Re: [PATCH 2/4] gpio: Add RDA Micro GPIO controller support

From: Bartosz Golaszewski
Date: Mon Oct 14 2019 - 10:25:44 EST

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In reply to: Manivannan Sadhasivam: "[PATCH 2/4] gpio: Add RDA Micro GPIO controller support"
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niedz., 13 paÅ 2019 o 13:40 Manivannan Sadhasivam
<manivannan.sadhasivam@xxxxxxxxxx> napisaÅ(a):
>
> Add support for GPIO controller from RDA Micro.

Looks nice and clean, just a couple nits.

>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
> ---
> 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.

> +
> +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.

> +
> +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.

> + 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.

> + /*
> + * 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.

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@xxxxxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> --
> 2.17.1
>

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