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pwm: sifive: Ensure the clk is enabled exactly once per running PWM
.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: 9e37a53eb0
(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>
This commit is contained in:
parent
1695b421e1
commit
ace41d7564
1 changed files with 37 additions and 9 deletions
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@ -216,6 +216,8 @@ static int pwm_sifive_probe(struct platform_device *pdev)
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struct pwm_sifive_ddata *ddata;
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struct pwm_chip *chip;
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int ret;
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u32 val;
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unsigned int enabled_pwms = 0, enabled_clks = 1;
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ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
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if (!ddata)
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@ -242,6 +244,33 @@ static int pwm_sifive_probe(struct platform_device *pdev)
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return ret;
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}
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val = readl(ddata->regs + PWM_SIFIVE_PWMCFG);
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if (val & PWM_SIFIVE_PWMCFG_EN_ALWAYS) {
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unsigned int i;
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for (i = 0; i < chip->npwm; ++i) {
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val = readl(ddata->regs + PWM_SIFIVE_PWMCMP(i));
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if (val > 0)
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++enabled_pwms;
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}
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}
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/* The clk should be on once for each running PWM. */
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if (enabled_pwms) {
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while (enabled_clks < enabled_pwms) {
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/* This is not expected to fail as the clk is already on */
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ret = clk_enable(ddata->clk);
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if (unlikely(ret)) {
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dev_err_probe(dev, ret, "Failed to enable clk\n");
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goto disable_clk;
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}
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++enabled_clks;
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}
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} else {
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clk_disable(ddata->clk);
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enabled_clks = 0;
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}
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/* Watch for changes to underlying clock frequency */
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ddata->notifier.notifier_call = pwm_sifive_clock_notifier;
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ret = clk_notifier_register(ddata->clk, &ddata->notifier);
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@ -264,7 +293,11 @@ static int pwm_sifive_probe(struct platform_device *pdev)
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unregister_clk:
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clk_notifier_unregister(ddata->clk, &ddata->notifier);
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disable_clk:
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clk_disable_unprepare(ddata->clk);
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while (enabled_clks) {
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clk_disable(ddata->clk);
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--enabled_clks;
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}
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clk_unprepare(ddata->clk);
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return ret;
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}
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@ -272,21 +305,16 @@ disable_clk:
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static int pwm_sifive_remove(struct platform_device *dev)
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{
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struct pwm_sifive_ddata *ddata = platform_get_drvdata(dev);
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bool is_enabled = false;
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struct pwm_device *pwm;
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int ch;
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for (ch = 0; ch < ddata->chip.npwm; ch++) {
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pwm = &ddata->chip.pwms[ch];
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if (pwm->state.enabled) {
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is_enabled = true;
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break;
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}
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if (pwm->state.enabled)
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clk_disable(ddata->clk);
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}
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if (is_enabled)
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clk_disable(ddata->clk);
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clk_disable_unprepare(ddata->clk);
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clk_unprepare(ddata->clk);
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pwmchip_remove(&ddata->chip);
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clk_notifier_unregister(ddata->clk, &ddata->notifier);
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