// SPDX-License-Identifier: GPL-2.0-or-later
/*
* EHRPWM PWM driver
*
* Copyright (C) 2012 Texas Instruments, Inc. - https://www.ti.com/
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/io.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
/* EHRPWM registers and bits definitions */
/* Time base module registers */
#define TBCTL 0x00
#define TBPRD 0x0A
#define TBCTL_PRDLD_MASK BIT(3)
#define TBCTL_PRDLD_SHDW 0
#define TBCTL_PRDLD_IMDT BIT(3)
#define TBCTL_CLKDIV_MASK (BIT(12) | BIT(11) | BIT(10) | BIT(9) | \
BIT(8) | BIT(7))
#define TBCTL_CTRMODE_MASK (BIT(1) | BIT(0))
#define TBCTL_CTRMODE_UP 0
#define TBCTL_CTRMODE_DOWN BIT(0)
#define TBCTL_CTRMODE_UPDOWN BIT(1)
#define TBCTL_CTRMODE_FREEZE (BIT(1) | BIT(0))
#define TBCTL_HSPCLKDIV_SHIFT 7
#define TBCTL_CLKDIV_SHIFT 10
#define CLKDIV_MAX 7
#define HSPCLKDIV_MAX 7
#define PERIOD_MAX 0xFFFF
/* compare module registers */
#define CMPA 0x12
#define CMPB 0x14
/* Action qualifier module registers */
#define AQCTLA 0x16
#define AQCTLB 0x18
#define AQSFRC 0x1A
#define AQCSFRC 0x1C
#define AQCTL_CBU_MASK (BIT(9) | BIT(8))
#define AQCTL_CBU_FRCLOW BIT(8)
#define AQCTL_CBU_FRCHIGH BIT(9)
#define AQCTL_CBU_FRCTOGGLE (BIT(9) | BIT(8))
#define AQCTL_CAU_MASK (BIT(5) | BIT(4))
#define AQCTL_CAU_FRCLOW BIT(4)
#define AQCTL_CAU_FRCHIGH BIT(5)
#define AQCTL_CAU_FRCTOGGLE (BIT(5) | BIT(4))
#define AQCTL_PRD_MASK (BIT(3) | BIT(2))
#define AQCTL_PRD_FRCLOW BIT(2)
#define AQCTL_PRD_FRCHIGH BIT(3)
#define AQCTL_PRD_FRCTOGGLE (BIT(3) | BIT(2))
#define AQCTL_ZRO_MASK (BIT(1) | BIT(0))
#define AQCTL_ZRO_FRCLOW BIT(0)
#define AQCTL_ZRO_FRCHIGH BIT(1)
#define AQCTL_ZRO_FRCTOGGLE (BIT(1) | BIT(0))
#define AQCTL_CHANA_POLNORMAL (AQCTL_CAU_FRCLOW | AQCTL_PRD_FRCHIGH | \
AQCTL_ZRO_FRCHIGH)
#define AQCTL_CHANA_POLINVERSED (AQCTL_CAU_FRCHIGH | AQCTL_PRD_FRCLOW | \
AQCTL_ZRO_FRCLOW)
#define AQCTL_CHANB_POLNORMAL (AQCTL_CBU_FRCLOW | AQCTL_PRD_FRCHIGH | \
AQCTL_ZRO_FRCHIGH)
#define AQCTL_CHANB_POLINVERSED (AQCTL_CBU_FRCHIGH | AQCTL_PRD_FRCLOW | \
AQCTL_ZRO_FRCLOW)
#define AQSFRC_RLDCSF_MASK (BIT(7) | BIT(6))
#define AQSFRC_RLDCSF_ZRO 0
#define AQSFRC_RLDCSF_PRD BIT(6)
#define AQSFRC_RLDCSF_ZROPRD BIT(7)
#define AQSFRC_RLDCSF_IMDT (BIT(7) | BIT(6))
#define AQCSFRC_CSFB_MASK (BIT(3) | BIT(2))
#define AQCSFRC_CSFB_FRCDIS 0
#define AQCSFRC_CSFB_FRCLOW BIT(2)
#define AQCSFRC_CSFB_FRCHIGH BIT(3)
#define AQCSFRC_CSFB_DISSWFRC (BIT(3) | BIT(2))
#define AQCSFRC_CSFA_MASK (BIT(1) | BIT(0))
#define AQCSFRC_CSFA_FRCDIS 0
#define AQCSFRC_CSFA_FRCLOW BIT(0)
#define AQCSFRC_CSFA_FRCHIGH BIT(1)
#define AQCSFRC_CSFA_DISSWFRC (BIT(1) | BIT(0))
#define NUM_PWM_CHANNEL 2 /* EHRPWM channels */
struct ehrpwm_context {
u16 tbctl;
u16 tbprd;
u16 cmpa;
u16 cmpb;
u16 aqctla;
u16 aqctlb;
u16 aqsfrc;
u16 aqcsfrc;
};
struct ehrpwm_pwm_chip {
unsigned long clk_rate;
void __iomem *mmio_base;
unsigned long period_cycles[NUM_PWM_CHANNEL];
enum pwm_polarity polarity[NUM_PWM_CHANNEL];
struct clk *tbclk;
struct ehrpwm_context ctx;
};
static inline struct ehrpwm_pwm_chip *to_ehrpwm_pwm_chip(struct pwm_chip *chip)
{
return pwmchip_get_drvdata(chip);
}
static inline u16 ehrpwm_read(void __iomem *base, unsigned int offset)
{
return readw(base + offset);
}
static inline void ehrpwm_write(void __iomem *base, unsigned int offset,
u16 value)
{
writew(value, base + offset);
}
static void ehrpwm_modify(void __iomem *base, unsigned int offset, u16 mask,
u16 value)
{
unsigned short val;
val = readw(base + offset);
val &= ~mask;
val |= value & mask;
writew(val, base + offset);
}
/**
* set_prescale_div - Set up the prescaler divider function
* @rqst_prescaler: prescaler value min
* @prescale_div: prescaler value set
* @tb_clk_div: Time Base Control prescaler bits
*/
static int set_prescale_div(unsigned long rqst_prescaler, u16 *prescale_div,
u16 *tb_clk_div)
{
unsigned int clkdiv, hspclkdiv;
for (clkdiv = 0; clkdiv <= CLKDIV_MAX; clkdiv++) {
for (hspclkdiv = 0; hspclkdiv <= HSPCLKDIV_MAX; hspclkdiv++) {
/*
* calculations for prescaler value :
* prescale_div = HSPCLKDIVIDER * CLKDIVIDER.
* HSPCLKDIVIDER = 2 ** hspclkdiv
* CLKDIVIDER = (1), if clkdiv == 0 *OR*
* (2 * clkdiv), if clkdiv != 0
*
* Configure prescale_div value such that period
* register value is less than 65535.
*/
*prescale_div = (1 << clkdiv) *
(hspclkdiv ? (hspclkdiv * 2) : 1);
if (*prescale_div > rqst_prescaler) {
*tb_clk_div = (clkdiv << TBCTL_CLKDIV_SHIFT) |
(hspclkdiv << TBCTL_HSPCLKDIV_SHIFT);
return 0;
}
}
}
return 1;
}
static void configure_polarity(struct ehrpwm_pwm_chip *pc, int chan)
{
u16 aqctl_val, aqctl_mask;
unsigned int aqctl_reg;
/*
* Configure PWM output to HIGH/LOW level on counter
* reaches compare register value and LOW/HIGH level
* on counter value reaches period register value and
* zero value on counter
*/
if (chan == 1) {
aqctl_reg = AQCTLB;
aqctl_mask = AQCTL_CBU_MASK;
if (pc->polarity[chan] == PWM_POLARITY_INVERSED)
aqctl_val = AQCTL_CHANB_POLINVERSED;
else
aqctl_val = AQCTL_CHANB_POLNORMAL;
} else {
aqctl_reg = AQCTLA;
aqctl_mask = AQCTL_CAU_MASK;
if (pc->polarity[chan] == PWM_POLARITY_INVERSED)
aqctl_val = AQCTL_CHANA_POLINVERSED;
else
aqctl_val = AQCTL_CHANA_POLNORMAL;
}
aqctl_mask |= AQCTL_PRD_MASK | AQCTL_ZRO_MASK;
ehrpwm_modify(pc->mmio_base, aqctl_reg, aqctl_mask, aqctl_val);
}
/*
* period_ns = 10^9 * (ps_divval * period_cycles) / PWM_CLK_RATE
* duty_ns = 10^9 * (ps_divval * duty_cycles) / PWM_CLK_RATE
*/
static int ehrpwm_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
u64 duty_ns, u64 period_ns)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
u32 period_cycles, duty_cycles;
u16 ps_divval, tb_divval;
unsigned int i, cmp_reg;
unsigned long long c;
if (period_ns > NSEC_PER_SEC)
return -ERANGE;
c = pc->clk_rate;
c = c * period_ns;
do_div(c, NSEC_PER_SEC);
period_cycles = (unsigned long)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 = (unsigned long)c;
}
/*
* Period values should be same for multiple PWM channels as IP uses
* same period register for multiple channels.
*/
for (i = 0; i < NUM_PWM_CHANNEL; i++) {
if (pc->period_cycles[i] &&
(pc->period_cycles[i] != period_cycles)) {
/*
* Allow channel to reconfigure period if no other
* channels being configured.
*/
if (i == pwm->hwpwm)
continue;
dev_err(pwmchip_parent(chip),
"period value conflicts with channel %u\n",
i);
return -EINVAL;
}
}
pc->period_cycles[pwm->hwpwm] = period_cycles;
/* Configure clock prescaler to support Low frequency PWM wave */
if (set_prescale_div(period_cycles/PERIOD_MAX, &ps_divval,
&tb_divval)) {
dev_err(pwmchip_parent(chip), "Unsupported values\n");
return -EINVAL;
}
pm_runtime_get_sync(pwmchip_parent(chip));
/* Update clock prescaler values */
ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CLKDIV_MASK, tb_divval);
/* Update period & duty cycle with presacler division */
period_cycles = period_cycles / ps_divval;
duty_cycles = duty_cycles / ps_divval;
/* Configure shadow loading on Period register */
ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_PRDLD_MASK, TBCTL_PRDLD_SHDW);
ehrpwm_write(pc->mmio_base, TBPRD, period_cycles);
/* Configure ehrpwm counter for up-count mode */
ehrpwm_modify(pc->mmio_base, TBCTL, TBCTL_CTRMODE_MASK,
TBCTL_CTRMODE_UP);
if (pwm->hwpwm == 1)
/* Channel 1 configured with compare B register */
cmp_reg = CMPB;
else
/* Channel 0 configured with compare A register */
cmp_reg = CMPA;
ehrpwm_write(pc->mmio_base, cmp_reg, duty_cycles);
pm_runtime_put_sync(pwmchip_parent(chip));
return 0;
}
static int ehrpwm_pwm_set_polarity(struct pwm_chip *chip,
struct pwm_device *pwm,
enum pwm_polarity polarity)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
/* Configuration of polarity in hardware delayed, do at enable */
pc->polarity[pwm->hwpwm] = polarity;
return 0;
}
static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
u16 aqcsfrc_val, aqcsfrc_mask;
int ret;
/* Leave clock enabled on enabling PWM */
pm_runtime_get_sync(pwmchip_parent(chip));
/* Disabling Action Qualifier on PWM output */
if (pwm->hwpwm) {
aqcsfrc_val = AQCSFRC_CSFB_FRCDIS;
aqcsfrc_mask = AQCSFRC_CSFB_MASK;
} else {
aqcsfrc_val = AQCSFRC_CSFA_FRCDIS;
aqcsfrc_mask = AQCSFRC_CSFA_MASK;
}
/* Changes to shadow mode */
ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
AQSFRC_RLDCSF_ZRO);
ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
/* Channels polarity can be configured from action qualifier module */
configure_polarity(pc, pwm->hwpwm);
/* Enable TBCLK */
ret = clk_enable(pc->tbclk);
if (ret) {
dev_err(pwmchip_parent(chip), "Failed to enable TBCLK for %s: %d\n",
dev_name(pwmchip_parent(chip)), ret);
return ret;
}
return 0;
}
static void ehrpwm_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
u16 aqcsfrc_val, aqcsfrc_mask;
/* Action Qualifier puts PWM output low forcefully */
if (pwm->hwpwm) {
aqcsfrc_val = AQCSFRC_CSFB_FRCLOW;
aqcsfrc_mask = AQCSFRC_CSFB_MASK;
} else {
aqcsfrc_val = AQCSFRC_CSFA_FRCLOW;
aqcsfrc_mask = AQCSFRC_CSFA_MASK;
}
/* Update shadow register first before modifying active register */
ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
AQSFRC_RLDCSF_ZRO);
ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
/*
* Changes to immediate action on Action Qualifier. This puts
* Action Qualifier control on PWM output from next TBCLK
*/
ehrpwm_modify(pc->mmio_base, AQSFRC, AQSFRC_RLDCSF_MASK,
AQSFRC_RLDCSF_IMDT);
ehrpwm_modify(pc->mmio_base, AQCSFRC, aqcsfrc_mask, aqcsfrc_val);
/* Disabling TBCLK on PWM disable */
clk_disable(pc->tbclk);
/* Disable clock on PWM disable */
pm_runtime_put_sync(pwmchip_parent(chip));
}
static void ehrpwm_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
if (pwm_is_enabled(pwm)) {
dev_warn(pwmchip_parent(chip), "Removing PWM device without disabling\n");
pm_runtime_put_sync(pwmchip_parent(chip));
}
/* set period value to zero on free */
pc->period_cycles[pwm->hwpwm] = 0;
}
static int ehrpwm_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
int err;
bool enabled = pwm->state.enabled;
if (state->polarity != pwm->state.polarity) {
if (enabled) {
ehrpwm_pwm_disable(chip, pwm);
enabled = false;
}
err = ehrpwm_pwm_set_polarity(chip, pwm, state->polarity);
if (err)
return err;
}
if (!state->enabled) {
if (enabled)
ehrpwm_pwm_disable(chip, pwm);
return 0;
}
err = ehrpwm_pwm_config(chip, pwm, state->duty_cycle, state->period);
if (err)
return err;
if (!enabled)
err = ehrpwm_pwm_enable(chip, pwm);
return err;
}
static const struct pwm_ops ehrpwm_pwm_ops = {
.free = ehrpwm_pwm_free,
.apply = ehrpwm_pwm_apply,
};
static const struct of_device_id ehrpwm_of_match[] = {
{ .compatible = "ti,am3352-ehrpwm" },
{ .compatible = "ti,am33xx-ehrpwm" },
{},
};
MODULE_DEVICE_TABLE(of, ehrpwm_of_match);
static int ehrpwm_pwm_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct ehrpwm_pwm_chip *pc;
struct pwm_chip *chip;
struct clk *clk;
int ret;
chip = devm_pwmchip_alloc(&pdev->dev, NUM_PWM_CHANNEL, sizeof(*pc));
if (IS_ERR(chip))
return PTR_ERR(chip);
pc = to_ehrpwm_pwm_chip(chip);
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))
return dev_err_probe(&pdev->dev, PTR_ERR(clk), "Failed to get fck\n");
pc->clk_rate = clk_get_rate(clk);
if (!pc->clk_rate) {
dev_err(&pdev->dev, "failed to get clock rate\n");
return -EINVAL;
}
chip->ops = &ehrpwm_pwm_ops;
pc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pc->mmio_base))
return PTR_ERR(pc->mmio_base);
/* Acquire tbclk for Time Base EHRPWM submodule */
pc->tbclk = devm_clk_get(&pdev->dev, "tbclk");
if (IS_ERR(pc->tbclk))
return dev_err_probe(&pdev->dev, PTR_ERR(pc->tbclk), "Failed to get tbclk\n");
ret = clk_prepare(pc->tbclk);
if (ret < 0) {
dev_err(&pdev->dev, "clk_prepare() failed: %d\n", ret);
return ret;
}
ret = pwmchip_add(chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
goto err_clk_unprepare;
}
platform_set_drvdata(pdev, chip);
pm_runtime_enable(&pdev->dev);
return 0;
err_clk_unprepare:
clk_unprepare(pc->tbclk);
return ret;
}
static void ehrpwm_pwm_remove(struct platform_device *pdev)
{
struct pwm_chip *chip = platform_get_drvdata(pdev);
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
pwmchip_remove(chip);
clk_unprepare(pc->tbclk);
pm_runtime_disable(&pdev->dev);
}
static void ehrpwm_pwm_save_context(struct pwm_chip *chip)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
pm_runtime_get_sync(pwmchip_parent(chip));
pc->ctx.tbctl = ehrpwm_read(pc->mmio_base, TBCTL);
pc->ctx.tbprd = ehrpwm_read(pc->mmio_base, TBPRD);
pc->ctx.cmpa = ehrpwm_read(pc->mmio_base, CMPA);
pc->ctx.cmpb = ehrpwm_read(pc->mmio_base, CMPB);
pc->ctx.aqctla = ehrpwm_read(pc->mmio_base, AQCTLA);
pc->ctx.aqctlb = ehrpwm_read(pc->mmio_base, AQCTLB);
pc->ctx.aqsfrc = ehrpwm_read(pc->mmio_base, AQSFRC);
pc->ctx.aqcsfrc = ehrpwm_read(pc->mmio_base, AQCSFRC);
pm_runtime_put_sync(pwmchip_parent(chip));
}
static void ehrpwm_pwm_restore_context(struct pwm_chip *chip)
{
struct ehrpwm_pwm_chip *pc = to_ehrpwm_pwm_chip(chip);
ehrpwm_write(pc->mmio_base, TBPRD, pc->ctx.tbprd);
ehrpwm_write(pc->mmio_base, CMPA, pc->ctx.cmpa);
ehrpwm_write(pc->mmio_base, CMPB, pc->ctx.cmpb);
ehrpwm_write(pc->mmio_base, AQCTLA, pc->ctx.aqctla);
ehrpwm_write(pc->mmio_base, AQCTLB, pc->ctx.aqctlb);
ehrpwm_write(pc->mmio_base, AQSFRC, pc->ctx.aqsfrc);
ehrpwm_write(pc->mmio_base, AQCSFRC, pc->ctx.aqcsfrc);
ehrpwm_write(pc->mmio_base, TBCTL, pc->ctx.tbctl);
}
static int ehrpwm_pwm_suspend(struct device *dev)
{
struct pwm_chip *chip = dev_get_drvdata(dev);
unsigned int i;
ehrpwm_pwm_save_context(chip);
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
if (!pwm_is_enabled(pwm))
continue;
/* Disable explicitly if PWM is running */
pm_runtime_put_sync(dev);
}
return 0;
}
static int ehrpwm_pwm_resume(struct device *dev)
{
struct pwm_chip *chip = dev_get_drvdata(dev);
unsigned int i;
for (i = 0; i < chip->npwm; i++) {
struct pwm_device *pwm = &chip->pwms[i];
if (!pwm_is_enabled(pwm))
continue;
/* Enable explicitly if PWM was running */
pm_runtime_get_sync(dev);
}
ehrpwm_pwm_restore_context(chip);
return 0;
}
static DEFINE_SIMPLE_DEV_PM_OPS(ehrpwm_pwm_pm_ops, ehrpwm_pwm_suspend,
ehrpwm_pwm_resume);
static struct platform_driver ehrpwm_pwm_driver = {
.driver = {
.name = "ehrpwm",
.of_match_table = ehrpwm_of_match,
.pm = pm_ptr(&ehrpwm_pwm_pm_ops),
},
.probe = ehrpwm_pwm_probe,
.remove = ehrpwm_pwm_remove,
};
module_platform_driver(ehrpwm_pwm_driver);
MODULE_DESCRIPTION("EHRPWM PWM driver");
MODULE_AUTHOR("Texas Instruments");
MODULE_LICENSE("GPL");
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