[PATCH v4 1/2] pwm: mc33xs2410: add hwmon support

Dimitri Fedrau via B4 Relay
2025-07-08T16:13:08Z

From: Dimitri Fedrau <dimitri.fedrau@liebherr.com>

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@liebherr.com>
---
drivers/pwm/Kconfig | 1 +
drivers/pwm/pwm-mc33xs2410.c | 64 ++++++++++++++++++++++++++++++++++++++++++--
include/linux/mc33xs2410.h | 14 ++++++++++
3 files changed, 77 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 6e113f8b4baf293284f017bc22fbc162633bb2fc..5b20230c5ccd99137efcd968efe603b8c8e2253f 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -427,6 +427,7 @@ 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..e70ed90bfdac77f5c777f0ba66d670331a515d12 100644
--- a/drivers/pwm/pwm-mc33xs2410.c
+++ b/drivers/pwm/pwm-mc33xs2410.c
@@ -18,10 +18,12 @@
* rather something in between.
*/

+#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 +122,19 @@ 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_NS_GPL(mc33xs2410_read_reg_ctrl, "PWM_MC33XS2410");

-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_NS_GPL(mc33xs2410_read_reg_diag, "PWM_MC33XS2410");
+
+int mc33xs2410_modify_reg(struct spi_device *spi, u8 reg, u8 mask, u8 val)
{
u16 tmp;
int ret;
@@ -139,6 +148,7 @@ static int mc33xs2410_modify_reg(struct spi_device *spi, u8 reg, u8 mask, u8 val

return mc33xs2410_write_reg(spi, reg, tmp);
}
+EXPORT_SYMBOL_NS_GPL(mc33xs2410_modify_reg, "PWM_MC33XS2410");

static u8 mc33xs2410_pwm_get_freq(u64 period)
{
@@ -297,6 +307,52 @@ static const struct pwm_ops mc33xs2410_pwm_ops = {
.get_state = mc33xs2410_pwm_get_state,
};

+static void mc33xs2410_adev_release(struct device *dev)
+{
+ struct auxiliary_device *adev = to_auxiliary_dev(dev);
+
+ kfree(adev);
+}
+
+static void mc33xs2410_unregister_adev(void *_adev)
+{
+ struct auxiliary_device *adev = _adev;
+
+ auxiliary_device_delete(adev);
+ auxiliary_device_uninit(adev);
+}
+
+static int mc33xs2410_hwmon_register(struct device *dev)
+{
+ struct auxiliary_device *adev;
+ int ret;
+
+ adev = kzalloc(sizeof(*adev), GFP_KERNEL);
+ if (!adev)
+ return -ENOMEM;
+
+ adev->name = "hwmon";
+ adev->dev.parent = dev;
+ adev->dev.release = mc33xs2410_adev_release;
+ adev->id = 0;
+
+ ret = auxiliary_device_init(adev);
+ if (ret)
+ return ret;
+
+ ret = auxiliary_device_add(adev);
+ if (ret) {
+ auxiliary_device_uninit(adev);
+ return ret;
+ }
+
+ ret = devm_add_action_or_reset(dev, mc33xs2410_unregister_adev, adev);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
static int mc33xs2410_reset(struct device *dev)
{
struct gpio_desc *reset_gpio;
@@ -361,6 +417,10 @@ static int mc33xs2410_probe(struct spi_device *spi)
if (ret < 0)
return dev_err_probe(dev, ret, "Failed to add pwm chip\n");

+ ret = mc33xs2410_hwmon_register(dev);
+ if (ret < 0)
+ return dev_err_probe(dev, ret, "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..15a0b0b595fe00a369cee45f2d30b2d912b612bb
--- /dev/null
+++ b/include/linux/mc33xs2410.h
@@ -0,0 +1,14 @@
+/* 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>
+
+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