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Subject[PATCH v4 1/4] pwm: jz4740: Use clocks from TCU driver
Date
The ingenic-timer "TCU" driver provides us with clocks, that can be
(un)gated, reparented or reclocked from devicetree, instead of having
these settings hardcoded in this driver.

The new code now uses a clk pointer per PWM (instead of a clk per
pwm-chip before). So the pointer is stored in per-pwm data now.
The calls to arch-specific timer code is replaced with standard
clock API calls to start and stop each channel's clock.

While this driver is devicetree-compatible, it is never (as of now)
probed from devicetree, so this change does not introduce a ABI problem
with current devicetree files.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Mathieu Malaterre <malat@debian.org>
Tested-by: Artur Rojek <contact@artur-rojek.eu>
---

Notes:
v2: This patch is now before the patch introducing regmap, so the code
has changed a bit.
v3: - Use %pe printf specifier to print error
- Update commit message
- Removed call to jz4740_timer_set_ctrl() in jz4740_pwm_free() which
was reseting the clock's parent.
v4: No change

drivers/pwm/Kconfig | 1 +
drivers/pwm/pwm-jz4740.c | 53 +++++++++++++++++++++++++++++-----------
2 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 30190beeb6e9..69f00eb9bd36 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -225,6 +225,7 @@ config PWM_IMX_TPM
config PWM_JZ4740
tristate "Ingenic JZ47xx PWM support"
depends on MACH_INGENIC
+ depends on COMMON_CLK
help
Generic PWM framework driver for Ingenic JZ47xx based
machines.
diff --git a/drivers/pwm/pwm-jz4740.c b/drivers/pwm/pwm-jz4740.c
index 9d78cc21cb12..ee50ac5fabb6 100644
--- a/drivers/pwm/pwm-jz4740.c
+++ b/drivers/pwm/pwm-jz4740.c
@@ -24,7 +24,6 @@

struct jz4740_pwm_chip {
struct pwm_chip chip;
- struct clk *clk;
};

static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)
@@ -34,6 +33,11 @@ static inline struct jz4740_pwm_chip *to_jz4740(struct pwm_chip *chip)

static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
{
+ struct jz4740_pwm_chip *jz = to_jz4740(chip);
+ struct clk *clk;
+ char clk_name[16];
+ int ret;
+
/*
* Timers 0 and 1 are used for system tasks, so they are unavailable
* for use as PWMs.
@@ -41,16 +45,32 @@ static int jz4740_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
if (pwm->hwpwm < 2)
return -EBUSY;

- jz4740_timer_start(pwm->hwpwm);
+ snprintf(clk_name, sizeof(clk_name), "timer%u", pwm->hwpwm);
+
+ clk = clk_get(chip->dev, clk_name);
+ if (IS_ERR(clk)) {
+ if (PTR_ERR(clk) != -EPROBE_DEFER)
+ dev_err(chip->dev, "Failed to get clock: %pe", clk);
+ return PTR_ERR(clk);
+ }
+
+ ret = clk_prepare_enable(clk);
+ if (ret) {
+ clk_put(clk);
+ return ret;
+ }
+
+ pwm_set_chip_data(pwm, clk);

return 0;
}

static void jz4740_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
{
- jz4740_timer_set_ctrl(pwm->hwpwm, 0);
+ struct clk *clk = pwm_get_chip_data(pwm);

- jz4740_timer_stop(pwm->hwpwm);
+ clk_disable_unprepare(clk);
+ clk_put(clk);
}

static int jz4740_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
@@ -91,17 +111,22 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
const struct pwm_state *state)
{
struct jz4740_pwm_chip *jz4740 = to_jz4740(pwm->chip);
+ struct clk *clk = pwm_get_chip_data(pwm),
+ *parent_clk = clk_get_parent(clk);
+ unsigned long rate, period, duty;
unsigned long long tmp;
- unsigned long period, duty;
unsigned int prescaler = 0;
uint16_t ctrl;
+ int err;

- tmp = (unsigned long long)clk_get_rate(jz4740->clk) * state->period;
+ rate = clk_get_rate(parent_clk);
+ tmp = (unsigned long long)rate * state->period;
do_div(tmp, 1000000000);
period = tmp;

while (period > 0xffff && prescaler < 6) {
period >>= 2;
+ rate >>= 2;
++prescaler;
}

@@ -117,14 +142,18 @@ static int jz4740_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,

jz4740_pwm_disable(chip, pwm);

+ err = clk_set_rate(clk, rate);
+ if (err) {
+ dev_err(chip->dev, "Unable to set rate: %d", err);
+ return err;
+ }
+
jz4740_timer_set_count(pwm->hwpwm, 0);
jz4740_timer_set_duty(pwm->hwpwm, duty);
jz4740_timer_set_period(pwm->hwpwm, period);

- ctrl = JZ_TIMER_CTRL_PRESCALER(prescaler) | JZ_TIMER_CTRL_SRC_EXT |
- JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;
-
- jz4740_timer_set_ctrl(pwm->hwpwm, ctrl);
+ ctrl = jz4740_timer_get_ctrl(pwm->hwpwm);
+ ctrl |= JZ_TIMER_CTRL_PWM_ABBRUPT_SHUTDOWN;

switch (state->polarity) {
case PWM_POLARITY_NORMAL:
@@ -158,10 +187,6 @@ static int jz4740_pwm_probe(struct platform_device *pdev)
if (!jz4740)
return -ENOMEM;

- jz4740->clk = devm_clk_get(&pdev->dev, "ext");
- if (IS_ERR(jz4740->clk))
- return PTR_ERR(jz4740->clk);
-
jz4740->chip.dev = &pdev->dev;
jz4740->chip.ops = &jz4740_pwm_ops;
jz4740->chip.npwm = NUM_PWM;
--
2.25.1
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