[PATCH v2 0/2] gpio: Add a driver for Cadence GPIO controller

[PATCH v2 0/2] gpio: Add a driver for Cadence GPIO controller

[Jan Kotas]

This patchset adds a driver support for Cadence GPIO controller.

Number of supported lines is configurable.
The driver initializes all pins as inputs in probe().
Currently it only supports level-sensitive interrupts.

The interrupts controller was tested with I2C and SPI IPs
acting as interrupt sources.

Changes since V1:
	Switched to generic GPIO infrastructure.
	Redesigned interrupts, now uses chained irqchip.
	Drop support for edge-sensitive interrupts.
	Restore bypass settings at unexport/remove.

Jan Kotas (2):
  dt-bindings: gpio: Add bindings for Cadence GPIO
  gpio: Add Cadence GPIO driver

 .../devicetree/bindings/gpio/cdns,gpio.txt         |  44 ++++
 drivers/gpio/Kconfig                               |   8 +
 drivers/gpio/Makefile                              |   1 +
 drivers/gpio/gpio-cadence.c                        | 275 +++++++++++++++++++++
 4 files changed, 328 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/cdns,gpio.txt
 create mode 100644 drivers/gpio/gpio-cadence.c

-- 
2.15.0

[PATCH v2 1/2] dt-bindings: gpio: Add bindings for Cadence GPIO

[Jan Kotas]

This patch adds a DT binding documentation for
Cadence GPIO controller.

Signed-off-by: Jan Kotas <jank@cadence.com>
---
 .../devicetree/bindings/gpio/cdns,gpio.txt         | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/cdns,gpio.txt

diff --git a/Documentation/devicetree/bindings/gpio/cdns,gpio.txt b/Documentation/devicetree/bindings/gpio/cdns,gpio.txt
new file mode 100644
index 000000000..c87a47827
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/cdns,gpio.txt
@@ -0,0 +1,44 @@
+Cadence GPIO controller bindings
+
+Required properties:
+- compatible: should be "cdns,gpio-r1p02".
+- reg: the register base address and size.
+- #gpio-cells: should be 2.
+	* first cell is the GPIO number.
+	* second cell specifies the GPIO flags, as defined in
+		<dt-bindings/gpio/gpio.h>. Only the GPIO_ACTIVE_HIGH
+		and GPIO_ACTIVE_LOW flags are supported.
+- gpio-controller: marks the device as a GPIO controller.
+- clocks: should contain one entry referencing the peripheral clock driving
+	the GPIO controller.
+
+Optional properties:
+- ngpios: integer number of gpio lines supported by this controller, up to 32.
+- interrupt-parent: phandle of the parent interrupt controller.
+- interrupts: interrupt specifier for the controllers interrupt.
+- interrupt-controller: marks the device as an interrupt controller. When
+	defined, interrupts, interrupt-parent and #interrupt-cells
+	are required.
+- interrupt-cells: should be 2.
+	* first cell is the GPIO number you want to use as an IRQ source.
+	* second cell specifies the IRQ type, as defined in
+		<dt-bindings/interrupt-controller/irq.h>.
+		Currently only level sensitive IRQs are supported.
+
+
+Example:
+	gpio0: gpio-controller@fd060000 {
+		compatible = "cdns,gpio-r1p02";
+		reg =<0xfd060000 0x1000>;
+
+		clocks = <&gpio_clk>;
+
+		interrupt-parent = <&gic>;
+		interrupts = <0 5 IRQ_TYPE_LEVEL_HIGH>;
+
+		gpio-controller;
+		#gpio-cells = <2>;
+
+		interrupt-controller;
+		#interrupt-cells = <2>;
+	};
-- 
2.15.0

[PATCH v2 2/2] gpio: Add Cadence GPIO driver

[Jan Kotas]

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@cadence.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@cadence.com>
+ *  Boris Brezillon <boris.brezillon@free-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@cadence.com>");
+MODULE_DESCRIPTION("Cadence GPIO driver");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:cdns-gpio");
-- 
2.15.0

Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver

[Bartosz Golaszewski]

pon., 17 gru 2018 o 16:37 Jan Kotas <jank@cadence.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@cadence.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@cadence.com>
> + *  Boris Brezillon <boris.brezillon@free-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@cadence.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

Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver

[Linus Walleij]

On Mon, Dec 17, 2018 at 4:51 PM Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:

> The driver looks good but is there any particular reason not to use
> regmap for register IO?

I thought we only use regmap for MMIO when the register range is
shared (as in a system controller) so that some registers are for this,
some register or even bits in a register for some other driver, so they
need the spinlock in the regmap to protect the register range.

It is also nice for shadowing/caching of register contents I guess,
wat does this driver get from regmap MMIO?

Yours,
Linus Walleij

Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver

[Bartosz Golaszewski]

pon., 17 gru 2018 o 23:22 Linus Walleij <linus.walleij@linaro.org> napisał(a):
>
> On Mon, Dec 17, 2018 at 4:51 PM Bartosz Golaszewski
> <bgolaszewski@baylibre.com> wrote:
>
> > The driver looks good but is there any particular reason not to use
> > regmap for register IO?
>
> I thought we only use regmap for MMIO when the register range is
> shared (as in a system controller) so that some registers are for this,
> some register or even bits in a register for some other driver, so they
> need the spinlock in the regmap to protect the register range.
>

This is what syscon is for. Regmap simply abstracts any register IO.
For instance: there's no locking in this driver. Are we sure it's not
needed? Regmap provides internal locking for you in the form of a
mutex or spinlock.

Also: it looks like the interrupts here are quite simple with a single
bit per interrupt in the status register and the same layout in the
mask register - it could probably profit from using the
regmap_irq_chip and not bother with reimplementing irq_chip callbacks.

> It is also nice for shadowing/caching of register contents I guess,
> wat does this driver get from regmap MMIO?
>

Code shrinkage IMO.

Note that I'm not blocking this from being merged - I just think that
using modern frameworks is always a good idea.

Best regards,
Bartosz Golaszewski

> Yours,
> Linus Walleij

Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver

[Janek Kotas]

> On 18 Dec 2018, at 13:50, Bartosz Golaszewski <bgolaszewski@baylibre.com> wrote:
> 
> 
> pon., 17 gru 2018 o 23:22 Linus Walleij <linus.walleij@linaro.org> napisał(a):
>> 
>> On Mon, Dec 17, 2018 at 4:51 PM Bartosz Golaszewski
>> <bgolaszewski@baylibre.com> wrote:
>> 
>>> The driver looks good but is there any particular reason not to use
>>> regmap for register IO?
>> 
>> I thought we only use regmap for MMIO when the register range is
>> shared (as in a system controller) so that some registers are for this,
>> some register or even bits in a register for some other driver, so they
>> need the spinlock in the regmap to protect the register range.
>> 
> 
> This is what syscon is for. Regmap simply abstracts any register IO.
> For instance: there's no locking in this driver. Are we sure it's not
> needed? Regmap provides internal locking for you in the form of a
> mutex or spinlock.
> 
> Also: it looks like the interrupts here are quite simple with a single
> bit per interrupt in the status register and the same layout in the
> mask register - it could probably profit from using the
> regmap_irq_chip and not bother with reimplementing irq_chip callbacks.
> 
>> It is also nice for shadowing/caching of register contents I guess,
>> wat does this driver get from regmap MMIO?
>> 
> 
> Code shrinkage IMO.
> 
> Note that I'm not blocking this from being merged - I just think that
> using modern frameworks is always a good idea.

I can reimplement the driver using regmap, but It seems in such case
I won’t be able to use the Generic GPIO Infrastructure, would I?
So I would need to provide functions for setting direction, etc.
I think it would make the driver code bigger.

Regards,
Jan

> Best regards,
> Bartosz Golaszewski
> 
>> Yours,
>> Linus Walleij

Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver

[Bartosz Golaszewski]

wt., 18 gru 2018 o 14:54 Janek Kotas <jank@cadence.com> napisał(a):
>
>
> > On 18 Dec 2018, at 13:50, Bartosz Golaszewski <bgolaszewski@baylibre.com> wrote:
> >
> >
> > pon., 17 gru 2018 o 23:22 Linus Walleij <linus.walleij@linaro.org> napisał(a):
> >>
> >> On Mon, Dec 17, 2018 at 4:51 PM Bartosz Golaszewski
> >> <bgolaszewski@baylibre.com> wrote:
> >>
> >>> The driver looks good but is there any particular reason not to use
> >>> regmap for register IO?
> >>
> >> I thought we only use regmap for MMIO when the register range is
> >> shared (as in a system controller) so that some registers are for this,
> >> some register or even bits in a register for some other driver, so they
> >> need the spinlock in the regmap to protect the register range.
> >>
> >
> > This is what syscon is for. Regmap simply abstracts any register IO.
> > For instance: there's no locking in this driver. Are we sure it's not
> > needed? Regmap provides internal locking for you in the form of a
> > mutex or spinlock.
> >
> > Also: it looks like the interrupts here are quite simple with a single
> > bit per interrupt in the status register and the same layout in the
> > mask register - it could probably profit from using the
> > regmap_irq_chip and not bother with reimplementing irq_chip callbacks.
> >
> >> It is also nice for shadowing/caching of register contents I guess,
> >> wat does this driver get from regmap MMIO?
> >>
> >
> > Code shrinkage IMO.
> >
> > Note that I'm not blocking this from being merged - I just think that
> > using modern frameworks is always a good idea.
>
> I can reimplement the driver using regmap, but It seems in such case
> I won’t be able to use the Generic GPIO Infrastructure, would I?
> So I would need to provide functions for setting direction, etc.
> I think it would make the driver code bigger.
>

Indeed. If anything: gpio-mmio would need to be converted to using regmap.

So I guess nevermind my comment.

Bart

Re: [PATCH v2 1/2] dt-bindings: gpio: Add bindings for Cadence GPIO

[Rob Herring]

On Mon, Dec 17, 2018 at 03:36:51PM +0000, Jan Kotas wrote:
> This patch adds a DT binding documentation for
> Cadence GPIO controller.
> 
> Signed-off-by: Jan Kotas <jank@cadence.com>
> ---
>  .../devicetree/bindings/gpio/cdns,gpio.txt         | 44 ++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/cdns,gpio.txt
> 
> diff --git a/Documentation/devicetree/bindings/gpio/cdns,gpio.txt b/Documentation/devicetree/bindings/gpio/cdns,gpio.txt
> new file mode 100644
> index 000000000..c87a47827
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/cdns,gpio.txt
> @@ -0,0 +1,44 @@
> +Cadence GPIO controller bindings
> +
> +Required properties:
> +- compatible: should be "cdns,gpio-r1p02".
> +- reg: the register base address and size.
> +- #gpio-cells: should be 2.
> +	* first cell is the GPIO number.
> +	* second cell specifies the GPIO flags, as defined in
> +		<dt-bindings/gpio/gpio.h>. Only the GPIO_ACTIVE_HIGH
> +		and GPIO_ACTIVE_LOW flags are supported.
> +- gpio-controller: marks the device as a GPIO controller.
> +- clocks: should contain one entry referencing the peripheral clock driving
> +	the GPIO controller.
> +
> +Optional properties:
> +- ngpios: integer number of gpio lines supported by this controller, up to 32.
> +- interrupt-parent: phandle of the parent interrupt controller.

Don't document interrupt-parent as it is implied and could be in a 
parent. Otherwise,

Reviewed-by: Rob Herring <robh@kernel.org>

Rob

Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver

[Linus Walleij]

On Mon, Dec 17, 2018 at 4:37 PM Jan Kotas <jank@cadence.com> wrote:

> 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@cadence.com>

Patch applied.

Yours,
Linus Walleij

Re: [PATCH v2 2/2] gpio: Add Cadence GPIO driver

[Linus Walleij]

On Tue, Dec 18, 2018 at 3:06 PM Bartosz Golaszewski
<bgolaszewski@baylibre.com> wrote:
> wt., 18 gru 2018 o 14:54 Janek Kotas <jank@cadence.com> napisał(a):

> > I can reimplement the driver using regmap, but It seems in such case
> > I won’t be able to use the Generic GPIO Infrastructure, would I?
> > So I would need to provide functions for setting direction, etc.
> > I think it would make the driver code bigger.
>
> Indeed. If anything: gpio-mmio would need to be converted to using regmap.

Ouch, let's go with this for now.

I think for gpio-mmio we have two new cases we really need to cover:
- port-mapped I/O (x86)
- regmap I/O

Augmenting gpio-mmio for these could probably strip out quite a
bunch of code from several drivers.

Yours,
Linus Walleij