[PATCH v2 2/4] pwm: atmel-tcb: switch to new binding

Alexandre Belloni
2020-10-30T18:37:20Z

The PWM is now a subnode of the used TCB. This is cleaner and it mainly
allows to stop wasting TCB channels when only 2 or 4 PWMs are used.

This also removes the atmel_tclib dependency

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-pwm@vger.kernel.org
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
drivers/pwm/Kconfig | 3 +-
drivers/pwm/pwm-atmel-tcb.c | 241 ++++++++++++++++++++----------------
2 files changed, 137 insertions(+), 107 deletions(-)

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 63be5362fd3a..ce02d7fe9513 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -75,7 +75,8 @@ config PWM_ATMEL_HLCDC_PWM

config PWM_ATMEL_TCB
tristate "Atmel TC Block PWM support"
- depends on ATMEL_TCLIB && OF
+ depends on OF
+ select REGMAP_MMIO
help
Generic PWM framework driver for Atmel Timer Counter Block.

diff --git a/drivers/pwm/pwm-atmel-tcb.c b/drivers/pwm/pwm-atmel-tcb.c
index 85c53701958c..82edb44fbbd8 100644
--- a/drivers/pwm/pwm-atmel-tcb.c
+++ b/drivers/pwm/pwm-atmel-tcb.c
@@ -16,13 +16,16 @@
#include <linux/err.h>
#include <linux/ioport.h>
#include <linux/io.h>
+#include <linux/mfd/syscon.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/regmap.h>
#include <linux/slab.h>
#include <soc/at91/atmel_tcb.h>

-#define NPWM 6
+#define NPWM 2

#define ATMEL_TC_ACMR_MASK (ATMEL_TC_ACPA | ATMEL_TC_ACPC | \
ATMEL_TC_AEEVT | ATMEL_TC_ASWTRG)
@@ -48,11 +51,17 @@ struct atmel_tcb_channel {
struct atmel_tcb_pwm_chip {
struct pwm_chip chip;
spinlock_t lock;
- struct atmel_tc *tc;
+ u8 channel;
+ u8 width;
+ struct regmap *regmap;
+ struct clk *clk;
+ struct clk *slow_clk;
struct atmel_tcb_pwm_device *pwms[NPWM];
- struct atmel_tcb_channel bkup[NPWM / 2];
+ struct atmel_tcb_channel bkup;
};

+const u8 atmel_tcb_divisors[] = { 2, 8, 32, 128, 0, };
+
static inline struct atmel_tcb_pwm_chip *to_tcb_chip(struct pwm_chip *chip)
{
return container_of(chip, struct atmel_tcb_pwm_chip, chip);
@@ -74,10 +83,6 @@ static int atmel_tcb_pwm_request(struct pwm_chip *chip,
{
struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
struct atmel_tcb_pwm_device *tcbpwm;
- struct atmel_tc *tc = tcbpwmc->tc;
- void __iomem *regs = tc->regs;
- unsigned group = pwm->hwpwm / 2;
- unsigned index = pwm->hwpwm % 2;
unsigned cmr;
int ret;

@@ -85,7 +90,7 @@ static int atmel_tcb_pwm_request(struct pwm_chip *chip,
if (!tcbpwm)
return -ENOMEM;

- ret = clk_prepare_enable(tc->clk[group]);
+ ret = clk_prepare_enable(tcbpwmc->clk);
if (ret) {
devm_kfree(chip->dev, tcbpwm);
return ret;
@@ -98,28 +103,31 @@ static int atmel_tcb_pwm_request(struct pwm_chip *chip,
tcbpwm->div = 0;

spin_lock(&tcbpwmc->lock);
- cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));
+ regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);
/*
* Get init config from Timer Counter registers if
* Timer Counter is already configured as a PWM generator.
*/
if (cmr & ATMEL_TC_WAVE) {
- if (index == 0)
- tcbpwm->duty =
- __raw_readl(regs + ATMEL_TC_REG(group, RA));
+ if (pwm->hwpwm == 0)
+ regmap_read(tcbpwmc->regmap,
+ ATMEL_TC_REG(tcbpwmc->channel, RA),
+ &tcbpwm->duty);
else
- tcbpwm->duty =
- __raw_readl(regs + ATMEL_TC_REG(group, RB));
+ regmap_read(tcbpwmc->regmap,
+ ATMEL_TC_REG(tcbpwmc->channel, RB),
+ &tcbpwm->duty);

tcbpwm->div = cmr & ATMEL_TC_TCCLKS;
- tcbpwm->period = __raw_readl(regs + ATMEL_TC_REG(group, RC));
+ regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, RC),
+ &tcbpwm->period);
cmr &= (ATMEL_TC_TCCLKS | ATMEL_TC_ACMR_MASK |
ATMEL_TC_BCMR_MASK);
} else
cmr = 0;

cmr |= ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO | ATMEL_TC_EEVT_XC0;
- __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));
+ regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);
spin_unlock(&tcbpwmc->lock);

tcbpwmc->pwms[pwm->hwpwm] = tcbpwm;
@@ -131,9 +139,8 @@ static void atmel_tcb_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
- struct atmel_tc *tc = tcbpwmc->tc;

- clk_disable_unprepare(tc->clk[pwm->hwpwm / 2]);
+ clk_disable_unprepare(tcbpwmc->clk);
tcbpwmc->pwms[pwm->hwpwm] = NULL;
devm_kfree(chip->dev, tcbpwm);
}
@@ -142,10 +149,6 @@ static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
- struct atmel_tc *tc = tcbpwmc->tc;
- void __iomem *regs = tc->regs;
- unsigned group = pwm->hwpwm / 2;
- unsigned index = pwm->hwpwm % 2;
unsigned cmr;
enum pwm_polarity polarity = tcbpwm->polarity;

@@ -161,10 +164,10 @@ static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
polarity = !polarity;

spin_lock(&tcbpwmc->lock);
- cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));
+ regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);

/* flush old setting and set the new one */
- if (index == 0) {
+ if (pwm->hwpwm == 0) {
cmr &= ~ATMEL_TC_ACMR_MASK;
if (polarity == PWM_POLARITY_INVERSED)
cmr |= ATMEL_TC_ASWTRG_CLEAR;
@@ -178,20 +181,22 @@ static void atmel_tcb_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
cmr |= ATMEL_TC_BSWTRG_SET;
}

- __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));
+ regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);

/*
* Use software trigger to apply the new setting.
* If both PWM devices in this group are disabled we stop the clock.
*/
if (!(cmr & (ATMEL_TC_ACPC | ATMEL_TC_BCPC))) {
- __raw_writel(ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS,
- regs + ATMEL_TC_REG(group, CCR));
- tcbpwmc->bkup[group].enabled = 1;
+ regmap_write(tcbpwmc->regmap,
+ ATMEL_TC_REG(tcbpwmc->channel, CCR),
+ ATMEL_TC_SWTRG | ATMEL_TC_CLKDIS);
+ tcbpwmc->bkup.enabled = 1;
} else {
- __raw_writel(ATMEL_TC_SWTRG, regs +
- ATMEL_TC_REG(group, CCR));
- tcbpwmc->bkup[group].enabled = 0;
+ regmap_write(tcbpwmc->regmap,
+ ATMEL_TC_REG(tcbpwmc->channel, CCR),
+ ATMEL_TC_SWTRG);
+ tcbpwmc->bkup.enabled = 0;
}

spin_unlock(&tcbpwmc->lock);
@@ -201,10 +206,6 @@ static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
{
struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
- struct atmel_tc *tc = tcbpwmc->tc;
- void __iomem *regs = tc->regs;
- unsigned group = pwm->hwpwm / 2;
- unsigned index = pwm->hwpwm % 2;
u32 cmr;
enum pwm_polarity polarity = tcbpwm->polarity;

@@ -220,12 +221,12 @@ static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
polarity = !polarity;

spin_lock(&tcbpwmc->lock);
- cmr = __raw_readl(regs + ATMEL_TC_REG(group, CMR));
+ regmap_read(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), &cmr);

/* flush old setting and set the new one */
cmr &= ~ATMEL_TC_TCCLKS;

- if (index == 0) {
+ if (pwm->hwpwm == 0) {
cmr &= ~ATMEL_TC_ACMR_MASK;

/* Set CMR flags according to given polarity */
@@ -248,7 +249,7 @@ static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
* this config till next config call.
*/
if (tcbpwm->duty != tcbpwm->period && tcbpwm->duty > 0) {
- if (index == 0) {
+ if (pwm->hwpwm == 0) {
if (polarity == PWM_POLARITY_INVERSED)
cmr |= ATMEL_TC_ACPA_SET | ATMEL_TC_ACPC_CLEAR;
else
@@ -263,19 +264,24 @@ static int atmel_tcb_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)

cmr |= (tcbpwm->div & ATMEL_TC_TCCLKS);

- __raw_writel(cmr, regs + ATMEL_TC_REG(group, CMR));
+ regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CMR), cmr);

- if (index == 0)
- __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RA));
+ if (pwm->hwpwm == 0)
+ regmap_write(tcbpwmc->regmap,
+ ATMEL_TC_REG(tcbpwmc->channel, RA),
+ tcbpwm->duty);
else
- __raw_writel(tcbpwm->duty, regs + ATMEL_TC_REG(group, RB));
+ regmap_write(tcbpwmc->regmap,
+ ATMEL_TC_REG(tcbpwmc->channel, RB),
+ tcbpwm->duty);

- __raw_writel(tcbpwm->period, regs + ATMEL_TC_REG(group, RC));
+ regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, RC),
+ tcbpwm->period);

/* Use software trigger to apply the new setting */
- __raw_writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
- regs + ATMEL_TC_REG(group, CCR));
- tcbpwmc->bkup[group].enabled = 1;
+ regmap_write(tcbpwmc->regmap, ATMEL_TC_REG(tcbpwmc->channel, CCR),
+ ATMEL_TC_SWTRG | ATMEL_TC_CLKEN);
+ tcbpwmc->bkup.enabled = 1;
spin_unlock(&tcbpwmc->lock);
return 0;
}
@@ -285,15 +291,12 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
{
struct atmel_tcb_pwm_chip *tcbpwmc = to_tcb_chip(chip);
struct atmel_tcb_pwm_device *tcbpwm = pwm_get_chip_data(pwm);
- unsigned group = pwm->hwpwm / 2;
- unsigned index = pwm->hwpwm % 2;
struct atmel_tcb_pwm_device *atcbpwm = NULL;
- struct atmel_tc *tc = tcbpwmc->tc;
int i;
int slowclk = 0;
unsigned period;
unsigned duty;
- unsigned rate = clk_get_rate(tc->clk[group]);
+ unsigned rate = clk_get_rate(tcbpwmc->clk);
unsigned long long min;
unsigned long long max;

@@ -301,13 +304,13 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
* Find best clk divisor:
* the smallest divisor which can fulfill the period_ns requirements.
*/
- for (i = 0; i < 5; ++i) {
- if (atmel_tc_divisors[i] == 0) {
+ for (i = 0; i < ARRAY_SIZE(atmel_tcb_divisors); ++i) {
+ if (atmel_tcb_divisors[i] == 0) {
slowclk = i;
continue;
}
- min = div_u64((u64)NSEC_PER_SEC * atmel_tc_divisors[i], rate);
- max = min << tc->tcb_config->counter_width;
+ min = div_u64((u64)NSEC_PER_SEC * atmel_tcb_divisors[i], rate);
+ max = min << tcbpwmc->width;
if (max >= period_ns)
break;
}
@@ -316,11 +319,11 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
* If none of the divisor are small enough to represent period_ns
* take slow clock (32KHz).
*/
- if (i == 5) {
+ if (i == ARRAY_SIZE(atmel_tcb_divisors)) {
i = slowclk;
- rate = clk_get_rate(tc->slow_clk);
+ rate = clk_get_rate(tcbpwmc->slow_clk);
min = div_u64(NSEC_PER_SEC, rate);
- max = min << tc->tcb_config->counter_width;
+ max = min << tcbpwmc->width;

/* If period is too big return ERANGE error */
if (max < period_ns)
@@ -330,17 +333,13 @@ static int atmel_tcb_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
duty = div_u64(duty_ns, min);
period = div_u64(period_ns, min);

- if (index == 0)
- atcbpwm = tcbpwmc->pwms[pwm->hwpwm + 1];
+ if (pwm->hwpwm == 0)
+ atcbpwm = tcbpwmc->pwms[1];
else
- atcbpwm = tcbpwmc->pwms[pwm->hwpwm - 1];
+ atcbpwm = tcbpwmc->pwms[0];

/*
- * PWM devices provided by TCB driver are grouped by 2:
- * - group 0: PWM 0 & 1
- * - group 1: PWM 2 & 3
- * - group 2: PWM 4 & 5
- *
+ * PWM devices provided by the TCB driver are grouped by 2.
* PWM devices in a given group must be configured with the
* same period_ns.
*
@@ -376,32 +375,63 @@ static const struct pwm_ops atmel_tcb_pwm_ops = {
.owner = THIS_MODULE,
};

+static struct atmel_tcb_config tcb_rm9200_config = {
+ .counter_width = 16,
+};
+
+static struct atmel_tcb_config tcb_sam9x5_config = {
+ .counter_width = 32,
+};
+
+static const struct of_device_id atmel_tcb_of_match[] = {
+ { .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, },
+ { .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, },
+ { /* sentinel */ }
+};
+
static int atmel_tcb_pwm_probe(struct platform_device *pdev)
{
+ const struct of_device_id *match;
struct atmel_tcb_pwm_chip *tcbpwm;
+ const struct atmel_tcb_config *config;
struct device_node *np = pdev->dev.of_node;
- struct atmel_tc *tc;
+ struct regmap *regmap;
+ struct clk *clk;
+ struct clk *slow_clk;
+ char clk_name[] = "t0_clk";
int err;
- int tcblock;
+ int channel;

- err = of_property_read_u32(np, "tc-block", &tcblock);
+ err = of_property_read_u32(np, "reg", &channel);
if (err < 0) {
dev_err(&pdev->dev,
- "failed to get Timer Counter Block number from device tree (error: %d)\n",
+ "failed to get Timer Counter Block channel from device tree (error: %d)\n",
err);
return err;
}

- tc = atmel_tc_alloc(tcblock);
- if (tc == NULL) {
- dev_err(&pdev->dev, "failed to allocate Timer Counter Block\n");
- return -ENOMEM;
- }
+ regmap = syscon_node_to_regmap(np->parent);
+ if (IS_ERR(regmap))
+ return PTR_ERR(regmap);
+
+ slow_clk = of_clk_get_by_name(np->parent, "slow_clk");
+ if (IS_ERR(slow_clk))
+ return PTR_ERR(slow_clk);
+
+ clk_name[1] += channel;
+ clk = of_clk_get_by_name(np->parent, clk_name);
+ if (IS_ERR(clk))
+ clk = of_clk_get_by_name(np->parent, "t0_clk");
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ match = of_match_node(atmel_tcb_of_match, np->parent);
+ config = match->data;

tcbpwm = devm_kzalloc(&pdev->dev, sizeof(*tcbpwm), GFP_KERNEL);
if (tcbpwm == NULL) {
err = -ENOMEM;
- goto err_free_tc;
+ goto err_slow_clk;
}

tcbpwm->chip.dev = &pdev->dev;
@@ -410,11 +440,15 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev)
tcbpwm->chip.of_pwm_n_cells = 3;
tcbpwm->chip.base = -1;
tcbpwm->chip.npwm = NPWM;
- tcbpwm->tc = tc;
+ tcbpwm->channel = channel;
+ tcbpwm->regmap = regmap;
+ tcbpwm->clk = clk;
+ tcbpwm->slow_clk = slow_clk;
+ tcbpwm->width = config->counter_width;

- err = clk_prepare_enable(tc->slow_clk);
+ err = clk_prepare_enable(slow_clk);
if (err)
- goto err_free_tc;
+ goto err_slow_clk;

spin_lock_init(&tcbpwm->lock);

@@ -427,10 +461,10 @@ static int atmel_tcb_pwm_probe(struct platform_device *pdev)
return 0;

err_disable_clk:
- clk_disable_unprepare(tcbpwm->tc->slow_clk);
+ clk_disable_unprepare(tcbpwm->slow_clk);

-err_free_tc:
- atmel_tc_free(tc);
+err_slow_clk:
+ clk_put(slow_clk);

return err;
}
@@ -440,14 +474,14 @@ static int atmel_tcb_pwm_remove(struct platform_device *pdev)
struct atmel_tcb_pwm_chip *tcbpwm = platform_get_drvdata(pdev);
int err;

- clk_disable_unprepare(tcbpwm->tc->slow_clk);
+ clk_disable_unprepare(tcbpwm->slow_clk);
+ clk_put(tcbpwm->slow_clk);
+ clk_put(tcbpwm->clk);

err = pwmchip_remove(&tcbpwm->chip);
if (err < 0)
return err;

- atmel_tc_free(tcbpwm->tc);
-
return 0;
}

@@ -461,38 +495,33 @@ MODULE_DEVICE_TABLE(of, atmel_tcb_pwm_dt_ids);
static int atmel_tcb_pwm_suspend(struct device *dev)
{
struct atmel_tcb_pwm_chip *tcbpwm = dev_get_drvdata(dev);
- void __iomem *base = tcbpwm->tc->regs;
- int i;
+ struct atmel_tcb_channel *chan = &tcbpwm->bkup;
+ unsigned int channel = tcbpwm->channel;

- for (i = 0; i < (NPWM / 2); i++) {
- struct atmel_tcb_channel *chan = &tcbpwm->bkup[i];
+ regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, CMR), &chan->cmr);
+ regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RA), &chan->ra);
+ regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RB), &chan->rb);
+ regmap_read(tcbpwm->regmap, ATMEL_TC_REG(channel, RC), &chan->rc);

- chan->cmr = readl(base + ATMEL_TC_REG(i, CMR));
- chan->ra = readl(base + ATMEL_TC_REG(i, RA));
- chan->rb = readl(base + ATMEL_TC_REG(i, RB));
- chan->rc = readl(base + ATMEL_TC_REG(i, RC));
- }
return 0;
}

static int atmel_tcb_pwm_resume(struct device *dev)
{
struct atmel_tcb_pwm_chip *tcbpwm = dev_get_drvdata(dev);
- void __iomem *base = tcbpwm->tc->regs;
- int i;
+ struct atmel_tcb_channel *chan = &tcbpwm->bkup;
+ unsigned int channel = tcbpwm->channel;

- for (i = 0; i < (NPWM / 2); i++) {
- struct atmel_tcb_channel *chan = &tcbpwm->bkup[i];
+ regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, CMR), chan->cmr);
+ regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RA), chan->ra);
+ regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RB), chan->rb);
+ regmap_write(tcbpwm->regmap, ATMEL_TC_REG(channel, RC), chan->rc);
+
+ if (chan->enabled)
+ regmap_write(tcbpwm->regmap,
+ ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
+ ATMEL_TC_REG(channel, CCR));

- writel(chan->cmr, base + ATMEL_TC_REG(i, CMR));
- writel(chan->ra, base + ATMEL_TC_REG(i, RA));
- writel(chan->rb, base + ATMEL_TC_REG(i, RB));
- writel(chan->rc, base + ATMEL_TC_REG(i, RC));
- if (chan->enabled) {
- writel(ATMEL_TC_CLKEN | ATMEL_TC_SWTRG,
- base + ATMEL_TC_REG(i, CCR));
- }
- }
return 0;
}
#endif
--
2.26.2