alistair23-linux/drivers/pwm/pwm-lpss-pci.c
Hans de Goede b997e3edca pwm: lpss: Set enable-bit before waiting for update-bit to go low
At least on cherrytrail, the update bit will never go low when the
enabled bit is not set.

This causes the backlight on my cube iwork8 air tablet to never turn on
again after being turned off because in the pwm_lpss_apply enable path
pwm_lpss_update will fail causing an error exit and the enable-bit to
never get set. Any following pwm_lpss_apply calls will fail the
pwm_lpss_is_updating check.

Since the docs say that the update bit should be set before the
enable-bit, split pwm_lpss_update into setting the update-bit and
pwm_lpss_wait_for_update, and move the pwm_lpss_wait_for_update call
in the enable path to after setting the enable-bit.

Fixes: 10d56a4 ("pwm: lpss: Avoid reconfiguring while UPDATE bit...")
Cc: Ilkka Koskinen <ilkka.koskinen@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2017-04-06 14:48:14 +02:00

131 lines
3.2 KiB
C

/*
* Intel Low Power Subsystem PWM controller PCI driver
*
* Copyright (C) 2014, Intel Corporation
*
* Derived from the original pwm-lpss.c
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.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,
};
/* Broxton */
static const struct pwm_lpss_boardinfo pwm_lpss_bxt_info = {
.clk_rate = 19200000,
.npwm = 4,
.base_unit_bits = 22,
.bypass = true,
};
/* Tangier */
static const struct pwm_lpss_boardinfo pwm_lpss_tng_info = {
.clk_rate = 19200000,
.npwm = 4,
.base_unit_bits = 22,
};
static int pwm_lpss_probe_pci(struct pci_dev *pdev,
const struct pci_device_id *id)
{
const struct pwm_lpss_boardinfo *info;
struct pwm_lpss_chip *lpwm;
int err;
err = pcim_enable_device(pdev);
if (err < 0)
return err;
info = (struct pwm_lpss_boardinfo *)id->driver_data;
lpwm = pwm_lpss_probe(&pdev->dev, &pdev->resource[0], info);
if (IS_ERR(lpwm))
return PTR_ERR(lpwm);
pci_set_drvdata(pdev, lpwm);
pm_runtime_put(&pdev->dev);
pm_runtime_allow(&pdev->dev);
return 0;
}
static void pwm_lpss_remove_pci(struct pci_dev *pdev)
{
struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev);
pm_runtime_forbid(&pdev->dev);
pm_runtime_get_sync(&pdev->dev);
pwm_lpss_remove(lpwm);
}
#ifdef CONFIG_PM
static int pwm_lpss_runtime_suspend_pci(struct device *dev)
{
/*
* The PCI core will handle transition to D3 automatically. We only
* need to provide runtime PM hooks for that to happen.
*/
return 0;
}
static int pwm_lpss_runtime_resume_pci(struct device *dev)
{
return 0;
}
#endif
static const struct dev_pm_ops pwm_lpss_pci_pm = {
SET_RUNTIME_PM_OPS(pwm_lpss_runtime_suspend_pci,
pwm_lpss_runtime_resume_pci, NULL)
};
static const struct pci_device_id pwm_lpss_pci_ids[] = {
{ PCI_VDEVICE(INTEL, 0x0ac8), (unsigned long)&pwm_lpss_bxt_info},
{ PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&pwm_lpss_byt_info},
{ PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&pwm_lpss_byt_info},
{ PCI_VDEVICE(INTEL, 0x11a5), (unsigned long)&pwm_lpss_tng_info},
{ PCI_VDEVICE(INTEL, 0x1ac8), (unsigned long)&pwm_lpss_bxt_info},
{ PCI_VDEVICE(INTEL, 0x2288), (unsigned long)&pwm_lpss_bsw_info},
{ PCI_VDEVICE(INTEL, 0x2289), (unsigned long)&pwm_lpss_bsw_info},
{ PCI_VDEVICE(INTEL, 0x31c8), (unsigned long)&pwm_lpss_bxt_info},
{ PCI_VDEVICE(INTEL, 0x5ac8), (unsigned long)&pwm_lpss_bxt_info},
{ },
};
MODULE_DEVICE_TABLE(pci, pwm_lpss_pci_ids);
static struct pci_driver pwm_lpss_driver_pci = {
.name = "pwm-lpss",
.id_table = pwm_lpss_pci_ids,
.probe = pwm_lpss_probe_pci,
.remove = pwm_lpss_remove_pci,
.driver = {
.pm = &pwm_lpss_pci_pm,
},
};
module_pci_driver(pwm_lpss_driver_pci);
MODULE_DESCRIPTION("PWM PCI driver for Intel LPSS");
MODULE_LICENSE("GPL v2");