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Date: Mon, 17 Dec 2018 16:51:25 +0100
From: Bartosz Golaszewski <bgolaszewski@...libre.com>
To: Jan Kotas <jank@...ence.com>
Cc: Linus Walleij <linus.walleij@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
linux-gpio <linux-gpio@...r.kernel.org>,
linux-devicetree <devicetree@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver
pon., 17 gru 2018 o 16:37 Jan Kotas <jank@...ence.com> napisał(a):
>
> This patch adds a driver for Cadence GPIO controller.
>
> It can be enabled with GPIO_CADENCE Kconfig option.
> It uses generic GPIO infrastructure and works
> as an interrupt controller.
> At the moment it only supports level sensitive irqs.
>
> Signed-off-by: Jan Kotas <jank@...ence.com>
> ---
> drivers/gpio/Kconfig | 8 ++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-cadence.c | 275 ++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 284 insertions(+)
> create mode 100644 drivers/gpio/gpio-cadence.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index 833a1b51c..8259f8f25 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -160,6 +160,14 @@ config GPIO_BRCMSTB
> help
> Say yes here to enable GPIO support for Broadcom STB (BCM7XXX) SoCs.
>
> +config GPIO_CADENCE
> + tristate "Cadence GPIO support"
> + depends on OF_GPIO
> + select GPIO_GENERIC
> + select GPIOLIB_IRQCHIP
> + help
> + Say yes here to enable support for Cadence GPIO controller.
> +
> config GPIO_CLPS711X
> tristate "CLPS711X GPIO support"
> depends on ARCH_CLPS711X || COMPILE_TEST
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 671c4477c..5fce8634a 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -37,6 +37,7 @@ obj-$(CONFIG_GPIO_BCM_KONA) += gpio-bcm-kona.o
> obj-$(CONFIG_GPIO_BD9571MWV) += gpio-bd9571mwv.o
> obj-$(CONFIG_GPIO_BRCMSTB) += gpio-brcmstb.o
> obj-$(CONFIG_GPIO_BT8XX) += gpio-bt8xx.o
> +obj-$(CONFIG_GPIO_CADENCE) += gpio-cadence.o
> obj-$(CONFIG_GPIO_CLPS711X) += gpio-clps711x.o
> obj-$(CONFIG_GPIO_CS5535) += gpio-cs5535.o
> obj-$(CONFIG_GPIO_CRYSTAL_COVE) += gpio-crystalcove.o
> diff --git a/drivers/gpio/gpio-cadence.c b/drivers/gpio/gpio-cadence.c
> new file mode 100644
> index 000000000..16cc9f50f
> --- /dev/null
> +++ b/drivers/gpio/gpio-cadence.c
> @@ -0,0 +1,275 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +/*
> + * Copyright 2017-2018 Cadence
> + *
> + * Authors:
> + * Jan Kotas <jank@...ence.com>
> + * Boris Brezillon <boris.brezillon@...e-electrons.com>
> + */
> +
> +#include <linux/gpio/driver.h>
> +#include <linux/clk.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#define CDNS_GPIO_BYPASS_MODE 0x00
> +#define CDNS_GPIO_DIRECTION_MODE 0x04
> +#define CDNS_GPIO_OUTPUT_EN 0x08
> +#define CDNS_GPIO_OUTPUT_VALUE 0x0c
> +#define CDNS_GPIO_INPUT_VALUE 0x10
> +#define CDNS_GPIO_IRQ_MASK 0x14
> +#define CDNS_GPIO_IRQ_EN 0x18
> +#define CDNS_GPIO_IRQ_DIS 0x1c
> +#define CDNS_GPIO_IRQ_STATUS 0x20
> +#define CDNS_GPIO_IRQ_TYPE 0x24
> +#define CDNS_GPIO_IRQ_VALUE 0x28
> +#define CDNS_GPIO_IRQ_ANY_EDGE 0x2c
> +
> +struct cdns_gpio_chip {
> + struct gpio_chip gc;
> + struct clk *pclk;
> + void __iomem *regs;
> + u32 bypass_orig;
> +};
> +
> +static int cdns_gpio_request(struct gpio_chip *chip, unsigned int offset)
> +{
> + struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
> +
> + iowrite32(ioread32(cgpio->regs + CDNS_GPIO_BYPASS_MODE) & ~BIT(offset),
> + cgpio->regs + CDNS_GPIO_BYPASS_MODE);
> +
> + return 0;
> +}
> +
> +static void cdns_gpio_free(struct gpio_chip *chip, unsigned int offset)
> +{
> + struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
> +
> + iowrite32(ioread32(cgpio->regs + CDNS_GPIO_BYPASS_MODE) |
> + (BIT(offset) & cgpio->bypass_orig),
> + cgpio->regs + CDNS_GPIO_BYPASS_MODE);
> +}
> +
> +static void cdns_gpio_irq_mask(struct irq_data *d)
> +{
> + struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
> + struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
> +
> + iowrite32(BIT(d->hwirq), cgpio->regs + CDNS_GPIO_IRQ_DIS);
> +}
> +
> +static void cdns_gpio_irq_unmask(struct irq_data *d)
> +{
> + struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
> + struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
> +
> + iowrite32(BIT(d->hwirq), cgpio->regs + CDNS_GPIO_IRQ_EN);
> +}
> +
> +static int cdns_gpio_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> + struct gpio_chip *chip = irq_data_get_irq_chip_data(d);
> + struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
> + u32 int_value = ioread32(cgpio->regs + CDNS_GPIO_IRQ_VALUE);
> + u32 int_type = ioread32(cgpio->regs + CDNS_GPIO_IRQ_TYPE);
> + u32 mask = BIT(d->hwirq);
> +
> + int_value &= ~mask;
> + int_type &= ~mask;
> +
> + /*
> + * The GPIO controller doesn't have an ACK register.
> + * All interrupt statuses are cleared on a status register read.
> + * Don't support edge interrupts for now.
> + */
> +
> + if (type == IRQ_TYPE_LEVEL_HIGH) {
> + int_type |= mask;
> + int_value |= mask;
> + } else if (type == IRQ_TYPE_LEVEL_LOW) {
> + int_type |= mask;
> + } else {
> + return -EINVAL;
> + }
> +
> + iowrite32(int_value, cgpio->regs + CDNS_GPIO_IRQ_VALUE);
> + iowrite32(int_type, cgpio->regs + CDNS_GPIO_IRQ_TYPE);
> +
> + return 0;
> +}
> +
> +static void cdns_gpio_irq_handler(struct irq_desc *desc)
> +{
> + struct gpio_chip *chip = irq_desc_get_handler_data(desc);
> + struct cdns_gpio_chip *cgpio = gpiochip_get_data(chip);
> + struct irq_chip *irqchip = irq_desc_get_chip(desc);
> + unsigned long status;
> + int hwirq;
> +
> + chained_irq_enter(irqchip, desc);
> +
> + status = ioread32(cgpio->regs + CDNS_GPIO_IRQ_STATUS) &
> + ~ioread32(cgpio->regs + CDNS_GPIO_IRQ_MASK);
> +
> + for_each_set_bit(hwirq, &status, chip->ngpio)
> + generic_handle_irq(irq_find_mapping(chip->irq.domain, hwirq));
> +
> + chained_irq_exit(irqchip, desc);
> +}
> +
> +static struct irq_chip cdns_gpio_irqchip = {
> + .name = "cdns-gpio",
> + .irq_mask = cdns_gpio_irq_mask,
> + .irq_unmask = cdns_gpio_irq_unmask,
> + .irq_set_type = cdns_gpio_irq_set_type
> +};
> +
> +static int cdns_gpio_probe(struct platform_device *pdev)
> +{
> + struct cdns_gpio_chip *cgpio;
> + struct resource *res;
> + int ret, irq;
> + u32 dir_prev;
> + u32 num_gpios = 32;
> +
> + cgpio = devm_kzalloc(&pdev->dev, sizeof(*cgpio), GFP_KERNEL);
> + if (!cgpio)
> + return -ENOMEM;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + cgpio->regs = devm_ioremap_resource(&pdev->dev, res);
> + if (IS_ERR(cgpio->regs))
> + return PTR_ERR(cgpio->regs);
> +
> + of_property_read_u32(pdev->dev.of_node, "ngpios", &num_gpios);
> +
> + if (num_gpios > 32) {
> + dev_err(&pdev->dev, "ngpios must be less or equal 32\n");
> + return -EINVAL;
> + }
> +
> + /*
> + * Set all pins as inputs by default, otherwise:
> + * gpiochip_lock_as_irq:
> + * tried to flag a GPIO set as output for IRQ
> + * Generic GPIO driver stores the direction value internally,
> + * so it needs to be changed before bgpio_init() is called.
> + */
> + dir_prev = ioread32(cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
> + iowrite32(GENMASK(num_gpios - 1, 0),
> + cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
> +
> + ret = bgpio_init(&cgpio->gc, &pdev->dev, 4,
> + cgpio->regs + CDNS_GPIO_INPUT_VALUE,
> + cgpio->regs + CDNS_GPIO_OUTPUT_VALUE,
> + NULL,
> + NULL,
> + cgpio->regs + CDNS_GPIO_DIRECTION_MODE,
> + BGPIOF_READ_OUTPUT_REG_SET);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to register generic gpio, %d\n",
> + ret);
> + goto err_revert_dir;
> + }
> +
> + cgpio->gc.label = dev_name(&pdev->dev);
> + cgpio->gc.ngpio = num_gpios;
> + cgpio->gc.parent = &pdev->dev;
> + cgpio->gc.base = -1;
> + cgpio->gc.owner = THIS_MODULE;
> + cgpio->gc.request = cdns_gpio_request;
> + cgpio->gc.free = cdns_gpio_free;
> +
> + cgpio->pclk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(cgpio->pclk)) {
> + ret = PTR_ERR(cgpio->pclk);
> + dev_err(&pdev->dev,
> + "Failed to retrieve peripheral clock, %d\n", ret);
> + goto err_revert_dir;
> + }
> +
> + ret = clk_prepare_enable(cgpio->pclk);
> + if (ret) {
> + dev_err(&pdev->dev,
> + "Failed to enable the peripheral clock, %d\n", ret);
> + goto err_revert_dir;
> + }
> +
> + ret = devm_gpiochip_add_data(&pdev->dev, &cgpio->gc, cgpio);
> + if (ret < 0) {
> + dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
> + goto err_disable_clk;
> + }
> +
> + /*
> + * irq_chip support
> + */
> + irq = platform_get_irq(pdev, 0);
> + if (irq >= 0) {
> + ret = gpiochip_irqchip_add(&cgpio->gc, &cdns_gpio_irqchip,
> + 0, handle_level_irq,
> + IRQ_TYPE_NONE);
> + if (ret) {
> + dev_err(&pdev->dev, "Could not add irqchip, %d\n",
> + ret);
> + goto err_disable_clk;
> + }
> + gpiochip_set_chained_irqchip(&cgpio->gc, &cdns_gpio_irqchip,
> + irq, cdns_gpio_irq_handler);
> + }
> +
> + cgpio->bypass_orig = ioread32(cgpio->regs + CDNS_GPIO_BYPASS_MODE);
> +
> + /*
> + * Enable gpio outputs, ignored for input direction
> + */
> + iowrite32(GENMASK(num_gpios - 1, 0),
> + cgpio->regs + CDNS_GPIO_OUTPUT_EN);
> + iowrite32(0, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
> +
> + platform_set_drvdata(pdev, cgpio);
> + return 0;
> +
> +err_disable_clk:
> + clk_disable_unprepare(cgpio->pclk);
> +
> +err_revert_dir:
> + iowrite32(dir_prev, cgpio->regs + CDNS_GPIO_DIRECTION_MODE);
> +
> + return ret;
> +}
> +
> +static int cdns_gpio_remove(struct platform_device *pdev)
> +{
> + struct cdns_gpio_chip *cgpio = platform_get_drvdata(pdev);
> +
> + iowrite32(cgpio->bypass_orig, cgpio->regs + CDNS_GPIO_BYPASS_MODE);
> + clk_disable_unprepare(cgpio->pclk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id cdns_of_ids[] = {
> + { .compatible = "cdns,gpio-r1p02" },
> + { /* sentinel */ },
> +};
> +
> +static struct platform_driver cdns_gpio_driver = {
> + .driver = {
> + .name = "cdns-gpio",
> + .of_match_table = cdns_of_ids,
> + },
> + .probe = cdns_gpio_probe,
> + .remove = cdns_gpio_remove,
> +};
> +module_platform_driver(cdns_gpio_driver);
> +
> +MODULE_AUTHOR("Jan Kotas <jank@...ence.com>");
> +MODULE_DESCRIPTION("Cadence GPIO driver");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:cdns-gpio");
> --
> 2.15.0
>
The driver looks good but is there any particular reason not to use
regmap for register IO?
Bart
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