[PATCH 2/3] pwm: rp1: Add RP1 PWM controller driver
Andrea della Porta
andrea.porta at suse.com
Fri Apr 3 07:31:55 PDT 2026
From: Naushir Patuck <naush at raspberrypi.com>
The Raspberry Pi RP1 southbridge features an embedded PWM
controller with 4 output channels, alongside an RPM interface
to read the fan speed on the Raspberry Pi 5.
Add the supporting driver.
Signed-off-by: Naushir Patuck <naush at raspberrypi.com>
Co-developed-by: Stanimir Varbanov <svarbanov at suse.de>
Signed-off-by: Stanimir Varbanov <svarbanov at suse.de>
Signed-off-by: Andrea della Porta <andrea.porta at suse.com>
---
drivers/pwm/Kconfig | 10 ++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-rp1.c | 244 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 255 insertions(+)
create mode 100644 drivers/pwm/pwm-rp1.c
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 6f3147518376a..22e4fc6385da2 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -625,6 +625,16 @@ config PWM_ROCKCHIP
Generic PWM framework driver for the PWM controller found on
Rockchip SoCs.
+config PWM_RP1
+ tristate "RP1 PWM support"
+ depends on MISC_RP1 || COMPILE_TEST
+ depends on HWMON
+ help
+ PWM framework driver for Raspberry Pi RP1 controller
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-rp1.
+
config PWM_SAMSUNG
tristate "Samsung PWM support"
depends on PLAT_SAMSUNG || ARCH_S5PV210 || ARCH_EXYNOS || COMPILE_TEST
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 0dc0d2b69025d..895a7c42fe9c0 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -56,6 +56,7 @@ obj-$(CONFIG_PWM_RENESAS_RZG2L_GPT) += pwm-rzg2l-gpt.o
obj-$(CONFIG_PWM_RENESAS_RZ_MTU3) += pwm-rz-mtu3.o
obj-$(CONFIG_PWM_RENESAS_TPU) += pwm-renesas-tpu.o
obj-$(CONFIG_PWM_ROCKCHIP) += pwm-rockchip.o
+obj-$(CONFIG_PWM_RP1) += pwm-rp1.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
obj-$(CONFIG_PWM_SIFIVE) += pwm-sifive.o
obj-$(CONFIG_PWM_SL28CPLD) += pwm-sl28cpld.o
diff --git a/drivers/pwm/pwm-rp1.c b/drivers/pwm/pwm-rp1.c
new file mode 100644
index 0000000000000..0a1c1c1dd27e9
--- /dev/null
+++ b/drivers/pwm/pwm-rp1.c
@@ -0,0 +1,244 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * pwm-rp1.c
+ *
+ * Raspberry Pi RP1 PWM.
+ *
+ * Copyright © 2026 Raspberry Pi Ltd.
+ *
+ * Author: Naushir Patuck (naush at raspberrypi.com)
+ *
+ * Based on the pwm-bcm2835 driver by:
+ * Bart Tanghe <bart.tanghe at thomasmore.be>
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pwm.h>
+
+#define PWM_GLOBAL_CTRL 0x000
+#define PWM_CHANNEL_CTRL(x) (0x014 + ((x) * 0x10))
+#define PWM_RANGE(x) (0x018 + ((x) * 0x10))
+#define PWM_PHASE(x) (0x01C + ((x) * 0x10))
+#define PWM_DUTY(x) (0x020 + ((x) * 0x10))
+
+/* 8:FIFO_POP_MASK + 0:Trailing edge M/S modulation */
+#define PWM_CHANNEL_DEFAULT (BIT(8) + BIT(0))
+#define PWM_CHANNEL_ENABLE(x) BIT(x)
+#define PWM_POLARITY BIT(3)
+#define SET_UPDATE BIT(31)
+#define PWM_MODE_MASK GENMASK(1, 0)
+
+#define NUM_PWMS 4
+
+struct rp1_pwm {
+ void __iomem *base;
+ struct clk *clk;
+};
+
+static const struct hwmon_channel_info * const rp1_fan_hwmon_info[] = {
+ HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
+ NULL
+};
+
+static umode_t rp1_fan_hwmon_is_visible(const void *data, enum hwmon_sensor_types type,
+ u32 attr, int channel)
+{
+ umode_t mode = 0;
+
+ if (type == hwmon_fan && attr == hwmon_fan_input)
+ mode = 0444;
+
+ return mode;
+}
+
+static int rp1_fan_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct rp1_pwm *rp1 = dev_get_drvdata(dev);
+
+ if (type != hwmon_fan || attr != hwmon_fan_input)
+ return -EOPNOTSUPP;
+
+ *val = readl(rp1->base + PWM_PHASE(2));
+
+ return 0;
+}
+
+static const struct hwmon_ops rp1_fan_hwmon_ops = {
+ .is_visible = rp1_fan_hwmon_is_visible,
+ .read = rp1_fan_hwmon_read,
+};
+
+static const struct hwmon_chip_info rp1_fan_hwmon_chip_info = {
+ .ops = &rp1_fan_hwmon_ops,
+ .info = rp1_fan_hwmon_info,
+};
+
+static void rp1_pwm_apply_config(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rp1_pwm *rp1 = pwmchip_get_drvdata(chip);
+ u32 value;
+
+ value = readl(rp1->base + PWM_GLOBAL_CTRL);
+ value |= SET_UPDATE;
+ writel(value, rp1->base + PWM_GLOBAL_CTRL);
+}
+
+static int rp1_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rp1_pwm *rp1 = pwmchip_get_drvdata(chip);
+
+ writel(PWM_CHANNEL_DEFAULT, rp1->base + PWM_CHANNEL_CTRL(pwm->hwpwm));
+ return 0;
+}
+
+static void rp1_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct rp1_pwm *rp1 = pwmchip_get_drvdata(chip);
+ u32 value;
+
+ value = readl(rp1->base + PWM_CHANNEL_CTRL(pwm->hwpwm));
+ value &= ~PWM_MODE_MASK;
+ writel(value, rp1->base + PWM_CHANNEL_CTRL(pwm->hwpwm));
+
+ rp1_pwm_apply_config(chip, pwm);
+}
+
+static int rp1_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
+ const struct pwm_state *state)
+{
+ struct rp1_pwm *rp1 = pwmchip_get_drvdata(chip);
+ unsigned long clk_rate = clk_get_rate(rp1->clk);
+ unsigned long clk_period;
+ u32 value;
+
+ if (!clk_rate) {
+ dev_err(&chip->dev, "failed to get clock rate\n");
+ return -EINVAL;
+ }
+
+ /* set period and duty cycle */
+ clk_period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, clk_rate);
+
+ writel(DIV_ROUND_CLOSEST(state->duty_cycle, clk_period),
+ rp1->base + PWM_DUTY(pwm->hwpwm));
+
+ writel(DIV_ROUND_CLOSEST(state->period, clk_period),
+ rp1->base + PWM_RANGE(pwm->hwpwm));
+
+ /* set polarity */
+ value = readl(rp1->base + PWM_CHANNEL_CTRL(pwm->hwpwm));
+ if (state->polarity == PWM_POLARITY_NORMAL)
+ value &= ~PWM_POLARITY;
+ else
+ value |= PWM_POLARITY;
+ writel(value, rp1->base + PWM_CHANNEL_CTRL(pwm->hwpwm));
+
+ /* enable/disable */
+ value = readl(rp1->base + PWM_GLOBAL_CTRL);
+ if (state->enabled)
+ value |= PWM_CHANNEL_ENABLE(pwm->hwpwm);
+ else
+ value &= ~PWM_CHANNEL_ENABLE(pwm->hwpwm);
+ writel(value, rp1->base + PWM_GLOBAL_CTRL);
+
+ rp1_pwm_apply_config(chip, pwm);
+
+ return 0;
+}
+
+static const struct pwm_ops rp1_pwm_ops = {
+ .request = rp1_pwm_request,
+ .free = rp1_pwm_free,
+ .apply = rp1_pwm_apply,
+};
+
+static int rp1_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device *hwmon_dev;
+ struct pwm_chip *chip;
+ struct rp1_pwm *rp1;
+ int ret;
+
+ chip = devm_pwmchip_alloc(dev, NUM_PWMS, sizeof(*rp1));
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+
+ rp1 = pwmchip_get_drvdata(chip);
+
+ rp1->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(rp1->base))
+ return PTR_ERR(rp1->base);
+
+ rp1->clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(rp1->clk))
+ return dev_err_probe(dev, PTR_ERR(rp1->clk), "clock not found\n");
+
+ ret = devm_clk_rate_exclusive_get(dev, rp1->clk);
+ if (ret)
+ return dev_err_probe(dev, ret, "fail to get exclusive rate\n");
+
+ chip->ops = &rp1_pwm_ops;
+
+ platform_set_drvdata(pdev, chip);
+
+ ret = devm_pwmchip_add(dev, chip);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to register PWM chip\n");
+
+ hwmon_dev = devm_hwmon_device_register_with_info(dev, "rp1_fan_tach", rp1,
+ &rp1_fan_hwmon_chip_info,
+ NULL);
+
+ if (IS_ERR(hwmon_dev))
+ return dev_err_probe(dev, PTR_ERR(hwmon_dev),
+ "failed to register hwmon fan device\n");
+
+ return 0;
+}
+
+static int rp1_pwm_suspend(struct device *dev)
+{
+ struct rp1_pwm *rp1 = dev_get_drvdata(dev);
+
+ clk_disable_unprepare(rp1->clk);
+
+ return 0;
+}
+
+static int rp1_pwm_resume(struct device *dev)
+{
+ struct rp1_pwm *rp1 = dev_get_drvdata(dev);
+
+ return clk_prepare_enable(rp1->clk);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(rp1_pwm_pm_ops, rp1_pwm_suspend, rp1_pwm_resume);
+
+static const struct of_device_id rp1_pwm_of_match[] = {
+ { .compatible = "raspberrypi,rp1-pwm" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rp1_pwm_of_match);
+
+static struct platform_driver rp1_pwm_driver = {
+ .probe = rp1_pwm_probe,
+ .driver = {
+ .name = "rp1-pwm",
+ .of_match_table = rp1_pwm_of_match,
+ .pm = pm_ptr(&rp1_pwm_pm_ops),
+ },
+};
+module_platform_driver(rp1_pwm_driver);
+
+MODULE_DESCRIPTION("RP1 PWM driver");
+MODULE_AUTHOR("Naushir Patuck <naush at raspberrypi.com>");
+MODULE_LICENSE("GPL");
--
2.35.3
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