pwm-lpss-platform.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Intel Low Power Subsystem PWM controller driver
*
* Copyright (C) 2014, Intel Corporation
*
* Derived from the original pwm-lpss.c
*/
#include <linux/acpi.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include "pwm-lpss.h"
/* BayTrail */
static const struct pwm_lpss_boardinfo pwm_lpss_byt_info = {
.clk_rate = 25000000,
.npwm = 1,
.base_unit_bits = 16,
};
/* Braswell */
static const struct pwm_lpss_boardinfo pwm_lpss_bsw_info = {
.clk_rate = 19200000,
.npwm = 1,
.base_unit_bits = 16,
.other_devices_aml_touches_pwm_regs = true,
};
/* Broxton */
static const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
.clk_rate = 19200000,
.npwm = 4,
.base_unit_bits = 22,
.bypass = true,
};
static int pwm_lpss_probe_platform(struct platform_device *pdev)
{
const struct pwm_lpss_boardinfo *info;
const struct acpi_device_id *id;
struct pwm_lpss_chip *lpwm;
struct resource *r;
id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
if (!id)
return -ENODEV;
info = (const struct pwm_lpss_boardinfo *)id->driver_data;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
lpwm = pwm_lpss_probe(&pdev->dev, r, info);
if (IS_ERR(lpwm))
return PTR_ERR(lpwm);
platform_set_drvdata(pdev, lpwm);
/*
* On Cherry Trail devices the GFX0._PS0 AML checks if the controller
* is on and if it is not on it turns it on and restores what it
* believes is the correct state to the PWM controller.
* Because of this we must disallow direct-complete, which keeps the
* controller (runtime)suspended on resume, to avoid 2 issues:
* 1. The controller getting turned on without the linux-pm code
* knowing about this. On devices where the controller is unused
* this causes it to stay on during the next suspend causing high
* battery drain (because S0i3 is not reached)
* 2. The state restoring code unexpectedly messing with the controller
*
* Leaving the controller runtime-suspended (skipping runtime-resume +
* normal-suspend) during suspend is fine.
*/
if (info->other_devices_aml_touches_pwm_regs)
dev_pm_set_driver_flags(&pdev->dev, DPM_FLAG_NO_DIRECT_COMPLETE|
DPM_FLAG_SMART_SUSPEND);
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
return 0;
}
static int pwm_lpss_remove_platform(struct platform_device *pdev)
{
pm_runtime_disable(&pdev->dev);
return 0;
}
static const struct acpi_device_id pwm_lpss_acpi_match[] = {
{ "80860F09", (unsigned long)&pwm_lpss_byt_info },
{ "80862288", (unsigned long)&pwm_lpss_bsw_info },
{ "80862289", (unsigned long)&pwm_lpss_bsw_info },
{ "80865AC8", (unsigned long)&pwm_lpss_bxt_info },
{ },
};
MODULE_DEVICE_TABLE(acpi, pwm_lpss_acpi_match);
static struct platform_driver pwm_lpss_driver_platform = {
.driver = {
.name = "pwm-lpss",
.acpi_match_table = pwm_lpss_acpi_match,
},
.probe = pwm_lpss_probe_platform,
.remove = pwm_lpss_remove_platform,
};
module_platform_driver(pwm_lpss_driver_platform);
MODULE_DESCRIPTION("PWM platform driver for Intel LPSS");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:pwm-lpss");