On Wed, Dec 24, 2014 at 9:22 AM, <thloh@xxxxxxxxxx> wrote:
> 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>
(...)
> +config GPIO_ALTERA
> + tristate "Altera GPIO"
> + depends on OF_GPIO
select GPIOLIB_IRQCHIP
Also, I think (see below)
select GENERIC_GPIO
> +#include <linux/gpio.h>
#include <linux/gpio/driver.h>
should be just fine instead of this old header.
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
Should not be needed.
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/irqdomain.h>
None of these should be needed.
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_gpio.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
#include <linux/basic_mmio_gpio.h>
with GENERIC_GPIO (see below).
> +
> +#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);
> +}
> +
> +static int altera_gpio_irq_set_type(struct irq_data *d,
> + unsigned int type)
> +{
> + struct altera_gpio_chip *altera_gc = irq_data_get_irq_chip_data(d);
> +
> + 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;
> +}
It took me a while to understand this. Write in a comment that
this is a hardware that is synthesized for a specific trigger
type, and that there is no way to software-configure the
trigger type.
> +
> +static unsigned int altera_gpio_irq_startup(struct irq_data *d)
> +{
> + altera_gpio_irq_unmask(d);
> +
> + return 0;
> +}
> +
> +static void altera_gpio_irq_shutdown(struct irq_data *d)
> +{
> + altera_gpio_irq_mask(d);
> +}
Instead of those pointless functions just assign
the unmask/mask functions in the vtable right below.
> +
> +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_shutdown,
i.e. here.
> +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) >> 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;
> +}
These calls seem like pretty vanilla generic GPIO functions.
Use GENERIC_GPIO with bgpio_init() and override the default
functions only when really needed.
See e.g. drivers/gpio/gpio-74xx-mmio.c
> +static int altera_gpio_irq_map(struct irq_domain *h, unsigned int irq,
> + irq_hw_number_t hw_irq_num)
> +{
> + irq_set_chip_data(irq, h->host_data);
> + irq_set_chip_and_handler(irq, &altera_irq_chip, handle_level_irq);
> +
> + return 0;
> +}
> +
> +static const struct irq_domain_ops altera_gpio_irq_ops = {
> + .map = altera_gpio_irq_map,
> + .xlate = irq_domain_xlate_onecell,
> +};
This looks like some leftover garbage. You don't need them with
GPIOLIB_IRQCHIP so delete these two.
> +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);
> +
> + irq_set_handler_data(altera_gc->mapped_irq, NULL);
> + irq_set_chained_handler(altera_gc->mapped_irq, NULL);
These two calls should not be needed either.
Yours,
Linus Walleij
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