[NEW DRIVER V1 5/7] DA9058 GPIO driver

[NEW DRIVER V1 5/7] DA9058 GPIO driver

[Anthony Olech]

This is the GPIO component driver of the Dialog DA9058 PMIC.
This driver is just one component of the whole DA9058 PMIC driver.
It depends on the core DA9058 MFD driver.

Signed-off-by: Tony Olech (at Home) <tony@olech.com>
---
 drivers/gpio/Kconfig       |   12 ++
 drivers/gpio/Makefile      |    1 +
 drivers/gpio/gpio-da9058.c |  375 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 388 insertions(+), 0 deletions(-)
 create mode 100644 drivers/gpio/gpio-da9058.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 542f0c0..63b574a 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -86,6 +86,18 @@ config GPIO_DA9052
 	help
 	  Say yes here to enable the GPIO driver for the DA9052 chip.
 
+config GPIO_DA9058
+	tristate "Dialog DA9058 GPIO"
+	depends on MFD_DA9058
+	help
+	  Say yes here to enable the GPIO driver for the DA9058 chip.
+
+	  The Dialog DA9058 PMIC chip has 2 GPIO pins that can be
+	  be controller by this driver.
+
+	  If driver is built as a module it will be called da9058-gpio.
+
+
 config GPIO_MAX730X
 	tristate
 
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 0f55662..209224a 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_GPIO_ADP5520)	+= gpio-adp5520.o
 obj-$(CONFIG_GPIO_ADP5588)	+= gpio-adp5588.o
 obj-$(CONFIG_GPIO_BT8XX)	+= gpio-bt8xx.o
 obj-$(CONFIG_GPIO_CS5535)	+= gpio-cs5535.o
+obj-$(CONFIG_GPIO_DA9058)	+= gpio-da9058.o
 obj-$(CONFIG_GPIO_DA9052)	+= gpio-da9052.o
 obj-$(CONFIG_ARCH_DAVINCI)	+= gpio-davinci.o
 obj-$(CONFIG_GPIO_EM)		+= gpio-em.o
diff --git a/drivers/gpio/gpio-da9058.c b/drivers/gpio/gpio-da9058.c
new file mode 100644
index 0000000..c0b34c5
--- /dev/null
+++ b/drivers/gpio/gpio-da9058.c
@@ -0,0 +1,375 @@
+/*
+ *  Copyright (C) 2012 Dialog Semiconductor Ltd.
+ *
+ *  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; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/uaccess.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/syscalls.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/mfd/core.h>
+
+#include <linux/mfd/da9058/version.h>
+#include <linux/mfd/da9058/registers.h>
+#include <linux/mfd/da9058/core.h>
+#include <linux/mfd/da9058/gpio.h>
+#include <linux/mfd/da9058/irq.h>
+#include <linux/mfd/da9058/pdata.h>
+
+/*
+ *  There are only 2 available GPIO pins on the DA9058 PMIC
+ *
+ *  Thus this driver distinguishes them by the offset number
+ *  being zero or non-zero for simplicity
+ */
+
+struct da9058_gpio {
+	struct da9058 *da9058;
+	struct platform_device *pdev;
+	struct gpio_chip gp;
+	struct mutex lock;
+	u8 inp_config;
+	u8 out_config;
+};
+
+static struct da9058_gpio *gpio_chip_to_da9058_gpio(struct gpio_chip *chip)
+{
+	return container_of(chip, struct da9058_gpio, gp);
+}
+
+static int da9058_gpio_get(struct gpio_chip *gc, unsigned offset)
+{
+	struct da9058_gpio *gpio = gpio_chip_to_da9058_gpio(gc);
+	struct da9058 *da9058 = gpio->da9058;
+	u8 gpio_level;
+	int ret;
+
+	if (offset > 1)
+		return -EINVAL;
+
+	mutex_lock(&gpio->lock);
+	ret = da9058_reg_read(da9058, DA9058_STATUSC_REG, &gpio_level);
+	mutex_unlock(&gpio->lock);
+	if (ret < 0)
+		return ret;
+
+	if (offset) {
+		if (gpio_level & DA9058_STATUSC_GPI1)
+			return 1;
+		else
+			return 0;
+	} else {
+		if (gpio_level & DA9058_STATUSC_GPI0)
+			return 1;
+		else
+			return 0;
+	}
+}
+
+static void da9058_gpio_set(struct gpio_chip *gc, unsigned offset, int value)
+{
+	struct da9058_gpio *gpio = gpio_chip_to_da9058_gpio(gc);
+	struct da9058 *da9058 = gpio->da9058;
+	u8 gpio_cntrl;
+	int ret;
+
+	if (offset > 1) {
+		dev_err(da9058->dev,
+			"Failed to set GPIO%d output=%d because illegal GPIO\n",
+			offset, value);
+		return;
+	}
+
+	mutex_lock(&gpio->lock);
+
+	ret = da9058_reg_read(da9058, DA9058_GPIO0001_REG, &gpio_cntrl);
+	if (ret)
+		goto exit;
+
+	if (offset) {
+		u8 value_bits = value ? 0x80 : 0x00;
+
+		gpio->out_config &= ~0x80;
+		gpio->out_config |= value_bits;
+
+		if (!(gpio_cntrl & 0x20))
+			goto exit;
+
+		gpio_cntrl &= ~0xF0;
+		gpio_cntrl |= 0xF0 & gpio->out_config;
+
+		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);
+	} else {
+		u8 value_bits = value ? 0x08 : 0x00;
+
+		gpio->out_config &= ~0x08;
+		gpio->out_config |= value_bits;
+
+		if (!(gpio_cntrl & 0x02))
+			goto exit;
+
+		gpio_cntrl &= ~0x0F;
+		gpio_cntrl |= 0x0F & gpio->out_config;
+
+		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);
+	}
+exit:
+	mutex_unlock(&gpio->lock);
+	if (ret)
+		dev_err(da9058->dev,
+			"Failed to set GPIO%d output=%d error=%d\n",
+			offset, value, ret);
+	return;
+}
+
+static int da9058_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
+{
+	struct da9058_gpio *gpio = gpio_chip_to_da9058_gpio(gc);
+	struct da9058 *da9058 = gpio->da9058;
+	u8 gpio_cntrl;
+	int ret;
+
+	if (offset > 1)
+		return -EINVAL;
+
+	mutex_lock(&gpio->lock);
+
+	ret = da9058_reg_read(da9058, DA9058_GPIO0001_REG, &gpio_cntrl);
+	if (ret)
+		goto exit;
+
+	if (offset) {
+		gpio_cntrl &= ~0xF0;
+		gpio_cntrl |= 0xF0 & gpio->inp_config;
+
+		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);
+	} else {
+		gpio_cntrl &= ~0x0F;
+		gpio_cntrl |= 0x0F & gpio->inp_config;
+
+		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);
+	}
+exit:
+	mutex_unlock(&gpio->lock);
+	if (ret)
+		dev_err(da9058->dev,
+			"Failed to set GPIO%d to output error=%d\n",
+			offset, ret);
+	return ret;
+}
+
+static int da9058_gpio_direction_output(struct gpio_chip *gc,
+					unsigned offset, int value)
+{
+	struct da9058_gpio *gpio = gpio_chip_to_da9058_gpio(gc);
+	struct da9058 *da9058 = gpio->da9058;
+	u8 gpio_cntrl;
+	int ret;
+
+	if (offset > 1)
+		return -EINVAL;
+
+	mutex_lock(&gpio->lock);
+
+	ret = da9058_reg_read(da9058, DA9058_GPIO0001_REG, &gpio_cntrl);
+	if (ret)
+		goto exit;
+
+	if (offset) {
+		gpio_cntrl &= ~0xF0;
+		gpio_cntrl |= 0xF0 & gpio->out_config;
+
+		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);
+	} else {
+		gpio_cntrl &= ~0x0F;
+		gpio_cntrl |= 0x0F & gpio->out_config;
+
+		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);
+	}
+exit:
+	mutex_unlock(&gpio->lock);
+	if (ret)
+		dev_err(da9058->dev,
+			"Failed to set GPIO%d to input error=%d\n",
+			offset, ret);
+	return ret;
+}
+/*
+ *  da9058_gpio_to_irq is an implementation of the GPIO Hook
+ *  @to_irq: supporting non-static gpio_to_irq() mappings
+ *  whose implementation may not sleep. This hook is called
+ *  when setting up the threaded GPIO irq handler.
+ */
+static int da9058_gpio_to_irq(struct gpio_chip *gc, u32 offset)
+{
+	struct da9058_gpio *gpio = gpio_chip_to_da9058_gpio(gc);
+	struct da9058 *da9058 = gpio->da9058;
+
+	if (offset > 1)
+		return -EINVAL;
+
+	if (offset)
+		return da9058_to_virt_irq_num(da9058, DA9058_IRQ_EGPI1);
+	else
+		return da9058_to_virt_irq_num(da9058, DA9058_IRQ_EGPI0);
+}
+
+static int da9058_gpio_set_debounce(struct gpio_chip *gc, unsigned offset,
+				unsigned debounce)
+{
+	struct da9058_gpio *gpio = gpio_chip_to_da9058_gpio(gc);
+	struct da9058 *da9058 = gpio->da9058;
+	int ret;
+	u8 gpio_cntrl;
+
+	if (offset > 1)
+		return -EINVAL;
+
+	mutex_lock(&gpio->lock);
+
+	ret = da9058_reg_read(da9058, DA9058_GPIO0001_REG, &gpio_cntrl);
+	if (ret)
+		goto exit;
+
+	if (offset) {
+		u8 debounce_bits = debounce ? 0x80 : 0x00;
+
+		gpio->inp_config &= ~0x80;
+		gpio->inp_config |= debounce_bits;
+
+		if (gpio_cntrl & 0x20)
+			goto exit;
+
+		gpio_cntrl &= ~0xF0;
+		gpio_cntrl |= 0xF0 & gpio->inp_config;
+
+		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);
+	} else {
+		u8 debounce_bits = debounce ? 0x08 : 0x00;
+
+		gpio->inp_config &= ~0x08;
+		gpio->inp_config |= debounce_bits;
+
+		if (gpio_cntrl & 0x02)
+			goto exit;
+
+		gpio_cntrl &= ~0x0F;
+		gpio_cntrl |= 0x0F & gpio->inp_config;
+
+		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);
+	}
+exit:
+	mutex_unlock(&gpio->lock);
+	if (ret)
+		dev_err(da9058->dev,
+			"Failed to set GPIO%d bounce=%d error=%d\n",
+			offset, debounce, ret);
+	return ret;
+}
+
+static int __devinit da9058_gpio_probe(struct platform_device *pdev)
+{
+	struct da9058 *da9058 = dev_get_drvdata(pdev->dev.parent);
+	const struct mfd_cell *cell = mfd_get_cell(pdev);
+	struct da9058_gpio_pdata *gpio_pdata;
+	struct da9058_gpio *gpio;
+	int ret;
+
+	if (cell == NULL) {
+		ret = -ENODEV;
+		goto exit;
+	}
+
+	gpio_pdata = cell->platform_data;
+
+	if (!gpio_pdata) {
+		ret = -EINVAL;
+		goto exit;
+	}
+
+	gpio = devm_kzalloc(&pdev->dev, sizeof(struct da9058_gpio), GFP_KERNEL);
+	if (!gpio) {
+		ret = -ENOMEM;
+		goto exit;
+	}
+
+	gpio->da9058 = da9058;
+	gpio->pdev = pdev;
+
+	gpio->gp.label = "da9058-gpio";
+	gpio->gp.owner = THIS_MODULE;
+	gpio->gp.get = da9058_gpio_get;
+	gpio->gp.set = da9058_gpio_set;
+	gpio->gp.direction_input = da9058_gpio_direction_input;
+	gpio->gp.direction_output = da9058_gpio_direction_output;
+	gpio->gp.to_irq = da9058_gpio_to_irq;
+	gpio->gp.set_debounce = da9058_gpio_set_debounce;
+	gpio->gp.can_sleep = 1;
+	gpio->gp.ngpio = gpio_pdata->ngpio;
+	gpio->gp.base = gpio_pdata->gpio_base;
+
+	gpio->inp_config = 0x99;
+	gpio->out_config = 0x66;
+
+	mutex_init(&gpio->lock);
+
+	ret = gpiochip_add(&gpio->gp);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Could not register gpiochip, %d\n", ret);
+		goto err;
+	}
+
+	platform_set_drvdata(pdev, gpio);
+
+	dev_info(&pdev->dev, "%d GPIO pins at base %d\n", gpio_pdata->ngpio,
+				gpio->gp.base);
+
+	mutex_lock(&gpio->lock);
+	ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio->inp_config);
+	mutex_unlock(&gpio->lock);
+	if (ret)
+		dev_err(da9058->dev,
+			"Failed to set GPIO0 as an output error = %d\n",
+				ret);
+err:
+exit:
+	return ret;
+}
+
+static int __devexit da9058_gpio_remove(struct platform_device *pdev)
+{
+	struct da9058_gpio *gpio = platform_get_drvdata(pdev);
+	int ret;
+
+	ret = gpiochip_remove(&gpio->gp);
+	if (ret == 0)
+		kfree(gpio);
+
+	return ret;
+}
+
+static struct platform_driver da9058_gpio_driver = {
+	.probe = da9058_gpio_probe,
+	.remove = __devexit_p(da9058_gpio_remove),
+	.driver = {
+		.name = "da9058-gpio",
+		.owner = THIS_MODULE,
+	},
+};
+
+module_platform_driver(da9058_gpio_driver);
+
+MODULE_DESCRIPTION("Dialog DA9058 PMIC General Purpose IO Driver");
+MODULE_AUTHOR("Anthony Olech <Anthony.Olech@diasemi.com>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:da9058-gpio");
-- 
end-of-patch for NEW DRIVER V1

Re: [NEW DRIVER V1 5/7] DA9058 GPIO driver

[Mark Brown]

On Thu, Aug 02, 2012 at 09:48:57AM +0100, Anthony Olech wrote:

> +	mutex_lock(&gpio->lock);
> +	ret = da9058_reg_read(da9058, DA9058_STATUSC_REG, &gpio_level);
> +	mutex_unlock(&gpio->lock);

regmap already does locking for you.

> +	ret = da9058_reg_read(da9058, DA9058_GPIO0001_REG, &gpio_cntrl);
> +	if (ret)
> +		goto exit;
> +
> +	if (offset) {
> +		gpio_cntrl &= ~0xF0;
> +		gpio_cntrl |= 0xF0 & gpio->out_config;
> +
> +		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);

Just use regmap_update_bits().

RE: [NEW DRIVER V1 5/7] DA9058 GPIO driver

[Opensource [Anthony Olech]]

Thanks Mark for looking at the DA9058 GPIO component driver.

I do realize that REGMAP does locking on individual register accesses,
however, the each GPIO line is controlled by 4-bits in a register, with
the meaning of the most significant bit depending on the GPIO direction,
so it is essential that the register be read first before do an update, thus
two sequential register accesses must be protected by a mutex to
prevent another process changing the register (and hence the meaning
of the most-significant bit) in the middle of the two accesses.

I hope this explains to your satisfaction why a driver mutex is required
in addition to the regmap's register access mutex

Tony Olech

-----Original Message-----
From: Mark Brown [mailto:broonie@opensource.wolfsonmicro.com] 
Sent: 02 August 2012 11:20
To: Opensource [Anthony Olech]
Cc: LKML
Subject: Re: [NEW DRIVER V1 5/7] DA9058 GPIO driver

On Thu, Aug 02, 2012 at 09:48:57AM +0100, Anthony Olech wrote:

> +	mutex_lock(&gpio->lock);
> +	ret = da9058_reg_read(da9058, DA9058_STATUSC_REG, &gpio_level);
> +	mutex_unlock(&gpio->lock);

regmap already does locking for you.

> +	ret = da9058_reg_read(da9058, DA9058_GPIO0001_REG, &gpio_cntrl);
> +	if (ret)
> +		goto exit;
> +
> +	if (offset) {
> +		gpio_cntrl &= ~0xF0;
> +		gpio_cntrl |= 0xF0 & gpio->out_config;
> +
> +		ret = da9058_reg_write(da9058, DA9058_GPIO0001_REG, gpio_cntrl);

Just use regmap_update_bits().

Re: [NEW DRIVER V1 5/7] DA9058 GPIO driver

[Mark Brown]

On Mon, Aug 06, 2012 at 03:15:17PM +0000, Opensource [Anthony Olech] wrote:

> I do realize that REGMAP does locking on individual register accesses,
> however, the each GPIO line is controlled by 4-bits in a register, with
> the meaning of the most significant bit depending on the GPIO direction,
> so it is essential that the register be read first before do an update, thus
> two sequential register accesses must be protected by a mutex to
> prevent another process changing the register (and hence the meaning
> of the most-significant bit) in the middle of the two accesses.

> I hope this explains to your satisfaction why a driver mutex is required
> in addition to the regmap's register access mutex

This seems a bit excessive and complicated - I'd be inclined to either
just say that the caller is responsible for avoiding confusion here
(obviously if you're changing the direction there's a race anyway) or
store the data in a variable locally rather than having to do I/O on the
device under lock every time it's interacted with.

RE: [NEW DRIVER V1 5/7] DA9058 GPIO driver

[Opensource [Anthony Olech]]

> -----Original Message-----
> From: Mark Brown [mailto:broonie@opensource.wolfsonmicro.com]
> Sent: 07 August 2012 18:15
> To: Opensource [Anthony Olech]
> Cc: LKML
> Subject: Re: [NEW DRIVER V1 5/7] DA9058 GPIO driver
> On Mon, Aug 06, 2012 at 03:15:17PM +0000, Opensource [Anthony Olech]
> wrote:
> > I do realize that REGMAP does locking on individual register accesses,
> > however, the each GPIO line is controlled by 4-bits in a register,
> > with the meaning of the most significant bit depending on the GPIO
> > direction, so it is essential that the register be read first before
> > do an update, thus two sequential register accesses must be protected
> > by a mutex to prevent another process changing the register (and hence
> > the meaning of the most-significant bit) in the middle of the two accesses.
> > I hope this explains to your satisfaction why a driver mutex is
> > required in addition to the regmap's register access mutex
> This seems a bit excessive and complicated - I'd be inclined to either just say
> that the caller is responsible for avoiding confusion here (obviously if you're
> changing the direction there's a race anyway) or store the data in a variable
> locally rather than having to do I/O on the device under lock every time it's
> interacted with.

By using a semaphore (mutex/critical region) as I do in the DA9058 GPIO
component driver, there is absolutely no set-direction-race-condition in
the driver. The driver will always be consistent, either INP or OUT for each
GPIO line. There may, indeed, be confusion between multiple users of the
GPIO lines, but that is, quite properly, their problem. Even though in practice
there will usually be only one GPIO consumer/user, it still seems to me to be
better to code for the worst case. If indeed there is only one GPIO consumer/
user then the mutex access will be fast and non-blocking.

The GPIO control register (as opposed to the status register) is marked as
non-volitile so there should be no i2c access overhead when reading it.

Tony