[PATCH v5 1/2] pwm: mc33xs2410: add hwmon support

From: Dimitri Fedrau via B4 Relay
Date: Wed Jul 23 2025 - 13:40:00 EST


From: Dimitri Fedrau <dimitri.fedrau@xxxxxxxxxxxx>

Support for hwmon is provided by a separate driver residing in hwmon
subsystem which is implemented as auxiliary device. Add handling of this
device.

Signed-off-by: Dimitri Fedrau <dimitri.fedrau@xxxxxxxxxxxx>
---
drivers/pwm/Kconfig | 1 +
drivers/pwm/pwm-mc33xs2410.c | 20 ++++++++++++++++++--
include/linux/mc33xs2410.h | 16 ++++++++++++++++
3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 3ef1757502ebd92b30584cd10611311a0fbfc03b..64f1c86340fdc7d0ef41bf14be5f6f0623a2bd31 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -436,6 +436,7 @@ config PWM_MC33XS2410
tristate "MC33XS2410 PWM support"
depends on OF
depends on SPI
+ select AUXILIARY_BUS
help
NXP MC33XS2410 high-side switch driver. The MC33XS2410 is a four
channel high-side switch. The device is operational from 3.0 V
diff --git a/drivers/pwm/pwm-mc33xs2410.c b/drivers/pwm/pwm-mc33xs2410.c
index a1ac3445ccdb4709d92e0075d424a8abc1416eee..6d99e3ff7239891d87711d98aa463ac158af70e1 100644
--- a/drivers/pwm/pwm-mc33xs2410.c
+++ b/drivers/pwm/pwm-mc33xs2410.c
@@ -17,11 +17,14 @@
* behavior of the output pin that is neither the old nor the new state,
* rather something in between.
*/
+#define DEFAULT_SYMBOL_NAMESPACE "PWM_MC33XS2410"

+#include <linux/auxiliary_bus.h>
#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/math64.h>
+#include <linux/mc33xs2410.h>
#include <linux/minmax.h>
#include <linux/module.h>
#include <linux/of.h>
@@ -120,12 +123,19 @@ static int mc33xs2410_read_reg(struct spi_device *spi, u8 reg, u16 *val, u8 flag
return mc33xs2410_read_regs(spi, &reg, flag, val, 1);
}

-static int mc33xs2410_read_reg_ctrl(struct spi_device *spi, u8 reg, u16 *val)
+int mc33xs2410_read_reg_ctrl(struct spi_device *spi, u8 reg, u16 *val)
{
return mc33xs2410_read_reg(spi, reg, val, MC33XS2410_FRAME_IN_DATA_RD);
}
+EXPORT_SYMBOL_GPL(mc33xs2410_read_reg_ctrl);

-static int mc33xs2410_modify_reg(struct spi_device *spi, u8 reg, u8 mask, u8 val)
+int mc33xs2410_read_reg_diag(struct spi_device *spi, u8 reg, u16 *val)
+{
+ return mc33xs2410_read_reg(spi, reg, val, 0);
+}
+EXPORT_SYMBOL_GPL(mc33xs2410_read_reg_diag);
+
+int mc33xs2410_modify_reg(struct spi_device *spi, u8 reg, u8 mask, u8 val)
{
u16 tmp;
int ret;
@@ -139,6 +149,7 @@ static int mc33xs2410_modify_reg(struct spi_device *spi, u8 reg, u8 mask, u8 val

return mc33xs2410_write_reg(spi, reg, tmp);
}
+EXPORT_SYMBOL_GPL(mc33xs2410_modify_reg);

static u8 mc33xs2410_pwm_get_freq(u64 period)
{
@@ -314,6 +325,7 @@ static int mc33xs2410_reset(struct device *dev)
static int mc33xs2410_probe(struct spi_device *spi)
{
struct device *dev = &spi->dev;
+ struct auxiliary_device *adev;
struct pwm_chip *chip;
int ret;

@@ -361,6 +373,10 @@ static int mc33xs2410_probe(struct spi_device *spi)
if (ret < 0)
return dev_err_probe(dev, ret, "Failed to add pwm chip\n");

+ adev = devm_auxiliary_device_create(dev, "hwmon", NULL);
+ if (!adev)
+ return dev_err_probe(dev, -ENODEV, "Failed to register hwmon device\n");
+
return 0;
}

diff --git a/include/linux/mc33xs2410.h b/include/linux/mc33xs2410.h
new file mode 100644
index 0000000000000000000000000000000000000000..31c0edf10dd7370a0c3e603947256577d4d40854
--- /dev/null
+++ b/include/linux/mc33xs2410.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2024 Liebherr-Electronics and Drives GmbH
+ */
+#ifndef _MC33XS2410_H
+#define _MC33XS2410_H
+
+#include <linux/spi/spi.h>
+
+MODULE_IMPORT_NS("PWM_MC33XS2410");
+
+int mc33xs2410_read_reg_ctrl(struct spi_device *spi, u8 reg, u16 *val);
+int mc33xs2410_read_reg_diag(struct spi_device *spi, u8 reg, u16 *val);
+int mc33xs2410_modify_reg(struct spi_device *spi, u8 reg, u8 mask, u8 val);
+
+#endif /* _MC33XS2410_H */

--
2.39.5