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linux-sg2042/drivers/pwm/pwm-dwc.c

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// SPDX-License-Identifier: GPL-2.0
/*
* DesignWare PWM Controller driver
*
* Copyright (C) 2018-2020 Intel Corporation
*
* Author: Felipe Balbi (Intel)
* Author: Jarkko Nikula <jarkko.nikula@linux.intel.com>
* Author: Raymond Tan <raymond.tan@intel.com>
*
* Limitations:
* - The hardware cannot generate a 0 % or 100 % duty cycle. Both high and low
* periods are one or more input clock periods long.
*/
#include <linux/bitops.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pm_runtime.h>
#include <linux/pwm.h>
#define DWC_TIM_LD_CNT(n) ((n) * 0x14)
#define DWC_TIM_LD_CNT2(n) (((n) * 4) + 0xb0)
#define DWC_TIM_CUR_VAL(n) (((n) * 0x14) + 0x04)
#define DWC_TIM_CTRL(n) (((n) * 0x14) + 0x08)
#define DWC_TIM_EOI(n) (((n) * 0x14) + 0x0c)
#define DWC_TIM_INT_STS(n) (((n) * 0x14) + 0x10)
#define DWC_TIMERS_INT_STS 0xa0
#define DWC_TIMERS_EOI 0xa4
#define DWC_TIMERS_RAW_INT_STS 0xa8
#define DWC_TIMERS_COMP_VERSION 0xac
#define DWC_TIMERS_TOTAL 8
#define DWC_CLK_PERIOD_NS 10
/* Timer Control Register */
#define DWC_TIM_CTRL_EN BIT(0)
#define DWC_TIM_CTRL_MODE BIT(1)
#define DWC_TIM_CTRL_MODE_FREE (0 << 1)
#define DWC_TIM_CTRL_MODE_USER (1 << 1)
#define DWC_TIM_CTRL_INT_MASK BIT(2)
#define DWC_TIM_CTRL_PWM BIT(3)
struct dwc_pwm_ctx {
u32 cnt;
u32 cnt2;
u32 ctrl;
};
struct dwc_pwm {
struct pwm_chip chip;
void __iomem *base;
struct dwc_pwm_ctx ctx[DWC_TIMERS_TOTAL];
};
#define to_dwc_pwm(p) (container_of((p), struct dwc_pwm, chip))
static inline u32 dwc_pwm_readl(struct dwc_pwm *dwc, u32 offset)
{
return readl(dwc->base + offset);
}
static inline void dwc_pwm_writel(struct dwc_pwm *dwc, u32 value, u32 offset)
{
writel(value, dwc->base + offset);
}
static void __dwc_pwm_set_enable(struct dwc_pwm *dwc, int pwm, int enabled)
{
u32 reg;
reg = dwc_pwm_readl(dwc, DWC_TIM_CTRL(pwm));
if (enabled)
reg |= DWC_TIM_CTRL_EN;
else
reg &= ~DWC_TIM_CTRL_EN;
dwc_pwm_writel(dwc, reg, DWC_TIM_CTRL(pwm));
}
static int __dwc_pwm_configure_timer(struct dwc_pwm *dwc,
struct pwm_device *pwm,
const struct pwm_state *state)
{
u64 tmp;
u32 ctrl;
u32 high;
u32 low;
/*
* Calculate width of low and high period in terms of input clock
* periods and check are the result within HW limits between 1 and
* 2^32 periods.
*/
tmp = DIV_ROUND_CLOSEST_ULL(state->duty_cycle, DWC_CLK_PERIOD_NS);
if (tmp < 1 || tmp > (1ULL << 32))
return -ERANGE;
low = tmp - 1;
tmp = DIV_ROUND_CLOSEST_ULL(state->period - state->duty_cycle,
DWC_CLK_PERIOD_NS);
if (tmp < 1 || tmp > (1ULL << 32))
return -ERANGE;
high = tmp - 1;
/*
* Specification says timer usage flow is to disable timer, then
* program it followed by enable. It also says Load Count is loaded
* into timer after it is enabled - either after a disable or
* a reset. Based on measurements it happens also without disable
* whenever Load Count is updated. But follow the specification.
*/
__dwc_pwm_set_enable(dwc, pwm->hwpwm, false);
/*
* Write Load Count and Load Count 2 registers. Former defines the
* width of low period and latter the width of high period in terms
* multiple of input clock periods:
* Width = ((Count + 1) * input clock period).
*/
dwc_pwm_writel(dwc, low, DWC_TIM_LD_CNT(pwm->hwpwm));
dwc_pwm_writel(dwc, high, DWC_TIM_LD_CNT2(pwm->hwpwm));
/*
* Set user-defined mode, timer reloads from Load Count registers
* when it counts down to 0.
* Set PWM mode, it makes output to toggle and width of low and high
* periods are set by Load Count registers.
*/
ctrl = DWC_TIM_CTRL_MODE_USER | DWC_TIM_CTRL_PWM;
dwc_pwm_writel(dwc, ctrl, DWC_TIM_CTRL(pwm->hwpwm));
/*
* Enable timer. Output starts from low period.
*/
__dwc_pwm_set_enable(dwc, pwm->hwpwm, state->enabled);
return 0;
}
static int dwc_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct dwc_pwm *dwc = to_dwc_pwm(chip);
if (state->polarity != PWM_POLARITY_INVERSED)
return -EINVAL;
if (state->enabled) {
if (!pwm->state.enabled)
pm_runtime_get_sync(chip->dev);
return __dwc_pwm_configure_timer(dwc, pwm, state);
} else {
if (pwm->state.enabled) {
__dwc_pwm_set_enable(dwc, pwm->hwpwm, false);
pm_runtime_put_sync(chip->dev);
}
}
return 0;
}
static void dwc_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct dwc_pwm *dwc = to_dwc_pwm(chip);
u64 duty, period;
pm_runtime_get_sync(chip->dev);
state->enabled = !!(dwc_pwm_readl(dwc,
DWC_TIM_CTRL(pwm->hwpwm)) & DWC_TIM_CTRL_EN);
duty = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(pwm->hwpwm));
duty += 1;
duty *= DWC_CLK_PERIOD_NS;
state->duty_cycle = duty;
period = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(pwm->hwpwm));
period += 1;
period *= DWC_CLK_PERIOD_NS;
period += duty;
state->period = period;
state->polarity = PWM_POLARITY_INVERSED;
pm_runtime_put_sync(chip->dev);
}
static const struct pwm_ops dwc_pwm_ops = {
.apply = dwc_pwm_apply,
.get_state = dwc_pwm_get_state,
.owner = THIS_MODULE,
};
static int dwc_pwm_probe(struct pci_dev *pci, const struct pci_device_id *id)
{
struct device *dev = &pci->dev;
struct dwc_pwm *dwc;
int ret;
dwc = devm_kzalloc(&pci->dev, sizeof(*dwc), GFP_KERNEL);
if (!dwc)
return -ENOMEM;
ret = pcim_enable_device(pci);
if (ret) {
dev_err(&pci->dev,
"Failed to enable device (%pe)\n", ERR_PTR(ret));
return ret;
}
pci_set_master(pci);
ret = pcim_iomap_regions(pci, BIT(0), pci_name(pci));
if (ret) {
dev_err(&pci->dev,
"Failed to iomap PCI BAR (%pe)\n", ERR_PTR(ret));
return ret;
}
dwc->base = pcim_iomap_table(pci)[0];
if (!dwc->base) {
dev_err(&pci->dev, "Base address missing\n");
return -ENOMEM;
}
pci_set_drvdata(pci, dwc);
dwc->chip.dev = dev;
dwc->chip.ops = &dwc_pwm_ops;
dwc->chip.npwm = DWC_TIMERS_TOTAL;
dwc->chip.base = -1;
ret = pwmchip_add(&dwc->chip);
if (ret)
return ret;
pm_runtime_put(dev);
pm_runtime_allow(dev);
return 0;
}
static void dwc_pwm_remove(struct pci_dev *pci)
{
struct dwc_pwm *dwc = pci_get_drvdata(pci);
pm_runtime_forbid(&pci->dev);
pm_runtime_get_noresume(&pci->dev);
pwmchip_remove(&dwc->chip);
}
#ifdef CONFIG_PM_SLEEP
static int dwc_pwm_suspend(struct device *dev)
{
struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
struct dwc_pwm *dwc = pci_get_drvdata(pdev);
int i;
for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
if (dwc->chip.pwms[i].state.enabled) {
dev_err(dev, "PWM %u in use by consumer (%s)\n",
i, dwc->chip.pwms[i].label);
return -EBUSY;
}
dwc->ctx[i].cnt = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT(i));
dwc->ctx[i].cnt2 = dwc_pwm_readl(dwc, DWC_TIM_LD_CNT2(i));
dwc->ctx[i].ctrl = dwc_pwm_readl(dwc, DWC_TIM_CTRL(i));
}
return 0;
}
static int dwc_pwm_resume(struct device *dev)
{
struct pci_dev *pdev = container_of(dev, struct pci_dev, dev);
struct dwc_pwm *dwc = pci_get_drvdata(pdev);
int i;
for (i = 0; i < DWC_TIMERS_TOTAL; i++) {
dwc_pwm_writel(dwc, dwc->ctx[i].cnt, DWC_TIM_LD_CNT(i));
dwc_pwm_writel(dwc, dwc->ctx[i].cnt2, DWC_TIM_LD_CNT2(i));
dwc_pwm_writel(dwc, dwc->ctx[i].ctrl, DWC_TIM_CTRL(i));
}
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(dwc_pwm_pm_ops, dwc_pwm_suspend, dwc_pwm_resume);
static const struct pci_device_id dwc_pwm_id_table[] = {
{ PCI_VDEVICE(INTEL, 0x4bb7) }, /* Elkhart Lake */
{ } /* Terminating Entry */
};
MODULE_DEVICE_TABLE(pci, dwc_pwm_id_table);
static struct pci_driver dwc_pwm_driver = {
.name = "pwm-dwc",
.probe = dwc_pwm_probe,
.remove = dwc_pwm_remove,
.id_table = dwc_pwm_id_table,
.driver = {
.pm = &dwc_pwm_pm_ops,
},
};
module_pci_driver(dwc_pwm_driver);
MODULE_AUTHOR("Felipe Balbi (Intel)");
MODULE_AUTHOR("Jarkko Nikula <jarkko.nikula@linux.intel.com>");
MODULE_AUTHOR("Raymond Tan <raymond.tan@intel.com>");
MODULE_DESCRIPTION("DesignWare PWM Controller");
MODULE_LICENSE("GPL");
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