From: Uwe Kleine-König u.kleine-koenig@pengutronix.de
[ Upstream commit ace41d7564e655c39f709a78c035188a460c7cbd ]
.apply() assumes the clk to be for a given PWM iff the PWM is enabled. So make sure this is the case when .probe() completes. And in .remove() disable the according number of times.
This fixes a clk enable/disable imbalance, if some PWMs are already running at probe time.
Fixes: 9e37a53eb051 (pwm: sifive: Add a driver for SiFive SoC PWM) Signed-off-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Tested-by: Emil Renner Berthing emil.renner.berthing@canonical.com Signed-off-by: Thierry Reding thierry.reding@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pwm/pwm-sifive.c | 46 ++++++++++++++++++++++++++++++++-------- 1 file changed, 37 insertions(+), 9 deletions(-)
diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c index cc32f7ce09a6..1def1bc59240 100644 --- a/drivers/pwm/pwm-sifive.c +++ b/drivers/pwm/pwm-sifive.c @@ -230,6 +230,8 @@ static int pwm_sifive_probe(struct platform_device *pdev) struct pwm_chip *chip; struct resource *res; int ret; + u32 val; + unsigned int enabled_pwms = 0, enabled_clks = 1;
ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); if (!ddata) @@ -260,6 +262,33 @@ static int pwm_sifive_probe(struct platform_device *pdev) return ret; }
+ val = readl(ddata->regs + PWM_SIFIVE_PWMCFG); + if (val & PWM_SIFIVE_PWMCFG_EN_ALWAYS) { + unsigned int i; + + for (i = 0; i < chip->npwm; ++i) { + val = readl(ddata->regs + PWM_SIFIVE_PWMCMP(i)); + if (val > 0) + ++enabled_pwms; + } + } + + /* The clk should be on once for each running PWM. */ + if (enabled_pwms) { + while (enabled_clks < enabled_pwms) { + /* This is not expected to fail as the clk is already on */ + ret = clk_enable(ddata->clk); + if (unlikely(ret)) { + dev_err_probe(dev, ret, "Failed to enable clk\n"); + goto disable_clk; + } + ++enabled_clks; + } + } else { + clk_disable(ddata->clk); + enabled_clks = 0; + } + /* Watch for changes to underlying clock frequency */ ddata->notifier.notifier_call = pwm_sifive_clock_notifier; ret = clk_notifier_register(ddata->clk, &ddata->notifier); @@ -282,7 +311,11 @@ static int pwm_sifive_probe(struct platform_device *pdev) unregister_clk: clk_notifier_unregister(ddata->clk, &ddata->notifier); disable_clk: - clk_disable_unprepare(ddata->clk); + while (enabled_clks) { + clk_disable(ddata->clk); + --enabled_clks; + } + clk_unprepare(ddata->clk);
return ret; } @@ -290,21 +323,16 @@ static int pwm_sifive_probe(struct platform_device *pdev) static int pwm_sifive_remove(struct platform_device *dev) { struct pwm_sifive_ddata *ddata = platform_get_drvdata(dev); - bool is_enabled = false; struct pwm_device *pwm; int ch;
for (ch = 0; ch < ddata->chip.npwm; ch++) { pwm = &ddata->chip.pwms[ch]; - if (pwm->state.enabled) { - is_enabled = true; - break; - } + if (pwm->state.enabled) + clk_disable(ddata->clk); } - if (is_enabled) - clk_disable(ddata->clk);
- clk_disable_unprepare(ddata->clk); + clk_unprepare(ddata->clk); pwmchip_remove(&ddata->chip); clk_notifier_unregister(ddata->clk, &ddata->notifier);