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linux/drivers/pwm/pwm-lpss.c
Heikki Krogerus 65accd8738 pwm: lpss: remove dependency on clk framework 
Unlike other Intel LPSS devices, the PWM does not have the
clock dividers or the gate. All we get from the clock is the
rate. Since PCI case uses the driver data to get the rate,
we can drop the clk and use the same data also in case of
ACPI. The frequency is the same.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Chew, Chiau Ee <chiau.ee.chew@intel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2014-08-07 13:18:03 +02:00

271 lines
6.4 KiB
C
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/*
* Intel Low Power Subsystem PWM controller driver
*
* Copyright (C) 2014, Intel Corporation
* Author: Mika Westerberg <mika.westerberg@linux.intel.com>
* Author: Chew Kean Ho <kean.ho.chew@intel.com>
* Author: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
* Author: Chew Chiau Ee <chiau.ee.chew@intel.com>
* Author: Alan Cox <alan@linux.intel.com>
*
* 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/acpi.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pwm.h>
#include <linux/platform_device.h>
#include <linux/pci.h>
static int pci_drv, plat_drv; /* So we know which drivers registered */
#define PWM 0x00000000
#define PWM_ENABLE BIT(31)
#define PWM_SW_UPDATE BIT(30)
#define PWM_BASE_UNIT_SHIFT 8
#define PWM_BASE_UNIT_MASK 0x00ffff00
#define PWM_ON_TIME_DIV_MASK 0x000000ff
#define PWM_DIVISION_CORRECTION 0x2
#define PWM_LIMIT (0x8000 + PWM_DIVISION_CORRECTION)
#define NSECS_PER_SEC 1000000000UL
struct pwm_lpss_chip {
struct pwm_chip chip;
void __iomem *regs;
unsigned long clk_rate;
};
struct pwm_lpss_boardinfo {
unsigned long clk_rate;
};
/* BayTrail */
static const struct pwm_lpss_boardinfo byt_info = {
25000000
};
static inline struct pwm_lpss_chip *to_lpwm(struct pwm_chip *chip)
{
return container_of(chip, struct pwm_lpss_chip, chip);
}
static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct pwm_lpss_chip *lpwm = to_lpwm(chip);
u8 on_time_div;
unsigned long c;
unsigned long long base_unit, freq = NSECS_PER_SEC;
u32 ctrl;
do_div(freq, period_ns);
/* The equation is: base_unit = ((freq / c) * 65536) + correction */
base_unit = freq * 65536;
c = lpwm->clk_rate;
if (!c)
return -EINVAL;
do_div(base_unit, c);
base_unit += PWM_DIVISION_CORRECTION;
if (base_unit > PWM_LIMIT)
return -EINVAL;
if (duty_ns <= 0)
duty_ns = 1;
on_time_div = 255 - (255 * duty_ns / period_ns);
ctrl = readl(lpwm->regs + PWM);
ctrl &= ~(PWM_BASE_UNIT_MASK | PWM_ON_TIME_DIV_MASK);
ctrl |= (u16) base_unit << PWM_BASE_UNIT_SHIFT;
ctrl |= on_time_div;
/* request PWM to update on next cycle */
ctrl |= PWM_SW_UPDATE;
writel(ctrl, lpwm->regs + PWM);
return 0;
}
static int pwm_lpss_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pwm_lpss_chip *lpwm = to_lpwm(chip);
u32 ctrl;
ctrl = readl(lpwm->regs + PWM);
writel(ctrl | PWM_ENABLE, lpwm->regs + PWM);
return 0;
}
static void pwm_lpss_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct pwm_lpss_chip *lpwm = to_lpwm(chip);
u32 ctrl;
ctrl = readl(lpwm->regs + PWM);
writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
}
static const struct pwm_ops pwm_lpss_ops = {
.config = pwm_lpss_config,
.enable = pwm_lpss_enable,
.disable = pwm_lpss_disable,
.owner = THIS_MODULE,
};
static struct pwm_lpss_chip *pwm_lpss_probe(struct device *dev,
struct resource *r,
const struct pwm_lpss_boardinfo *info)
{
struct pwm_lpss_chip *lpwm;
int ret;
lpwm = devm_kzalloc(dev, sizeof(*lpwm), GFP_KERNEL);
if (!lpwm)
return ERR_PTR(-ENOMEM);
lpwm->regs = devm_ioremap_resource(dev, r);
if (IS_ERR(lpwm->regs))
return ERR_CAST(lpwm->regs);
lpwm->clk_rate = info->clk_rate;
lpwm->chip.dev = dev;
lpwm->chip.ops = &pwm_lpss_ops;
lpwm->chip.base = -1;
lpwm->chip.npwm = 1;
ret = pwmchip_add(&lpwm->chip);
if (ret) {
dev_err(dev, "failed to add PWM chip: %d\n", ret);
return ERR_PTR(ret);
}
return lpwm;
}
static int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
{
u32 ctrl;
ctrl = readl(lpwm->regs + PWM);
writel(ctrl & ~PWM_ENABLE, lpwm->regs + PWM);
return pwmchip_remove(&lpwm->chip);
}
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 = pci_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);
return 0;
}
static void pwm_lpss_remove_pci(struct pci_dev *pdev)
{
struct pwm_lpss_chip *lpwm = pci_get_drvdata(pdev);
pwm_lpss_remove(lpwm);
pci_disable_device(pdev);
}
static struct pci_device_id pwm_lpss_pci_ids[] = {
{ PCI_VDEVICE(INTEL, 0x0f08), (unsigned long)&byt_info},
{ PCI_VDEVICE(INTEL, 0x0f09), (unsigned long)&byt_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,
};
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;
r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
info = (struct pwm_lpss_boardinfo *)id->driver_data;
lpwm = pwm_lpss_probe(&pdev->dev, r, info);
if (IS_ERR(lpwm))
return PTR_ERR(lpwm);
platform_set_drvdata(pdev, lpwm);
return 0;
}
static int pwm_lpss_remove_platform(struct platform_device *pdev)
{
struct pwm_lpss_chip *lpwm = platform_get_drvdata(pdev);
return pwm_lpss_remove(lpwm);
}
static const struct acpi_device_id pwm_lpss_acpi_match[] = {
{ "80860F09", (unsigned long)&byt_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,
};
static int __init pwm_init(void)
{
pci_drv = pci_register_driver(&pwm_lpss_driver_pci);
plat_drv = platform_driver_register(&pwm_lpss_driver_platform);
if (pci_drv && plat_drv)
return pci_drv;
return 0;
}
module_init(pwm_init);
static void __exit pwm_exit(void)
{
if (!pci_drv)
pci_unregister_driver(&pwm_lpss_driver_pci);
if (!plat_drv)
platform_driver_unregister(&pwm_lpss_driver_platform);
}
module_exit(pwm_exit);
MODULE_DESCRIPTION("PWM driver for Intel LPSS");
MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:pwm-lpss");
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