linux/drivers/pwm/pwm-mxs.c
Uwe Kleine-König e9fdf122cf pwm: Simplify all drivers with explicit of_pwm_n_cells = 3
With the previous commit there is no need for the lowlevel driver any
more to specify it it uses two or three cells. So simplify accordingly.

The only non-trival change affects the pwm-rockchip driver: It used to only
support three cells if the hardware supports polarity. Now the default
number depends on the device tree which has to match hardware anyhow
(and if it doesn't the error is just a bit delayed as a PWM handle with
an inverted setting is catched when pwm_apply_state() is called).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2021-05-25 18:19:15 +02:00

194 lines
4.6 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright 2012 Freescale Semiconductor, Inc.
*/
#include <linux/clk.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/stmp_device.h>
#define SET 0x4
#define CLR 0x8
#define TOG 0xc
#define PWM_CTRL 0x0
#define PWM_ACTIVE0 0x10
#define PWM_PERIOD0 0x20
#define PERIOD_PERIOD(p) ((p) & 0xffff)
#define PERIOD_PERIOD_MAX 0x10000
#define PERIOD_ACTIVE_HIGH (3 << 16)
#define PERIOD_ACTIVE_LOW (2 << 16)
#define PERIOD_INACTIVE_HIGH (3 << 18)
#define PERIOD_INACTIVE_LOW (2 << 18)
#define PERIOD_POLARITY_NORMAL (PERIOD_ACTIVE_HIGH | PERIOD_INACTIVE_LOW)
#define PERIOD_POLARITY_INVERSE (PERIOD_ACTIVE_LOW | PERIOD_INACTIVE_HIGH)
#define PERIOD_CDIV(div) (((div) & 0x7) << 20)
#define PERIOD_CDIV_MAX 8
static const u8 cdiv_shift[PERIOD_CDIV_MAX] = {
0, 1, 2, 3, 4, 6, 8, 10
};
struct mxs_pwm_chip {
struct pwm_chip chip;
struct clk *clk;
void __iomem *base;
};
#define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip)
static int mxs_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
int ret, div = 0;
unsigned int period_cycles, duty_cycles;
unsigned long rate;
unsigned long long c;
unsigned int pol_bits;
/*
* If the PWM channel is disabled, make sure to turn on the
* clock before calling clk_get_rate() and writing to the
* registers. Otherwise, just keep it enabled.
*/
if (!pwm_is_enabled(pwm)) {
ret = clk_prepare_enable(mxs->clk);
if (ret)
return ret;
}
if (!state->enabled && pwm_is_enabled(pwm))
writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR);
rate = clk_get_rate(mxs->clk);
while (1) {
c = rate >> cdiv_shift[div];
c = c * state->period;
do_div(c, 1000000000);
if (c < PERIOD_PERIOD_MAX)
break;
div++;
if (div >= PERIOD_CDIV_MAX)
return -EINVAL;
}
period_cycles = c;
c *= state->duty_cycle;
do_div(c, state->period);
duty_cycles = c;
/*
* The data sheet the says registers must be written to in
* this order (ACTIVEn, then PERIODn). Also, the new settings
* only take effect at the beginning of a new period, avoiding
* glitches.
*/
pol_bits = state->polarity == PWM_POLARITY_NORMAL ?
PERIOD_POLARITY_NORMAL : PERIOD_POLARITY_INVERSE;
writel(duty_cycles << 16,
mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20);
writel(PERIOD_PERIOD(period_cycles) | pol_bits | PERIOD_CDIV(div),
mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20);
if (state->enabled) {
if (!pwm_is_enabled(pwm)) {
/*
* The clock was enabled above. Just enable
* the channel in the control register.
*/
writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET);
}
} else {
clk_disable_unprepare(mxs->clk);
}
return 0;
}
static const struct pwm_ops mxs_pwm_ops = {
.apply = mxs_pwm_apply,
.owner = THIS_MODULE,
};
static int mxs_pwm_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct mxs_pwm_chip *mxs;
int ret;
mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL);
if (!mxs)
return -ENOMEM;
mxs->base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(mxs->base))
return PTR_ERR(mxs->base);
mxs->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(mxs->clk))
return PTR_ERR(mxs->clk);
mxs->chip.dev = &pdev->dev;
mxs->chip.ops = &mxs_pwm_ops;
ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
if (ret < 0) {
dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret);
return ret;
}
ret = pwmchip_add(&mxs->chip);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, mxs);
ret = stmp_reset_block(mxs->base);
if (ret)
goto pwm_remove;
return 0;
pwm_remove:
pwmchip_remove(&mxs->chip);
return ret;
}
static int mxs_pwm_remove(struct platform_device *pdev)
{
struct mxs_pwm_chip *mxs = platform_get_drvdata(pdev);
return pwmchip_remove(&mxs->chip);
}
static const struct of_device_id mxs_pwm_dt_ids[] = {
{ .compatible = "fsl,imx23-pwm", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, mxs_pwm_dt_ids);
static struct platform_driver mxs_pwm_driver = {
.driver = {
.name = "mxs-pwm",
.of_match_table = mxs_pwm_dt_ids,
},
.probe = mxs_pwm_probe,
.remove = mxs_pwm_remove,
};
module_platform_driver(mxs_pwm_driver);
MODULE_ALIAS("platform:mxs-pwm");
MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
MODULE_DESCRIPTION("Freescale MXS PWM Driver");
MODULE_LICENSE("GPL v2");