Re: [PATCHv4 3/3] gpio: sch: Enable IRQ support for Quark X1000

Mika Westerberg
2014-11-28T11:05:16Z

On Wed, Nov 26, 2014 at 12:48:00PM +0800, Chang Rebecca Swee Fun wrote:
> ntel Quark X1000 GPIO controller supports interrupt handling for

Typo it should say Intel.

> both core power well and resume power well. This patch is to enable
> the IRQ support and provide IRQ handling for Intel Quark X1000
> GPIO-SCH device driver.
>
> This piece of work is derived from Dan O'Donovan's initial work for
> Quark X1000 enabling.
>
> Signed-off-by: Chang Rebecca Swee Fun <rebecca.swee.fun.chang@intel.com>
> ---
> drivers/gpio/gpio-sch.c | 231 +++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 224 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpio/gpio-sch.c b/drivers/gpio/gpio-sch.c
> index 1a465bb..498746c 100644
> --- a/drivers/gpio/gpio-sch.c
> +++ b/drivers/gpio/gpio-sch.c
> @@ -28,17 +28,30 @@
> #include <linux/pci_ids.h>
>
> #include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
>
> #define GEN 0x00
> #define GIO 0x04
> #define GLV 0x08
> +#define GTPE 0x0C
> +#define GTNE 0x10
> +#define GGPE 0x14
> +#define GSMI 0x18
> +#define GTS 0x1C
> +#define CGNMIEN 0x40
> +#define RGNMIEN 0x44
>
> struct sch_gpio {
> struct gpio_chip chip;
> + struct irq_data data;
> spinlock_t lock;
> unsigned short iobase;
> unsigned short core_base;
> unsigned short resume_base;
> + int irq;
> + int irq_base;
> + bool irq_support;
> };
>
> #define to_sch_gpio(c) container_of(c, struct sch_gpio, chip)
> @@ -98,10 +111,11 @@ static void sch_gpio_reg_set(struct gpio_chip *gc, unsigned gpio, unsigned reg,
> static int sch_gpio_direction_in(struct gpio_chip *gc, unsigned gpio_num)
> {
> struct sch_gpio *sch = to_sch_gpio(gc);
> + unsigned long flags;
>
> - spin_lock(&sch->lock);
> + spin_lock_irqsave(&sch->lock, flags);
> sch_gpio_reg_set(sch, gpio_num, GIO, 1);
> - spin_unlock(&sch->lock);
> + spin_unlock_irqrestore(&sch->lock, flags);
> return 0;
> }
>
> @@ -113,20 +127,22 @@ static int sch_gpio_get(struct gpio_chip *gc, unsigned gpio_num)
> static void sch_gpio_set(struct gpio_chip *gc, unsigned gpio_num, int val)
> {
> struct sch_gpio *sch = to_sch_gpio(gc);
> + unsigned long flags;
>
> - spin_lock(&sch->lock);
> + spin_lock_irqsave(&sch->lock, flags);
> sch_gpio_reg_set(gc, gpio_num, GLV, val);
> - spin_unlock(&sch->lock);
> + spin_unlock_irqrestore(&sch->lock, flags);
> }
>
> static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
> int val)
> {
> struct sch_gpio *sch = to_sch_gpio(gc);
> + unsigned long flags;
>
> - spin_lock(&sch->lock);
> + spin_lock_irqsave(&sch->lock, flags);
> sch_gpio_reg_set(sch, gpio_num, GIO, 0);
> - spin_unlock(&sch->lock);
> + spin_unlock_irqrestore(&sch->lock, flags);
>
> /*
> * according to the datasheet, writing to the level register has no
> @@ -141,6 +157,13 @@ static int sch_gpio_direction_out(struct gpio_chip *gc, unsigned gpio_num,
> return 0;
> }
>
> +static int sch_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
> +{
> + struct sch_gpio *sch = to_sch_gpio(gc);
> +
> + return sch->irq_base + offset;
> +}
> +
> static struct gpio_chip sch_gpio_chip = {
> .label = "sch_gpio",
> .owner = THIS_MODULE,
> @@ -148,12 +171,155 @@ static struct gpio_chip sch_gpio_chip = {
> .get = sch_gpio_get,
> .direction_output = sch_gpio_direction_out,
> .set = sch_gpio_set,
> + .to_irq = sch_gpio_to_irq,
> +};
> +
> +static void sch_gpio_irq_enable(struct irq_data *d)
> +{
> + struct sch_gpio *sch = container_of(d, struct sch_gpio, data);
> + u32 gpio_num;
> +
> + gpio_num = d->irq - sch->irq_base;
> + sch_gpio_reg_set(sch, gpio_num, GGPE, 1);

Don't you need to take the lock here before calling sch_gpio_reg_set()?

> +}
> +
> +static void sch_gpio_irq_disable(struct irq_data *d)
> +{
> + struct sch_gpio *sch = container_of(d, struct sch_gpio, data);
> + u32 gpio_num;
> +
> + gpio_num = d->irq - sch->irq_base;
> + sch_gpio_reg_set(sch, gpio_num, GGPE, 0);

Ditto

> +}
> +
> +static void sch_gpio_irq_ack(struct irq_data *d)
> +{
> + struct sch_gpio *sch = container_of(d, struct sch_gpio, data);
> + u32 gpio_num;
> +
> + gpio_num = d->irq - sch->irq_base;
> + sch_gpio_reg_set(&(sch->chip), gpio_num, GTS, 1);

Ditto

> +}
> +
> +static int sch_gpio_irq_type(struct irq_data *d, unsigned type)
> +{
> + struct sch_gpio *sch = container_of(d, struct sch_gpio, data);
> + unsigned long flags;
> + u32 gpio_num;
> +
> + gpio_num = d->irq - sch->irq_base;
> +
> + spin_lock_irqsave(&sch->lock, flags);
> +
> + switch (type) {
> + case IRQ_TYPE_EDGE_RISING:
> + sch_gpio_reg_set(sch, gpio_num, GTPE, 1);
> + sch_gpio_reg_set(sch, gpio_num, GTNE, 0);
> + break;
> +
> + case IRQ_TYPE_EDGE_FALLING:
> + sch_gpio_reg_set(sch, gpio_num, GTNE, 1);
> + sch_gpio_reg_set(sch, gpio_num, GTPE, 0);
> + break;
> +
> + case IRQ_TYPE_EDGE_BOTH:
> + sch_gpio_reg_set(sch, gpio_num, GTPE, 1);
> + sch_gpio_reg_set(sch, gpio_num, GTNE, 1);
> + break;
> +
> + case IRQ_TYPE_NONE:
> + sch_gpio_reg_set(sch, gpio_num, GTPE, 0);
> + sch_gpio_reg_set(sch, gpio_num, GTNE, 0);
> + break;
> +
> + default:
> + spin_unlock_irqrestore(&sch->lock, flags);
> + return -EINVAL;
> + }
> +
> + spin_unlock_irqrestore(&sch->lock, flags);
> +
> + return 0;
> +}
> +
> +static struct irq_chip sch_irq_chip = {
> + .irq_enable = sch_gpio_irq_enable,
> + .irq_disable = sch_gpio_irq_disable,
> + .irq_ack = sch_gpio_irq_ack,
> + .irq_set_type = sch_gpio_irq_type,
> };
>
> +static void sch_gpio_irqs_init(struct sch_gpio *sch, unsigned int num)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < num; i++) {
> + irq_set_chip_data(i + sch->irq_base, sch);
> + irq_set_chip_and_handler_name(i + sch->irq_base, &sch_irq_chip,
> + handle_simple_irq, "sch_gpio_irq_chip");
> + }
> +}
> +
> +static void sch_gpio_irqs_deinit(struct sch_gpio *sch, unsigned int num)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < num; i++) {
> + irq_set_chip_data(i + sch->irq_base, 0);
> + irq_set_chip_and_handler_name(i + sch->irq_base, 0, 0, 0);
> + }
> +}
> +
> +static void sch_gpio_irq_disable_all(struct sch_gpio *sch, unsigned int num)
> +{
> + unsigned long flags;
> + unsigned int gpio_num;
> +
> + spin_lock_irqsave(&sch->lock, flags);
> +
> + for (gpio_num = 0; gpio_num < num; gpio_num++) {
> + sch_gpio_reg_set(sch, gpio_num, GTPE, 0);
> + sch_gpio_reg_set(sch, gpio_num, GTNE, 0);
> + sch_gpio_reg_set(sch, gpio_num, GGPE, 0);
> + sch_gpio_reg_set(sch, gpio_num, GSMI, 0);
> +
> + if (gpio_num >= 2)
> + sch_gpio_reg_set(sch, gpio_num, RGNMIEN, 0);
> + else
> + sch_gpio_reg_set(sch, gpio_num, CGNMIEN, 0);
> +
> + /* clear any pending interrupts */
> + sch_gpio_reg_set(&sch->chip, gpio_num, GTS, 1);
> + }
> +
> + spin_unlock_irqrestore(&sch->lock, flags);
> +}
> +
> +static irqreturn_t sch_gpio_irq_handler(int irq, void *dev_id)
> +{
> + struct sch_gpio *sch = dev_id;
> + int res;
> + unsigned int i;
> + int ret = IRQ_NONE;
> +
> + for (i = 0; i < sch->chip.ngpio; i++) {
> + res = sch_gpio_reg_get(&sch->chip, i, GTS);
> + if (res) {
> + /* clear by setting GTS to 1 */
> + sch_gpio_reg_set(&sch->chip, i, GTS, 1);
> + generic_handle_irq(sch->irq_base + i);
> + ret = IRQ_HANDLED;
> + }
> + }
> +
> + return ret;
> +}
> +
> static int sch_gpio_probe(struct platform_device *pdev)
> {
> struct sch_gpio *sch;
> struct resource *res;
> + int err;
>
> sch = devm_kzalloc(&pdev->dev, sizeof(*sch), GFP_KERNEL);
> if (!sch)
> @@ -167,6 +333,15 @@ static int sch_gpio_probe(struct platform_device *pdev)
> pdev->name))
> return -EBUSY;
>
> + sch->irq = platform_get_irq(pdev, 0);
> + if (sch->irq >= 0) {
> + sch->irq_support = true;
> + } else {
> + dev_warn(&pdev->dev,
> + "failed to obtain irq number for device\n");

Why dev_warn()?

If I use this driver on Minnowboard which does not support interrupts,
this kind of warning makes me think that there is something wrong even
if it is actually OK.

> + sch->irq_support = false;
> + }
> +
> spin_lock_init(&sch->lock);
> sch->iobase = res->start;
> sch->chip = sch_gpio_chip;
> @@ -215,15 +390,57 @@ static int sch_gpio_probe(struct platform_device *pdev)
> return -ENODEV;
> }
>
> + gpiochip_add(&sch->chip);
> +
> + if (sch->irq_support) {
> + sch->irq_base = irq_alloc_descs(-1, 0, sch->chip.ngpio,
> + NUMA_NO_NODE);
> + if (sch->irq_base < 0) {
> + dev_err(&pdev->dev,
> + "failed to allocate GPIO IRQ descs\n");
> + goto err_sch_intr_chip;
> + }
> +
> + /* disable interrupts */
> + sch_gpio_irq_disable_all(sch, sch->chip.ngpio);
> +
> + err = request_irq(sch->irq, sch_gpio_irq_handler, IRQF_SHARED,
> + KBUILD_MODNAME, sch);
> + if (err) {
> + dev_err(&pdev->dev,
> + "%s failed to request IRQ\n", __func__);
> + goto err_sch_request_irq;
> + }
> +
> + sch_gpio_irqs_init(sch, sch->chip.ngpio);
> + }
> +
> platform_set_drvdata(pdev, sch);
>
> - return gpiochip_add(&sch->chip);
> + return 0;
> +
> +err_sch_request_irq:
> + irq_free_descs(sch->irq_base, sch->chip.ngpio);
> +
> +err_sch_intr_chip:
> + gpiochip_remove(&sch->chip);
> +
> + return err;
> }
>
> static int sch_gpio_remove(struct platform_device *pdev)
> {
> struct sch_gpio *sch = platform_get_drvdata(pdev);
>
> + if (sch->irq_support) {
> + sch_gpio_irqs_deinit(sch, sch->chip.ngpio);
> +
> + if (sch->irq >= 0)
> + free_irq(sch->irq, sch);
> +
> + irq_free_descs(sch->irq_base, sch->chip.ngpio);
> + }
> +
> gpiochip_remove(&sch->chip);
> return 0;
> }
> --
> 1.7.9.5