Hi,
Thanks for your review.
On Mon, Sep 21, 2020 at 06:00:26PM +0900, Punit Agrawal wrote:
> Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@xxxxxxxxxxxxx> writes:
>
> > From: Nobuhiro Iwamatsu <iwamatsu@xxxxxxxxxxx>
> >
> > Add a driver for the PWM controller on Toshiba Visconti ARM SoC.
> >
> > Signed-off-by: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>
> > ---
> > drivers/pwm/Kconfig | 9 +++
> > drivers/pwm/Makefile | 1 +
> > drivers/pwm/pwm-visconti.c | 141 +++++++++++++++++++++++++++++++++++++
> > 3 files changed, 151 insertions(+)
> > create mode 100644 drivers/pwm/pwm-visconti.c
> >
> > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> > index cb8d739067d2..f99d48f74c76 100644
> > --- a/drivers/pwm/Kconfig
> > +++ b/drivers/pwm/Kconfig
> > @@ -533,6 +533,15 @@ config PWM_TIEHRPWM
> > To compile this driver as a module, choose M here: the module
> > will be called pwm-tiehrpwm.
> >
> > +config PWM_VISCONTI
> > + tristate "Toshiba Visconti PWM support"
> > + depends on ARCH_VISCONTI || COMPILE_TEST
> > + help
> > + PWM Subsystem driver support for Toshiba Visconti SoCs.
> > +
> > + To compile this driver as a module, choose M here: the module
> > + will be called pwm-visconti.
> > +
>
> The entries in the file seem to be alphabetically sorted. Can you please
> move this to the appropriate location.
>
OK, I will this.
> > config PWM_TWL
> > tristate "TWL4030/6030 PWM support"
> > depends on TWL4030_CORE
> > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> > index a59c710e98c7..ef6dc1af7c17 100644
> > --- a/drivers/pwm/Makefile
> > +++ b/drivers/pwm/Makefile
> > @@ -51,6 +51,7 @@ obj-$(CONFIG_PWM_SUN4I) += pwm-sun4i.o
> > obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
> > obj-$(CONFIG_PWM_TIECAP) += pwm-tiecap.o
> > obj-$(CONFIG_PWM_TIEHRPWM) += pwm-tiehrpwm.o
> > +obj-$(CONFIG_PWM_VISCONTI) += pwm-visconti.o
>
> Same comment as above.
>
> > obj-$(CONFIG_PWM_TWL) += pwm-twl.o
> > obj-$(CONFIG_PWM_TWL_LED) += pwm-twl-led.o
> > obj-$(CONFIG_PWM_VT8500) += pwm-vt8500.o
> > diff --git a/drivers/pwm/pwm-visconti.c b/drivers/pwm/pwm-visconti.c
> > new file mode 100644
> > index 000000000000..601450111166
> > --- /dev/null
> > +++ b/drivers/pwm/pwm-visconti.c
> > @@ -0,0 +1,141 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Toshiba Visconti pulse-width-modulation controller driver
> > + *
> > + * Copyright (c) 2020 TOSHIBA CORPORATION
> > + * Copyright (c) 2020 Toshiba Electronic Devices & Storage Corporation
> > + * Copyright (c) 2020 Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@xxxxxxxxxxxxx>
> > + *
> > + */
> > +
> > +#include <linux/err.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of_device.h>
> > +#include <linux/pwm.h>
> > +#include <linux/platform_device.h>
> > +
> > +#define PWMC0_PWMACT BIT(5)
> > +
> > +#define REG_PCSR(ch) (0x400 + 4 * (ch))
> > +#define REG_PDUT(ch) (0x420 + 4 * (ch))
> > +#define REG_PWM0(ch) (0x440 + 4 * (ch))
> > +
> > +struct visconti_pwm_chip {
> > + struct pwm_chip chip;
> > + struct device *dev;
>
> "dev" can be dropped from the structure if ..
>
Indeed. I will drop this.
> > + void __iomem *base;
> > +};
> > +
> > +#define to_visconti_chip(chip) \
> > + container_of(chip, struct visconti_pwm_chip, chip)
> > +
> > +static int visconti_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> > + const struct pwm_state *state)
> > +{
> > + struct visconti_pwm_chip *priv = to_visconti_chip(chip);
> > + u32 period, duty, pwmc0;
> > +
> > + dev_dbg(priv->dev, "%s: ch = %d en = %d p = 0x%llx d = 0x%llx\n", __func__,
> > + pwm->hwpwm, state->enabled, state->period, state->duty_cycle);
>
> ... the usage here is replaced by "chip->dev" instead of "priv->dev".
>
I will fix this line.
> > + if (state->enabled) {
> > + period = state->period / 1000;
> > + duty = state->duty_cycle / 1000;
>
> Does it make sense to replace the constant 1000 here with the macro -
> NSEC_PER_USEC?
I see. I will change NSEC_PER_USEC instead of 1000.
>
> Also, period and duty_cycle are defined as u64 in the pwm_state
> structure. Is there any chance for the values to be truncated due to
> them being u32 in the driver?
As you pointed out, the registers of this IP are 32bit.
Therefore, the value may be truncated. I will fix it.
>
> > + if (period < 0x10000)
> > + pwmc0 = 0;
> > + else if (period < 0x20000)
> > + pwmc0 = 1;
> > + else if (period < 0x40000)
> > + pwmc0 = 2;
> > + else if (period < 0x80000)
> > + pwmc0 = 3;
> > + else
> > + return -EINVAL;
> > +
> > + if (pwmc0) {
> > + period /= BIT(pwmc0);
> > + duty /= BIT(pwmc0);
>
> It would be better to replace division with right-shift operator.
>
> period >>= pwmc0;
> duty >>= pwmc0;
I will change to use shift.
>
> > + }
> > +
> > + if (state->polarity == PWM_POLARITY_INVERSED)
> > + pwmc0 |= PWMC0_PWMACT;
> > +
> > + writel(pwmc0, priv->base + REG_PWM0(pwm->hwpwm));
> > + writel(duty, priv->base + REG_PDUT(pwm->hwpwm));
> > + writel(period, priv->base + REG_PCSR(pwm->hwpwm));
> > + } else {
> > + writel(0, priv->base + REG_PCSR(pwm->hwpwm));
> > + }
>
> One suggestion - the else condition can be handled first to reduce
> indentation for the state->enabled condition,
>
>
> if (!state->enabled) {
> ...
> return 0;
> }
>
>
> <handle state enabled case>
>
> But so far the driver is simple enough so I'll leave it upto you which
> way you prefer.
I see.
I will change to your suggestion.
>
> > +
> > + return 0;
> > +}
> > +
> > +static const struct pwm_ops visconti_pwm_ops = {
> > + .apply = visconti_pwm_apply,
> > + .owner = THIS_MODULE,
> > +};
> > +
> > +static int visconti_pwm_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct visconti_pwm_chip *priv;
> > + int ret;
> > +
> > + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> > + if (!priv)
> > + return -ENOMEM;
> > +
> > + priv->dev = &pdev->dev;
> > +
> > + priv->base = devm_platform_ioremap_resource(pdev, 0);
> > + if (IS_ERR(priv->base)) {
> > + dev_err(dev, "unable to map I/O space\n");
> > + return PTR_ERR(priv->base);
> > + }
> > +
> > + platform_set_drvdata(pdev, priv);
> > +
> > + priv->chip.dev = dev;
> > + priv->chip.ops = &visconti_pwm_ops;
> > + priv->chip.base = -1;
> > + priv->chip.npwm = 4;
> > +
> > + ret = pwmchip_add(&priv->chip);
> > + if (ret < 0) {
> > + dev_err(dev, "Cannot register visconti PWM: %d\n", ret);
> > + return ret;
> > + }
> > +
> > + dev_info(&pdev->dev, "visconti PWM registered\n");
> > +
> > + return 0;
> > +}
> > +
> > +static int visconti_pwm_remove(struct platform_device *pdev)
> > +{
> > + struct visconti_pwm_chip *priv = platform_get_drvdata(pdev);
> > +
> > + return pwmchip_remove(&priv->chip);
> > +}
> > +
> > +static const struct of_device_id visconti_pwm_of_match[] = {
> > + { .compatible = "toshiba,pwm-visconti", },
> > + { }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, visconti_pwm_of_match);
> > +
> > +static struct platform_driver visconti_pwm_driver = {
> > + .driver = {
> > + .name = "pwm-visconti",
> > + .of_match_table = visconti_pwm_of_match,
> > + },
> > + .probe = visconti_pwm_probe,
> > + .remove = visconti_pwm_remove,
> > +};
> > +
> > +module_platform_driver(visconti_pwm_driver);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_AUTHOR("Toshiba");
>
> Please use the author name / email here.
>
I see. I will change MODULE_AUTHOR to my name and email.
> > +MODULE_ALIAS("platform:visconti-pwm");
>
> Thanks,
> Punit
>
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