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kamel-bouharalag-linaro
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pwm: max7360: Add MAX7360 PWM support
Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to 8 independent PWM outputs. Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com> Co-developed-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Uwe Kleine-König <ukleinek@kernel.org> Link: https://lore.kernel.org/r/20250824-mdb-max7360-support-v14-4-435cfda2b1ea@bootlin.com Signed-off-by: Lee Jones <lee@kernel.org>
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‎drivers/pwm/Kconfig‎

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@@ -432,6 +432,16 @@ config PWM_LPSS_PLATFORM
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To compile this driver as a module, choose M here: the module
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will be called pwm-lpss-platform.
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config PWM_MAX7360
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tristate "MAX7360 PWMs"
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depends on MFD_MAX7360
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help
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PWM driver for Maxim Integrated MAX7360 multifunction device, with
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support for up to 8 PWM outputs.
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To compile this driver as a module, choose M here: the module
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will be called pwm-max7360.
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config PWM_MC33XS2410
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tristate "MC33XS2410 PWM support"
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depends on OF

‎drivers/pwm/Makefile‎

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@@ -38,6 +38,7 @@ obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
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obj-$(CONFIG_PWM_LPSS) += pwm-lpss.o
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obj-$(CONFIG_PWM_LPSS_PCI) += pwm-lpss-pci.o
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obj-$(CONFIG_PWM_LPSS_PLATFORM) += pwm-lpss-platform.o
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obj-$(CONFIG_PWM_MAX7360) += pwm-max7360.o
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obj-$(CONFIG_PWM_MC33XS2410) += pwm-mc33xs2410.o
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obj-$(CONFIG_PWM_MEDIATEK) += pwm-mediatek.o
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obj-$(CONFIG_PWM_MESON) += pwm-meson.o

‎drivers/pwm/pwm-max7360.c‎

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// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2025 Bootlin
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*
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* Author: Kamel BOUHARA <kamel.bouhara@bootlin.com>
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* Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
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*
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* PWM functionality of the MAX7360 multi-function device.
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* https://www.analog.com/media/en/technical-documentation/data-sheets/MAX7360.pdf
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*
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* Limitations:
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* - Only supports normal polarity.
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* - The period is fixed to 2 ms.
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* - Only the duty cycle can be changed, new values are applied at the beginning
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* of the next cycle.
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* - When disabled, the output is put in Hi-Z immediately.
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*/
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#include <linux/bits.h>
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#include <linux/dev_printk.h>
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#include <linux/err.h>
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#include <linux/math64.h>
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#include <linux/mfd/max7360.h>
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#include <linux/minmax.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/pwm.h>
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#include <linux/regmap.h>
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#include <linux/time.h>
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#include <linux/types.h>
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#define MAX7360_NUM_PWMS 8
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#define MAX7360_PWM_MAX 255
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#define MAX7360_PWM_STEPS 256
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#define MAX7360_PWM_PERIOD_NS (2 * NSEC_PER_MSEC)
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struct max7360_pwm_waveform {
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u8 duty_steps;
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bool enabled;
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};
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static int max7360_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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struct regmap *regmap = pwmchip_get_drvdata(chip);
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/*
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* Make sure we use the individual PWM configuration register and not
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* the global one.
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* We never need to use the global one, so there is no need to revert
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* that in the .free() callback.
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*/
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return regmap_write_bits(regmap, MAX7360_REG_PWMCFG(pwm->hwpwm),
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MAX7360_PORT_CFG_COMMON_PWM, 0);
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}
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static int max7360_pwm_round_waveform_tohw(struct pwm_chip *chip,
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struct pwm_device *pwm,
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const struct pwm_waveform *wf,
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void *_wfhw)
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{
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struct max7360_pwm_waveform *wfhw = _wfhw;
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u64 duty_steps;
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/*
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* Ignore user provided values for period_length_ns and duty_offset_ns:
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* we only support fixed period of MAX7360_PWM_PERIOD_NS and offset of 0.
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* Values from 0 to 254 as duty_steps will provide duty cycles of 0/256
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* to 254/256, while value 255 will provide a duty cycle of 100%.
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*/
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if (wf->duty_length_ns >= MAX7360_PWM_PERIOD_NS) {
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duty_steps = MAX7360_PWM_MAX;
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} else {
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duty_steps = (u32)wf->duty_length_ns * MAX7360_PWM_STEPS / MAX7360_PWM_PERIOD_NS;
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if (duty_steps == MAX7360_PWM_MAX)
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duty_steps = MAX7360_PWM_MAX - 1;
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}
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wfhw->duty_steps = min(MAX7360_PWM_MAX, duty_steps);
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wfhw->enabled = !!wf->period_length_ns;
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if (wf->period_length_ns && wf->period_length_ns < MAX7360_PWM_PERIOD_NS)
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return 1;
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else
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return 0;
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}
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static int max7360_pwm_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm,
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const void *_wfhw, struct pwm_waveform *wf)
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{
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const struct max7360_pwm_waveform *wfhw = _wfhw;
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wf->period_length_ns = wfhw->enabled ? MAX7360_PWM_PERIOD_NS : 0;
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wf->duty_offset_ns = 0;
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if (wfhw->enabled) {
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if (wfhw->duty_steps == MAX7360_PWM_MAX)
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wf->duty_length_ns = MAX7360_PWM_PERIOD_NS;
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else
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wf->duty_length_ns = DIV_ROUND_UP(wfhw->duty_steps * MAX7360_PWM_PERIOD_NS,
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MAX7360_PWM_STEPS);
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} else {
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wf->duty_length_ns = 0;
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}
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return 0;
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}
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static int max7360_pwm_write_waveform(struct pwm_chip *chip,
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struct pwm_device *pwm,
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const void *_wfhw)
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{
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struct regmap *regmap = pwmchip_get_drvdata(chip);
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const struct max7360_pwm_waveform *wfhw = _wfhw;
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unsigned int val;
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int ret;
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if (wfhw->enabled) {
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ret = regmap_write(regmap, MAX7360_REG_PWM(pwm->hwpwm), wfhw->duty_steps);
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if (ret)
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return ret;
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}
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val = wfhw->enabled ? BIT(pwm->hwpwm) : 0;
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return regmap_write_bits(regmap, MAX7360_REG_GPIOCTRL, BIT(pwm->hwpwm), val);
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}
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static int max7360_pwm_read_waveform(struct pwm_chip *chip,
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struct pwm_device *pwm,
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void *_wfhw)
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{
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struct regmap *regmap = pwmchip_get_drvdata(chip);
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struct max7360_pwm_waveform *wfhw = _wfhw;
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unsigned int val;
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int ret;
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ret = regmap_read(regmap, MAX7360_REG_GPIOCTRL, &val);
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if (ret)
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return ret;
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if (val & BIT(pwm->hwpwm)) {
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wfhw->enabled = true;
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ret = regmap_read(regmap, MAX7360_REG_PWM(pwm->hwpwm), &val);
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if (ret)
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return ret;
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wfhw->duty_steps = val;
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} else {
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wfhw->enabled = false;
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wfhw->duty_steps = 0;
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}
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return 0;
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}
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static const struct pwm_ops max7360_pwm_ops = {
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.request = max7360_pwm_request,
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.round_waveform_tohw = max7360_pwm_round_waveform_tohw,
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.round_waveform_fromhw = max7360_pwm_round_waveform_fromhw,
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.read_waveform = max7360_pwm_read_waveform,
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.write_waveform = max7360_pwm_write_waveform,
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};
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static int max7360_pwm_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct pwm_chip *chip;
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struct regmap *regmap;
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int ret;
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regmap = dev_get_regmap(dev->parent, NULL);
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if (!regmap)
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return dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
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/*
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* This MFD sub-device does not have any associated device tree node:
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* properties are stored in the device node of the parent (MFD) device
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* and this same node is used in phandles of client devices.
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* Reuse this device tree node here, as otherwise the PWM subsystem
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* would be confused by this topology.
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*/
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device_set_of_node_from_dev(dev, dev->parent);
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chip = devm_pwmchip_alloc(dev, MAX7360_NUM_PWMS, 0);
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if (IS_ERR(chip))
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return PTR_ERR(chip);
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chip->ops = &max7360_pwm_ops;
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pwmchip_set_drvdata(chip, regmap);
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ret = devm_pwmchip_add(dev, chip);
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if (ret)
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return dev_err_probe(dev, ret, "Failed to add PWM chip\n");
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return 0;
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}
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static struct platform_driver max7360_pwm_driver = {
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.driver = {
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.name = "max7360-pwm",
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.probe_type = PROBE_PREFER_ASYNCHRONOUS,
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},
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.probe = max7360_pwm_probe,
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};
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module_platform_driver(max7360_pwm_driver);
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MODULE_DESCRIPTION("MAX7360 PWM driver");
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MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@bootlin.com>");
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MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
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MODULE_LICENSE("GPL");

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