diff options
Diffstat (limited to 'drivers/gpio/gpio-altera.c')
| -rw-r--r-- | drivers/gpio/gpio-altera.c | 374 |
1 files changed, 374 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-altera.c b/drivers/gpio/gpio-altera.c new file mode 100644 index 0000000..4d41196 --- /dev/null +++ b/drivers/gpio/gpio-altera.c @@ -0,0 +1,374 @@ +/* + * 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 2 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/io.h> +#include <linux/of_gpio.h> +#include <linux/platform_device.h> + +#define ALTERA_GPIO_MAX_NGPIO 32 +#define ALTERA_GPIO_DATA 0x0 +#define ALTERA_GPIO_DIR 0x4 +#define ALTERA_GPIO_IRQ_MASK 0x8 +#define ALTERA_GPIO_EDGE_CAP 0xc + +/** +* struct altera_gpio_chip +* @mmchip : memory mapped chip structure. +* @gpio_lock : synchronization lock so that new irq/set/get requests + will be blocked until the current one completes. +* @interrupt_trigger : specifies the hardware configured IRQ trigger type + (rising, falling, both, high) +* @mapped_irq : kernel mapped irq number. +*/ +struct altera_gpio_chip { + struct of_mm_gpio_chip mmchip; + spinlock_t gpio_lock; + int interrupt_trigger; + int mapped_irq; +}; + +static void altera_gpio_irq_unmask(struct irq_data *d) +{ + struct altera_gpio_chip *altera_gc; + struct of_mm_gpio_chip *mm_gc; + unsigned long flags; + u32 intmask; + + altera_gc = irq_data_get_irq_chip_data(d); + mm_gc = &altera_gc->mmchip; + + 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 |= BIT(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; + struct of_mm_gpio_chip *mm_gc; + unsigned long flags; + u32 intmask; + + altera_gc = irq_data_get_irq_chip_data(d); + mm_gc = &altera_gc->mmchip; + + 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 &= ~BIT(irqd_to_hwirq(d)); + writel(intmask, mm_gc->regs + ALTERA_GPIO_IRQ_MASK); + spin_unlock_irqrestore(&altera_gc->gpio_lock, flags); +} + +/** + * This controller's IRQ type is synthesized in hardware, so this function + * just checks if the requested set_type matches the synthesized IRQ type + */ +static int altera_gpio_irq_set_type(struct irq_data *d, + unsigned int type) +{ + struct altera_gpio_chip *altera_gc; + + altera_gc = irq_data_get_irq_chip_data(d); + + if (type == IRQ_TYPE_NONE) + return 0; + if (type == IRQ_TYPE_LEVEL_HIGH && + altera_gc->interrupt_trigger == IRQ_TYPE_LEVEL_HIGH) + return 0; + if (type == IRQ_TYPE_EDGE_RISING && + altera_gc->interrupt_trigger == IRQ_TYPE_EDGE_RISING) + return 0; + if (type == IRQ_TYPE_EDGE_FALLING && + altera_gc->interrupt_trigger == IRQ_TYPE_EDGE_FALLING) + return 0; + if (type == IRQ_TYPE_EDGE_BOTH && + altera_gc->interrupt_trigger == IRQ_TYPE_EDGE_BOTH) + return 0; + + return -EINVAL; +} + +static unsigned int altera_gpio_irq_startup(struct irq_data *d) { + altera_gpio_irq_unmask(d); + + return 0; +} + +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, + .irq_startup = altera_gpio_irq_startup, + .irq_shutdown = altera_gpio_irq_mask, +}; + +static int altera_gpio_get(struct gpio_chip *gc, unsigned offset) +{ + struct of_mm_gpio_chip *mm_gc; + + mm_gc = to_of_mm_gpio_chip(gc); + + return !!(readl(mm_gc->regs + ALTERA_GPIO_DATA) & BIT(offset)); +} + +static void altera_gpio_set(struct gpio_chip *gc, unsigned offset, int value) +{ + struct of_mm_gpio_chip *mm_gc; + struct altera_gpio_chip *chip; + unsigned long flags; + unsigned int data_reg; + + mm_gc = to_of_mm_gpio_chip(gc); + chip = container_of(mm_gc, struct altera_gpio_chip, mmchip); + + spin_lock_irqsave(&chip->gpio_lock, flags); + data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA); + if (value) + data_reg |= BIT(offset); + else + data_reg &= ~BIT(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; + struct altera_gpio_chip *chip; + unsigned long flags; + unsigned int gpio_ddr; + + mm_gc = to_of_mm_gpio_chip(gc); + chip = container_of(mm_gc, struct altera_gpio_chip, mmchip); + + 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 &= ~BIT(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; + struct altera_gpio_chip *chip; + unsigned long flags; + unsigned int data_reg, gpio_ddr; + + mm_gc = to_of_mm_gpio_chip(gc); + chip = container_of(mm_gc, struct altera_gpio_chip, mmchip); + + spin_lock_irqsave(&chip->gpio_lock, flags); + /* Sets the GPIO value */ + data_reg = readl(mm_gc->regs + ALTERA_GPIO_DATA); + if (value) + data_reg |= BIT(offset); + else + data_reg &= ~BIT(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 |= BIT(offset); + writel(gpio_ddr, mm_gc->regs + ALTERA_GPIO_DIR); + spin_unlock_irqrestore(&chip->gpio_lock, flags); + + return 0; +} + +static void altera_gpio_irq_edge_handler(unsigned int irq, + struct irq_desc *desc) +{ + struct altera_gpio_chip *altera_gc; + struct irq_chip *chip; + struct of_mm_gpio_chip *mm_gc; + struct irq_domain *irqdomain; + unsigned long status; + int i; + + altera_gc = irq_desc_get_handler_data(desc); + chip = irq_desc_get_chip(desc); + mm_gc = &altera_gc->mmchip; + irqdomain = altera_gc->mmchip.gc.irqdomain; + + chained_irq_enter(chip, desc); + + while ((status = + (readl(mm_gc->regs + ALTERA_GPIO_EDGE_CAP) & + readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK)))) { + writel(status, mm_gc->regs + ALTERA_GPIO_EDGE_CAP); + for_each_set_bit(i, &status, mm_gc->gc.ngpio) { + generic_handle_irq(irq_find_mapping(irqdomain, i)); + } + } + + chained_irq_exit(chip, desc); +} + + +static void altera_gpio_irq_leveL_high_handler(unsigned int irq, + struct irq_desc *desc) +{ + struct altera_gpio_chip *altera_gc; + struct irq_chip *chip; + struct of_mm_gpio_chip *mm_gc; + struct irq_domain *irqdomain; + unsigned long status; + int i; + + altera_gc = irq_desc_get_handler_data(desc); + chip = irq_desc_get_chip(desc); + mm_gc = &altera_gc->mmchip; + irqdomain = altera_gc->mmchip.gc.irqdomain; + + chained_irq_enter(chip, desc); + + status = readl(mm_gc->regs + ALTERA_GPIO_DATA); + status &= readl(mm_gc->regs + ALTERA_GPIO_IRQ_MASK); + + for_each_set_bit(i, &status, mm_gc->gc.ngpio) { + generic_handle_irq(irq_find_mapping(irqdomain, i)); + } + chained_irq_exit(chip, desc); +} + +int altera_gpio_probe(struct platform_device *pdev) +{ + struct device_node *node = pdev->dev.of_node; + int reg, ret; + struct altera_gpio_chip *altera_gc; + + altera_gc = devm_kzalloc(&pdev->dev, sizeof(*altera_gc), GFP_KERNEL); + if (!altera_gc) + return -ENOMEM; + + spin_lock_init(&altera_gc->gpio_lock); + + if (of_property_read_u32(node, "altr,ngpio", ®)) + /* By default assume maximum ngpio */ + altera_gc->mmchip.gc.ngpio = ALTERA_GPIO_MAX_NGPIO; + else + altera_gc->mmchip.gc.ngpio = reg; + + if (altera_gc->mmchip.gc.ngpio > ALTERA_GPIO_MAX_NGPIO) { + dev_warn(&pdev->dev, + "ngpio is greater than %d, defaulting to %d\n", + ALTERA_GPIO_MAX_NGPIO, ALTERA_GPIO_MAX_NGPIO); + altera_gc->mmchip.gc.ngpio = ALTERA_GPIO_MAX_NGPIO; + } + + 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.owner = THIS_MODULE; + altera_gc->mmchip.gc.dev = &pdev->dev; + + ret = of_mm_gpiochip_add(node, &altera_gc->mmchip); + if (ret) { + dev_err(&pdev->dev, "Failed adding memory mapped gpiochip\n"); + return ret; + } + + platform_set_drvdata(pdev, altera_gc); + + altera_gc->mapped_irq = platform_get_irq(pdev, 0); + + if (altera_gc->mapped_irq < 0) + goto skip_irq; + + if (of_property_read_u32(node, "altr,interrupt-type", ®)) { + ret = -EINVAL; + dev_err(&pdev->dev, + "altr,interrupt-type value not set in device tree\n"); + goto teardown; + } + altera_gc->interrupt_trigger = reg; + + ret = gpiochip_irqchip_add(&altera_gc->mmchip.gc, &altera_irq_chip, 0, + handle_simple_irq, IRQ_TYPE_NONE); + + if (ret) { + dev_info(&pdev->dev, "could not add irqchip\n"); + return ret; + } + + gpiochip_set_chained_irqchip(&altera_gc->mmchip.gc, + &altera_irq_chip, + altera_gc->mapped_irq, + altera_gc->interrupt_trigger == IRQ_TYPE_LEVEL_HIGH ? + altera_gpio_irq_leveL_high_handler : + altera_gpio_irq_edge_handler); + +skip_irq: + return 0; +teardown: + pr_err("%s: registration failed with status %d\n", + node->full_name, ret); + + return ret; +} + +static int altera_gpio_remove(struct platform_device *pdev) +{ + struct altera_gpio_chip *altera_gc = platform_get_drvdata(pdev); + + gpiochip_remove(&altera_gc->mmchip.gc); + + return -EIO; +} + +static const struct of_device_id altera_gpio_of_match[] = { + { .compatible = "altr,pio-1.0", }, + {}, +}; +MODULE_DEVICE_TABLE(of, altera_gpio_of_match); + +static struct platform_driver altera_gpio_driver = { + .driver = { + .name = "altera_gpio", + .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_AUTHOR("Tien Hock Loh <thloh@altera.com>"); +MODULE_DESCRIPTION("Altera GPIO driver"); +MODULE_LICENSE("GPL"); |
