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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* ECAP PWM driver
*
* Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/pwm.h>
#include <linux/of.h>
/* ECAP registers and bits definitions */
#define CAP1 0x08
#define CAP2 0x0C
#define CAP3 0x10
#define CAP4 0x14
#define ECCTL2 0x2A
#define ECCTL2_APWM_POL_LOW BIT(10)
#define ECCTL2_APWM_MODE BIT(9)
#define ECCTL2_SYNC_SEL_DISA (BIT(7) | BIT(6))
#define ECCTL2_TSCTR_FREERUN BIT(4)
struct ecap_context {
u32 cap3;
u32 cap4;
u16 ecctl2;
};
struct ecap_pwm_chip {
struct pwm_chip chip;
unsigned int clk_rate;
void __iomem *mmio_base;
struct ecap_context ctx;
};
static inline struct ecap_pwm_chip *to_ecap_pwm_chip(struct pwm_chip *chip)
{
return container_of(chip, struct ecap_pwm_chip, chip);
}
/*
* period_ns = 10^9 * period_cycles / PWM_CLK_RATE
* duty_ns = 10^9 * duty_cycles / PWM_CLK_RATE
*/
static int ecap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns, int enabled)
{
struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
u32 period_cycles, duty_cycles;
unsigned long long c;
u16 value;
c = pc->clk_rate;
c = c * period_ns;
do_div(c, NSEC_PER_SEC);
period_cycles = (u32)c;
if (period_cycles < 1) {
period_cycles = 1;
duty_cycles = 1;
} else {
c = pc->clk_rate;
c = c * duty_ns;
do_div(c, NSEC_PER_SEC);
duty_cycles = (u32)c;
}
pm_runtime_get_sync(pc->chip.dev);
value = readw(pc->mmio_base + ECCTL2);
/* Configure APWM mode & disable sync option */
value |= ECCTL2_APWM_MODE | ECCTL2_SYNC_SEL_DISA;
writew(value, pc->mmio_base + ECCTL2);
if (!enabled) {
/* Update active registers if not running */
writel(duty_cycles, pc->mmio_base + CAP2);
writel(period_cycles, pc->mmio_base + CAP1);
} else {
/*
* Update shadow registers to configure period and
* compare values. This helps current PWM period to
* complete on reconfiguring
*/
writel(duty_cycles, pc->mmio_base + CAP4);
writel(period_cycles, pc->mmio_base + CAP3);
}
if (!enabled) {
value = readw(pc->mmio_base + ECCTL2);
/* Disable APWM mode to put APWM output Low */
value &= ~ECCTL2_APWM_MODE;
writew(value, pc->mmio_base + ECCTL2);
}
pm_runtime_put_sync(pc->chip.dev);
return 0;
}
static int ecap_pwm_set_polarity(struct pwm_chip *chip, struct pwm_device *pwm,
enum pwm_polarity polarity)
{
struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
u16 value;
pm_runtime_get_sync(pc->chip.dev);
value = readw(pc->mmio_base + ECCTL2);
if (polarity == PWM_POLARITY_INVERSED)
/* Duty cycle defines LOW period of PWM */
value |= ECCTL2_APWM_POL_LOW;
else
/* Duty cycle defines HIGH period of PWM */
value &= ~ECCTL2_APWM_POL_LOW;
writew(value, pc->mmio_base + ECCTL2);
pm_runtime_put_sync(pc->chip.dev);
return 0;
}
static int ecap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
u16 value;
/* Leave clock enabled on enabling PWM */
pm_runtime_get_sync(pc->chip.dev);
/*
* Enable 'Free run Time stamp counter mode' to start counter
* and 'APWM mode' to enable APWM output
*/
value = readw(pc->mmio_base + ECCTL2);
value |= ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE;
writew(value, pc->mmio_base + ECCTL2);
return 0;
}
static void ecap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ecap_pwm_chip *pc = to_ecap_pwm_chip(chip);
u16 value;
/*
* Disable 'Free run Time stamp counter mode' to stop counter
* and 'APWM mode' to put APWM output to low
*/
value = readw(pc->mmio_base + ECCTL2);
value &= ~(ECCTL2_TSCTR_FREERUN | ECCTL2_APWM_MODE);
writew(value, pc->mmio_base + ECCTL2);
/* Disable clock on PWM disable */
pm_runtime_put_sync(pc->chip.dev);
}
static int ecap_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
int err;
int enabled = pwm->state.enabled;
if (state->polarity != pwm->state.polarity) {
if (enabled) {
ecap_pwm_disable(chip, pwm);
enabled = false;
}
err = ecap_pwm_set_polarity(chip, pwm, state->polarity);
if (err)
return err;
}
if (!state->enabled) {
if (enabled)
ecap_pwm_disable(chip, pwm);
return 0;
}
if (state->period > NSEC_PER_SEC)
return -ERANGE;
err = ecap_pwm_config(chip, pwm, state->duty_cycle,
state->period, enabled);
if (err)
return err;
if (!enabled)
return ecap_pwm_enable(chip, pwm);
return 0;
}
static const struct pwm_ops ecap_pwm_ops = {
.apply = ecap_pwm_apply,
};
static const struct of_device_id ecap_of_match[] = {
{ .compatible = "ti,am3352-ecap" },
{ .compatible = "ti,am33xx-ecap" },
{},
};
MODULE_DEVICE_TABLE(of, ecap_of_match);
static int ecap_pwm_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct ecap_pwm_chip *pc;
struct clk *clk;
int ret;
pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
if (!pc)
return -ENOMEM;
clk = devm_clk_get(&pdev->dev, "fck");
if (IS_ERR(clk)) {
if (of_device_is_compatible(np, "ti,am33xx-ecap")) {
dev_warn(&pdev->dev, "Binding is obsolete.\n");
clk = devm_clk_get(pdev->dev.parent, "fck");
}
}
if (IS_ERR(clk)) {
dev_err(&pdev->dev, "failed to get clock\n");
return PTR_ERR(clk);
}
pc->clk_rate = clk_get_rate(clk);
if (!pc->clk_rate) {
dev_err(&pdev->dev, "failed to get clock rate\n");
return -EINVAL;
}
pc->chip.dev = &pdev->dev;
pc->chip.ops = &ecap_pwm_ops;
pc->chip.npwm = 1;
pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pc->mmio_base))
return PTR_ERR(pc->mmio_base);
ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
return ret;
}
platform_set_drvdata(pdev, pc);
pm_runtime_enable(&pdev->dev);
return 0;
}
static void ecap_pwm_remove(struct platform_device *pdev)
{
pm_runtime_disable(&pdev->dev);
}
#ifdef CONFIG_PM_SLEEP
static void ecap_pwm_save_context(struct ecap_pwm_chip *pc)
{
pm_runtime_get_sync(pc->chip.dev);
pc->ctx.ecctl2 = readw(pc->mmio_base + ECCTL2);
pc->ctx.cap4 = readl(pc->mmio_base + CAP4);
pc->ctx.cap3 = readl(pc->mmio_base + CAP3);
pm_runtime_put_sync(pc->chip.dev);
}
static void ecap_pwm_restore_context(struct ecap_pwm_chip *pc)
{
writel(pc->ctx.cap3, pc->mmio_base + CAP3);
writel(pc->ctx.cap4, pc->mmio_base + CAP4);
writew(pc->ctx.ecctl2, pc->mmio_base + ECCTL2);
}
static int ecap_pwm_suspend(struct device *dev)
{
struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
struct pwm_device *pwm = pc->chip.pwms;
ecap_pwm_save_context(pc);
/* Disable explicitly if PWM is running */
if (pwm_is_enabled(pwm))
pm_runtime_put_sync(dev);
return 0;
}
static int ecap_pwm_resume(struct device *dev)
{
struct ecap_pwm_chip *pc = dev_get_drvdata(dev);
struct pwm_device *pwm = pc->chip.pwms;
/* Enable explicitly if PWM was running */
if (pwm_is_enabled(pwm))
pm_runtime_get_sync(dev);
ecap_pwm_restore_context(pc);
return 0;
}
#endif
static SIMPLE_DEV_PM_OPS(ecap_pwm_pm_ops, ecap_pwm_suspend, ecap_pwm_resume);
static struct platform_driver ecap_pwm_driver = {
.driver = {
.name = "ecap",
.of_match_table = ecap_of_match,
.pm = &ecap_pwm_pm_ops,
},
.probe = ecap_pwm_probe,
.remove_new = ecap_pwm_remove,
};
module_platform_driver(ecap_pwm_driver);
MODULE_DESCRIPTION("ECAP PWM driver");
MODULE_AUTHOR("Texas Instruments");
MODULE_LICENSE("GPL");
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