| Message ID | 20241127071450.3082761-1-haibo.chen@nxp.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | gpio: gpio-pca953x: do not enable regmap cache when there is no regulator | expand |
On Wed, Nov 27, 2024 at 8:15 AM <haibo.chen@nxp.com> wrote: > > From: Haibo Chen <haibo.chen@nxp.com> > > Regmap cache mechanism is enabled in default. Thus, IO expander wouldn't > handle GPIO set really before resuming back. > > But there are cases need to toggle gpio in NO_IRQ stage. > e.g. To align with PCIe specification, PERST# signal connected on the IO > expander must be toggled during PCIe RC's NO_IRQ_RESUME. > > Do not enable the regmap cache when IO expander doesn't have the regulator > during system PM. That means the power of IO expander would be kept on, > and the GPIOs of the IO expander can be toggled really during system PM. > > Signed-off-by: Haibo Chen <haibo.chen@nxp.com> > --- The commit title should be: "gpio: pca953x: ..." This description makes it sound like a fix, can you add a Fixes: tag? Bart
> -----Original Message----- > From: Bartosz Golaszewski <brgl@bgdev.pl> > Sent: 2024年11月27日 21:05 > To: Bough Chen <haibo.chen@nxp.com> > Cc: linus.walleij@linaro.org; lgirdwood@gmail.com; broonie@kernel.org; > linux-gpio@vger.kernel.org; linux-kernel@vger.kernel.org; imx@lists.linux.dev; > marek.vasut@gmail.com > Subject: Re: [PATCH] gpio: gpio-pca953x: do not enable regmap cache when > there is no regulator > > On Wed, Nov 27, 2024 at 8:15 AM <haibo.chen@nxp.com> wrote: > > > > From: Haibo Chen <haibo.chen@nxp.com> > > > > Regmap cache mechanism is enabled in default. Thus, IO expander > > wouldn't handle GPIO set really before resuming back. > > > > But there are cases need to toggle gpio in NO_IRQ stage. > > e.g. To align with PCIe specification, PERST# signal connected on the > > IO expander must be toggled during PCIe RC's NO_IRQ_RESUME. > > > > Do not enable the regmap cache when IO expander doesn't have the > > regulator during system PM. That means the power of IO expander would > > be kept on, and the GPIOs of the IO expander can be toggled really during > system PM. > > > > Signed-off-by: Haibo Chen <haibo.chen@nxp.com> > > --- > > The commit title should be: "gpio: pca953x: ..." > > This description makes it sound like a fix, can you add a Fixes: tag? Okay, will add in next version Regards Haibo Chen > > Bart
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index 272febc3230e..6503ef0d7562 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -1040,9 +1040,15 @@ static int pca953x_get_and_enable_regulator(struct pca953x_chip *chip) struct regulator *reg = chip->regulator; int ret; - reg = devm_regulator_get(dev, "vcc"); - if (IS_ERR(reg)) - return dev_err_probe(dev, PTR_ERR(reg), "reg get err\n"); + reg = devm_regulator_get_optional(dev, "vcc"); + if (IS_ERR(reg)) { + if (PTR_ERR(reg) == -ENODEV) { + chip->regulator = NULL; + return 0; + } else { + return dev_err_probe(dev, PTR_ERR(reg), "reg get err\n"); + } + } ret = regulator_enable(reg); if (ret) @@ -1240,11 +1246,20 @@ static int pca953x_suspend(struct device *dev) { struct pca953x_chip *chip = dev_get_drvdata(dev); - pca953x_save_context(chip); + /* + * Only save context when has regulator, if no + * regulator, power keeps on, can also handle + * gpio related operation. + * e.g. PCIe RC need to toggle the RST pin in + * NOIRQ resume stage, so can't open regmap + * cache if there is no regulator. + */ + if (chip->regulator) + pca953x_save_context(chip); if (atomic_read(&chip->wakeup_path)) device_set_wakeup_path(dev); - else + else if (chip->regulator) regulator_disable(chip->regulator); return 0; @@ -1255,7 +1270,7 @@ static int pca953x_resume(struct device *dev) struct pca953x_chip *chip = dev_get_drvdata(dev); int ret; - if (!atomic_read(&chip->wakeup_path)) { + if (!atomic_read(&chip->wakeup_path) && chip->regulator) { ret = regulator_enable(chip->regulator); if (ret) { dev_err(dev, "Failed to enable regulator: %d\n", ret); @@ -1263,9 +1278,11 @@ static int pca953x_resume(struct device *dev) } } - ret = pca953x_restore_context(chip); - if (ret) - dev_err(dev, "Failed to restore register map: %d\n", ret); + if (chip->regulator) { + ret = pca953x_restore_context(chip); + if (ret) + dev_err(dev, "Failed to restore register map: %d\n", ret); + } return ret; }