RE: [PATCH 1/1] drivers/gpio: Altera soft IP GPIO driver

From: Tien Hock Loh
Date: Tue Mar 19 2013 - 02:01:46 EST

Hi,

Are the codes good for upstream?

Thanks.

-----Original Message-----
From: Tien Hock Loh
Sent: Tuesday, March 12, 2013 1:38 PM
To: Linus Walleij; Rob Landley
Cc: linux-doc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Tien Hock Loh
Subject: [PATCH 1/1] drivers/gpio: Altera soft IP GPIO driver

From: Tien Hock Loh <thloh@xxxxxxxxxx>

Adds a new driver for Altera soft GPIO IP. The driver is able to do read/write and allows GPIO to be a interrupt controller.

Tested on Altera GHRD on interrupt handling and IO.

Signed-off-by: Tien Hock Loh <thloh@xxxxxxxxxx>
---
.../devicetree/bindings/gpio/gpio-altera.txt | 37 +++
drivers/gpio/Kconfig | 7 +
drivers/gpio/Makefile | 1 +
drivers/gpio/gpio-altera.c | 363 +++++++++++++++++++++
4 files changed, 408 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-altera.txt
create mode 100644 drivers/gpio/gpio-altera.c

diff --git a/Documentation/devicetree/bindings/gpio/gpio-altera.txt b/Documentation/devicetree/bindings/gpio/gpio-altera.txt
new file mode 100644
index 0000000..3bdb8b6
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-altera.txt
@@ -0,0 +1,37 @@
+Altera GPIO controller bindings
+
+Required properties:
+- compatible:
+ - "altr,pio-1.0"
+- reg: Physical base address and length of the controller's registers.
+- #gpio-cells : Should be two.
+ - first cell is the pin number
+ - second cell is used to specify optional parameters (unused)
+- gpio-controller : Marks the device node as a GPIO controller.
+- #interrupt-cells : Should be 1.
+- interrupts: Specify the interrupt.
+- interrupt-controller: Mark the device node as an interrupt controller
+ The first cell is the GPIO number.
+
+Altera GPIO specific properties:
+- width: Width of the GPIO bank, range from 1-32
+- level_trigger: Specifies whether the GPIO interrupt is level trigger.
+ This field is required if the Altera GPIO controller used has IRQ enabled.
+
+Note: If the Altera GPIO is set to be built as a module, peripherals
+that uses Altera GPIO as interrupt-parent should be a module so that
+the peripheral doesn't get initialized before Altera GPIO is initialized.
+
+Example:
+
+gpio_altr: gpio_altr {
+ compatible = "altr,pio-1.0";
+ reg = <0xff200000 0x10>;
+ interrupts = <0 45 4>;
+ width = <32>;
+ level_trigger = <0>;
+ #gpio-cells = <2>;
+ gpio-controller;
+ #interrupt-cells = <1>;
+ interrupt-controller;
+};
diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index 93aaadf..953e9f2 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -119,6 +119,13 @@ config GPIO_GENERIC_PLATFORM
help
Say yes here to support basic platform_device memory-mapped GPIO controllers.

+config GPIO_ALTERA
+ tristate "Altera GPIO"
+ select IRQ_DOMAIN
+ depends on OF_GPIO
+ help
+ Say yes here to support the Altera PIO device.
+
config GPIO_IT8761E
tristate "IT8761E GPIO support"
depends on X86 # unconditional access to IO space.
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile index 22e07bc..c57449c 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_GPIO_74X164) += gpio-74x164.o
obj-$(CONFIG_GPIO_ADNP) += gpio-adnp.o
obj-$(CONFIG_GPIO_ADP5520) += gpio-adp5520.o
obj-$(CONFIG_GPIO_ADP5588) += gpio-adp5588.o
+obj-$(CONFIG_GPIO_ALTERA) += gpio-altera.o
obj-$(CONFIG_GPIO_AMD8111) += gpio-amd8111.o
obj-$(CONFIG_GPIO_ARIZONA) += gpio-arizona.o
obj-$(CONFIG_GPIO_BT8XX) += gpio-bt8xx.o
diff --git a/drivers/gpio/gpio-altera.c b/drivers/gpio/gpio-altera.c new file mode 100644 index 0000000..b832a3a
--- /dev/null
+++ b/drivers/gpio/gpio-altera.c
@@ -0,0 +1,363 @@
+/*
+ * Copyright (C) 2013 Altera Corporation
+ * Based on gpio-mpc8xxx.c
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>
+*/
+
+#include <linux/gpio.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/of_irq.h>
+#include <linux/irqdomain.h>
+#include <linux/interrupt.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+
+#define ALTERA_GPIO_DATA 0x0
+#define ALTERA_GPIO_DIR 0x4
+#define ALTERA_GPIO_IRQ_MASK 0x8
+#define ALTERA_GPIO_EDGE_CAP 0xc
+#define ALTERA_GPIO_OUTSET 0x10
+#define ALTERA_GPIO_OUTCLEAR 0x14
+
+struct altera_gpio_chip {
+ struct of_mm_gpio_chip mmchip;
+ struct irq_domain *irq; /* GPIO controller IRQ number */
+ spinlock_t gpio_lock; /* Lock used for synchronization */
+ int level_trigger;
+ int hwirq;
+};
+
+static void altera_gpio_irq_unmask(struct irq_data *d) {
+ struct altera_gpio_chip *altera_gc = irq_data_get_irq_chip_data(d);
+ struct of_mm_gpio_chip *mm_gc = &altera_gc->mmchip;
+ unsigned long flags;
+ unsigned int intmask;
+
+ spin_lock_irqsave(&altera_gc->gpio_lock, flags);
+ intmask = readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
+ /* Set ALTERA_GPIO_IRQ_MASK bit to unmask */
+ intmask |= (1 << irqd_to_hwirq(d));
+ writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
+ spin_unlock_irqrestore(&altera_gc->gpio_lock, flags); }
+
+static void altera_gpio_irq_mask(struct irq_data *d) {
+ struct altera_gpio_chip *altera_gc = irq_data_get_irq_chip_data(d);
+ struct of_mm_gpio_chip *mm_gc = &altera_gc->mmchip;
+ unsigned long flags;
+ unsigned int intmask;
+
+ spin_lock_irqsave(&altera_gc->gpio_lock, flags);
+ intmask = readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
+ /* Clear ALTERA_GPIO_IRQ_MASK bit to mask */
+ intmask &= ~(1 << irqd_to_hwirq(d));
+ writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
+ spin_unlock_irqrestore(&altera_gc->gpio_lock, flags); }
+
+static int altera_gpio_irq_set_type(struct irq_data *d,
+ unsigned int type)
+{
+ if (type == IRQ_TYPE_NONE)
+ return 0;
+ return -EINVAL;
+}
+
+static struct irq_chip altera_irq_chip = {
+ .name = "altera-gpio",
+ .irq_mask = altera_gpio_irq_mask,
+ .irq_unmask = altera_gpio_irq_unmask,
+ .irq_set_type = altera_gpio_irq_set_type,
+};
+
+static int altera_gpio_get(struct gpio_chip *gc, unsigned offset) {
+ struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+
+ return (readl(mm_gc->regs + ALTERA_GPIO_DATA) >> offset) & 1; }
+
+static void altera_gpio_set(struct gpio_chip *gc, unsigned offset, int
+value) {
+ struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+ struct altera_gpio_chip *chip = container_of(mm_gc,
+ struct altera_gpio_chip, mmchip);
+ unsigned long flags;
+ unsigned int data_reg;
+
+ spin_lock_irqsave(&chip->gpio_lock, flags);
+ data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA);
+ data_reg = (data_reg & ~(1 << offset)) | (value << offset);
+ writel(data_reg, mm_gc->regs + ALTERA_GPIO_DATA);
+ spin_unlock_irqrestore(&chip->gpio_lock, flags); }
+
+static int altera_gpio_direction_input(struct gpio_chip *gc, unsigned
+offset) {
+ struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+ struct altera_gpio_chip *chip = container_of(mm_gc,
+ struct altera_gpio_chip, mmchip);
+ unsigned long flags;
+ unsigned int gpio_ddr;
+
+ spin_lock_irqsave(&chip->gpio_lock, flags);
+ /* Set pin as input, assumes software controlled IP */
+ gpio_ddr = readl(mm_gc->regs + ALTERA_GPIO_DIR);
+ gpio_ddr &= ~(1 << offset);
+ writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR);
+ spin_unlock_irqrestore(&chip->gpio_lock, flags);
+
+ return 0;
+}
+
+static int altera_gpio_direction_output(struct gpio_chip *gc,
+ unsigned offset, int value)
+{
+ struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+ struct altera_gpio_chip *chip = container_of(mm_gc,
+ struct altera_gpio_chip, mmchip);
+ unsigned long flags;
+ unsigned int data_reg, gpio_ddr;
+
+ spin_lock_irqsave(&chip->gpio_lock, flags);
+ /* Sets the GPIO value */
+ data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA);
+ data_reg = (data_reg & ~(1 << offset)) | (value << offset);
+ writel(data_reg, mm_gc->regs + ALTERA_GPIO_DATA);
+
+ /* Set pin as output, assumes software controlled IP */
+ gpio_ddr = readl(mm_gc->regs + ALTERA_GPIO_DIR);
+ gpio_ddr |= (1 << offset);
+ writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR);
+ spin_unlock_irqrestore(&chip->gpio_lock, flags);
+
+ return 0;
+}
+
+static int altera_gpio_to_irq(struct gpio_chip *gc, unsigned offset) {
+ struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+ struct altera_gpio_chip *altera_gc = container_of(mm_gc,
+ struct altera_gpio_chip, mmchip);
+
+ if (altera_gc->irq == 0)
+ return -ENXIO;
+ if ((altera_gc->irq && offset) < altera_gc->mmchip.gc.ngpio)
+ return irq_create_mapping(altera_gc->irq, offset);
+ else
+ return -ENXIO;
+}
+
+static void altera_gpio_irq_handler(unsigned int irq, struct irq_desc
+*desc) {
+ struct altera_gpio_chip *altera_gc = irq_desc_get_handler_data(desc);
+ struct irq_chip *chip = irq_desc_get_chip(desc);
+ struct of_mm_gpio_chip *mm_gc = &altera_gc->mmchip;
+ unsigned long status;
+
+ int base;
+ chip->irq_mask(&desc->irq_data);
+
+ if (altera_gc->level_trigger)
+ status = readl(mm_gc->regs + ALTERA_GPIO_DATA);
+ else {
+ status = readl(mm_gc->regs + ALTERA_GPIO_EDGE_CAP);
+ writel(status, mm_gc->regs + ALTERA_GPIO_EDGE_CAP);
+ }
+
+ status &= readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK);
+
+ for (base = 0; base < mm_gc->gc.ngpio; base++) {
+ if ((1 << base) & status) {
+ generic_handle_irq(
+ irq_linear_revmap(altera_gc->irq, base));
+ }
+ }
+ chip->irq_eoi(irq_desc_get_irq_data(desc));
+ chip->irq_unmask(&desc->irq_data);
+}
+
+static int altera_gpio_irq_map(struct irq_domain *h, unsigned int virq,
+ irq_hw_number_t hw_irq_num)
+{
+ irq_set_chip_data(virq, h->host_data);
+ irq_set_chip_and_handler(virq, &altera_irq_chip, handle_level_irq);
+ irq_set_irq_type(virq, IRQ_TYPE_NONE);
+
+ return 0;
+}
+
+static struct irq_domain_ops altera_gpio_irq_ops = {
+ .map = altera_gpio_irq_map,
+ .xlate = irq_domain_xlate_twocell,
+};
+
+int altera_gpio_probe(struct platform_device *pdev) {
+ struct device_node *node = pdev->dev.of_node;
+ int id, reg, ret;
+ struct altera_gpio_chip *altera_gc = devm_kzalloc(&pdev->dev,
+ sizeof(*altera_gc), GFP_KERNEL);
+ if (altera_gc == NULL) {
+ ret = -ENOMEM;
+ pr_err("%s: registration failed with status %d\n",
+ node->full_name, ret);
+ return ret;
+ }
+ altera_gc->irq = 0;
+
+ spin_lock_init(&altera_gc->gpio_lock);
+
+ id = pdev->id;
+
+ if (of_property_read_u32(node, "width", &reg))
+ /*By default assume full GPIO controller*/
+ altera_gc->mmchip.gc.ngpio = 32;
+ else
+ altera_gc->mmchip.gc.ngpio = reg;
+
+ if (altera_gc->mmchip.gc.ngpio > 32) {
+ pr_warn("%s: ngpio is greater than 32, defaulting to 32\n",
+ node->full_name);
+ altera_gc->mmchip.gc.ngpio = 32;
+ }
+
+ altera_gc->mmchip.gc.direction_input = altera_gpio_direction_input;
+ altera_gc->mmchip.gc.direction_output = altera_gpio_direction_output;
+ altera_gc->mmchip.gc.get = altera_gpio_get;
+ altera_gc->mmchip.gc.set = altera_gpio_set;
+ altera_gc->mmchip.gc.to_irq = altera_gpio_to_irq;
+ altera_gc->mmchip.gc.owner = THIS_MODULE;
+
+ ret = of_mm_gpiochip_add(node, &altera_gc->mmchip);
+ if (ret)
+ goto err;
+
+ platform_set_drvdata(pdev, altera_gc);
+
+ if (of_get_property(node, "interrupts", &reg) == NULL)
+ goto skip_irq;
+ altera_gc->hwirq = irq_of_parse_and_map(node, 0);
+
+ if (altera_gc->hwirq == NO_IRQ)
+ goto skip_irq;
+
+ altera_gc->irq = irq_domain_add_linear(node, altera_gc->mmchip.gc.ngpio,
+ &altera_gpio_irq_ops, altera_gc);
+
+ if (!altera_gc->irq) {
+ ret = -ENODEV;
+ goto dispose_irq;
+ }
+
+ if (of_property_read_u32(node, "level_trigger", &reg)) {
+ ret = -EINVAL;
+ pr_err("%s: level_trigger value not set in device tree\n",
+ node->full_name);
+ goto teardown;
+ }
+ altera_gc->level_trigger = reg;
+
+ irq_set_handler_data(altera_gc->hwirq, altera_gc);
+ irq_set_chained_handler(altera_gc->hwirq, altera_gpio_irq_handler);
+
+ return 0;
+
+teardown:
+ irq_domain_remove(altera_gc->irq);
+dispose_irq:
+ irq_dispose_mapping(altera_gc->hwirq);
+ WARN_ON(gpiochip_remove(&altera_gc->mmchip.gc) < 0);
+
+err:
+ pr_err("%s: registration failed with status %d\n",
+ node->full_name, ret);
+ devm_kfree(&pdev->dev, altera_gc);
+
+ return ret;
+skip_irq:
+ return 0;
+}
+
+static int altera_gpio_remove(struct platform_device *pdev) {
+ unsigned int irq, i;
+ int status;
+ struct altera_gpio_chip *altera_gc = platform_get_drvdata(pdev);
+
+ status = gpiochip_remove(&altera_gc->mmchip.gc);
+
+ if (status < 0)
+ return status;
+
+ if (altera_gc->irq) {
+ irq_dispose_mapping(altera_gc->hwirq);
+
+ for (i = 0; i < altera_gc->mmchip.gc.ngpio; i++) {
+ irq = irq_find_mapping(altera_gc->irq, i);
+ if (irq > 0)
+ irq_dispose_mapping(irq);
+ }
+
+ irq_domain_remove(altera_gc->irq);
+ }
+
+ irq_set_handler_data(altera_gc->hwirq, NULL);
+ irq_set_chained_handler(altera_gc->hwirq, NULL);
+ devm_kfree(&pdev->dev, altera_gc);
+ return -EIO;
+}
+
+#ifdef CONFIG_OF
+static struct of_device_id altera_gpio_of_match[] = {
+ { .compatible = "altr,pio-1.0", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, altera_gpio_of_match); #else #define
+altera_gpio_of_match NULL #endif
+
+static struct platform_driver altera_gpio_driver = {
+ .driver = {
+ .name = "altera_gpio",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(altera_gpio_of_match),
+ },
+ .probe = altera_gpio_probe,
+ .remove = altera_gpio_remove,
+};
+
+static int __init altera_gpio_init(void) {
+ return platform_driver_register(&altera_gpio_driver);
+}
+subsys_initcall(altera_gpio_init);
+
+static void __exit altera_gpio_exit(void) {
+ platform_driver_unregister(&altera_gpio_driver);
+}
+module_exit(altera_gpio_exit);
+
+MODULE_DESCRIPTION("Altera GPIO driver"); MODULE_LICENSE("GPL");
--
1.7.11.GIT


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