// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2016 Broadcom
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/math64.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#define IPROC_PWM_CTRL_OFFSET 0x00
#define IPROC_PWM_CTRL_TYPE_SHIFT(ch) (15 + (ch))
#define IPROC_PWM_CTRL_POLARITY_SHIFT(ch) (8 + (ch))
#define IPROC_PWM_CTRL_EN_SHIFT(ch) (ch)
#define IPROC_PWM_PERIOD_OFFSET(ch) (0x04 + ((ch) << 3))
#define IPROC_PWM_PERIOD_MIN 0x02
#define IPROC_PWM_PERIOD_MAX 0xffff
#define IPROC_PWM_DUTY_CYCLE_OFFSET(ch) (0x08 + ((ch) << 3))
#define IPROC_PWM_DUTY_CYCLE_MIN 0x00
#define IPROC_PWM_DUTY_CYCLE_MAX 0xffff
#define IPROC_PWM_PRESCALE_OFFSET 0x24
#define IPROC_PWM_PRESCALE_BITS 0x06
#define IPROC_PWM_PRESCALE_SHIFT(ch) ((3 - (ch)) * \
IPROC_PWM_PRESCALE_BITS)
#define IPROC_PWM_PRESCALE_MASK(ch) (IPROC_PWM_PRESCALE_MAX << \
IPROC_PWM_PRESCALE_SHIFT(ch))
#define IPROC_PWM_PRESCALE_MIN 0x00
#define IPROC_PWM_PRESCALE_MAX 0x3f
struct iproc_pwmc {
void __iomem *base;
struct clk *clk;
};
static inline struct iproc_pwmc *to_iproc_pwmc(struct pwm_chip *chip)
{
return pwmchip_get_drvdata(chip);
}
static void iproc_pwmc_enable(struct iproc_pwmc *ip, unsigned int channel)
{
u32 value;
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
value |= 1 << IPROC_PWM_CTRL_EN_SHIFT(channel);
writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
/* must be a 400 ns delay between clearing and setting enable bit */
ndelay(400);
}
static void iproc_pwmc_disable(struct iproc_pwmc *ip, unsigned int channel)
{
u32 value;
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
value &= ~(1 << IPROC_PWM_CTRL_EN_SHIFT(channel));
writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
/* must be a 400 ns delay between clearing and setting enable bit */
ndelay(400);
}
static int iproc_pwmc_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
struct pwm_state *state)
{
struct iproc_pwmc *ip = to_iproc_pwmc(chip);
u64 tmp, multi, rate;
u32 value, prescale;
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
if (value & BIT(IPROC_PWM_CTRL_EN_SHIFT(pwm->hwpwm)))
state->enabled = true;
else
state->enabled = false;
if (value & BIT(IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm)))
state->polarity = PWM_POLARITY_NORMAL;
else
state->polarity = PWM_POLARITY_INVERSED;
rate = clk_get_rate(ip->clk);
if (rate == 0) {
state->period = 0;
state->duty_cycle = 0;
return 0;
}
value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
prescale = value >> IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
prescale &= IPROC_PWM_PRESCALE_MAX;
multi = NSEC_PER_SEC * (prescale + 1);
value = readl(ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
state->period = div64_u64(tmp, rate);
value = readl(ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
tmp = (value & IPROC_PWM_PERIOD_MAX) * multi;
state->duty_cycle = div64_u64(tmp, rate);
return 0;
}
static int iproc_pwmc_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
unsigned long prescale = IPROC_PWM_PRESCALE_MIN;
struct iproc_pwmc *ip = to_iproc_pwmc(chip);
u32 value, period, duty;
u64 rate;
rate = clk_get_rate(ip->clk);
/*
* Find period count, duty count and prescale to suit duty_cycle and
* period. This is done according to formulas described below:
*
* period_ns = 10^9 * (PRESCALE + 1) * PC / PWM_CLK_RATE
* duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE
*
* PC = (PWM_CLK_RATE * period_ns) / (10^9 * (PRESCALE + 1))
* DC = (PWM_CLK_RATE * duty_ns) / (10^9 * (PRESCALE + 1))
*/
while (1) {
u64 value, div;
div = NSEC_PER_SEC * (prescale + 1);
value = rate * state->period;
period = div64_u64(value, div);
value = rate * state->duty_cycle;
duty = div64_u64(value, div);
if (period < IPROC_PWM_PERIOD_MIN)
return -EINVAL;
if (period <= IPROC_PWM_PERIOD_MAX &&
duty <= IPROC_PWM_DUTY_CYCLE_MAX)
break;
/* Otherwise, increase prescale and recalculate counts */
if (++prescale > IPROC_PWM_PRESCALE_MAX)
return -EINVAL;
}
iproc_pwmc_disable(ip, pwm->hwpwm);
/* Set prescale */
value = readl(ip->base + IPROC_PWM_PRESCALE_OFFSET);
value &= ~IPROC_PWM_PRESCALE_MASK(pwm->hwpwm);
value |= prescale << IPROC_PWM_PRESCALE_SHIFT(pwm->hwpwm);
writel(value, ip->base + IPROC_PWM_PRESCALE_OFFSET);
/* set period and duty cycle */
writel(period, ip->base + IPROC_PWM_PERIOD_OFFSET(pwm->hwpwm));
writel(duty, ip->base + IPROC_PWM_DUTY_CYCLE_OFFSET(pwm->hwpwm));
/* set polarity */
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
if (state->polarity == PWM_POLARITY_NORMAL)
value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm);
else
value &= ~(1 << IPROC_PWM_CTRL_POLARITY_SHIFT(pwm->hwpwm));
writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
if (state->enabled)
iproc_pwmc_enable(ip, pwm->hwpwm);
return 0;
}
static const struct pwm_ops iproc_pwm_ops = {
.apply = iproc_pwmc_apply,
.get_state = iproc_pwmc_get_state,
};
static int iproc_pwmc_probe(struct platform_device *pdev)
{
struct pwm_chip *chip;
struct iproc_pwmc *ip;
unsigned int i;
u32 value;
int ret;
chip = devm_pwmchip_alloc(&pdev->dev, 4, sizeof(*ip));
if (IS_ERR(chip))
return PTR_ERR(chip);
ip = to_iproc_pwmc(chip);
platform_set_drvdata(pdev, ip);
chip->ops = &iproc_pwm_ops;
ip->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(ip->base))
return PTR_ERR(ip->base);
ip->clk = devm_clk_get_enabled(&pdev->dev, NULL);
if (IS_ERR(ip->clk))
return dev_err_probe(&pdev->dev, PTR_ERR(ip->clk),
"failed to get clock\n");
/* Set full drive and normal polarity for all channels */
value = readl(ip->base + IPROC_PWM_CTRL_OFFSET);
for (i = 0; i < chip->npwm; i++) {
value &= ~(1 << IPROC_PWM_CTRL_TYPE_SHIFT(i));
value |= 1 << IPROC_PWM_CTRL_POLARITY_SHIFT(i);
}
writel(value, ip->base + IPROC_PWM_CTRL_OFFSET);
ret = devm_pwmchip_add(&pdev->dev, chip);
if (ret < 0)
return dev_err_probe(&pdev->dev, ret,
"failed to add PWM chip\n");
return 0;
}
static const struct of_device_id bcm_iproc_pwmc_dt[] = {
{ .compatible = "brcm,iproc-pwm" },
{ },
};
MODULE_DEVICE_TABLE(of, bcm_iproc_pwmc_dt);
static struct platform_driver iproc_pwmc_driver = {
.driver = {
.name = "bcm-iproc-pwm",
.of_match_table = bcm_iproc_pwmc_dt,
},
.probe = iproc_pwmc_probe,
};
module_platform_driver(iproc_pwmc_driver);
MODULE_AUTHOR("Yendapally Reddy Dhananjaya Reddy <[email protected]>");
MODULE_DESCRIPTION("Broadcom iProc PWM driver");
MODULE_LICENSE("GPL v2");
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