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linux/drivers/pwm/pwm-tiehrpwm.c
Uwe Kleine-König 91e92e82b1 pwm: tiehrpwm: Convert to platform remove callback returning void 
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
2023-03-30 16:26:39 +02:00

612 lines
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// 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_device.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 {
struct pwm_chip 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 container_of(chip, struct ehrpwm_pwm_chip, 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(chip->dev,
"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(chip->dev, "Unsupported values\n");
return -EINVAL;
}
pm_runtime_get_sync(chip->dev);
/* 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(chip->dev);
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(chip->dev);
/* 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(chip->dev, "Failed to enable TBCLK for %s: %d\n",
dev_name(pc->chip.dev), 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(chip->dev);
}
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(chip->dev, "Removing PWM device without disabling\n");
pm_runtime_put_sync(chip->dev);
}
/* 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,
.owner = THIS_MODULE,
};
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 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))
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;
}
pc->chip.dev = &pdev->dev;
pc->chip.ops = &ehrpwm_pwm_ops;
pc->chip.npwm = NUM_PWM_CHANNEL;
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(&pc->chip);
if (ret < 0) {
dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
goto err_clk_unprepare;
}
platform_set_drvdata(pdev, pc);
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 ehrpwm_pwm_chip *pc = platform_get_drvdata(pdev);
pwmchip_remove(&pc->chip);
clk_unprepare(pc->tbclk);
pm_runtime_disable(&pdev->dev);
}
#ifdef CONFIG_PM_SLEEP
static void ehrpwm_pwm_save_context(struct ehrpwm_pwm_chip *pc)
{
pm_runtime_get_sync(pc->chip.dev);
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(pc->chip.dev);
}
static void ehrpwm_pwm_restore_context(struct ehrpwm_pwm_chip *pc)
{
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 ehrpwm_pwm_chip *pc = dev_get_drvdata(dev);
unsigned int i;
ehrpwm_pwm_save_context(pc);
for (i = 0; i < pc->chip.npwm; i++) {
struct pwm_device *pwm = &pc->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 ehrpwm_pwm_chip *pc = dev_get_drvdata(dev);
unsigned int i;
for (i = 0; i < pc->chip.npwm; i++) {
struct pwm_device *pwm = &pc->chip.pwms[i];
if (!pwm_is_enabled(pwm))
continue;
/* Enable explicitly if PWM was running */
pm_runtime_get_sync(dev);
}
ehrpwm_pwm_restore_context(pc);
return 0;
}
#endif
static 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 = &ehrpwm_pwm_pm_ops,
},
.probe = ehrpwm_pwm_probe,
.remove_new = 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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