- 根目录:
- drivers
- pwm
- pwm-samsung.c
/*
* Copyright (c) 2007 Ben Dooks
* Copyright (c) 2008 Simtec Electronics
* Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
* Copyright (c) 2013 Tomasz Figa <tomasz.figa@gmail.com>
*
* PWM driver for Samsung SoCs
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License.
*/
#include <linux/bitops.h>
#include <linux/clk.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/time.h>
/* For struct samsung_timer_variant and samsung_pwm_lock. */
#include <clocksource/samsung_pwm.h>
#define REG_TCFG0 0x00
#define REG_TCFG1 0x04
#define REG_TCON 0x08
#define REG_TCNTB(chan) (0x0c + ((chan) * 0xc))
#define REG_TCMPB(chan) (0x10 + ((chan) * 0xc))
#define TCFG0_PRESCALER_MASK 0xff
#define TCFG0_PRESCALER1_SHIFT 8
#define TCFG1_MUX_MASK 0xf
#define TCFG1_SHIFT(chan) (4 * (chan))
/*
* Each channel occupies 4 bits in TCON register, but there is a gap of 4
* bits (one channel) after channel 0, so channels have different numbering
* when accessing TCON register. See to_tcon_channel() function.
*
* In addition, the location of autoreload bit for channel 4 (TCON channel 5)
* in its set of bits is 2 as opposed to 3 for other channels.
*/
#define TCON_START(chan) BIT(4 * (chan) + 0)
#define TCON_MANUALUPDATE(chan) BIT(4 * (chan) + 1)
#define TCON_INVERT(chan) BIT(4 * (chan) + 2)
#define _TCON_AUTORELOAD(chan) BIT(4 * (chan) + 3)
#define _TCON_AUTORELOAD4(chan) BIT(4 * (chan) + 2)
#define TCON_AUTORELOAD(chan) \
((chan < 5) ? _TCON_AUTORELOAD(chan) : _TCON_AUTORELOAD4(chan))
/**
* struct samsung_pwm_channel - private data of PWM channel
* @period_ns: current period in nanoseconds programmed to the hardware
* @duty_ns: current duty time in nanoseconds programmed to the hardware
* @tin_ns: time of one timer tick in nanoseconds with current timer rate
*/
struct samsung_pwm_channel {
u32 period_ns;
u32 duty_ns;
u32 tin_ns;
};
/**
* struct samsung_pwm_chip - private data of PWM chip
* @chip: generic PWM chip
* @variant: local copy of hardware variant data
* @inverter_mask: inverter status for all channels - one bit per channel
* @base: base address of mapped PWM registers
* @base_clk: base clock used to drive the timers
* @tclk0: external clock 0 (can be ERR_PTR if not present)
* @tclk1: external clock 1 (can be ERR_PTR if not present)
*/
struct samsung_pwm_chip {
struct pwm_chip chip;
struct samsung_pwm_variant variant;
u8 inverter_mask;
void __iomem *base;
struct clk *base_clk;
struct clk *tclk0;
struct clk *tclk1;
};
#ifndef CONFIG_CLKSRC_SAMSUNG_PWM
/*
* PWM block is shared between pwm-samsung and samsung_pwm_timer drivers
* and some registers need access synchronization. If both drivers are
* compiled in, the spinlock is defined in the clocksource driver,
* otherwise following definition is used.
*
* Currently we do not need any more complex synchronization method
* because all the supported SoCs contain only one instance of the PWM
* IP. Should this change, both drivers will need to be modified to
* properly synchronize accesses to particular instances.
*/
static DEFINE_SPINLOCK(samsung_pwm_lock);
#endif
static inline
struct samsung_pwm_chip *to_samsung_pwm_chip(struct pwm_chip *chip)
{
return container_of(chip, struct samsung_pwm_chip, chip);
}
static inline unsigned int to_tcon_channel(unsigned int channel)
{
/* TCON register has a gap of 4 bits (1 channel) after channel 0 */
return (channel == 0) ? 0 : (channel + 1);
}
static void pwm_samsung_set_divisor(struct samsung_pwm_chip *pwm,
unsigned int channel, u8 divisor)
{
u8 shift = TCFG1_SHIFT(channel);
unsigned long flags;
u32 reg;
u8 bits;
bits = (fls(divisor) - 1) - pwm->variant.div_base;
spin_lock_irqsave(&samsung_pwm_lock, flags);
reg = readl(pwm->base + REG_TCFG1);
reg &= ~(TCFG1_MUX_MASK << shift);
reg |= bits << shift;
writel(reg, pwm->base + REG_TCFG1);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static int pwm_samsung_is_tdiv(struct samsung_pwm_chip *chip, unsigned int chan)
{
struct samsung_pwm_variant *variant = &chip->variant;
u32 reg;
reg = readl(chip->base + REG_TCFG1);
reg >>= TCFG1_SHIFT(chan);
reg &= TCFG1_MUX_MASK;
return (BIT(reg) & variant->tclk_mask) == 0;
}
static unsigned long pwm_samsung_get_tin_rate(struct samsung_pwm_chip *chip,
unsigned int chan)
{
unsigned long rate;
u32 reg;
rate = clk_get_rate(chip->base_clk);
reg = readl(chip->base + REG_TCFG0);
if (chan >= 2)
reg >>= TCFG0_PRESCALER1_SHIFT;
reg &= TCFG0_PRESCALER_MASK;
return rate / (reg + 1);
}
static unsigned long pwm_samsung_calc_tin(struct samsung_pwm_chip *chip,
unsigned int chan, unsigned long freq)
{
struct samsung_pwm_variant *variant = &chip->variant;
unsigned long rate;
struct clk *clk;
u8 div;
if (!pwm_samsung_is_tdiv(chip, chan)) {
clk = (chan < 2) ? chip->tclk0 : chip->tclk1;
if (!IS_ERR(clk)) {
rate = clk_get_rate(clk);
if (rate)
return rate;
}
dev_warn(chip->chip.dev,
"tclk of PWM %d is inoperational, using tdiv\n", chan);
}
rate = pwm_samsung_get_tin_rate(chip, chan);
dev_dbg(chip->chip.dev, "tin parent at %lu\n", rate);
/*
* Compare minimum PWM frequency that can be achieved with possible
* divider settings and choose the lowest divisor that can generate
* frequencies lower than requested.
*/
for (div = variant->div_base; div < 4; ++div)
if ((rate >> (variant->bits + div)) < freq)
break;
pwm_samsung_set_divisor(chip, chan, BIT(div));
return rate >> div;
}
static int pwm_samsung_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
struct samsung_pwm_channel *our_chan;
if (!(our_chip->variant.output_mask & BIT(pwm->hwpwm))) {
dev_warn(chip->dev,
"tried to request PWM channel %d without output\n",
pwm->hwpwm);
return -EINVAL;
}
our_chan = devm_kzalloc(chip->dev, sizeof(*our_chan), GFP_KERNEL);
if (!our_chan)
return -ENOMEM;
pwm_set_chip_data(pwm, our_chan);
return 0;
}
static void pwm_samsung_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
devm_kfree(chip->dev, pwm_get_chip_data(pwm));
pwm_set_chip_data(pwm, NULL);
}
static int pwm_samsung_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
unsigned long flags;
u32 tcon;
spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl(our_chip->base + REG_TCON);
tcon &= ~TCON_START(tcon_chan);
tcon |= TCON_MANUALUPDATE(tcon_chan);
writel(tcon, our_chip->base + REG_TCON);
tcon &= ~TCON_MANUALUPDATE(tcon_chan);
tcon |= TCON_START(tcon_chan) | TCON_AUTORELOAD(tcon_chan);
writel(tcon, our_chip->base + REG_TCON);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
return 0;
}
static void pwm_samsung_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
unsigned int tcon_chan = to_tcon_channel(pwm->hwpwm);
unsigned long flags;
u32 tcon;
spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl(our_chip->base + REG_TCON);
tcon &= ~TCON_AUTORELOAD(tcon_chan);
writel(tcon, our_chip->base + REG_TCON);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static int pwm_samsung_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
u32 tin_ns = chan->tin_ns, tcnt, tcmp;
/*
* We currently avoid using 64bit arithmetic by using the
* fact that anything faster than 1Hz is easily representable
* by 32bits.
*/
if (period_ns > NSEC_PER_SEC)
return -ERANGE;
if (period_ns == chan->period_ns && duty_ns == chan->duty_ns)
return 0;
tcnt = readl(our_chip->base + REG_TCNTB(pwm->hwpwm));
/* We need tick count for calculation, not last tick. */
++tcnt;
/* Check to see if we are changing the clock rate of the PWM. */
if (chan->period_ns != period_ns) {
unsigned long tin_rate;
u32 period;
period = NSEC_PER_SEC / period_ns;
dev_dbg(our_chip->chip.dev, "duty_ns=%d, period_ns=%d (%u)\n",
duty_ns, period_ns, period);
tin_rate = pwm_samsung_calc_tin(our_chip, pwm->hwpwm, period);
dev_dbg(our_chip->chip.dev, "tin_rate=%lu\n", tin_rate);
tin_ns = NSEC_PER_SEC / tin_rate;
tcnt = period_ns / tin_ns;
}
/* Period is too short. */
if (tcnt <= 1)
return -ERANGE;
/* Note that counters count down. */
tcmp = duty_ns / tin_ns;
/* 0% duty is not available */
if (!tcmp)
++tcmp;
tcmp = tcnt - tcmp;
/* Decrement to get tick numbers, instead of tick counts. */
--tcnt;
/* -1UL will give 100% duty. */
--tcmp;
dev_dbg(our_chip->chip.dev,
"tin_ns=%u, tcmp=%u/%u\n", tin_ns, tcmp, tcnt);
/* Update PWM registers. */
writel(tcnt, our_chip->base + REG_TCNTB(pwm->hwpwm));
writel(tcmp, our_chip->base + REG_TCMPB(pwm->hwpwm));
if (test_bit(PWMF_ENABLED, &pwm->flags))
pwm_samsung_enable(chip, pwm);
chan->period_ns = period_ns;
chan->tin_ns = tin_ns;
chan->duty_ns = duty_ns;
return 0;
}
static void pwm_samsung_set_invert(struct samsung_pwm_chip *chip,
unsigned int channel, bool invert)
{
unsigned int tcon_chan = to_tcon_channel(channel);
unsigned long flags;
u32 tcon;
spin_lock_irqsave(&samsung_pwm_lock, flags);
tcon = readl(chip->base + REG_TCON);
if (invert) {
chip->inverter_mask |= BIT(channel);
tcon |= TCON_INVERT(tcon_chan);
} else {
chip->inverter_mask &= ~BIT(channel);
tcon &= ~TCON_INVERT(tcon_chan);
}
writel(tcon, chip->base + REG_TCON);
spin_unlock_irqrestore(&samsung_pwm_lock, flags);
}
static int pwm_samsung_set_polarity(struct pwm_chip *chip,
struct pwm_device *pwm,
enum pwm_polarity polarity)
{
struct samsung_pwm_chip *our_chip = to_samsung_pwm_chip(chip);
bool invert = (polarity == PWM_POLARITY_NORMAL);
/* Inverted means normal in the hardware. */
pwm_samsung_set_invert(our_chip, pwm->hwpwm, invert);
return 0;
}
static const struct pwm_ops pwm_samsung_ops = {
.request = pwm_samsung_request,
.free = pwm_samsung_free,
.enable = pwm_samsung_enable,
.disable = pwm_samsung_disable,
.config = pwm_samsung_config,
.set_polarity = pwm_samsung_set_polarity,
.owner = THIS_MODULE,
};
#ifdef CONFIG_OF
static const struct samsung_pwm_variant s3c24xx_variant = {
.bits = 16,
.div_base = 1,
.has_tint_cstat = false,
.tclk_mask = BIT(4),
};
static const struct samsung_pwm_variant s3c64xx_variant = {
.bits = 32,
.div_base = 0,
.has_tint_cstat = true,
.tclk_mask = BIT(7) | BIT(6) | BIT(5),
};
static const struct samsung_pwm_variant s5p64x0_variant = {
.bits = 32,
.div_base = 0,
.has_tint_cstat = true,
.tclk_mask = 0,
};
static const struct samsung_pwm_variant s5pc100_variant = {
.bits = 32,
.div_base = 0,
.has_tint_cstat = true,
.tclk_mask = BIT(5),
};
static const struct of_device_id samsung_pwm_matches[] = {
{ .compatible = "samsung,s3c2410-pwm", .data = &s3c24xx_variant },
{ .compatible = "samsung,s3c6400-pwm", .data = &s3c64xx_variant },
{ .compatible = "samsung,s5p6440-pwm", .data = &s5p64x0_variant },
{ .compatible = "samsung,s5pc100-pwm", .data = &s5pc100_variant },
{ .compatible = "samsung,exynos4210-pwm", .data = &s5p64x0_variant },
{},
};
static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip)
{
struct device_node *np = chip->chip.dev->of_node;
const struct of_device_id *match;
struct property *prop;
const __be32 *cur;
u32 val;
match = of_match_node(samsung_pwm_matches, np);
if (!match)
return -ENODEV;
memcpy(&chip->variant, match->data, sizeof(chip->variant));
of_property_for_each_u32(np, "samsung,pwm-outputs", prop, cur, val) {
if (val >= SAMSUNG_PWM_NUM) {
dev_err(chip->chip.dev,
"%s: invalid channel index in samsung,pwm-outputs property\n",
__func__);
continue;
}
chip->variant.output_mask |= BIT(val);
}
return 0;
}
#else
static int pwm_samsung_parse_dt(struct samsung_pwm_chip *chip)
{
return -ENODEV;
}
#endif
static int pwm_samsung_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct samsung_pwm_chip *chip;
struct resource *res;
unsigned int chan;
int ret;
chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
if (chip == NULL)
return -ENOMEM;
chip->chip.dev = &pdev->dev;
chip->chip.ops = &pwm_samsung_ops;
chip->chip.base = -1;
chip->chip.npwm = SAMSUNG_PWM_NUM;
chip->inverter_mask = BIT(SAMSUNG_PWM_NUM) - 1;
if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) {
ret = pwm_samsung_parse_dt(chip);
if (ret)
return ret;
chip->chip.of_xlate = of_pwm_xlate_with_flags;
chip->chip.of_pwm_n_cells = 3;
} else {
if (!pdev->dev.platform_data) {
dev_err(&pdev->dev, "no platform data specified\n");
return -EINVAL;
}
memcpy(&chip->variant, pdev->dev.platform_data,
sizeof(chip->variant));
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
chip->base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(chip->base))
return PTR_ERR(chip->base);
chip->base_clk = devm_clk_get(&pdev->dev, "timers");
if (IS_ERR(chip->base_clk)) {
dev_err(dev, "failed to get timer base clk\n");
return PTR_ERR(chip->base_clk);
}
ret = clk_prepare_enable(chip->base_clk);
if (ret < 0) {
dev_err(dev, "failed to enable base clock\n");
return ret;
}
for (chan = 0; chan < SAMSUNG_PWM_NUM; ++chan)
if (chip->variant.output_mask & BIT(chan))
pwm_samsung_set_invert(chip, chan, true);
/* Following clocks are optional. */
chip->tclk0 = devm_clk_get(&pdev->dev, "pwm-tclk0");
chip->tclk1 = devm_clk_get(&pdev->dev, "pwm-tclk1");
platform_set_drvdata(pdev, chip);
ret = pwmchip_add(&chip->chip);
if (ret < 0) {
dev_err(dev, "failed to register PWM chip\n");
clk_disable_unprepare(chip->base_clk);
return ret;
}
dev_dbg(dev, "base_clk at %lu, tclk0 at %lu, tclk1 at %lu\n",
clk_get_rate(chip->base_clk),
!IS_ERR(chip->tclk0) ? clk_get_rate(chip->tclk0) : 0,
!IS_ERR(chip->tclk1) ? clk_get_rate(chip->tclk1) : 0);
return 0;
}
static int pwm_samsung_remove(struct platform_device *pdev)
{
struct samsung_pwm_chip *chip = platform_get_drvdata(pdev);
int ret;
ret = pwmchip_remove(&chip->chip);
if (ret < 0)
return ret;
clk_disable_unprepare(chip->base_clk);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int pwm_samsung_suspend(struct device *dev)
{
struct samsung_pwm_chip *chip = dev_get_drvdata(dev);
unsigned int i;
/*
* No one preserves these values during suspend so reset them.
* Otherwise driver leaves PWM unconfigured if same values are
* passed to pwm_config() next time.
*/
for (i = 0; i < SAMSUNG_PWM_NUM; ++i) {
struct pwm_device *pwm = &chip->chip.pwms[i];
struct samsung_pwm_channel *chan = pwm_get_chip_data(pwm);
if (!chan)
continue;
chan->period_ns = 0;
chan->duty_ns = 0;
}
return 0;
}
static int pwm_samsung_resume(struct device *dev)
{
struct samsung_pwm_chip *chip = dev_get_drvdata(dev);
unsigned int chan;
/*
* Inverter setting must be preserved across suspend/resume
* as nobody really seems to configure it more than once.
*/
for (chan = 0; chan < SAMSUNG_PWM_NUM; ++chan) {
if (chip->variant.output_mask & BIT(chan))
pwm_samsung_set_invert(chip, chan,
chip->inverter_mask & BIT(chan));
}
return 0;
}
#endif
static const struct dev_pm_ops pwm_samsung_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(pwm_samsung_suspend, pwm_samsung_resume)
};
static struct platform_driver pwm_samsung_driver = {
.driver = {
.name = "samsung-pwm",
.owner = THIS_MODULE,
.pm = &pwm_samsung_pm_ops,
.of_match_table = of_match_ptr(samsung_pwm_matches),
},
.probe = pwm_samsung_probe,
.remove = pwm_samsung_remove,
};
module_platform_driver(pwm_samsung_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Tomasz Figa <tomasz.figa@gmail.com>");
MODULE_ALIAS("platform:samsung-pwm");