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Message-ID: <20120821105333.GW10347@arwen.pp.htv.fi>
Date: Tue, 21 Aug 2012 13:53:34 +0300
From: Felipe Balbi <balbi@...com>
To: Sourav Poddar <sourav.poddar@...com>
Cc: devicetree-discuss@...ts.ozlabs.org,
linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-input@...r.kernel.org
Subject: Re: [RFC/PATCH 4/4] gpio: smscece: Add support for gpio IO expander
feature
Hi,
On Tue, Aug 21, 2012 at 04:15:40PM +0530, Sourav Poddar wrote:
> smsc can be used as an gpio io expander device also. So adding
> support for configuring smsc pins as a gpio.
>
> Cc: Benoit Cousson <b-cousson@...com>
> Cc: Felipe Balbi <balbi@...com>
> Cc: Santosh Shilimkar <santosh.shilimkar@...com>
> Signed-off-by: Sourav Poddar <sourav.poddar@...com>
> ---
> drivers/gpio/Kconfig | 7 +
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-smscece.c | 373 +++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 381 insertions(+), 0 deletions(-)
> create mode 100644 drivers/gpio/gpio-smscece.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index b16c8a7..e883929 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -444,6 +444,13 @@ config GPIO_ADP5588_IRQ
> Say yes here to enable the adp5588 to be used as an interrupt
> controller. It requires the driver to be built in the kernel.
>
> +config GPIO_SMSCECE
> + tristate "SMSCECE 1099 I2C GPIO expander"
> + depends on I2C
> + help
> + This option enables support for 18 GPIOs found
> + on SMSC ECE 1099 GPIO Expanders.
> +
> comment "PCI GPIO expanders:"
>
> config GPIO_CS5535
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 153cace..7c803c5 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -12,6 +12,7 @@ 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-$(CONFIG_GPIO_SMSCECE) += gpio-smscece.o
> obj-$(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-smscece.c b/drivers/gpio/gpio-smscece.c
> new file mode 100644
> index 0000000..0cb0959
> --- /dev/null
> +++ b/drivers/gpio/gpio-smscece.c
> @@ -0,0 +1,373 @@
> +/*
> + * GPIO Chip driver for smsc
> + * SMSC I/O Expander and QWERTY Keypad Controller
> + *
> + * Copyright 2012 Texas Instruments Inc.
> + *
> + * Licensed under the GPL-2 or later.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/init.h>
> +#include <linux/i2c.h>
> +#include <linux/gpio.h>
> +#include <linux/interrupt.h>
> +#include <linux/irqdomain.h>
> +#include <linux/irq.h>
> +#include <linux/mfd/smsc.h>
> +#include <linux/err.h>
> +
> +struct smsc_gpio {
> + struct device *dev;
> + struct smsc *smsc;
> + struct gpio_chip gpio_chip;
> + struct mutex lock; /* protect cached dir, dat_out */
> + /* protect serialized access to the interrupt controller bus */
> + struct mutex irq_lock;
> + unsigned gpio_start;
> + int type;
> + int flags;
> + int irq;
> + int irq_base;
> + unsigned int gpio_base;
> + unsigned int dat_out[5];
> + unsigned int dir[5];
> + unsigned int int_lvl[5];
> + unsigned int int_en[5];
> + unsigned int irq_mask[5];
> + unsigned int irq_stat[5];
> +};
> +
> +static int smsc_gpio_get_value(struct gpio_chip *chip, unsigned off)
> +{
> + struct smsc_gpio *sg =
> + container_of(chip, struct smsc_gpio, gpio_chip);
> + unsigned int get;
> + return !!(smsc_read(sg->dev,
> + (SMSC_GPIO_DATA_IN_START + SMSC_BANK(off)) & SMSC_BIT(off),
> + &get));
> +}
> +
> +static void smsc_gpio_set_value(struct gpio_chip *chip,
> + unsigned off, int val)
> +{
> + unsigned bank, bit;
> + struct smsc_gpio *sg =
> + container_of(chip, struct smsc_gpio, gpio_chip);
> +
> + bank = SMSC_BANK(off);
> + bit = SMSC_BIT(off);
> +
> + mutex_lock(&sg->lock);
> + if (val)
> + sg->dat_out[bank] |= bit;
> + else
> + sg->dat_out[bank] &= ~bit;
> +
> + smsc_write(sg->dev, SMSC_GPIO_DATA_OUT_START + bank,
> + sg->dat_out[bank]);
> + mutex_unlock(&sg->lock);
> +}
> +
> +static int smsc_gpio_direction_input(struct gpio_chip *chip, unsigned off)
> +{
> + unsigned int reg;
> + struct smsc_gpio *sg =
> + container_of(chip, struct smsc_gpio, gpio_chip);
> + int reg_dir;
> +
> + mutex_lock(&sg->lock);
> + reg_dir = SMSC_CFG_START + off;
> + smsc_read(sg->dev, reg_dir, ®);
> + reg |= SMSC_GPIO_INPUT_LOW;
> + mutex_unlock(&sg->lock);
> +
> + return smsc_write(sg->dev, reg_dir, reg);
> +}
> +
> +static int smsc_gpio_direction_output(struct gpio_chip *chip,
> + unsigned off, int val)
> +{
> + unsigned int reg;
> + struct smsc_gpio *sg =
> + container_of(chip, struct smsc_gpio, gpio_chip);
> + int reg_dir;
> +
> + mutex_lock(&sg->lock);
> + reg_dir = SMSC_CFG_START + off;
> + smsc_read(sg->dev, reg_dir, ®);
> + reg |= SMSC_GPIO_OUTPUT_PP;
> + mutex_unlock(&sg->lock);
> +
> + return smsc_write(sg->dev, reg_dir, reg);
> +}
> +
> +static int smsc_gpio_to_irq(struct gpio_chip *chip, unsigned off)
> +{
> + struct smsc_gpio *sg =
> + container_of(chip, struct smsc_gpio, gpio_chip);
> + return sg->irq_base + off;
> +}
> +
> +static void smsc_irq_bus_lock(struct irq_data *d)
> +{
> + struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
> +
> + mutex_lock(&sg->irq_lock);
> +}
> +
> +static void smsc_irq_bus_sync_unlock(struct irq_data *d)
> +{
> + struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
> + int i;
> +
> + for (i = 0; i < SMSC_BANK(SMSC_MAXGPIO); i++)
> + if (sg->int_en[i] ^ sg->irq_mask[i]) {
> + sg->int_en[i] = sg->irq_mask[i];
> + smsc_write(sg->dev, SMSC_GPIO_INT_MASK_START + i,
> + sg->int_en[i]);
> + }
> +
> + mutex_unlock(&sg->irq_lock);
> +}
> +
> +static void smsc_irq_mask(struct irq_data *d)
> +{
> + struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
> + unsigned gpio = d->irq - sg->irq_base;
> +
> + sg->irq_mask[SMSC_BANK(gpio)] &= ~SMSC_BIT(gpio);
> +}
> +
> +static void smsc_irq_unmask(struct irq_data *d)
> +{
> + struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
> + unsigned gpio = d->irq - sg->irq_base;
> +
> + sg->irq_mask[SMSC_BANK(gpio)] |= SMSC_BIT(gpio);
> +}
> +
> +static int smsc_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> + struct smsc_gpio *sg = irq_data_get_irq_chip_data(d);
> + uint16_t gpio = d->irq - sg->irq_base;
> + unsigned bank, bit;
> +
> + if ((type & IRQ_TYPE_EDGE_BOTH)) {
> + dev_err(sg->dev, "irq %d: unsupported type %d\n",
> + d->irq, type);
> + return -EINVAL;
> + }
> +
> + bank = SMSC_BANK(gpio);
> + bit = SMSC_BIT(gpio);
> +
> + if (type & IRQ_TYPE_LEVEL_HIGH)
> + sg->int_lvl[bank] |= bit;
> + else if (type & IRQ_TYPE_LEVEL_LOW)
> + sg->int_lvl[bank] &= ~bit;
> + else
> + return -EINVAL;
this looks wrong. You could have a user who wants to trigger on both
HIGH and LOW levels, no ?
> + smsc_gpio_direction_input(&sg->gpio_chip, gpio);
> + smsc_write(sg->dev, SMSC_CFG_START + gpio,
> + sg->int_lvl[bank]);
> +
> + return 0;
> +}
> +
> +static struct irq_chip smsc_irq_chip = {
> + .name = "smsc",
> + .irq_mask = smsc_irq_mask,
> + .irq_unmask = smsc_irq_unmask,
> + .irq_bus_lock = smsc_irq_bus_lock,
> + .irq_bus_sync_unlock = smsc_irq_bus_sync_unlock,
> + .irq_set_type = smsc_irq_set_type,
> +};
> +
> +static int smsc_gpio_read_intstat(struct smsc_gpio *sg,
> + unsigned int *buf, int i)
> +{
> + int ret = smsc_read(sg->dev,
> + SMSC_GPIO_INT_STAT_START + i, buf);
> +
> + if (ret < 0)
> + dev_err(sg->dev, "Read INT_STAT Error\n");
> +
> + return ret;
> +}
> +
> +static irqreturn_t smsc_irq_handler(int irq, void *devid)
> +{
> + struct smsc_gpio *sg = devid;
> + unsigned int status, bank, pending;
> + int ret;
> + smsc_read(sg->dev, GRP_INT_STAT, &status);
> +
> + if (!(status & SMSC_GPI_INT))
> + goto out;
> +
> + for (bank = 0; bank <= SMSC_BANK(SMSC_MAXGPIO);
> + bank++) {
> + pending = sg->irq_stat[bank] & sg->irq_mask[bank];
> + ret = smsc_gpio_read_intstat(sg,
> + &sg->irq_stat[bank], bank);
> + if (ret < 0)
> + memset(&sg->irq_stat[bank], 0,
> + ARRAY_SIZE(sg->irq_stat));
> +
> + while (pending) {
> + unsigned long bit = __ffs(pending);
> + unsigned int irq;
> +
> + pending &= ~BIT(bit);
> + irq = bit + sg->irq_base;
> + handle_nested_irq(irq);
> + }
> + }
> +
> +out:
> + smsc_write(sg->dev, GRP_INT_STAT, status); /* Status is W1C */
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int smsc_irq_setup(struct smsc_gpio *sg)
> +{
> + unsigned gpio;
> + int ret;
> +
> + mutex_init(&sg->irq_lock);
> +
> + for (gpio = 0; gpio < sg->gpio_chip.ngpio; gpio++) {
> + int irq = gpio + sg->irq_base;
> + irq_set_chip_data(irq, sg);
> + irq_set_chip_and_handler(irq, &smsc_irq_chip,
> + handle_level_irq);
> + irq_set_nested_thread(irq, 1);
> +#ifdef CONFIG_ARM
> + set_irq_flags(irq, IRQF_VALID);
> +#else
> + irq_set_noprobe(irq);
> +#endif
> + }
> +
> + ret = request_threaded_irq(sg->irq, NULL,
> + smsc_irq_handler, sg->flags,
> + "smsc_gpio", sg);
would be nice to stick to devm_request_threaded_irq() like on the other
patch.
> + if (ret) {
> + dev_err(sg->dev, "failed to request irq %d\n",
> + sg->irq);
> + }
> +
> + sg->gpio_chip.to_irq = smsc_gpio_to_irq;
> +
> + return 0;
> +}
> +
> +static int __devinit smsc_gpio_probe(struct platform_device *pdev)
> +{
> + struct smsc_gpio *sg;
> + struct gpio_chip *gc;
> + struct smsc *smsc = dev_get_drvdata(pdev->dev.parent);
> + int ret, i, temp;
> + struct device *dev = &pdev->dev;
> + struct device_node *np = dev->of_node;
> + int irq_base;
> +
> + sg = devm_kzalloc(dev, sizeof(*sg), GFP_KERNEL);
> + if (sg == NULL) {
> + dev_err(&pdev->dev, "failed to alloc memory\n");
> + return -ENOMEM;
> + }
> +
> + sg->irq = platform_get_irq(pdev, 0);
> + if (np) {
> + of_property_read_u32(np, "gpio,base", &temp);
> + of_property_read_u32(np, "flags", &sg->flags);
> + }
> +
> + gc = &sg->gpio_chip;
> + gc->direction_input = smsc_gpio_direction_input;
> + gc->direction_output = smsc_gpio_direction_output;
> + gc->get = smsc_gpio_get_value;
> + gc->set = smsc_gpio_set_value;
> + gc->can_sleep = 1;
> +
> + gc->base = temp;
> + gc->ngpio = SMSC_MAXGPIO;
> + gc->owner = THIS_MODULE;
> +
> + sg->smsc = smsc;
> + sg->dev = dev;
> + mutex_init(&sg->lock);
> +
> + for (i = 0; i <= SMSC_BANK(SMSC_MAXGPIO); i++)
> + smsc_read(sg->dev, SMSC_GPIO_DATA_OUT_START + i,
> + &sg->dat_out[i]);
> +
> + for (i = 0; i < SMSC_MAXGPIO; i++)
> + smsc_read(sg->dev, SMSC_CFG_START + i, &sg->dir[i]);
> +
> + irq_base = irq_alloc_descs(-1, 0, sg->gpio_chip.ngpio, 0);
> + if (IS_ERR_VALUE(irq_base)) {
> + dev_err(sg->dev, "Fail to allocate IRQ descs\n");
> + return irq_base;
> + }
> + sg->irq_base = irq_base;
> +
> + irq_domain_add_legacy(pdev->dev.of_node, sg->gpio_chip.ngpio,
> + sg->irq_base, 0, &irq_domain_simple_ops, NULL);
> +
> + ret = smsc_irq_setup(sg);
> + if (ret)
> + goto err;
> +
> + ret = gpiochip_add(&sg->gpio_chip);
> + if (ret)
> + goto err;
> +
> + return 0;
> +
> +err:
> + kfree(sg);
using devm_kzalloc(), not needed to free.
> +
> + return ret;
> +}
> +
> +static int __devexit smsc_gpio_remove(struct platform_device *pdev)
> +{
> + struct smsc_gpio *sg = dev_get_drvdata(&pdev->dev);
> + int ret;
> +
> + ret = gpiochip_remove(&sg->gpio_chip);
> + if (ret) {
> + dev_err(&pdev->dev, "gpiochip_remove failed %d\n", ret);
> + return ret;
> + }
this will leak the irq (please move to devm_request_threaded_irq).
It's also leaking irq_descs and irq_domain, you need to free those
resources by calling irq_domain_remove and irq_free_descs.
--
balbi
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