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pwm: sun4i: Prefer "mod" clock to unnamed 

New device tree bindings called the source clock of the module
"mod" when several clocks are defined.

Try to get a clock called "mod" if nothing is found try to get
an unnamed clock.

Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Clément Péron <peron.clem@gmail.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Clément Péron 2019-11-24 18:29:04 +01:00 committed by Thierry Reding
parent a7fe985633
commit b8d74644f3
1 changed files with 27 additions and 2 deletions
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29
drivers/pwm/pwm-sun4i.c
View File

@ -362,9 +362,34 @@ static int sun4i_pwm_probe(struct platform_device *pdev)
if (IS_ERR(pwm->base))
return PTR_ERR(pwm->base);
pwm->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pwm->clk))
/*
* All hardware variants need a source clock that is divided and
* then feeds the counter that defines the output wave form. In the
* device tree this clock is either unnamed or called "mod".
* Some variants (e.g. H6) need another clock to access the
* hardware registers; this is called "bus".
* So we request "mod" first (and ignore the corner case that a
* parent provides a "mod" clock while the right one would be the
* unnamed one of the PWM device) and if this is not found we fall
* back to the first clock of the PWM.
*/
pwm->clk = devm_clk_get_optional(&pdev->dev, "mod");
if (IS_ERR(pwm->clk)) {
if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
dev_err(&pdev->dev, "get mod clock failed %pe\n",
pwm->clk);
return PTR_ERR(pwm->clk);
}
if (!pwm->clk) {
pwm->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pwm->clk)) {
if (PTR_ERR(pwm->rst) != -EPROBE_DEFER)
dev_err(&pdev->dev, "get unnamed clock failed %pe\n",
pwm->clk);
return PTR_ERR(pwm->clk);
}
}
pwm->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
if (IS_ERR(pwm->rst)) {