Subject: [PATCH v7 2/4] pinctrl: cygnus: add gpio/pinconf driver

From: [email-masked] (Dmitry Torokhov)
Date: Tue, 3 Feb 2015 17:41:52 -0800

On Tue, Feb 03, 2015 at 05:09:06PM -0800, Ray Jui wrote:
> This adds the initial support of the Broadcom Cygnus GPIO/PINCONF driver
> that supports all 3 GPIO controllers on Cygnus including the ASIU GPIO
> controller, the chipCommonG GPIO controller, and the always-on GPIO
> controller. Basic PINCONF configurations such as bias pull up/down, and
> drive strength are also supported in this driver.
> 
> Pins from the ASIU GPIO controller can be individually muxed to GPIO
> function, through interaction with the Cygnus IOMUX controller
> 
> Signed-off-by: Ray Jui <[email-masked]>
> Reviewed-by: Scott Branden <[email-masked]>
> ---
>  drivers/pinctrl/bcm/Kconfig               |   22 +
>  drivers/pinctrl/bcm/Makefile              |    1 +
>  drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c |  920 +++++++++++++++++++++++++++++
>  3 files changed, 943 insertions(+)
>  create mode 100644 drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c
> 
> diff --git a/drivers/pinctrl/bcm/Kconfig b/drivers/pinctrl/bcm/Kconfig
> index eb13201..cd11d4d 100644
> --- a/drivers/pinctrl/bcm/Kconfig
> +++ b/drivers/pinctrl/bcm/Kconfig
> @@ -20,6 +20,28 @@ config PINCTRL_BCM2835
>  	select PINMUX
>  	select PINCONF
>  
> +config PINCTRL_CYGNUS_GPIO
> +	bool "Broadcom Cygnus GPIO (with PINCONF) driver"
> +	depends on OF_GPIO && ARCH_BCM_CYGNUS
> +	select GPIOLIB_IRQCHIP
> +	select PINCONF
> +	select GENERIC_PINCONF
> +	default ARCH_BCM_CYGNUS
> +	help
> +	  Say yes here to enable the Broadcom Cygnus GPIO driver.
> +
> +	  The Broadcom Cygnus SoC has 3 GPIO controllers including the ASIU
> +	  GPIO controller (ASIU), the chipCommonG GPIO controller (CCM), and
> +	  the always-ON GPIO controller (CRMU/AON). All 3 GPIO controllers are
> +	  supported by this driver.
> +
> +	  All 3 Cygnus GPIO controllers support basic PINCONF functions such
> +	  as bias pull up, pull down, and drive strength configurations, when
> +	  these pins are muxed to GPIO.
> +
> +	  Pins from the ASIU GPIO can be individually muxed to GPIO function,
> +	  through interaction with the Cygnus IOMUX controller.
> +
>  config PINCTRL_CYGNUS_MUX
>  	bool "Broadcom Cygnus IOMUX driver"
>  	depends on (ARCH_BCM_CYGNUS || COMPILE_TEST)
> diff --git a/drivers/pinctrl/bcm/Makefile b/drivers/pinctrl/bcm/Makefile
> index bb6beb6..2b2f70e 100644
> --- a/drivers/pinctrl/bcm/Makefile
> +++ b/drivers/pinctrl/bcm/Makefile
> @@ -2,4 +2,5 @@
>  
>  obj-$(CONFIG_PINCTRL_BCM281XX)		+= pinctrl-bcm281xx.o
>  obj-$(CONFIG_PINCTRL_BCM2835)		+= pinctrl-bcm2835.o
> +obj-$(CONFIG_PINCTRL_CYGNUS_GPIO)	+= pinctrl-cygnus-gpio.o
>  obj-$(CONFIG_PINCTRL_CYGNUS_MUX)	+= pinctrl-cygnus-mux.o
> diff --git a/drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c b/drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c
> new file mode 100644
> index 0000000..cfe4478
> --- /dev/null
> +++ b/drivers/pinctrl/bcm/pinctrl-cygnus-gpio.c
> @@ -0,0 +1,920 @@
> +/*
> + * Copyright (C) 2014-2015 Broadcom Corporation
> + *
> + * 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 version 2.
> + *
> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> + * kind, whether express or implied; without even the implied warranty
> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * This file contains the Broadcom Cygnus GPIO driver that supports 3
> + * GPIO controllers on Cygnus including the ASIU GPIO controller, the
> + * chipCommonG GPIO controller, and the always-on GPIO controller. Basic
> + * PINCONF such as bias pull up/down, and drive strength are also supported
> + * in this driver.
> + *
> + * Pins from the ASIU GPIO can be individually muxed to GPIO function,
> + * through the interaction with the Cygnus IOMUX controller
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/module.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/gpio.h>
> +#include <linux/ioport.h>
> +#include <linux/of_device.h>
> +#include <linux/of_irq.h>
> +#include <linux/pinctrl/pinctrl.h>
> +#include <linux/pinctrl/pinmux.h>
> +#include <linux/pinctrl/pinconf.h>
> +#include <linux/pinctrl/pinconf-generic.h>
> +
> +#include "../pinctrl-utils.h"
> +
> +#define CYGNUS_GPIO_DATA_IN_OFFSET   0x00
> +#define CYGNUS_GPIO_DATA_OUT_OFFSET  0x04
> +#define CYGNUS_GPIO_OUT_EN_OFFSET    0x08
> +#define CYGNUS_GPIO_IN_TYPE_OFFSET   0x0c
> +#define CYGNUS_GPIO_INT_DE_OFFSET    0x10
> +#define CYGNUS_GPIO_INT_EDGE_OFFSET  0x14
> +#define CYGNUS_GPIO_INT_MSK_OFFSET   0x18
> +#define CYGNUS_GPIO_INT_STAT_OFFSET  0x1c
> +#define CYGNUS_GPIO_INT_MSTAT_OFFSET 0x20
> +#define CYGNUS_GPIO_INT_CLR_OFFSET   0x24
> +#define CYGNUS_GPIO_PAD_RES_OFFSET   0x34
> +#define CYGNUS_GPIO_RES_EN_OFFSET    0x38
> +
> +/* drive strength control for ASIU GPIO */
> +#define CYGNUS_GPIO_ASIU_DRV0_CTRL_OFFSET 0x58
> +
> +/* drive strength control for CCM/CRMU (AON) GPIO */
> +#define CYGNUS_GPIO_DRV0_CTRL_OFFSET  0x00
> +
> +#define GPIO_BANK_SIZE 0x200
> +#define NGPIOS_PER_BANK 32
> +#define GPIO_BANK(pin) ((pin) / NGPIOS_PER_BANK)
> +
> +#define CYGNUS_GPIO_REG(pin, reg) (GPIO_BANK(pin) * GPIO_BANK_SIZE + (reg))
> +#define CYGNUS_GPIO_SHIFT(pin) ((pin) % NGPIOS_PER_BANK)
> +
> +#define GPIO_DRV_STRENGTH_BIT_SHIFT  20
> +#define GPIO_DRV_STRENGTH_BITS       3
> +#define GPIO_DRV_STRENGTH_BIT_MASK   ((1 << GPIO_DRV_STRENGTH_BITS) - 1)
> +
> +/*
> + * Cygnus GPIO core
> + *
> + * @dev: pointer to device
> + * @base: I/O register base for Cygnus GPIO controller
> + * @io_ctrl: I/O register base for certain type of Cygnus GPIO controller that
> + * has the PINCONF support implemented outside of the GPIO block
> + * @lock: lock to protect access to I/O registers
> + * @gc: GPIO chip
> + * @num_banks: number of GPIO banks, each bank supports up to 32 GPIOs
> + * @pinmux_is_supported: flag to indicate this GPIO controller contains pins
> + * that can be individually muxed to GPIO
> + * @pctl: pointer to pinctrl_dev
> + * @pctldesc: pinctrl descriptor
> + * @pins: pointer to array of pins
> + */
> +struct cygnus_gpio {
> +	struct device *dev;
> +
> +	void __iomem *base;
> +	void __iomem *io_ctrl;
> +
> +	spinlock_t lock;
> +
> +	struct gpio_chip gc;
> +	unsigned num_banks;
> +
> +	int pinmux_is_supported;

bool?

> +
> +	struct pinctrl_dev *pctl;
> +	struct pinctrl_desc pctldesc;
> +	struct pinctrl_pin_desc *pins;
> +};
> +
> +static struct cygnus_gpio *to_cygnus_gpio(struct gpio_chip *gc)
> +{
> +	return container_of(gc, struct cygnus_gpio, gc);
> +}
> +
> +/*
> + * Mapping from PINCONF pins to GPIO pins is 1-to-1
> + */
> +static unsigned cygnus_pin_to_gpio(unsigned pin)
> +{
> +	return pin;
> +}
> +
> +static u32 cygnus_readl(struct cygnus_gpio *chip, unsigned int offset)
> +{
> +	return readl(chip->base + offset);
> +}
> +
> +static void cygnus_writel(struct cygnus_gpio *chip, unsigned int offset,
> +			  u32 val)
> +{
> +	writel(val, chip->base + offset);
> +}
> +
> +/**
> + *  cygnus_set_bit - set or clear one bit (corresponding to the GPIO pin) in a
> + *  Cygnus GPIO register
> + *
> + *  @cygnus_gpio: Cygnus GPIO device
> + *  @reg: register offset
> + *  @gpio: GPIO pin
> + *  @set: set or clear. 1 - set; 0 -clear
> + */
> +static void cygnus_set_bit(struct cygnus_gpio *chip, unsigned int reg,
> +			   unsigned gpio, int set)
> +{
> +	unsigned int offset = CYGNUS_GPIO_REG(gpio, reg);
> +	unsigned int shift = CYGNUS_GPIO_SHIFT(gpio);
> +	u32 val;
> +
> +	val = cygnus_readl(chip, offset);
> +	if (set)
> +		val |= BIT(shift);
> +	else
> +		val &= ~BIT(shift);
> +	cygnus_writel(chip, offset, val);
> +}
> +
> +static int cygnus_get_bit(struct cygnus_gpio *chip, unsigned int reg,
> +			  unsigned gpio)
> +{
> +	unsigned int offset = CYGNUS_GPIO_REG(gpio, reg);
> +	unsigned int shift = CYGNUS_GPIO_SHIFT(gpio);
> +	u32 val;
> +
> +	val = cygnus_readl(chip, offset) & BIT(shift);
> +	if (val)
> +		return 1;
> +	else
> +		return 0;
> +}
> +
> +static void cygnus_gpio_irq_handler(unsigned int irq, struct irq_desc *desc)
> +{
> +	struct gpio_chip *gc = irq_desc_get_handler_data(desc);
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	struct irq_chip *irq_chip = irq_desc_get_chip(desc);
> +	int i, bit;
> +
> +	chained_irq_enter(irq_chip, desc);
> +
> +	/* go through the entire GPIO banks and handle all interrupts */
> +	for (i = 0; i < chip->num_banks; i++) {
> +		unsigned long val = cygnus_readl(chip,
> +				(i * GPIO_BANK_SIZE) +
> +				CYGNUS_GPIO_INT_MSTAT_OFFSET);
> +
> +		for_each_set_bit(bit, &val, NGPIOS_PER_BANK) {
> +			unsigned pin = NGPIOS_PER_BANK * i + bit;
> +			int child_irq = irq_find_mapping(gc->irqdomain, pin);
> +
> +			/*
> +			 * Clear the interrupt before invoking the
> +			 * handler, so we do not leave any window
> +			 */
> +			cygnus_writel(chip, (i * GPIO_BANK_SIZE) +
> +				      CYGNUS_GPIO_INT_CLR_OFFSET, BIT(bit));
> +
> +			generic_handle_irq(child_irq);
> +		}
> +	}
> +
> +	chained_irq_exit(irq_chip, desc);
> +}
> +
> +
> +static void cygnus_gpio_irq_ack(struct irq_data *d)
> +{
> +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned gpio = d->hwirq;
> +	unsigned int offset = CYGNUS_GPIO_REG(gpio,
> +			CYGNUS_GPIO_INT_CLR_OFFSET);
> +	unsigned int shift = CYGNUS_GPIO_SHIFT(gpio);
> +	u32 val = BIT(shift);
> +
> +	cygnus_writel(chip, offset, val);
> +}
> +
> +/**
> + *  cygnus_gpio_irq_set_mask - mask/unmask a GPIO interrupt
> + *
> + *  @d: IRQ chip data
> + *  @mask: mask/unmask GPIO interrupt. 0 - mask (disable); 1 - unmask (enable)
> + */
> +static void cygnus_gpio_irq_set_mask(struct irq_data *d, int mask)
> +{
> +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned gpio = d->hwirq;
> +
> +	cygnus_set_bit(chip, CYGNUS_GPIO_INT_MSK_OFFSET, gpio, mask);
> +}
> +
> +static void cygnus_gpio_irq_mask(struct irq_data *d)
> +{
> +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	cygnus_gpio_irq_set_mask(d, 0);
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +}
> +
> +static void cygnus_gpio_irq_unmask(struct irq_data *d)
> +{
> +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	cygnus_gpio_irq_set_mask(d, 1);
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +}
> +
> +static int cygnus_gpio_irq_set_type(struct irq_data *d, unsigned int type)
> +{
> +	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned gpio = d->hwirq;
> +	int int_type = 0, dual_edge = 0, edge_lvl = 0;
> +	unsigned long flags;
> +
> +	switch (type & IRQ_TYPE_SENSE_MASK) {
> +	case IRQ_TYPE_EDGE_RISING:
> +		edge_lvl = 1;
> +		break;
> +
> +	case IRQ_TYPE_EDGE_FALLING:
> +		break;
> +
> +	case IRQ_TYPE_EDGE_BOTH:
> +		dual_edge = 1;
> +		break;
> +
> +	case IRQ_TYPE_LEVEL_HIGH:
> +		int_type = 1;
> +		edge_lvl = 1;
> +		break;
> +
> +	case IRQ_TYPE_LEVEL_LOW:
> +		int_type = 1;
> +		break;
> +
> +	default:
> +		dev_err(chip->dev, "invalid GPIO IRQ type 0x%x\n",
> +			type);
> +		return -EINVAL;
> +	}
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	cygnus_set_bit(chip, CYGNUS_GPIO_IN_TYPE_OFFSET, gpio, int_type);
> +	cygnus_set_bit(chip, CYGNUS_GPIO_INT_DE_OFFSET, gpio, dual_edge);
> +	cygnus_set_bit(chip, CYGNUS_GPIO_INT_EDGE_OFFSET, gpio,
> +		       edge_lvl);
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +
> +	dev_dbg(chip->dev,
> +		"gpio:%u set int_type:%d dual_edge:%d edge_lvl:%d\n",
> +		gpio, int_type, dual_edge, edge_lvl);
> +
> +	return 0;
> +}
> +
> +static struct irq_chip cygnus_gpio_irq_chip = {
> +	.name = "bcm-cygnus-gpio",
> +	.irq_ack = cygnus_gpio_irq_ack,
> +	.irq_mask = cygnus_gpio_irq_mask,
> +	.irq_unmask = cygnus_gpio_irq_unmask,
> +	.irq_set_type = cygnus_gpio_irq_set_type,
> +};
> +
> +/*
> + * Request the Cygnus IOMUX pinmux controller to mux individual pins to GPIO
> + */
> +static int cygnus_gpio_request(struct gpio_chip *gc, unsigned offset)
> +{
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned gpio = gc->base + offset;
> +
> +	/* not all Cygnus GPIO pins can be muxed individually */
> +	if (!chip->pinmux_is_supported)
> +		return 0;
> +
> +	return pinctrl_request_gpio(gpio);
> +}
> +
> +static void cygnus_gpio_free(struct gpio_chip *gc, unsigned offset)
> +{
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned gpio = gc->base + offset;
> +
> +	if (!chip->pinmux_is_supported)
> +		return;
> +
> +	pinctrl_free_gpio(gpio);
> +}
> +
> +static int cygnus_gpio_direction_input(struct gpio_chip *gc, unsigned gpio)
> +{
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	cygnus_set_bit(chip, CYGNUS_GPIO_OUT_EN_OFFSET, gpio, 0);
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +
> +	dev_dbg(chip->dev, "gpio:%u set input\n", gpio);
> +
> +	return 0;
> +}
> +
> +static int cygnus_gpio_direction_output(struct gpio_chip *gc, unsigned gpio,
> +					int value)
> +{
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	cygnus_set_bit(chip, CYGNUS_GPIO_OUT_EN_OFFSET, gpio, 1);
> +	cygnus_set_bit(chip, CYGNUS_GPIO_DATA_OUT_OFFSET, gpio, value);
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +
> +	dev_dbg(chip->dev, "gpio:%u set output, value:%d\n", gpio, value);
> +
> +	return 0;
> +}
> +
> +static void cygnus_gpio_set(struct gpio_chip *gc, unsigned gpio, int value)
> +{
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	cygnus_set_bit(chip, CYGNUS_GPIO_DATA_OUT_OFFSET, gpio, value);
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +
> +	dev_dbg(chip->dev, "gpio:%u set, value:%d\n", gpio, value);
> +}
> +
> +static int cygnus_gpio_get(struct gpio_chip *gc, unsigned gpio)
> +{
> +	struct cygnus_gpio *chip = to_cygnus_gpio(gc);
> +	unsigned int offset = CYGNUS_GPIO_REG(gpio,
> +					      CYGNUS_GPIO_DATA_IN_OFFSET);
> +	unsigned int shift = CYGNUS_GPIO_SHIFT(gpio);
> +
> +	return !!(cygnus_readl(chip, offset) & BIT(shift));
> +}
> +
> +static int cygnus_get_groups_count(struct pinctrl_dev *pctldev)
> +{
> +	return 1;
> +}
> +
> +/*
> + * Only one group: "gpio_grp", since this local pinctrl device only performs
> + * GPIO specific PINCONF configurations
> + */
> +static const char *cygnus_get_group_name(struct pinctrl_dev *pctldev,
> +					 unsigned selector)
> +{
> +

Extra blank line.

> +	return "gpio_grp";
> +}
> +
> +static const struct pinctrl_ops cygnus_pctrl_ops = {
> +	.get_groups_count = cygnus_get_groups_count,
> +	.get_group_name = cygnus_get_group_name,
> +	.dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
> +	.dt_free_map = pinctrl_utils_dt_free_map,
> +};
> +
> +static int cygnus_gpio_set_pull(struct cygnus_gpio *chip, unsigned gpio,
> +				int disable, int pull_up)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +
> +	if (disable) {
> +		cygnus_set_bit(chip, CYGNUS_GPIO_RES_EN_OFFSET, gpio, 0);
> +	} else {
> +		cygnus_set_bit(chip, CYGNUS_GPIO_PAD_RES_OFFSET, gpio,
> +			       pull_up);
> +		cygnus_set_bit(chip, CYGNUS_GPIO_RES_EN_OFFSET, gpio, 1);
> +	}
> +
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +
> +	dev_dbg(chip->dev, "gpio:%u set pullup:%d\n", gpio, pull_up);
> +
> +	return 0;
> +}
> +
> +static void cygnus_gpio_get_pull(struct cygnus_gpio *chip, unsigned gpio,
> +				 int *disable, int *pull_up)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	*disable = !cygnus_get_bit(chip, CYGNUS_GPIO_RES_EN_OFFSET, gpio);
> +	*pull_up = cygnus_get_bit(chip, CYGNUS_GPIO_PAD_RES_OFFSET, gpio);
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +}
> +
> +static int cygnus_gpio_set_strength(struct cygnus_gpio *chip, unsigned gpio,
> +				    unsigned strength)
> +{
> +	void __iomem *base;
> +	unsigned int i, offset, shift;
> +	u32 val;
> +	unsigned long flags;
> +
> +	/* make sure drive strength is supported */
> +	if (strength < 2 ||  strength > 16 || (strength % 2))
> +		return -ENOTSUPP;
> +
> +	if (chip->io_ctrl) {
> +		base = chip->io_ctrl;
> +		offset = CYGNUS_GPIO_DRV0_CTRL_OFFSET;
> +	} else {
> +		base = chip->base;
> +		offset = CYGNUS_GPIO_REG(gpio,
> +					 CYGNUS_GPIO_ASIU_DRV0_CTRL_OFFSET);
> +	}
> +
> +	shift = CYGNUS_GPIO_SHIFT(gpio);
> +
> +	dev_dbg(chip->dev, "gpio:%u set drive strength:%d mA\n", gpio,
> +		strength);
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	strength = (strength / 2) - 1;
> +	for (i = 0; i < GPIO_DRV_STRENGTH_BITS; i++) {
> +		val = readl(base + offset);
> +		val &= ~BIT(shift);
> +		val |= ((strength >> i) & 0x1) << shift;
> +		writel(val, base + offset);
> +		offset += 4;
> +	}
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int cygnus_gpio_get_strength(struct cygnus_gpio *chip, unsigned gpio,
> +				    u16 *strength)
> +{
> +	void __iomem *base;
> +	unsigned int i, offset, shift;
> +	u32 val;
> +	unsigned long flags;
> +
> +	if (chip->io_ctrl) {
> +		base = chip->io_ctrl;
> +		offset = CYGNUS_GPIO_DRV0_CTRL_OFFSET;
> +	} else {
> +		base = chip->base;
> +		offset = CYGNUS_GPIO_REG(gpio,
> +					 CYGNUS_GPIO_ASIU_DRV0_CTRL_OFFSET);
> +	}
> +
> +	shift = CYGNUS_GPIO_SHIFT(gpio);
> +
> +	spin_lock_irqsave(&chip->lock, flags);
> +	*strength = 0;
> +	for (i = 0; i < GPIO_DRV_STRENGTH_BITS; i++) {
> +		val = readl(base + offset) & BIT(shift);
> +		val >>= shift;
> +		*strength += (val << i);
> +		offset += 4;
> +	}
> +
> +	/* convert to mA */
> +	*strength = (*strength + 1) * 2;
> +	spin_unlock_irqrestore(&chip->lock, flags);
> +
> +	return 0;
> +}
> +
> +static int cygnus_pin_config_get(struct pinctrl_dev *pctldev, unsigned pin,
> +				 unsigned long *config)
> +{
> +	struct cygnus_gpio *chip = pinctrl_dev_get_drvdata(pctldev);
> +	enum pin_config_param param = pinconf_to_config_param(*config);
> +	unsigned gpio = cygnus_pin_to_gpio(pin);
> +	u16 arg;
> +	int disable, pull_up, ret;
> +
> +	switch (param) {
> +	case PIN_CONFIG_BIAS_DISABLE:
> +		cygnus_gpio_get_pull(chip, gpio, &disable, &pull_up);
> +		if (disable)
> +			return 0;
> +		else
> +			return -EINVAL;
> +
> +	case PIN_CONFIG_BIAS_PULL_UP:
> +		cygnus_gpio_get_pull(chip, gpio, &disable, &pull_up);
> +		if (!disable && pull_up)
> +			return 0;
> +		else
> +			return -EINVAL;
> +
> +	case PIN_CONFIG_BIAS_PULL_DOWN:
> +		cygnus_gpio_get_pull(chip, gpio, &disable, &pull_up);
> +		if (!disable && !pull_up)
> +			return 0;
> +		else
> +			return -EINVAL;
> +
> +	case PIN_CONFIG_DRIVE_STRENGTH:
> +		ret = cygnus_gpio_get_strength(chip, gpio, &arg);
> +		if (ret)
> +			return ret;
> +		else
> +			*config = pinconf_to_config_packed(param, arg);
> +
> +		return 0;
> +
> +	default:
> +		return -ENOTSUPP;
> +	}
> +
> +	return -ENOTSUPP;
> +}
> +
> +static int cygnus_pin_config_set(struct pinctrl_dev *pctldev, unsigned pin,
> +				 unsigned long *configs, unsigned num_configs)
> +{
> +	struct cygnus_gpio *chip = pinctrl_dev_get_drvdata(pctldev);
> +	enum pin_config_param param;
> +	u16 arg;
> +	unsigned i, gpio = cygnus_pin_to_gpio(pin);
> +	int ret = -ENOTSUPP;
> +
> +	for (i = 0; i < num_configs; i++) {
> +		param = pinconf_to_config_param(configs[i]);
> +		arg = pinconf_to_config_argument(configs[i]);
> +
> +		switch (param) {
> +		case PIN_CONFIG_BIAS_DISABLE:
> +			ret = cygnus_gpio_set_pull(chip, gpio, 1, 0);
> +			if (ret < 0)
> +				goto out;
> +			break;
> +
> +		case PIN_CONFIG_BIAS_PULL_UP:
> +			ret = cygnus_gpio_set_pull(chip, gpio, 0, 1);
> +			if (ret < 0)
> +				goto out;
> +			break;
> +
> +		case PIN_CONFIG_BIAS_PULL_DOWN:
> +			ret = cygnus_gpio_set_pull(chip, gpio, 0, 0);
> +			if (ret < 0)
> +				goto out;
> +			break;
> +
> +		case PIN_CONFIG_DRIVE_STRENGTH:
> +			ret = cygnus_gpio_set_strength(chip, gpio, arg);
> +			if (ret < 0)
> +				goto out;
> +			break;
> +
> +		default:
> +			dev_err(chip->dev, "invalid configuration\n");
> +			return -ENOTSUPP;
> +		}
> +	} /* for each config */
> +
> +out:
> +	return ret;
> +}
> +
> +static const struct pinconf_ops cygnus_pconf_ops = {
> +	.is_generic = true,
> +	.pin_config_get = cygnus_pin_config_get,
> +	.pin_config_set = cygnus_pin_config_set,
> +};
> +
> +/*
> + * Map a GPIO in the local gpio_chip pin space to a pin in the Cygnus IOMUX
> + * pinctrl pin space
> + */
> +struct cygnus_gpio_pin_range {
> +	unsigned offset;
> +	unsigned pin_base;
> +	unsigned num_pins;
> +};
> +
> +#define CYGNUS_PINRANGE(o, p, n) { .offset = o, .pin_base = p, .num_pins = n }
> +
> +/*
> + * Pin mapping table for mapping local GPIO pins to Cygnus IOMUX pinctrl pins
> + */
> +static const struct cygnus_gpio_pin_range cygnus_gpio_pintable[] = {
> +	CYGNUS_PINRANGE(0, 42, 1),
> +	CYGNUS_PINRANGE(1, 44, 3),
> +	CYGNUS_PINRANGE(4, 48, 1),
> +	CYGNUS_PINRANGE(5, 50, 3),
> +	CYGNUS_PINRANGE(8, 126, 1),
> +	CYGNUS_PINRANGE(9, 155, 1),
> +	CYGNUS_PINRANGE(10, 152, 1),
> +	CYGNUS_PINRANGE(11, 154, 1),
> +	CYGNUS_PINRANGE(12, 153, 1),
> +	CYGNUS_PINRANGE(13, 127, 3),
> +	CYGNUS_PINRANGE(16, 140, 1),
> +	CYGNUS_PINRANGE(17, 145, 7),
> +	CYGNUS_PINRANGE(24, 130, 10),
> +	CYGNUS_PINRANGE(34, 141, 4),
> +	CYGNUS_PINRANGE(38, 54, 1),
> +	CYGNUS_PINRANGE(39, 56, 3),
> +	CYGNUS_PINRANGE(42, 60, 3),
> +	CYGNUS_PINRANGE(45, 64, 3),
> +	CYGNUS_PINRANGE(48, 68, 2),
> +	CYGNUS_PINRANGE(50, 84, 6),
> +	CYGNUS_PINRANGE(56, 94, 6),
> +	CYGNUS_PINRANGE(62, 72, 1),
> +	CYGNUS_PINRANGE(63, 70, 1),
> +	CYGNUS_PINRANGE(64, 80, 1),
> +	CYGNUS_PINRANGE(65, 74, 3),
> +	CYGNUS_PINRANGE(68, 78, 1),
> +	CYGNUS_PINRANGE(69, 82, 1),
> +	CYGNUS_PINRANGE(70, 156, 17),
> +	CYGNUS_PINRANGE(87, 104, 12),
> +	CYGNUS_PINRANGE(99, 102, 2),
> +	CYGNUS_PINRANGE(101, 90, 4),
> +	CYGNUS_PINRANGE(105, 116, 10),
> +	CYGNUS_PINRANGE(123, 11, 1),
> +	CYGNUS_PINRANGE(124, 38, 4),
> +	CYGNUS_PINRANGE(128, 43, 1),
> +	CYGNUS_PINRANGE(129, 47, 1),
> +	CYGNUS_PINRANGE(130, 49, 1),
> +	CYGNUS_PINRANGE(131, 53, 1),
> +	CYGNUS_PINRANGE(132, 55, 1),
> +	CYGNUS_PINRANGE(133, 59, 1),
> +	CYGNUS_PINRANGE(134, 63, 1),
> +	CYGNUS_PINRANGE(135, 67, 1),
> +	CYGNUS_PINRANGE(136, 71, 1),
> +	CYGNUS_PINRANGE(137, 73, 1),
> +	CYGNUS_PINRANGE(138, 77, 1),
> +	CYGNUS_PINRANGE(139, 79, 1),
> +	CYGNUS_PINRANGE(140, 81, 1),
> +	CYGNUS_PINRANGE(141, 83, 1),
> +	CYGNUS_PINRANGE(142, 10, 1)
> +};
> +
> +/*
> + * The Cygnus IOMUX controller mainly supports group based mux configuration,
> + * but certain pins can be muxed to GPIO individually. Only the ASIU GPIO
> + * controller can support this, so it's an optional configuration
> + *
> + * Return -ENODEV means no support and that's fine
> + */
> +static int cygnus_gpio_pinmux_add_range(struct cygnus_gpio *chip)
> +{
> +	struct device_node *node = chip->dev->of_node;
> +	struct device_node *pinmux_node;
> +	struct platform_device *pinmux_pdev;
> +	struct gpio_chip *gc = &chip->gc;
> +	int i, ret;
> +
> +	/* parse DT to find the phandle to the pinmux controller */
> +	pinmux_node = of_parse_phandle(node, "pinmux", 0);
> +	if (!pinmux_node)
> +		return -ENODEV;
> +
> +	pinmux_pdev = of_find_device_by_node(pinmux_node);
> +	if (!pinmux_pdev) {
> +		dev_err(chip->dev, "failed to get pinmux device\n");
> +		return -EINVAL;
> +	}
> +
> +	/* now need to create the mapping between local GPIO and PINMUX pins */
> +	for (i = 0; i < ARRAY_SIZE(cygnus_gpio_pintable); i++) {
> +		ret = gpiochip_add_pin_range(gc, dev_name(&pinmux_pdev->dev),
> +					     cygnus_gpio_pintable[i].offset,
> +					     cygnus_gpio_pintable[i].pin_base,
> +					     cygnus_gpio_pintable[i].num_pins);
> +		if (ret) {
> +			dev_err(chip->dev, "unable to add GPIO pin range\n");
> +			goto err_rm_pin_range;
> +		}
> +	}
> +
> +	chip->pinmux_is_supported = 1;

	chip->pinmux_is_supported = true;

?

> +	return 0;
> +
> +err_rm_pin_range:
> +	gpiochip_remove_pin_ranges(gc);

I think you need:

	put_dveice(&pinmux_pdev->dev);

since of_find_device_by_node calls bus_find_device() that takes
reference to found device.

... And now that I look at this majority of users of
of_find_device_by_node() is broken like that :(

BTW, it looks like you only need pinmux_dev for it's name so you
probably need to drop reference in success path as well.

> +	return ret;
> +}
> +
> +static void cygnus_gpio_pinmux_remove_range(struct cygnus_gpio *chip)
> +{
> +	struct gpio_chip *gc = &chip->gc;
> +
> +	if (chip->pinmux_is_supported)
> +		gpiochip_remove_pin_ranges(gc);
> +}
> +
> +/*
> + * Cygnus GPIO controller supports some PINCONF related configurations such as
> + * pull up, pull down, and drive strength, when the pin is configured to GPIO
> + *
> + * Here a local pinctrl device is created with simple 1-to-1 pin mapping to the
> + * local GPIO pins
> + */
> +static int cygnus_gpio_register_pinconf(struct cygnus_gpio *chip)
> +{
> +	struct pinctrl_desc *pctldesc = &chip->pctldesc;
> +	struct pinctrl_pin_desc *pins;
> +	struct gpio_chip *gc = &chip->gc;
> +	int i, ret;
> +
> +	pins = devm_kcalloc(chip->dev, gc->ngpio, sizeof(*pins), GFP_KERNEL);
> +	if (!pins)
> +		return -ENOMEM;
> +	chip->pins = pins;
> +
> +	for (i = 0; i < gc->ngpio; i++) {
> +		pins[i].number = i;
> +		pins[i].name = kasprintf(GFP_KERNEL, "gpio-%d", i);

We have devm_kasprintf().

> +		if (!pins[i].name) {
> +			ret = -ENOMEM;
> +			goto err_kfree;
> +		}
> +	}
> +
> +	pctldesc->name = dev_name(chip->dev);
> +	pctldesc->pctlops = &cygnus_pctrl_ops;
> +	pctldesc->pins = pins;
> +	pctldesc->npins = gc->ngpio;
> +	pctldesc->confops = &cygnus_pconf_ops;
> +
> +	chip->pctl = pinctrl_register(pctldesc, chip->dev, chip);
> +	if (!chip->pctl) {
> +		dev_err(chip->dev, "unable to register pinctrl device\n");
> +		ret = -EINVAL;
> +		goto err_kfree;
> +	}
> +
> +	return 0;
> +
> +err_kfree:
> +	for (i = 0; i < gc->ngpio; i++)
> +		kfree(pins[i].name);
> +
> +	return ret;
> +}
> +
> +static void cygnus_gpio_unregister_pinconf(struct cygnus_gpio *chip)
> +{
> +	struct gpio_chip *gc = &chip->gc;
> +	int i;
> +
> +	if (chip->pctl)
> +		pinctrl_unregister(chip->pctl);
> +
> +	for (i = 0; i < gc->ngpio; i++)
> +		kfree(chip->pins[i].name);

Should not be needed if you use devm_kasprintf.

> +}
> +
> +static const struct of_device_id cygnus_gpio_of_match[] = {
> +	{ .compatible = "brcm,cygnus-gpio" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, cygnus_gpio_of_match);
> +
> +static int cygnus_gpio_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	struct cygnus_gpio *chip;
> +	struct gpio_chip *gc;
> +	u32 ngpios;
> +	int irq, ret;
> +
> +	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
> +	if (!chip)
> +		return -ENOMEM;
> +
> +	chip->dev = dev;
> +	platform_set_drvdata(pdev, chip);
> +
> +	if (of_property_read_u32(dev->of_node, "ngpios", &ngpios)) {
> +		dev_err(dev, "missing ngpios DT property\n");
> +		return -ENODEV;
> +	}
> +	chip->num_banks = (ngpios + NGPIOS_PER_BANK - 1) / NGPIOS_PER_BANK;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	chip->base = devm_ioremap_resource(dev, res);
> +	if (IS_ERR(chip->base)) {
> +		dev_err(dev, "unable to map I/O memory\n");
> +		return PTR_ERR(chip->base);
> +	}
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
> +	if (res) {
> +		chip->io_ctrl = devm_ioremap_resource(dev, res);
> +		if (IS_ERR(chip->io_ctrl)) {
> +			dev_err(dev, "unable to map I/O memory\n");
> +			return PTR_ERR(chip->io_ctrl);
> +		}
> +	}
> +
> +	spin_lock_init(&chip->lock);
> +
> +	gc = &chip->gc;
> +	gc->base = -1;
> +	gc->ngpio = ngpios;
> +	gc->label = dev_name(dev);
> +	gc->dev = dev;
> +	gc->of_node = dev->of_node;
> +	gc->request = cygnus_gpio_request;
> +	gc->free = cygnus_gpio_free;
> +	gc->direction_input = cygnus_gpio_direction_input;
> +	gc->direction_output = cygnus_gpio_direction_output;
> +	gc->set = cygnus_gpio_set;
> +	gc->get = cygnus_gpio_get;
> +
> +	ret = gpiochip_add(gc);
> +	if (ret < 0) {
> +		dev_err(dev, "unable to add GPIO chip\n");
> +		return ret;
> +	}
> +
> +	ret = cygnus_gpio_pinmux_add_range(chip);
> +	if (ret && ret != -ENODEV) {
> +		dev_err(dev, "unable to add GPIO pin range\n");
> +		goto err_rm_gpiochip;
> +	}
> +
> +	ret = cygnus_gpio_register_pinconf(chip);
> +	if (ret) {
> +		dev_err(dev, "unable to register pinconf\n");
> +		goto err_rm_range;
> +	}
> +
> +	/* optional GPIO interrupt support */
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq) {
> +		ret = gpiochip_irqchip_add(gc, &cygnus_gpio_irq_chip, 0,
> +					   handle_simple_irq, IRQ_TYPE_NONE);
> +		if (ret) {
> +			dev_err(dev, "no GPIO irqchip\n");
> +			goto err_unregister_pinconf;
> +		}
> +
> +		gpiochip_set_chained_irqchip(gc, &cygnus_gpio_irq_chip, irq,
> +					     cygnus_gpio_irq_handler);
> +	}
> +
> +	return 0;
> +
> +err_unregister_pinconf:
> +	cygnus_gpio_unregister_pinconf(chip);
> +
> +err_rm_range:
> +	cygnus_gpio_pinmux_remove_range(chip);
> +
> +err_rm_gpiochip:
> +	gpiochip_remove(gc);
> +
> +	return ret;
> +}
> +
> +static struct platform_driver cygnus_gpio_driver = {
> +	.driver = {
> +		.name = "cygnus-gpio",
> +		.of_match_table = cygnus_gpio_of_match,
> +	},
> +	.probe = cygnus_gpio_probe,

The same comment about suppress_bind_attrs.

> +};
> +
> +static int __init cygnus_gpio_init(void)
> +{
> +	return platform_driver_probe(&cygnus_gpio_driver, cygnus_gpio_probe);
> +}
> +arch_initcall_sync(cygnus_gpio_init);
> +
> +MODULE_AUTHOR("Ray Jui <[email-masked]>");
> +MODULE_DESCRIPTION("Broadcom Cygnus GPIO Driver");
> +MODULE_LICENSE("GPL v2");
> -- 
> 1.7.9.5
> 

Thanks.

-- 
Dmitry