Message-ID: <5047A10D.6070106@ti.com>
Date:	Thu, 6 Sep 2012 00:29:25 +0530
From:	Vaibhav Hiremath <hvaibhav@...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>, <santosh.shilimkar@...com>,
	<b-cousson@...com>, <balbi@...com>
Subject: Re: [PATCHv2 4/4] gpio: smscece: Add support for gpio IO expander
 feature



On 9/5/2012 5:07 PM, 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>
> ---
> Changes since v1: 
>  - Use edge triggering instead of level
>  - Use devm_reuest_threaded_irq
>  - In remove part, use "irq_free_desc" and
>      "irq_remove_domain" api.
>  drivers/gpio/Kconfig        |    7 +
>  drivers/gpio/Makefile       |    1 +
>  drivers/gpio/gpio-smscece.c |  380 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 388 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..68a17fa
> --- /dev/null
> +++ b/drivers/gpio/gpio-smscece.c
> @@ -0,0 +1,380 @@
> +/*
> + * 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.

Can you put proper license here?

> + */
> +
> +#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;
> +	struct irq_domain       *irq_domain;
> +	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 irq_trig_fall[5];
> +	unsigned int irq_trig_raise[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);
> +	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);
> +	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_EDGE_FALLING)
> +		sg->irq_trig_fall[bank] |= bit;
> +	else
> +		sg->irq_trig_fall[bank] &= ~bit;
> +
> +	if (type & IRQ_TYPE_EDGE_RISING)
> +		sg->irq_trig_raise[bank] |= bit;
> +	else
> +		sg->irq_trig_raise[bank] &= ~bit;
> +
> +	smsc_gpio_direction_input(&sg->gpio_chip, gpio);
> +	smsc_write(sg->dev, SMSC_CFG_START + gpio,
> +			sg->irq_trig_fall[bank] | sg->irq_trig_raise[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);
> +

Add blank line before read statement above.

> +	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 = devm_request_threaded_irq(sg->dev, sg->irq, NULL,
> +			smsc_irq_handler, sg->flags,
> +			"smsc_gpio", sg);
> +	if (ret) {
> +		dev_err(sg->dev, "failed to request irq %d\n",
> +			sg->irq);
> +	}

Isn't return err required here?

> +
> +	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;
> +
> +	sg->irq_domain = 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;
> +

You don't need separate return statements here.

On the other side, did you also submit DTS changes for GPIO?
Without review will not be complete.

Thanks,
Vaibhav

> +err:
> +	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;
> +	}
> +
> +	irq_domain_remove(sg->irq_domain);
> +	irq_free_descs(sg->irq_base, sg->gpio_chip.ngpio);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id smsc_gpio_dt_match[] = {
> +	{ .compatible = "smsc,gpio" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, smsc_gpio_dt_match);
> +
> +static struct platform_driver smsc_gpio_driver = {
> +	.driver = {
> +		   .name = "smsc_gpio",
> +		   .of_match_table = of_match_ptr(smsc_gpio_dt_match),
> +		   },
> +	.probe = smsc_gpio_probe,
> +	.remove = __devexit_p(smsc_gpio_remove),
> +};
> +
> +module_platform_driver(smsc_gpio_driver);
> +
> +MODULE_AUTHOR("Sourav Poddar <sourav.poddar@...com>");
> +MODULE_DESCRIPTION("GPIO SMSC Driver");
> +MODULE_LICENSE("GPL v2");
> 
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