek@...nel.org>,
William Breathitt Gray <wbg@...nel.org>,
Sebastian Reichel <sebastian.reichel@...labora.com>,
Kever Yang <kever.yang@...k-chips.com>
Cc: linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org,
linux-kernel@...r.kernel.org, linux-pwm@...r.kernel.org,
linux-iio@...r.kernel.org, kernel@...labora.com,
Jonas Karlman <jonas@...boo.se>,
Detlev Casanova <detlev.casanova@...labora.com>,
Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
Subject: [PATCH 4/7] soc: rockchip: add mfpwm driver
With the Rockchip RK3576, the PWM IP used by Rockchip has changed
substantially. Looking at both the downstream pwm-rockchip driver as
well as the mainline pwm-rockchip driver made it clear that with all its
additional features and its differences from previous IP revisions, it
is best supported in a new driver.
This brings us to the question as to what such a new driver should be.
To me, it soon became clear that it should actually be several new
drivers, most prominently when Uwe Kleine-König let me know that I
should not implement the pwm subsystem's capture callback, but instead
write a counter driver for this functionality.
Combined with the other as-of-yet unimplemented functionality of this
new IP, it became apparent that it needs to be spread across several
subsystems.
For this reason, we add a new platform bus based driver, called mfpwm
(short for "Multi-function PWM"). This "parent" driver makes sure that
only one device function driver is using the device at a time, and is in
charge of registering the platform bus devices for the individual device
functions offered by the device.
An acquire/release pattern is used to guarantee that device function
drivers don't step on each other's toes.
Signed-off-by: Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
---
MAINTAINERS | 2 +
drivers/soc/rockchip/Kconfig | 13 +
drivers/soc/rockchip/Makefile | 1 +
drivers/soc/rockchip/mfpwm.c | 608 ++++++++++++++++++++++++++++++++++++++++++
include/soc/rockchip/mfpwm.h | 505 +++++++++++++++++++++++++++++++++++
5 files changed, 1129 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index 407179d2a90dd49800f2bb5770a1280c5afebb5a..e6a9347be1e7889089e1d9e655cb23c2d8399b40 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20891,6 +20891,8 @@ L: linux-rockchip@...ts.infradead.org
L: linux-pwm@...r.kernel.org
S: Maintained
F: Documentation/devicetree/bindings/pwm/rockchip,rk3576-pwm.yaml
+F: drivers/soc/rockchip/mfpwm.c
+F: include/soc/rockchip/mfpwm.h
ROCKCHIP RK3568 RANDOM NUMBER GENERATOR SUPPORT
M: Daniel Golle <daniel@...rotopia.org>
diff --git a/drivers/soc/rockchip/Kconfig b/drivers/soc/rockchip/Kconfig
index 785f60c6f3ad1a09f517e69a69726a8178bed168..4e1e4926c514a5a2c4d4caf8cf9809a098badc7d 100644
--- a/drivers/soc/rockchip/Kconfig
+++ b/drivers/soc/rockchip/Kconfig
@@ -30,4 +30,17 @@ config ROCKCHIP_DTPM
on this platform. That will create all the power capping capable
devices.
+config ROCKCHIP_MFPWM
+ tristate "Rockchip multi-function PWM controller"
+ depends on OF
+ depends on HAS_IOMEM
+ help
+ Some Rockchip SoCs, such as the RK3576, use a PWM controller that has
+ several different functions, such as generating PWM waveforms but also
+ counting waveforms.
+
+ This driver manages the overall device, and selects between different
+ functionalities at runtime as needed, with drivers for them
+ implemented in their respective subsystems.
+
endif
diff --git a/drivers/soc/rockchip/Makefile b/drivers/soc/rockchip/Makefile
index 23d414433c8c58557effc214337ec8e6ff17a461..ba12dbd01ac794910d9407c268e89071cd2b3139 100644
--- a/drivers/soc/rockchip/Makefile
+++ b/drivers/soc/rockchip/Makefile
@@ -5,3 +5,4 @@
obj-$(CONFIG_ROCKCHIP_GRF) += grf.o
obj-$(CONFIG_ROCKCHIP_IODOMAIN) += io-domain.o
obj-$(CONFIG_ROCKCHIP_DTPM) += dtpm.o
+obj-$(CONFIG_ROCKCHIP_MFPWM) += mfpwm.o
diff --git a/drivers/soc/rockchip/mfpwm.c b/drivers/soc/rockchip/mfpwm.c
new file mode 100644
index 0000000000000000000000000000000000000000..9331c530f0581573e2b74f62a6622b8625c5b2c5
--- /dev/null
+++ b/drivers/soc/rockchip/mfpwm.c
@@ -0,0 +1,608 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (c) 2025 Collabora Ltd.
+ *
+ * A driver to manage all the different functionalities exposed by Rockchip's
+ * PWMv4 hardware.
+ *
+ * This driver is chiefly focused on guaranteeing non-concurrent operation
+ * between the different device functions, as well as setting the clocks.
+ * It registers the device function platform devices, e.g. PWM output or
+ * PWM capture.
+ *
+ * Authors:
+ * Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/overflow.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <soc/rockchip/mfpwm.h>
+
+/**
+ * struct rockchip_mfpwm - private mfpwm driver instance state struct
+ * @pdev: pointer to this instance's &struct platform_device
+ * @base: pointer to the memory mapped registers of this device
+ * @pwm_clk: pointer to the PLL clock the PWM signal may be derived from
+ * @osc_clk: pointer to the fixed crystal the PWM signal may be derived from
+ * @chosen_clk: is one of either @pwm_clk or @osc_clk, depending on choice.
+ * May only be swapped out while holding @state_lock.
+ * @pclk: pointer to the APB bus clock needed for mmio register access
+ * @pwm_dev: pointer to the &struct platform_device of the pwm output driver
+ * @counter_dev: pointer to the &struct platform_device of the counter driver
+ * @active_func: pointer to the currently active device function, or %NULL if no
+ * device function is currently actively using any of the shared
+ * resources. May only be checked/modified with @state_lock held.
+ * @acquire_cnt: number of times @active_func has currently mfpwm_acquire()'d
+ * it. Must only be checked or modified while holding @state_lock.
+ * @pwmclk_enable_cnt: number of times @active_func has enabled the pwmclk sans
+ * disabling it. Must only be checked or modified while
+ * holding @state_lock. Only exists to fix a splat on mfpwm
+ * driver remove.
+ * @state_lock: this lock is held while either the active device function, the
+ * enable register, or the chosen clock is being changed.
+ * @irq: the IRQ number of this device
+ */
+struct rockchip_mfpwm {
+ struct platform_device *pdev;
+ void __iomem *base;
+ struct clk *pwm_clk;
+ struct clk *osc_clk;
+ struct clk *chosen_clk;
+ struct clk *pclk;
+ struct platform_device *pwm_dev;
+ struct platform_device *counter_dev;
+ struct rockchip_mfpwm_func *active_func;
+ unsigned int acquire_cnt;
+ unsigned int pwmclk_enable_cnt;
+ spinlock_t state_lock;
+ int irq;
+};
+
+static atomic_t subdev_id = ATOMIC_INIT(0);
+
+static inline struct rockchip_mfpwm *to_rockchip_mfpwm(struct platform_device *pdev)
+{
+ return platform_get_drvdata(pdev);
+}
+
+unsigned long mfpwm_clk_get_rate(struct rockchip_mfpwm *mfpwm)
+{
+ if (!mfpwm || !mfpwm->chosen_clk)
+ return 0;
+
+ return clk_get_rate(mfpwm->chosen_clk);
+}
+EXPORT_SYMBOL_NS_GPL(mfpwm_clk_get_rate, "ROCKCHIP_MFPWM");
+
+static int mfpwm_check_pwmf(const struct rockchip_mfpwm_func *pwmf,
+ const char *fname)
+{
+ if (IS_ERR_OR_NULL(pwmf)) {
+ WARN(1, "called %s with an erroneous handle, no effect\n",
+ fname);
+ return -EINVAL;
+ }
+
+ if (IS_ERR_OR_NULL(pwmf->parent)) {
+ WARN(1, "called %s with an erroneous mfpwm_func parent, no effect\n",
+ fname);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+__attribute__((nonnull))
+static bool mfpwm_pwmf_is_active_pwmf(const struct rockchip_mfpwm_func *pwmf)
+{
+ if (pwmf->parent->active_func) {
+ if (pwmf->parent->active_func->id == pwmf->id)
+ return true;
+ }
+
+ return false;
+}
+
+int mfpwm_pwmclk_enable(struct rockchip_mfpwm_func *pwmf)
+{
+ unsigned long flags;
+ int ret;
+
+ ret = mfpwm_check_pwmf(pwmf, "mfpwm_pwmclk_enable");
+ if (ret)
+ return ret;
+
+ spin_lock_irqsave(&pwmf->parent->state_lock, flags);
+ if (mfpwm_pwmf_is_active_pwmf(pwmf)) {
+ ret = clk_enable(pwmf->parent->chosen_clk);
+ pwmf->parent->pwmclk_enable_cnt++;
+ } else {
+ ret = -EBUSY;
+ }
+
+ spin_unlock_irqrestore(&pwmf->parent->state_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_NS_GPL(mfpwm_pwmclk_enable, "ROCKCHIP_MFPWM");
+
+void mfpwm_pwmclk_disable(struct rockchip_mfpwm_func *pwmf)
+{
+ unsigned long flags;
+
+ if (mfpwm_check_pwmf(pwmf, "mfpwm_pwmclk_enable"))
+ return;
+
+ spin_lock_irqsave(&pwmf->parent->state_lock, flags);
+ if (mfpwm_pwmf_is_active_pwmf(pwmf)) {
+ clk_disable(pwmf->parent->chosen_clk);
+ pwmf->parent->pwmclk_enable_cnt--;
+ }
+ spin_unlock_irqrestore(&pwmf->parent->state_lock, flags);
+}
+EXPORT_SYMBOL_NS_GPL(mfpwm_pwmclk_disable, "ROCKCHIP_MFPWM");
+
+__attribute__((nonnull))
+static int mfpwm_do_acquire(struct rockchip_mfpwm_func *pwmf)
+{
+ struct rockchip_mfpwm *mfpwm = pwmf->parent;
+ unsigned int cnt;
+
+ if (mfpwm->active_func && pwmf->id != mfpwm->active_func->id)
+ return -EBUSY;
+
+ if (!mfpwm->active_func)
+ mfpwm->active_func = pwmf;
+
+ if (!check_add_overflow(mfpwm->acquire_cnt, 1, &cnt)) {
+ mfpwm->acquire_cnt = cnt;
+ } else {
+ WARN(1, "prevented acquire counter overflow in %s\n", __func__);
+ return -EOVERFLOW;
+ }
+
+ dev_dbg(&mfpwm->pdev->dev, "%d acquired mfpwm, acquires now at %u\n",
+ pwmf->id, mfpwm->acquire_cnt);
+
+ return clk_enable(mfpwm->pclk);
+}
+
+int mfpwm_acquire(struct rockchip_mfpwm_func *pwmf)
+{
+ struct rockchip_mfpwm *mfpwm;
+ unsigned long flags;
+ int ret = 0;
+
+ ret = mfpwm_check_pwmf(pwmf, "mfpwm_acquire");
+ if (ret)
+ return ret;
+
+ mfpwm = pwmf->parent;
+ dev_dbg(&mfpwm->pdev->dev, "%d is attempting to acquire\n", pwmf->id);
+
+ if (!spin_trylock_irqsave(&mfpwm->state_lock, flags))
+ return -EBUSY;
+
+ ret = mfpwm_do_acquire(pwmf);
+
+ spin_unlock_irqrestore(&mfpwm->state_lock, flags);
+
+ return ret;
+}
+EXPORT_SYMBOL_NS_GPL(mfpwm_acquire, "ROCKCHIP_MFPWM");
+
+__attribute__((nonnull))
+static void mfpwm_do_release(const struct rockchip_mfpwm_func *pwmf)
+{
+ struct rockchip_mfpwm *mfpwm = pwmf->parent;
+
+ if (!mfpwm->active_func)
+ return;
+
+ if (mfpwm->active_func->id != pwmf->id)
+ return;
+
+ /*
+ * No need to check_sub_overflow here, !mfpwm->active_func above catches
+ * this type of problem already.
+ */
+ mfpwm->acquire_cnt--;
+
+ if (!mfpwm->acquire_cnt)
+ mfpwm->active_func = NULL;
+
+ clk_disable(mfpwm->pclk);
+}
+
+void mfpwm_release(const struct rockchip_mfpwm_func *pwmf)
+{
+ struct rockchip_mfpwm *mfpwm;
+ unsigned long flags;
+
+ if (mfpwm_check_pwmf(pwmf, "mfpwm_release"))
+ return;
+
+ mfpwm = pwmf->parent;
+
+ spin_lock_irqsave(&mfpwm->state_lock, flags);
+ mfpwm_do_release(pwmf);
+ dev_dbg(&mfpwm->pdev->dev, "%d released mfpwm, acquires now at %u\n",
+ pwmf->id, mfpwm->acquire_cnt);
+ spin_unlock_irqrestore(&mfpwm->state_lock, flags);
+}
+EXPORT_SYMBOL_NS_GPL(mfpwm_release, "ROCKCHIP_MFPWM");
+
+void mfpwm_remove_func(struct rockchip_mfpwm_func *pwmf)
+{
+ struct rockchip_mfpwm *mfpwm;
+ unsigned long flags;
+
+ if (mfpwm_check_pwmf(pwmf, "mfpwm_remove_func"))
+ return;
+
+ mfpwm = pwmf->parent;
+ spin_lock_irqsave(&mfpwm->state_lock, flags);
+
+ if (mfpwm_pwmf_is_active_pwmf(pwmf)) {
+ dev_dbg(&mfpwm->pdev->dev, "removing active function %d\n",
+ pwmf->id);
+
+ while (mfpwm->acquire_cnt > 0)
+ mfpwm_do_release(pwmf);
+ for (; mfpwm->pwmclk_enable_cnt > 0; mfpwm->pwmclk_enable_cnt--)
+ clk_disable(mfpwm->chosen_clk);
+
+ mfpwm_reg_write(mfpwm->base, PWMV4_REG_ENABLE,
+ PWMV4_EN(false) | PWMV4_CLK_EN(false));
+ }
+
+ if (mfpwm->pwm_dev && mfpwm->pwm_dev->id == pwmf->id) {
+ dev_dbg(&mfpwm->pdev->dev, "clearing pwm_dev pointer\n");
+ mfpwm->pwm_dev = NULL;
+ } else if (mfpwm->counter_dev && mfpwm->counter_dev->id == pwmf->id) {
+ dev_dbg(&mfpwm->pdev->dev, "clearing counter_dev pointer\n");
+ mfpwm->counter_dev = NULL;
+ } else {
+ WARN(1, "trying to remove an unknown mfpwm device function");
+ }
+
+ spin_unlock_irqrestore(&mfpwm->state_lock, flags);
+}
+EXPORT_SYMBOL_NS_GPL(mfpwm_remove_func, "ROCKCHIP_MFPWM");
+
+/**
+ * mfpwm_register_subdev - register a single mfpwm_func
+ * @mfpwm: pointer to the parent &struct rockchip_mfpwm
+ * @target: pointer to where the &struct platform_device pointer should be
+ * stored, usually a member of @mfpwm
+ * @name: sub-device name string
+ *
+ * Allocate a single &struct mfpwm_func, fill its members with appropriate data,
+ * and register a new platform device, saving its pointer to @target. The
+ * allocation is devres tracked, so will be automatically freed on mfpwm remove.
+ *
+ * Returns: 0 on success, negative errno on error
+ */
+static int mfpwm_register_subdev(struct rockchip_mfpwm *mfpwm,
+ struct platform_device **target,
+ const char *name)
+{
+ struct rockchip_mfpwm_func *func;
+ struct platform_device *child;
+
+ func = devm_kzalloc(&mfpwm->pdev->dev, sizeof(*func), GFP_KERNEL);
+ if (IS_ERR(func))
+ return PTR_ERR(func);
+ func->irq = mfpwm->irq;
+ func->parent = mfpwm;
+ func->id = atomic_inc_return(&subdev_id);
+ func->base = mfpwm->base;
+ child = platform_device_register_data(&mfpwm->pdev->dev, name, func->id,
+ func, sizeof(*func));
+
+ if (IS_ERR(child))
+ return PTR_ERR(child);
+
+ *target = child;
+
+ return 0;
+}
+
+static int mfpwm_register_subdevs(struct rockchip_mfpwm *mfpwm)
+{
+ int ret;
+
+ ret = mfpwm_register_subdev(mfpwm, &mfpwm->pwm_dev, "pwm-rockchip-v4");
+ if (ret)
+ return ret;
+
+ ret = mfpwm_register_subdev(mfpwm, &mfpwm->counter_dev,
+ "rockchip-pwm-capture");
+ if (ret)
+ goto err_unreg_pwm_dev;
+
+ return 0;
+
+err_unreg_pwm_dev:
+ platform_device_unregister(mfpwm->pwm_dev);
+
+ return ret;
+}
+
+/**
+ * mfpwm_get_clk_src - read the currently selected clock source
+ * @mfpwm: pointer to the driver's private &struct rockchip_mfpwm instance
+ *
+ * Read the device register to extract the currently selected clock source,
+ * and return it.
+ *
+ * Returns:
+ * * the numeric clock source ID on success, 0 <= id <= 2
+ * * negative errno on error
+ */
+static int mfpwm_get_clk_src(struct rockchip_mfpwm *mfpwm)
+{
+ u32 val;
+
+ clk_enable(mfpwm->pclk);
+ val = mfpwm_reg_read(mfpwm->base, PWMV4_REG_CLK_CTRL);
+ clk_disable(mfpwm->pclk);
+
+ return (val & PWMV4_CLK_SRC_MASK) >> PWMV4_CLK_SRC_SHIFT;
+}
+
+static int mfpwm_choose_clk(struct rockchip_mfpwm *mfpwm)
+{
+ int ret;
+
+ ret = mfpwm_get_clk_src(mfpwm);
+ if (ret < 0) {
+ dev_err(&mfpwm->pdev->dev, "couldn't get current clock source: %pe\n",
+ ERR_PTR(ret));
+ return ret;
+ }
+ if (ret == PWMV4_CLK_SRC_CRYSTAL) {
+ if (mfpwm->osc_clk) {
+ mfpwm->chosen_clk = mfpwm->osc_clk;
+ } else {
+ dev_warn(&mfpwm->pdev->dev, "initial state wanted 'osc' as clock source, but it's unavailable. Defaulting to 'pwm'.\n");
+ mfpwm->chosen_clk = mfpwm->pwm_clk;
+ }
+ } else {
+ mfpwm->chosen_clk = mfpwm->pwm_clk;
+ }
+
+ return clk_rate_exclusive_get(mfpwm->chosen_clk);
+}
+
+/**
+ * mfpwm_switch_clk_src - switch between PWM clock sources
+ * @mfpwm: pointer to &struct rockchip_mfpwm driver data
+ * @clk_src: one of either %PWMV4_CLK_SRC_CRYSTAL or %PWMV4_CLK_SRC_PLL
+ *
+ * Switch between clock sources, ``_exclusive_put``ing the old rate,
+ * ``clk_rate_exclusive_get``ing the new one, writing the registers and
+ * swapping out the &struct_rockchip_mfpwm->chosen_clk.
+ *
+ * Returns:
+ * * %0 - Success
+ * * %-EINVAL - A wrong @clk_src was given or it is unavailable
+ * * %-EBUSY - Device is currently in use, try again later
+ */
+__attribute__((nonnull))
+static int mfpwm_switch_clk_src(struct rockchip_mfpwm *mfpwm,
+ unsigned int clk_src)
+{
+ struct clk *prev;
+ int ret = 0;
+
+ scoped_cond_guard(spinlock_try, return -EBUSY, &mfpwm->state_lock) {
+ /* Don't fiddle with any of this stuff if the PWM is on */
+ if (mfpwm->active_func)
+ return -EBUSY;
+
+ prev = mfpwm->chosen_clk;
+ ret = mfpwm_get_clk_src(mfpwm);
+ if (ret < 0)
+ return ret;
+ if (ret == clk_src)
+ return 0;
+
+ switch (clk_src) {
+ case PWMV4_CLK_SRC_PLL:
+ mfpwm->chosen_clk = mfpwm->pwm_clk;
+ break;
+ case PWMV4_CLK_SRC_CRYSTAL:
+ if (!mfpwm->osc_clk)
+ return -EINVAL;
+ mfpwm->chosen_clk = mfpwm->osc_clk;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ clk_enable(mfpwm->pclk);
+
+ mfpwm_reg_write(mfpwm->base, PWMV4_REG_CLK_CTRL,
+ PWMV4_CLK_SRC(clk_src));
+ clk_rate_exclusive_get(mfpwm->chosen_clk);
+ if (prev)
+ clk_rate_exclusive_put(prev);
+
+ clk_disable(mfpwm->pclk);
+ }
+
+ return ret;
+}
+
+static ssize_t chosen_clock_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rockchip_mfpwm *mfpwm = dev_get_drvdata(dev);
+ unsigned long clk_src = 0;
+
+ /*
+ * Why the weird indirection here? I have the suspicion that if we
+ * emitted to sysfs with the lock still held, then a nefarious program
+ * could hog the lock by somehow forcing a full buffer condition and
+ * then refusing to read from it. Don't know whether that's feasible
+ * to achieve in reality, but I don't want to find out the hard way
+ * either.
+ */
+ scoped_guard(spinlock, &mfpwm->state_lock) {
+ if (mfpwm->chosen_clk == mfpwm->pwm_clk)
+ clk_src = PWMV4_CLK_SRC_PLL;
+ else if (mfpwm->osc_clk && mfpwm->chosen_clk == mfpwm->osc_clk)
+ clk_src = PWMV4_CLK_SRC_CRYSTAL;
+ else
+ return -ENODEV;
+ }
+
+ if (clk_src == PWMV4_CLK_SRC_PLL)
+ return sysfs_emit(buf, "pll\n");
+ else if (clk_src == PWMV4_CLK_SRC_CRYSTAL)
+ return sysfs_emit(buf, "crystal\n");
+
+ return -ENODEV;
+}
+
+static ssize_t chosen_clock_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct rockchip_mfpwm *mfpwm = dev_get_drvdata(dev);
+ int ret;
+
+ if (sysfs_streq(buf, "pll")) {
+ ret = mfpwm_switch_clk_src(mfpwm, PWMV4_CLK_SRC_PLL);
+ if (ret)
+ return ret;
+ return count;
+ } else if (sysfs_streq(buf, "crystal")) {
+ ret = mfpwm_switch_clk_src(mfpwm, PWMV4_CLK_SRC_CRYSTAL);
+ if (ret)
+ return ret;
+ return count;
+ } else {
+ return -EINVAL;
+ }
+}
+
+static DEVICE_ATTR_RW(chosen_clock);
+
+static ssize_t available_clocks_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rockchip_mfpwm *mfpwm = dev_get_drvdata(dev);
+ ssize_t size = 0;
+
+ size += sysfs_emit_at(buf, size, "pll\n");
+ if (mfpwm->osc_clk)
+ size += sysfs_emit_at(buf, size, "crystal\n");
+
+ return size;
+}
+
+static DEVICE_ATTR_RO(available_clocks);
+
+static struct attribute *mfpwm_attrs[] = {
+ &dev_attr_available_clocks.attr,
+ &dev_attr_chosen_clock.attr,
+ NULL,
+};
+
+ATTRIBUTE_GROUPS(mfpwm);
+
+static int rockchip_mfpwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct rockchip_mfpwm *mfpwm;
+ int ret = 0;
+
+ mfpwm = devm_kzalloc(&pdev->dev, sizeof(*mfpwm), GFP_KERNEL);
+ if (IS_ERR(mfpwm))
+ return PTR_ERR(mfpwm);
+
+ mfpwm->pdev = pdev;
+
+ spin_lock_init(&mfpwm->state_lock);
+
+ mfpwm->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(mfpwm->base))
+ return dev_err_probe(dev, PTR_ERR(mfpwm->base),
+ "failed to ioremap address\n");
+
+ mfpwm->pclk = devm_clk_get_prepared(dev, "pclk");
+ if (IS_ERR(mfpwm->pclk))
+ return dev_err_probe(dev, PTR_ERR(mfpwm->pclk),
+ "couldn't get and prepare 'pclk' clock\n");
+
+ mfpwm->irq = platform_get_irq(pdev, 0);
+ if (mfpwm->irq < 0)
+ return dev_err_probe(dev, mfpwm->irq, "couldn't get irq 0\n");
+
+ mfpwm->pwm_clk = devm_clk_get_prepared(dev, "pwm");
+ if (IS_ERR(mfpwm->pwm_clk))
+ return dev_err_probe(dev, PTR_ERR(mfpwm->pwm_clk),
+ "couldn't get and prepare 'pwm' clock\n");
+
+ mfpwm->osc_clk = devm_clk_get_optional_prepared(dev, "osc");
+ if (IS_ERR(mfpwm->osc_clk))
+ return dev_err_probe(dev, PTR_ERR(mfpwm->osc_clk),
+ "couldn't get and prepare 'osc' clock\n");
+
+ ret = mfpwm_choose_clk(mfpwm);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, mfpwm);
+
+ ret = mfpwm_register_subdevs(mfpwm);
+ if (ret) {
+ dev_err(dev, "failed to register sub-devices: %pe\n",
+ ERR_PTR(ret));
+ return ret;
+ }
+
+ return ret;
+}
+
+static void rockchip_mfpwm_remove(struct platform_device *pdev)
+{
+ struct rockchip_mfpwm *mfpwm = to_rockchip_mfpwm(pdev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&mfpwm->state_lock, flags);
+
+ if (mfpwm->chosen_clk)
+ clk_rate_exclusive_put(mfpwm->chosen_clk);
+
+ spin_unlock_irqrestore(&mfpwm->state_lock, flags);
+}
+
+static const struct of_device_id rockchip_mfpwm_of_match[] = {
+ {
+ .compatible = "rockchip,rk3576-pwm",
+ },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rockchip_mfpwm_of_match);
+
+static struct platform_driver rockchip_mfpwm_driver = {
+ .driver = {
+ .name = KBUILD_MODNAME,
+ .of_match_table = rockchip_mfpwm_of_match,
+ .dev_groups = mfpwm_groups,
+ },
+ .probe = rockchip_mfpwm_probe,
+ .remove = rockchip_mfpwm_remove,
+};
+module_platform_driver(rockchip_mfpwm_driver);
+
+MODULE_AUTHOR("Nicolas Frattaroli <nicolas.frattaroli@...labora.com>");
+MODULE_DESCRIPTION("Rockchip MFPWM Driver");
+MODULE_LICENSE("GPL");
diff --git a/include/soc/rockchip/mfpwm.h b/include/soc/rockchip/mfpwm.h
new file mode 100644
index 0000000000000000000000000000000000000000..345f13f438b57159a15cb2e0ae250800fb96ed43
--- /dev/null
+++ b/include/soc/rockchip/mfpwm.h
@@ -0,0 +1,505 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2025 Collabora Ltd.
+ *
+ * Common header file for all the Rockchip Multi-function PWM controller
+ * drivers that are spread across subsystems.
+ *
+ * Authors:
+ * Nicolas Frattaroli <nicolas.frattaroli@...labora.com>
+ */
+
+#ifndef __SOC_ROCKCHIP_MFPWM_H__
+#define __SOC_ROCKCHIP_MFPWM_H__
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/spinlock.h>
+#include <soc/rockchip/utils.h>
+
+struct rockchip_mfpwm;
+
+/**
+ * struct rockchip_mfpwm_func - struct representing a single function driver
+ *
+ * @id: unique id for this function driver instance
+ * @base: pointer to start of MMIO registers
+ * @parent: a pointer to the parent mfpwm struct
+ * @irq: the shared IRQ gotten from the parent mfpwm device
+ */
+struct rockchip_mfpwm_func {
+ int id;
+ void __iomem *base;
+ struct rockchip_mfpwm *parent;
+ int irq;
+};
+
+/*
+ * PWMV4 Register Definitions
+ * --------------------------
+ *
+ * Attributes:
+ * RW - Read-Write
+ * RO - Read-Only
+ * WO - Write-Only
+ * W1T - Write high, Self-clearing
+ * W1C - Write high to clear interrupt
+ *
+ * Bit ranges to be understood with Verilog-like semantics,
+ * e.g. [03:00] is 4 bits: 0, 1, 2 and 3.
+ *
+ * All registers must be accessed with 32-bit width accesses only
+ */
+
+#define PWMV4_REG_VERSION 0x000
+/*
+ * VERSION Register Description
+ * [31:24] RO | Hardware Major Version
+ * [23:16] RO | Hardware Minor Version docArrive
+ * [15:15] RO | Reserved
+ * [14:14] RO | Hardware supports biphasic counters
+ * [13:13] RO | Hardware supports filters
+ * [12:12] RO | Hardware supports waveform generation
+ * [11:11] RO | Hardware supports counter
+ * [10:10] RO | Hardware supports frequency metering
+ * [09:09] RO | Hardware supports power key functionality
+ * [08:08] RO | Hardware supports infrared transmissions
+ * [07:04] RO | Channel index of this instance
+ * [03:00] RO | Number of channels the base instance supports
+ */
+static inline __pure u32 pwmv4_ver_chn_num(u32 val)
+{
+ return (val & GENMASK(3, 0));
+}
+
+static inline __pure u32 pwmv4_ver_chn_idx(u32 val)
+{
+ return (val & GENMASK(7, 4)) >> 4;
+}
+
+static inline __pure u32 pwmv4_ver_major(u32 val)
+{
+ return (val & GENMASK(31, 24)) >> 24;
+}
+
+static inline __pure u32 pwmv4_ver_minor(u32 val)
+{
+ return (val & GENMASK(23, 16)) >> 16;
+}
+
+#define PWMV4_REG_ENABLE 0x004
+/*
+ * ENABLE Register Description
+ * [31:16] WO | Write Enable Mask for the lower half of the register
+ * Set bit `n` here to 1 if you wish to modify bit `n >> 16` in
+ * the same write operation
+ * [15:06] RO | Reserved
+ * [05:05] RW | PWM Channel Counter Read Enable, 1 = enabled
+ */
+#define PWMV4_CHN_CNT_RD_EN(v) REG_UPDATE_BIT_WE((v), 5)
+/*
+ * [04:04] W1T | PWM Globally Joined Control Enable
+ * 1 = this PWM channel will be enabled by a global pwm enable
+ * bit instead of the PWM Enable bit.
+ */
+#define PWMV4_GLOBAL_CTRL_EN(v) REG_UPDATE_BIT_WE((v), 4)
+/*
+ * [03:03] RW | Force Clock Enable
+ * 0 = disabled, if the PWM channel is inactive then so is the
+ * clock prescale module
+ */
+#define PWMV4_FORCE_CLK_EN(v) REG_UPDATE_BIT_WE((v), 3)
+/*
+ * [02:02] W1T | PWM Control Update Enable
+ * 1 = enabled, commits modifications of _CTRL, _PERIOD, _DUTY and
+ * _OFFSET registers once 1 is written to it
+ */
+#define PWMV4_CTRL_UPDATE_EN(v) REG_UPDATE_BIT_WE((v), 2)
+#define PWMV4_CTRL_UPDATE_EN_MASK BIT(2)
+/*
+ * [01:01] RW | PWM Enable, 1 = enabled
+ * If in one-shot mode, clears after end of operation
+ */
+#define PWMV4_EN(v) REG_UPDATE_BIT_WE((v), 1)
+#define PWMV4_EN_MASK BIT(1)
+/*
+ * [00:00] RW | PWM Clock Enable, 1 = enabled
+ * If in one-shot mode, clears after end of operation
+ */
+#define PWMV4_CLK_EN(v) REG_UPDATE_BIT_WE((v), 0)
+#define PWMV4_CLK_EN_MASK BIT(0)
+#define PWMV4_EN_BOTH_MASK (PWMV4_EN_MASK | PWMV4_CLK_EN_MASK)
+static inline __pure bool pwmv4_is_enabled(unsigned int val)
+{
+ return (val & PWMV4_EN_BOTH_MASK);
+}
+
+#define PWMV4_REG_CLK_CTRL 0x008
+/*
+ * CLK_CTRL Register Description
+ * [31:16] WO | Write Enable Mask for the lower half of the register
+ * Set bit `n` here to 1 if you wish to modify bit `n >> 16` in
+ * the same write operation
+ * [15:15] RW | Clock Global Selection
+ * 0 = current channel scale clock
+ * 1 = global channel scale clock
+ */
+#define PWMV4_CLK_GLOBAL(v) REG_UPDATE_BIT_WE((v), 15)
+/*
+ * [14:13] RW | Clock Source Selection
+ * 0 = Clock from PLL, frequency can be configured
+ * 1 = Clock from crystal oscillator, frequency is fixed
+ * 2 = Clock from RC oscillator, frequency is fixed
+ * 3 = Reserved
+ * NOTE: This reg is of questionable usefulness on RK3576, as it
+ * just muxes between 100m_50m_24m and 24m directly. The
+ * only use-case I can come up with is if you must use 100m
+ * or 50m PWM on one channel but absolutely require to use
+ * the lower rate 24m clock on another channel on the same
+ * chip, which doesn't seem like a realistic use case. I
+ * suspect that's why downstream doesn't use it.
+ */
+#define PWMV4_CLK_SRC_PLL 0x0U
+#define PWMV4_CLK_SRC_CRYSTAL 0x1U
+#define PWMV4_CLK_SRC_RC 0x2U
+#define PWMV4_CLK_SRC(v) REG_UPDATE_WE((v), 13, 14)
+#define PWMV4_CLK_SRC_SHIFT 13
+#define PWMV4_CLK_SRC_MASK GENMASK(14, 13)
+/*
+ * [12:04] RW | Scale Factor to apply to pre-scaled clock
+ * 1 <= v <= 256, v means clock divided by 2*v
+ */
+#define PWMV4_CLK_SCALE_F(v) REG_UPDATE_WE((v), 4, 12)
+/*
+ * [03:03] RO | Reserved
+ * [02:00] RW | Prescale Factor
+ * v here means the input clock is divided by pow(2, v)
+ */
+#define PWMV4_CLK_PRESCALE_F(v) REG_UPDATE_WE((v), 0, 2)
+
+#define PWMV4_REG_CTRL 0x00C
+/*
+ * CTRL Register Description
+ * [31:16] WO | Write Enable Mask for the lower half of the register
+ * Set bit `n` here to 1 if you wish to modify bit `n >> 16` in
+ * the same write operation
+ * [15:09] RO | Reserved
+ * [08:06] RW | PWM Input Channel Selection
+ * By default, the channel selects its own input, but writing v
+ * here selects PWM input from channel v instead.
+ */
+#define PWMV4_CTRL_IN_SEL(v) REG_UPDATE_WE((v), 6, 8)
+/* [05:05] RW | Aligned Mode, 0 = Valid, 1 = Invalid */
+#define PWMV4_CTRL_UNALIGNED(v) REG_UPDATE_BIT_WE((v), 5)
+/* [04:04] RW | Output Mode, 0 = Left Aligned, 1 = Centre Aligned */
+#define PWMV4_LEFT_ALIGNED 0x0U
+#define PWMV4_CENTRE_ALIGNED 0x1U
+#define PWMV4_CTRL_OUT_MODE(v) REG_UPDATE_BIT_WE((v), 4)
+/*
+ * [03:03] RW | Inactive Polarity for when the channel is either disabled or
+ * has completed outputting the entire waveform in one-shot mode.
+ * 0 = Negative, 1 = Positive
+ */
+#define PWMV4_POLARITY_N 0x0U
+#define PWMV4_POLARITY_P 0x1U
+#define PWMV4_INACTIVE_POL(v) REG_UPDATE_BIT_WE((v), 3)
+/*
+ * [02:02] RW | Duty Cycle Polarity to use at the start of the waveform.
+ * 0 = Negative, 1 = Positive
+ */
+#define PWMV4_DUTY_POL(v) REG_UPDATE_BIT_WE((v), 2)
+#define PWMV4_DUTY_POL_MASK BIT(2)
+#define PWMV4_DUTY_POL_SHIFT 2
+/*
+ * [01:00] RW | PWM Mode
+ * 0 = One-shot mode, PWM generates waveform RPT times
+ * 1 = Continuous mode
+ * 2 = Capture mode, PWM measures cycles of input waveform
+ * 3 = Reserved
+ */
+#define PWMV4_MODE_ONESHOT 0x0U
+#define PWMV4_MODE_CONT 0x1U
+#define PWMV4_MODE_CAPTURE 0x2U
+#define PWMV4_MODE(v) REG_UPDATE_WE((v), 0, 1)
+#define PWMV4_CTRL_COM_FLAGS (PWMV4_INACTIVE_POL(PWMV4_POLARITY_N) | \
+ PWMV4_DUTY_POL(PWMV4_POLARITY_P) | \
+ PWMV4_CTRL_OUT_MODE(PWMV4_LEFT_ALIGNED) | \
+ PWMV4_CTRL_UNALIGNED(true))
+#define PWMV4_CTRL_CONT_FLAGS (PWMV4_MODE(PWMV4_MODE_CONT) | \
+ PWMV4_CTRL_COM_FLAGS)
+#define PWMV4_CTRL_CAP_FLAGS (PWMV4_MODE(PWMV4_MODE_CAPTURE) | \
+ PWMV4_CTRL_COM_FLAGS)
+
+#define PWMV4_REG_PERIOD 0x010
+/*
+ * PERIOD Register Description
+ * [31:00] RW | Period of the output waveform
+ * Constraints: should be even if CTRL_OUT_MODE is CENTRE_ALIGNED
+ */
+
+#define PWMV4_REG_DUTY 0x014
+/*
+ * DUTY Register Description
+ * [31:00] RW | Duty cycle of the output waveform
+ * Constraints: should be even if CTRL_OUT_MODE is CENTRE_ALIGNED
+ */
+
+#define PWMV4_REG_OFFSET 0x018
+/*
+ * OFFSET Register Description
+ * [31:00] RW | Offset of the output waveform, based on the PWM clock
+ * Constraints: 0 <= v <= (PERIOD - DUTY)
+ */
+
+#define PWMV4_REG_RPT 0x01C
+/*
+ * RPT Register Description
+ * [31:16] RW | Second dimensional of the effective number of waveform
+ * repetitions. Increases by one every first dimensional times.
+ * Value `n` means `n + 1` repetitions. The final number of
+ * repetitions of the waveform in one-shot mode is:
+ * `(first_dimensional + 1) * (second_dimensional + 1)`
+ * [15:00] RW | First dimensional of the effective number of waveform
+ * repetitions. Value `n` means `n + 1` repetitions.
+ */
+
+#define PWMV4_REG_FILTER_CTRL 0x020
+/*
+ * FILTER_CTRL Register Description
+ * [31:16] WO | Write Enable Mask for the lower half of the register
+ * Set bit `n` here to 1 if you wish to modify bit `n >> 16` in
+ * the same write operation
+ * [15:10] RO | Reserved
+ * [09:04] RW | Filter window number
+ * [03:01] RO | Reserved
+ * [00:00] RW | Filter Enable, 0 = disabled, 1 = enabled
+ */
+
+#define PWMV4_REG_CNT 0x024
+/*
+ * CNT Register Description
+ * [31:00] RO | Current value of the PWM Channel 0 counter in pwm clock cycles,
+ * 0 <= v <= 2^32-1
+ */
+
+#define PWMV4_REG_ENABLE_DELAY 0x028
+/*
+ * ENABLE_DELAY Register Description
+ * [31:16] RO | Reserved
+ * [15:00] RW | PWM enable delay, in an unknown unit but probably cycles
+ */
+
+#define PWMV4_REG_HPC 0x02C
+/*
+ * HPC Register Description
+ * [31:00] RW | Number of effective high polarity cycles of the input waveform
+ * in capture mode. Based on the PWM clock. 0 <= v <= 2^32-1
+ */
+
+#define PWMV4_REG_LPC 0x030
+/*
+ * LPC Register Description
+ * [31:00] RW | Number of effective low polarity cycles of the input waveform
+ * in capture mode. Based on the PWM clock. 0 <= v <= 2^32-1
+ */
+
+#define PWMV4_REG_BIPHASIC_CNT_CTRL0 0x040
+/*
+ * BIPHASIC_CNT_CTRL0 Register Description
+ * [31:16] WO | Write Enable Mask for the lower half of the register
+ * Set bit `n` here to 1 if you wish to modify bit `n >> 16` in
+ * the same write operation
+ * [15:10] RO | Reserved
+ * [09:09] RW | Biphasic Counter Phase Edge Selection for mode 0,
+ * 0 = rising edge (posedge), 1 = falling edge (negedge)
+ * [08:08] RW | Biphasic Counter Clock force enable, 1 = force enable
+ * [07:07] W1T | Synchronous Enable
+ * [06:06] W1T | Mode Switch
+ * 0 = Normal Mode, 1 = Switch timer clock and measured clock
+ * Constraints: "Biphasic Counter Mode" must be 0 if this is 1
+ * [05:03] RW | Biphasic Counter Mode
+ * 0x0 = Mode 0, 0x1 = Mode 1, 0x2 = Mode 2, 0x3 = Mode 3,
+ * 0x4 = Mode 4, 0x5 = Reserved
+ * [02:02] RW | Biphasic Counter Clock Selection
+ * 0 = clock is from PLL and frequency can be configured
+ * 1 = clock is from crystal oscillator and frequency is fixed
+ * [01:01] RW | Biphasic Counter Continuous Mode
+ * [00:00] W1T | Biphasic Counter Enable
+ */
+
+#define PWMV4_REG_BIPHASIC_CNT_CTRL1 0x044
+/*
+ * BIPHASIC_CNT_CTRL1 Register Description
+ * [31:16] WO | Write Enable Mask for the lower half of the register
+ * Set bit `n` here to 1 if you wish to modify bit `n >> 16` in
+ * the same write operation
+ * [15:11] RO | Reserved
+ * [10:04] RW | Biphasic Counter Filter Window Number
+ * [03:01] RO | Reserved
+ * [00:00] RW | Biphasic Counter Filter Enable
+ */
+
+#define PWMV4_REG_BIPHASIC_CNT_TIMER 0x048
+/*
+ * BIPHASIC_CNT_TIMER Register Description
+ * [31:00] RW | Biphasic Counter Timer Value, in number of biphasic counter
+ * timer clock cycles
+ */
+
+#define PWMV4_REG_BIPHASIC_CNT_RES 0x04C
+/*
+ * BIPHASIC_CNT_RES Register Description
+ * [31:00] RO | Biphasic Counter Result Value
+ * Constraints: Can only be read after INTSTS[9] is asserted
+ */
+
+#define PWMV4_REG_BIPHASIC_CNT_RES_S 0x050
+/*
+ * BIPHASIC_CNT_RES_S Register Description
+ * [31:00] RO | Biphasic Counter Result Value with synchronised processing
+ * Can be read in real-time if BIPHASIC_CNT_CTRL0[7] was set to 1
+ */
+
+#define PWMV4_REG_INTSTS 0x070
+/*
+ * INTSTS Register Description
+ * [31:10] RO | Reserved
+ * [09:09] W1C | Biphasic Counter Interrupt Status, 1 = interrupt asserted
+ * [08:08] W1C | Waveform Middle Interrupt Status, 1 = interrupt asserted
+ * [07:07] W1C | Waveform Max Interrupt Status, 1 = interrupt asserted
+ * [06:06] W1C | IR Transmission End Interrupt Status, 1 = interrupt asserted
+ * [05:05] W1C | Power Key Match Interrupt Status, 1 = interrupt asserted
+ * [04:04] W1C | Frequency Meter Interrupt Status, 1 = interrupt asserted
+ * [03:03] W1C | Reload Interrupt Status, 1 = interrupt asserted
+ * [02:02] W1C | Oneshot End Interrupt Status, 1 = interrupt asserted
+ * [01:01] W1C | HPC Capture Interrupt Status, 1 = interrupt asserted
+ * [00:00] W1C | LPC Capture Interrupt Status, 1 = interrupt asserted
+ */
+#define PWMV4_INT_LPC BIT(0)
+#define PWMV4_INT_HPC BIT(1)
+#define PWMV4_INT_LPC_W(v) REG_UPDATE_BIT_WE(((v) ? 1 : 0), 0)
+#define PWMV4_INT_HPC_W(v) REG_UPDATE_BIT_WE(((v) ? 1 : 0), 1)
+
+#define PWMV4_REG_INT_EN 0x074
+/*
+ * INT_EN Register Description
+ * [31:16] WO | Write Enable Mask for the lower half of the register
+ * Set bit `n` here to 1 if you wish to modify bit `n >> 16` in
+ * the same write operation
+ * [15:10] RO | Reserved
+ * [09:09] RW | Biphasic Counter Interrupt Enable, 1 = enabled
+ * [08:08] W1C | Waveform Middle Interrupt Enable, 1 = enabled
+ * [07:07] W1C | Waveform Max Interrupt Enable, 1 = enabled
+ * [06:06] W1C | IR Transmission End Interrupt Enable, 1 = enabled
+ * [05:05] W1C | Power Key Match Interrupt Enable, 1 = enabled
+ * [04:04] W1C | Frequency Meter Interrupt Enable, 1 = enabled
+ * [03:03] W1C | Reload Interrupt Enable, 1 = enabled
+ * [02:02] W1C | Oneshot End Interrupt Enable, 1 = enabled
+ * [01:01] W1C | HPC Capture Interrupt Enable, 1 = enabled
+ * [00:00] W1C | LPC Capture Interrupt Enable, 1 = enabled
+ */
+
+#define PWMV4_REG_INT_MASK 0x078
+/*
+ * INT_MASK Register Description
+ * [31:16] WO | Write Enable Mask for the lower half of the register
+ * Set bit `n` here to 1 if you wish to modify bit `n >> 16` in
+ * the same write operation
+ * [15:10] RO | Reserved
+ * [09:09] RW | Biphasic Counter Interrupt Masked, 1 = masked
+ * [08:08] W1C | Waveform Middle Interrupt Masked, 1 = masked
+ * [07:07] W1C | Waveform Max Interrupt Masked, 1 = masked
+ * [06:06] W1C | IR Transmission End Interrupt Masked, 1 = masked
+ * [05:05] W1C | Power Key Match Interrupt Masked, 1 = masked
+ * [04:04] W1C | Frequency Meter Interrupt Masked, 1 = masked
+ * [03:03] W1C | Reload Interrupt Masked, 1 = masked
+ * [02:02] W1C | Oneshot End Interrupt Masked, 1 = masked
+ * [01:01] W1C | HPC Capture Interrupt Masked, 1 = masked
+ * [00:00] W1C | LPC Capture Interrupt Masked, 1 = masked
+ */
+
+inline u32 mfpwm_reg_read(void __iomem *base, u32 reg)
+{
+ return readl(base + reg);
+}
+
+inline void mfpwm_reg_write(void __iomem *base, u32 reg, u32 val)
+{
+ writel(val, base + reg);
+}
+
+/**
+ * mfpwm_clk_get_rate - get the currently used clock's rate, in Hz
+ * @mfpwm: pointer to the &struct rockchip_mfpwm instance
+ *
+ * Returns: %0 on error, clock rate in Hz on success
+ */
+unsigned long mfpwm_clk_get_rate(struct rockchip_mfpwm *mfpwm);
+
+/**
+ * mfpwm_acquire - try becoming the active mfpwm function device
+ * @pwmf: pointer to the calling driver instance's &struct rockchip_mfpwm_func
+ *
+ * mfpwm device "function" drivers must call this function before doing anything
+ * that either modifies or relies on the parent device's state, such as clocks,
+ * enabling/disabling outputs, modifying shared regs etc.
+ *
+ * The return statues should always be checked.
+ *
+ * All mfpwm_acquire() calls must be balanced with corresponding mfpwm_release()
+ * calls once the device is no longer making changes that affect other devices,
+ * or stops producing user-visible effects that depend on the current device
+ * state being kept as-is. (e.g. after the PWM output signal is stopped)
+ *
+ * The same device function may mfpwm_acquire() multiple times while it already
+ * is active, i.e. it is re-entrant, though it needs to balance this with the
+ * same number of mfpwm_release() calls.
+ *
+ * Context: This function does not sleep.
+ *
+ * Return:
+ * * %0 - success
+ * * %-EBUSY - a different device function is active
+ * * %-EOVERFLOW - the acquire counter is at its maximum
+ */
+int __must_check mfpwm_acquire(struct rockchip_mfpwm_func *pwmf);
+
+/**
+ * mfpwm_release - drop usage of active mfpwm device function by 1
+ * @pwmf: pointer to the calling driver instance's &struct rockchip_mfpwm_func
+ *
+ * This is the balancing call to mfpwm_acquire(). If no users of the device
+ * function remain, set the mfpwm device to have no active device function,
+ * allowing other device functions to claim it.
+ */
+void mfpwm_release(const struct rockchip_mfpwm_func *pwmf);
+
+/**
+ * mfpwm_pwmclk_enable - enable the pwm clock the signal and timing is based on
+ * @pwmf: pointer to the calling driver instance's &struct rockchip_mfpwm_func
+ *
+ * Context: must be the active device function to call this
+ *
+ * Returns: 0 on success, negative errno on error.
+ */
+int mfpwm_pwmclk_enable(struct rockchip_mfpwm_func *pwmf);
+
+/**
+ * mfpwm_pwmclk_disable - disable the pwm clock the signal and timing is based on
+ * @pwmf: pointer to the calling driver instance's &struct rockchip_mfpwm_func
+ *
+ * Context: must be the active device function to call this
+ */
+void mfpwm_pwmclk_disable(struct rockchip_mfpwm_func *pwmf);
+
+/**
+ * mfpwm_remove_func - remove a device function driver from the mfpwm
+ * @pwmf: pointer to the calling driver instance's &struct rockchip_mfpwm_func
+ *
+ * If the device function driver described by @pwmf is the currently active
+ * device function, then it'll have its mfpwm_acquires and its pwmclk_enables
+ * balanced and be removed as the active device function driver.
+ */
+void mfpwm_remove_func(struct rockchip_mfpwm_func *pwmf);
+
+#endif /* __SOC_ROCKCHIP_MFPWM_H__ */
--
2.49.0
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