This driver supports the Altera PIO core. Signed-off-by: Thomas Chou <[email protected]> Signed-off-by: Tobias Klauser <[email protected]> --- This driver was submitted already about a year ago by Thomas, was adjusted by him according to some remarks made by Grant and was then included in the -mm tree [1] for some time but dropped again (couldn't find out when and why exactly).
[0] http://article.gmane.org/gmane.linux.drivers.devicetree/4231 [1] http://article.gmane.org/gmane.linux.kernel.commits.mm/65119 So this is a new attempt towards getting this driver into mainline from the nios2 tree. The following changes have been made atop the version submitted by Thomas: - Changed driver name to new naming convention - Usage of of_property_read_u32 in the probe function .../devicetree/bindings/gpio/altera_gpio.txt | 7 + drivers/gpio/Kconfig | 6 + drivers/gpio/Makefile | 1 + drivers/gpio/gpio-altera.c | 256 ++++++++++++++++++++ 4 files changed, 270 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/gpio/altera_gpio.txt create mode 100644 drivers/gpio/gpio-altera.c diff --git a/Documentation/devicetree/bindings/gpio/altera_gpio.txt b/Documentation/devicetree/bindings/gpio/altera_gpio.txt new file mode 100644 index 0000000..5ab751a --- /dev/null +++ b/Documentation/devicetree/bindings/gpio/altera_gpio.txt @@ -0,0 +1,7 @@ +Altera GPIO + +Required properties: +- compatible : should be "ALTR,pio-1.0". +Optional properties: +- resetvalue : the reset value of the output port. +- width : the width of the port in number of bits. diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig index eaa7d38..3ba4526 100644 --- a/drivers/gpio/Kconfig +++ b/drivers/gpio/Kconfig @@ -85,6 +85,12 @@ config GPIO_GENERIC_PLATFORM help Say yes here to support basic platform_device memory-mapped GPIO controllers. +config GPIO_ALTERA + bool "Altera GPIO" + depends on OF + 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 8863a7f..973c066 100644 --- a/drivers/gpio/Makefile +++ b/drivers/gpio/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_GPIO_74X164) += gpio-74x164.o obj-$(CONFIG_GPIO_AB8500) += gpio-ab8500.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_BT8XX) += gpio-bt8xx.o obj-$(CONFIG_GPIO_CS5535) += gpio-cs5535.o obj-$(CONFIG_GPIO_DA9052) += gpio-da9052.o diff --git a/drivers/gpio/gpio-altera.c b/drivers/gpio/gpio-altera.c new file mode 100644 index 0000000..bfbcb6b --- /dev/null +++ b/drivers/gpio/gpio-altera.c @@ -0,0 +1,256 @@ +/* + * Altera GPIO driver + * + * Copyright (C) 2012 Tobias Klauser <[email protected]> + * Copyright (C) 2011 Thomas Chou <[email protected]> + * + * Based on Xilinx gpio driver, which is + * Copyright 2008 Xilinx, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/errno.h> +#include <linux/of_device.h> +#include <linux/of_platform.h> +#include <linux/of_gpio.h> +#include <linux/of_irq.h> +#include <linux/io.h> +#include <linux/gpio.h> +#include <linux/slab.h> + +#define DRV_NAME "altera_gpio" + +/* Register Offset Definitions */ +#define ALTERA_GPIO_DATA_OFFSET 0x0 /* Data register */ +#define ALTERA_GPIO_DIR_OFFSET 0x4 /* I/O direction register */ +#define ALTERA_GPIO_IRQ_MASK 0x8 +#define ALTERA_GPIO_EDGE_CAP 0xc + +struct altera_gpio_instance { + struct of_mm_gpio_chip mmchip; + u32 gpio_state; /* GPIO state shadow register */ + u32 gpio_dir; /* GPIO direction shadow register */ + int irq; /* GPIO irq number */ + spinlock_t gpio_lock; /* Lock used for synchronization */ +}; + +static inline struct altera_gpio_instance *to_altera_gpio( + struct of_mm_gpio_chip *mm_gc) +{ + return container_of(mm_gc, struct altera_gpio_instance, mmchip); +} + +/* + * altera_gpio_get - Read the specified signal of the GPIO device. + * @gc: Pointer to gpio_chip device structure. + * @gpio: GPIO signal number. + * + * This function reads the specified signal of the GPIO device. It returns 0 if + * the signal clear, 1 if signal is set or negative value on error. + */ +static int altera_gpio_get(struct gpio_chip *gc, unsigned int gpio) +{ + struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); + struct altera_gpio_instance *chip = to_altera_gpio(mm_gc); + + if (chip->irq >= 0) { + if (readl(mm_gc->regs + ALTERA_GPIO_EDGE_CAP) & (1 << gpio)) + writel(1 << gpio, mm_gc->regs + ALTERA_GPIO_EDGE_CAP); + } + return (readl(mm_gc->regs + ALTERA_GPIO_DATA_OFFSET) >> gpio) & 1; +} + +/* + * altera_gpio_set - Write the specified signal of the GPIO device. + * @gc: Pointer to gpio_chip device structure. + * @gpio: GPIO signal number. + * @val: Value to be written to specified signal. + * + * This function writes the specified value in to the specified signal of the + * GPIO device. + */ +static void altera_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val) +{ + unsigned long flags; + struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); + struct altera_gpio_instance *chip = to_altera_gpio(mm_gc); + + spin_lock_irqsave(&chip->gpio_lock, flags); + + /* Write to shadow register and output */ + if (val) + chip->gpio_state |= 1 << gpio; + else + chip->gpio_state &= ~(1 << gpio); + writel(chip->gpio_state, mm_gc->regs + ALTERA_GPIO_DATA_OFFSET); + + spin_unlock_irqrestore(&chip->gpio_lock, flags); +} + +/* + * altera_gpio_dir_in - Set the direction of the specified GPIO signal as input. + * @gc: Pointer to gpio_chip device structure. + * @gpio: GPIO signal number. + * + * This function sets the direction of specified GPIO signal as input. + * It returns 0 if direction of GPIO signals is set as input otherwise it + * returns negative error value. + */ +static int altera_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio) +{ + unsigned long flags; + struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); + struct altera_gpio_instance *chip = to_altera_gpio(mm_gc); + + spin_lock_irqsave(&chip->gpio_lock, flags); + + /* Clear the GPIO bit in shadow register and set direction as input */ + chip->gpio_dir &= ~(1 << gpio); + writel(chip->gpio_dir, mm_gc->regs + ALTERA_GPIO_DIR_OFFSET); + + spin_unlock_irqrestore(&chip->gpio_lock, flags); + + return 0; +} + +/* + * altera_gpio_dir_out - Set the direction of the specified GPIO as output. + * @gc: Pointer to gpio_chip device structure. + * @gpio: GPIO signal number. + * @val: Value to be written to specified signal. + * + * This function sets the direction of specified GPIO signal as output. If all + * GPIO signals of GPIO chip is configured as input then it returns + * error otherwise it returns 0. + */ +static int altera_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val) +{ + unsigned long flags; + struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); + struct altera_gpio_instance *chip = to_altera_gpio(mm_gc); + + spin_lock_irqsave(&chip->gpio_lock, flags); + + /* Write state of GPIO signal */ + if (val) + chip->gpio_state |= 1 << gpio; + else + chip->gpio_state &= ~(1 << gpio); + writel(chip->gpio_state, mm_gc->regs + ALTERA_GPIO_DATA_OFFSET); + + /* Set the GPIO bit in shadow register and set direction as output */ + chip->gpio_dir |= (1 << gpio); + writel(chip->gpio_dir, mm_gc->regs + ALTERA_GPIO_DIR_OFFSET); + + spin_unlock_irqrestore(&chip->gpio_lock, flags); + + return 0; +} + +/* + * altera_gpio_save_regs - Set initial values of GPIO pins + * @mm_gc: pointer to memory mapped GPIO chip structure + */ +static void altera_gpio_save_regs(struct of_mm_gpio_chip *mm_gc) +{ + struct altera_gpio_instance *chip = to_altera_gpio(mm_gc); + + writel(chip->gpio_state, mm_gc->regs + ALTERA_GPIO_DATA_OFFSET); + writel(chip->gpio_dir, mm_gc->regs + ALTERA_GPIO_DIR_OFFSET); +} + +static int altera_gpio_to_irq(struct gpio_chip *gc, unsigned int gpio) +{ + struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc); + struct altera_gpio_instance *chip = to_altera_gpio(mm_gc); + + return chip->irq; +} + +/* + * altera_gpio_of_probe - Probe method for the GPIO device. + * @np: pointer to device tree node + * + * This function probes the GPIO device in the device tree. It initializes the + * driver data structure. It returns 0, if the driver is bound to the GPIO + * device, or a negative value if there is an error. + */ +static int __devinit altera_gpio_of_probe(struct device_node *np) +{ + struct altera_gpio_instance *chip; + int status = 0; + u32 reg; + + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + + /* Update GPIO state shadow register with default value */ + if (of_property_read_u32(np, "resetvalue", ®) == 0) + chip->gpio_state = reg; + + /* Update GPIO direction shadow register with default value */ + chip->gpio_dir = 0; /* By default, all pins are inputs */ + + /* Check device node for device width */ + if (of_property_read_u32(np, "width", ®) == 0) + chip->mmchip.gc.ngpio = reg; + else + chip->mmchip.gc.ngpio = 32; /* By default assume full GPIO controller */ + + /* Check device node for interrupt */ + chip->irq = of_irq_count(np) ? of_irq_to_resource(np, 0, NULL) : -ENXIO; + + spin_lock_init(&chip->gpio_lock); + + chip->mmchip.gc.direction_input = altera_gpio_dir_in; + chip->mmchip.gc.direction_output = altera_gpio_dir_out; + chip->mmchip.gc.get = altera_gpio_get; + chip->mmchip.gc.set = altera_gpio_set; + chip->mmchip.gc.to_irq = altera_gpio_to_irq; + + chip->mmchip.save_regs = altera_gpio_save_regs; + + /* Call the OF gpio helper to setup and register the GPIO device */ + status = of_mm_gpiochip_add(np, &chip->mmchip); + if (status) { + kfree(chip); + pr_err("%s: error in probe function with status %d\n", + np->full_name, status); + return status; + } + if (chip->irq >= 0) { + /* clear edge and enable irq */ + writel(UINT_MAX, chip->mmchip.regs + ALTERA_GPIO_EDGE_CAP); + writel(UINT_MAX, chip->mmchip.regs + ALTERA_GPIO_IRQ_MASK); + } + return 0; +} + +static struct of_device_id altera_gpio_of_match[] __devinitdata = { + { .compatible = "ALTR,pio-1.0", }, + {}, +}; + +/* Make sure we get initialized before anyone else tries to use us */ +void __init altera_gpio_init(void) +{ + struct device_node *np; + + for_each_matching_node(np, altera_gpio_of_match) + altera_gpio_of_probe(np); +} + +MODULE_DESCRIPTION("Altera GPIO driver"); +MODULE_AUTHOR("Thomas Chou <[email protected]>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:" DRV_NAME); -- 1.7.5.4 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
