Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 15 Oct 2019 22:21:39 +0530
From:   Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To:     Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc:     Linus Walleij <linus.walleij@linaro.org>,
        arm-soc <linux-arm-kernel@lists.infradead.org>,
        linux-unisoc@lists.infradead.org,
        linux-gpio <linux-gpio@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Orson Zhai <orsonzhai@gmail.com>
Subject: Re: [PATCH 2/4] gpio: Add RDA Micro GPIO controller support
Message-ID: <20191015165139.GA11788@Mani-XPS-13-9360>
References: <20191013114037.9845-1-manivannan.sadhasivam@linaro.org>
 <20191013114037.9845-3-manivannan.sadhasivam@linaro.org>
 <CAMpxmJU6odqXcsAbZiYoh94Ett44z+R05WMygB66jCg8xd0UZw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <CAMpxmJU6odqXcsAbZiYoh94Ett44z+R05WMygB66jCg8xd0UZw@mail.gmail.com>
User-Agent: Mutt/1.9.4 (2018-02-28)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Bartosz,

Thanks for the quick review! Please find the reply inline.

On Mon, Oct 14, 2019 at 04:25:29PM +0200, Bartosz Golaszewski wrote:
> niedz., 13 paź 2019 o 13:40 Manivannan Sadhasivam
> <manivannan.sadhasivam@linaro.org> napisał(a):
> >
> > Add support for GPIO controller from RDA Micro.
> 
> Looks nice and clean, just a couple nits.
> 
> >
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > ---
> >  drivers/gpio/Kconfig    |   8 +
> >  drivers/gpio/Makefile   |   1 +
> >  drivers/gpio/gpio-rda.c | 334 ++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 343 insertions(+)
> >  create mode 100644 drivers/gpio/gpio-rda.c
> >
> > diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> > index 38e096e6925f..71826e61fdb3 100644
> > --- a/drivers/gpio/Kconfig
> > +++ b/drivers/gpio/Kconfig
> > @@ -435,6 +435,14 @@ config GPIO_RCAR
> >         help
> >           Say yes here to support GPIO on Renesas R-Car SoCs.
> >
> > +config GPIO_RDA
> > +       bool "RDA Micro GPIO controller support"
> > +       depends on ARCH_RDA || COMPILE_TEST
> > +       depends on OF_GPIO
> > +       select GPIOLIB_IRQCHIP
> > +       help
> > +         Say Y here to support RDA Micro GPIO controller.
> > +
> >  config GPIO_REG
> >         bool
> >         help
> > diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> > index d2fd19c15bae..5c68c9a48fa3 100644
> > --- a/drivers/gpio/Makefile
> > +++ b/drivers/gpio/Makefile
> > @@ -115,6 +115,7 @@ obj-$(CONFIG_GPIO_PXA)                      += gpio-pxa.o
> >  obj-$(CONFIG_GPIO_RASPBERRYPI_EXP)     += gpio-raspberrypi-exp.o
> >  obj-$(CONFIG_GPIO_RC5T583)             += gpio-rc5t583.o
> >  obj-$(CONFIG_GPIO_RCAR)                        += gpio-rcar.o
> > +obj-$(CONFIG_GPIO_RDA)                 += gpio-rda.o
> >  obj-$(CONFIG_GPIO_RDC321X)             += gpio-rdc321x.o
> >  obj-$(CONFIG_GPIO_REG)                 += gpio-reg.o
> >  obj-$(CONFIG_ARCH_SA1100)              += gpio-sa1100.o
> > diff --git a/drivers/gpio/gpio-rda.c b/drivers/gpio/gpio-rda.c
> > new file mode 100644
> > index 000000000000..5a4adeb25f72
> > --- /dev/null
> > +++ b/drivers/gpio/gpio-rda.c
> > @@ -0,0 +1,334 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * RDA Micro GPIO driver
> > + *
> > + * Copyright (C) 2012 RDA Micro Inc.
> > + * Copyright (C) 2019 Manivannan Sadhasivam
> > + */
> > +
> > +#include <linux/bitops.h>
> > +#include <linux/gpio/driver.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of_device.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/spinlock.h>
> > +
> > +#define RDA_GPIO_OEN_VAL               0x00
> > +#define RDA_GPIO_OEN_SET_OUT           0x04
> > +#define RDA_GPIO_OEN_SET_IN            0x08
> > +#define RDA_GPIO_VAL                   0x0c
> > +#define RDA_GPIO_SET                   0x10
> > +#define RDA_GPIO_CLR                   0x14
> > +#define RDA_GPIO_INT_CTRL_SET          0x18
> > +#define RDA_GPIO_INT_CTRL_CLR          0x1c
> > +#define RDA_GPIO_INT_CLR               0x20
> > +#define RDA_GPIO_INT_STATUS            0x24
> > +
> > +#define RDA_GPIO_IRQ_RISE_SHIFT                0
> > +#define RDA_GPIO_IRQ_FALL_SHIFT                8
> > +#define RDA_GPIO_DEBOUCE_SHIFT         16
> > +#define RDA_GPIO_LEVEL_SHIFT           24
> > +
> > +#define RDA_GPIO_IRQ_MASK              0xff
> > +
> > +/* Each bank consists of 32 GPIOs */
> > +#define RDA_GPIO_BANK_NR       32
> > +
> > +struct rda_gpio {
> > +       struct gpio_chip chip;
> > +       void __iomem *base;
> > +       spinlock_t lock;
> > +       struct irq_chip irq_chip;
> > +       int irq;
> > +};
> > +
> > +static void rda_gpio_update(struct gpio_chip *chip, unsigned int offset,
> > +                           u16 reg, int val)
> > +{
> > +       struct rda_gpio *rda_gpio = gpiochip_get_data(chip);
> > +       void __iomem *base = rda_gpio->base;
> > +       unsigned long flags;
> > +       u32 tmp;
> > +
> > +       spin_lock_irqsave(&rda_gpio->lock, flags);
> > +       tmp = readl_relaxed(base + reg);
> > +
> > +       if (val)
> > +               tmp |= BIT(offset);
> > +       else
> > +               tmp &= ~BIT(offset);
> > +
> > +       writel_relaxed(tmp, base + reg);
> > +       spin_unlock_irqrestore(&rda_gpio->lock, flags);
> > +}
> 
> If you used the mmio regmap, you could save all this code and reuse
> regmap's update helpers. This is just a suggestion, not a requirement
> though.
> 

Agree. I'll post a patch later once this driver gets in.

> > +
> > +static int rda_gpio_request(struct gpio_chip *chip, unsigned int offset)
> > +{
> > +       /* Not supported currently */
> > +       return 0;
> > +}
> > +
> > +static void rda_gpio_free(struct gpio_chip *chip, unsigned int offset)
> > +{
> > +       /* Not supported currently */
> > +}
> 
> Just don't implement these callbacks if they're doing nothing.
> 

Hmm. Since these are some critical callbacks, I thought the drivers should
explicitly expose even not implemented. But I can remove them.

> > +
> > +static int rda_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
> > +{
> > +       rda_gpio_update(chip, offset, RDA_GPIO_OEN_SET_IN, 1);
> > +
> > +       return 0;
> > +}
> > +
> > +static int rda_gpio_direction_output(struct gpio_chip *chip,
> > +                                    unsigned int offset, int value)
> > +{
> > +       rda_gpio_update(chip, offset, RDA_GPIO_OEN_SET_OUT, 1);
> > +
> > +       return 0;
> > +}
> > +
> > +static int rda_gpio_get(struct gpio_chip *chip, unsigned int offset)
> > +{
> > +       struct rda_gpio *rda_gpio = gpiochip_get_data(chip);
> > +       void __iomem *base = rda_gpio->base;
> > +
> > +       if (readl_relaxed(base + RDA_GPIO_OEN_VAL) & BIT(offset))
> > +               return !!(readl_relaxed(base + RDA_GPIO_VAL) & BIT(offset));
> > +       else
> > +               return !!(readl_relaxed(base + RDA_GPIO_SET) & BIT(offset));
> > +}
> > +
> > +static void rda_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
> > +{
> > +       if (value)
> > +               rda_gpio_update(chip, offset, RDA_GPIO_SET, 1);
> > +       else
> > +               rda_gpio_update(chip, offset, RDA_GPIO_CLR, 1);
> > +}
> > +
> > +static void rda_gpio_irq_mask(struct irq_data *data)
> > +{
> > +       struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
> > +       struct rda_gpio *rda_gpio = gpiochip_get_data(chip);
> > +       void __iomem *base = rda_gpio->base;
> > +       u32 offset = irqd_to_hwirq(data);
> > +       u32 value;
> > +
> > +       value = BIT(offset) << RDA_GPIO_IRQ_RISE_SHIFT;
> > +       value |= BIT(offset) << RDA_GPIO_IRQ_FALL_SHIFT;
> > +
> > +       writel_relaxed(value, base + RDA_GPIO_INT_CTRL_CLR);
> > +}
> > +
> > +static void rda_gpio_irq_ack(struct irq_data *data)
> > +{
> > +       struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
> > +       u32 offset = irqd_to_hwirq(data);
> > +
> > +       rda_gpio_update(chip, offset, RDA_GPIO_INT_CLR, 1);
> > +}
> > +
> > +static int rda_gpio_set_irq(struct gpio_chip *chip, u32 offset,
> > +                           unsigned int flow_type)
> > +{
> > +       struct rda_gpio *rda_gpio = gpiochip_get_data(chip);
> > +       void __iomem *base = rda_gpio->base;
> > +       u32 value;
> > +
> > +       switch (flow_type) {
> > +       case IRQ_TYPE_EDGE_RISING:
> > +               /* Set rising edge trigger */
> > +               value = BIT(offset) << RDA_GPIO_IRQ_RISE_SHIFT;
> > +               writel_relaxed(value, base + RDA_GPIO_INT_CTRL_SET);
> > +
> > +               /* Switch to edge trigger interrupt */
> > +               value = BIT(offset) << RDA_GPIO_LEVEL_SHIFT;
> > +               writel_relaxed(value, base + RDA_GPIO_INT_CTRL_CLR);
> > +               break;
> > +
> > +       case IRQ_TYPE_EDGE_FALLING:
> > +               /* Set falling edge trigger */
> > +               value = BIT(offset) << RDA_GPIO_IRQ_FALL_SHIFT;
> > +               writel_relaxed(value, base + RDA_GPIO_INT_CTRL_SET);
> > +
> > +               /* Switch to edge trigger interrupt */
> > +               value = BIT(offset) << RDA_GPIO_LEVEL_SHIFT;
> > +               writel_relaxed(value, base + RDA_GPIO_INT_CTRL_CLR);
> > +               break;
> > +
> > +       case IRQ_TYPE_EDGE_BOTH:
> > +               /* Set both edge trigger */
> > +               value = BIT(offset) << RDA_GPIO_IRQ_RISE_SHIFT;
> > +               value |= BIT(offset) << RDA_GPIO_IRQ_FALL_SHIFT;
> > +               writel_relaxed(value, base + RDA_GPIO_INT_CTRL_SET);
> > +
> > +               /* Switch to edge trigger interrupt */
> > +               value = BIT(offset) << RDA_GPIO_LEVEL_SHIFT;
> > +               writel_relaxed(value, base + RDA_GPIO_INT_CTRL_CLR);
> > +               break;
> > +
> > +       case IRQ_TYPE_LEVEL_HIGH:
> > +               /* Set high level trigger */
> > +               value = BIT(offset) << RDA_GPIO_IRQ_RISE_SHIFT;
> > +
> > +               /* Switch to level trigger interrupt */
> > +               value |= BIT(offset) << RDA_GPIO_LEVEL_SHIFT;
> > +               writel_relaxed(value, base + RDA_GPIO_INT_CTRL_SET);
> > +               break;
> > +
> > +       case IRQ_TYPE_LEVEL_LOW:
> > +               /* Set low level trigger */
> > +               value = BIT(offset) << RDA_GPIO_IRQ_FALL_SHIFT;
> > +
> > +               /* Switch to level trigger interrupt */
> > +               value |= BIT(offset) << RDA_GPIO_LEVEL_SHIFT;
> > +               writel_relaxed(value, base + RDA_GPIO_INT_CTRL_SET);
> > +               break;
> > +
> > +       default:
> > +               return -EINVAL;
> > +       }
> > +
> > +       return 0;
> > +}
> > +
> > +static void rda_gpio_irq_unmask(struct irq_data *data)
> > +{
> > +       struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
> > +       u32 offset = irqd_to_hwirq(data);
> > +       u32 trigger = irqd_get_trigger_type(data);
> > +
> > +       rda_gpio_set_irq(chip, offset, trigger);
> > +}
> > +
> > +static int rda_gpio_irq_set_type(struct irq_data *data, unsigned int flow_type)
> > +{
> > +       struct gpio_chip *chip = irq_data_get_irq_chip_data(data);
> > +       u32 offset = irqd_to_hwirq(data);
> > +       int ret;
> > +
> > +       ret = rda_gpio_set_irq(chip, offset, flow_type);
> > +       if (ret)
> > +               return ret;
> > +
> > +       if (flow_type & (IRQ_TYPE_LEVEL_LOW | IRQ_TYPE_LEVEL_HIGH))
> > +               irq_set_handler_locked(data, handle_level_irq);
> > +       else if (flow_type & (IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
> > +               irq_set_handler_locked(data, handle_edge_irq);
> > +
> > +       return 0;
> > +}
> > +
> > +static void rda_gpio_irq_handler(struct irq_desc *desc)
> > +{
> > +       struct gpio_chip *chip = irq_desc_get_handler_data(desc);
> > +       struct irq_chip *ic = irq_desc_get_chip(desc);
> > +       struct rda_gpio *rda_gpio = gpiochip_get_data(chip);
> > +       unsigned long status;
> > +       u32 n, girq;
> > +
> > +       chained_irq_enter(ic, desc);
> > +
> > +       status = readl_relaxed(rda_gpio->base + RDA_GPIO_INT_STATUS);
> > +       /* Only lower 8 bits are capable of generating interrupts */
> > +       status &= RDA_GPIO_IRQ_MASK;
> > +
> > +       for_each_set_bit(n, &status, RDA_GPIO_BANK_NR) {
> > +               girq = irq_find_mapping(chip->irq.domain, n);
> > +               generic_handle_irq(girq);
> > +       }
> > +
> > +       chained_irq_exit(ic, desc);
> > +}
> > +
> > +static int rda_gpio_probe(struct platform_device *pdev)
> > +{
> > +       struct device_node *np = pdev->dev.of_node;
> > +       struct gpio_irq_chip *irq;
> 
> Can you call this variable irq_chip? Visually it interferes with
> rda_gpio->irq too much.
> 

okay.

> > +       struct rda_gpio *rda_gpio;
> > +       u32 ngpios;
> > +       int ret;
> > +
> > +       rda_gpio = devm_kzalloc(&pdev->dev, sizeof(*rda_gpio), GFP_KERNEL);
> > +       if (!rda_gpio)
> > +               return -ENOMEM;
> > +
> > +       ret = of_property_read_u32(np, "ngpios", &ngpios);
> > +       if (ret < 0)
> > +               return ret;
> > +
> 
> Please use the generic device property helpers unless it's really
> necessary to use of_ variants. Also: remove the of_device.h include.
> 

okay.

> > +       /*
> > +        * Not all ports have interrupt capability. For instance, on
> > +        * RDA8810PL, GPIOC doesn't support interrupt. So we must handle
> > +        * those also.
> > +        */
> > +       rda_gpio->irq = platform_get_irq(pdev, 0);
> > +
> > +       rda_gpio->base = devm_platform_ioremap_resource(pdev, 0);
> > +       if (IS_ERR(rda_gpio->base))
> > +               return PTR_ERR(rda_gpio->base);
> > +
> > +       spin_lock_init(&rda_gpio->lock);
> > +
> > +       rda_gpio->chip.label = dev_name(&pdev->dev);
> > +       rda_gpio->chip.ngpio = ngpios;
> > +       rda_gpio->chip.base = -1;
> > +       rda_gpio->chip.parent = &pdev->dev;
> > +       rda_gpio->chip.of_node = np;
> > +       rda_gpio->chip.request = rda_gpio_request;
> > +       rda_gpio->chip.free = rda_gpio_free;
> > +       rda_gpio->chip.get = rda_gpio_get;
> > +       rda_gpio->chip.set = rda_gpio_set;
> > +       rda_gpio->chip.direction_input = rda_gpio_direction_input;
> > +       rda_gpio->chip.direction_output = rda_gpio_direction_output;
> > +
> > +       if (rda_gpio->irq >= 0) {
> > +               rda_gpio->irq_chip.name = "rda-gpio",
> > +               rda_gpio->irq_chip.irq_ack = rda_gpio_irq_ack,
> > +               rda_gpio->irq_chip.irq_mask = rda_gpio_irq_mask,
> > +               rda_gpio->irq_chip.irq_unmask = rda_gpio_irq_unmask,
> > +               rda_gpio->irq_chip.irq_set_type = rda_gpio_irq_set_type,
> > +               rda_gpio->irq_chip.flags = IRQCHIP_SKIP_SET_WAKE,
> > +
> > +               irq = &rda_gpio->chip.irq;
> > +               irq->chip = &rda_gpio->irq_chip;
> > +               irq->handler = handle_bad_irq;
> > +               irq->default_type = IRQ_TYPE_NONE;
> > +               irq->parent_handler = rda_gpio_irq_handler;
> > +               irq->parent_handler_data = rda_gpio;
> > +               irq->num_parents = 1;
> > +               irq->parents = &rda_gpio->irq;
> > +       }
> > +
> > +       ret = devm_gpiochip_add_data(&pdev->dev, &rda_gpio->chip, rda_gpio);
> 
> I'd simply do 'return devm_gpiochip_add_data()' here, not much else
> can fail in this driver's probe.
> 

okay. I'll just move the platform_set_drvdata() call up and return directly.

Thanks,
Mani

> Bart
> 
> > +       if (ret < 0) {
> > +               dev_err(&pdev->dev, "Could not register gpiochip %d\n", ret);
> > +               return ret;
> > +       }
> > +
> > +       platform_set_drvdata(pdev, rda_gpio);
> > +
> > +       return 0;
> > +}
> > +
> > +static const struct of_device_id rda_gpio_of_match[] = {
> > +       { .compatible = "rda,8810pl-gpio", },
> > +       { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, rda_gpio_of_match);
> > +
> > +static struct platform_driver rda_gpio_driver = {
> > +       .probe = rda_gpio_probe,
> > +       .driver = {
> > +               .name = "rda-gpio",
> > +               .of_match_table = rda_gpio_of_match,
> > +       },
> > +};
> > +
> > +module_platform_driver_probe(rda_gpio_driver, rda_gpio_probe);
> > +
> > +MODULE_DESCRIPTION("RDA Micro GPIO driver");
> > +MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 2.17.1
> >