[PATCH 0/2] Driver for 74xx-ICs with MMIO access

[PATCH 0/2] Driver for 74xx-ICs with MMIO access

[Alexander Shiyan]

This driver is an attempt to resolve a dispute about adding "generic"
memory-mapped GPIO support for DT:
http://comments.gmane.org/gmane.linux.kernel.gpio/2

Alexander Shiyan (2):
  GPIO: Add driver for 74xx-ICs with MMIO access
  GPIO: 74xx-mmio: Add DT bindings documentation

 .../devicetree/bindings/gpio/gpio-74xx-mmio.txt    |  30 ++++
 drivers/gpio/Kconfig                               |  14 ++
 drivers/gpio/Makefile                              |   1 +
 drivers/gpio/gpio-74xx-mmio.c                      | 170 +++++++++++++++++++++
 4 files changed, 215 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-74xx-mmio.txt
 create mode 100644 drivers/gpio/gpio-74xx-mmio.c

-- 
1.8.5.5

[PATCH 1/2] GPIO: Add driver for 74xx-ICs with MMIO access

[Alexander Shiyan]

This patch adds driver to support GPIO functionality for 74xx-compatible
ICs with MMIO access. Compatible models include:
 1 bit:   74AHC1G125 (Input), 74AUC1G74 (Output)
 2 bits:  74LVC2G125 (Input), 74HC74 (Output)
 4 bits:  74HC125 (Input), 74HC175 (Output)
 6 bits:  74HC365 (Input), 74HC174 (Output)
 8 bits:  74HC244 (Input), 74HC273 (Output)
 16 bits: 74AC1624 (Input), 74AC16374 (Output)

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 drivers/gpio/Kconfig          |  14 ++++
 drivers/gpio/Makefile         |   1 +
 drivers/gpio/gpio-74xx-mmio.c | 170 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 185 insertions(+)
 create mode 100644 drivers/gpio/gpio-74xx-mmio.c

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index ec398be..5397dfa6 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -112,6 +112,20 @@ config GPIO_MAX730X
 
 comment "Memory mapped GPIO drivers:"
 
+config GPIO_74XX_MMIO
+	tristate "GPIO driver for 74xx-ICs with MMIO access"
+	depends on OF_GPIO
+	select GPIO_GENERIC
+	help
+	  Say yes here to support GPIO functionality for 74xx-compatible ICs
+	  with MMIO access. Compatible models include:
+	    1 bit:<---->74AHC1G125 (Input), 74AUC1G74 (Output)
+	    2 bits:<--->74LVC2G125 (Input), 74HC74 (Output)
+	    4 bits:<--->74HC125 (Input), 74HC175 (Output)
+	    6 bits:<--->74HC365 (Input), 74HC174 (Output)
+	    8 bits:<--->74HC244 (Input), 74HC273 (Output)
+	    16 bits:<-->74AC1624 (Input), 74AC16374 (Output)
+
 config GPIO_CLPS711X
 	tristate "CLPS711X GPIO support"
 	depends on ARCH_CLPS711X || COMPILE_TEST
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index e5d346c..4486bbd 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_GPIO_ACPI)		+= gpiolib-acpi.o
 obj-$(CONFIG_GPIO_GENERIC)	+= gpio-generic.o
 
 obj-$(CONFIG_GPIO_74X164)	+= gpio-74x164.o
+obj-$(CONFIG_GPIO_74XX_MMIO)	+= gpio-74xx-mmio.o
 obj-$(CONFIG_GPIO_ADNP)		+= gpio-adnp.o
 obj-$(CONFIG_GPIO_ADP5520)	+= gpio-adp5520.o
 obj-$(CONFIG_GPIO_ADP5588)	+= gpio-adp5588.o
diff --git a/drivers/gpio/gpio-74xx-mmio.c b/drivers/gpio/gpio-74xx-mmio.c
new file mode 100644
index 0000000..6efa7ed
--- /dev/null
+++ b/drivers/gpio/gpio-74xx-mmio.c
@@ -0,0 +1,170 @@
+/*
+ * 74xx MMIO GPIO driver
+ *
+ *  Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
+ *
+ * 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/err.h>
+#include <linux/gpio.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/basic_mmio_gpio.h>
+#include <linux/platform_device.h>
+
+#define MMIO_74XX_DIR_IN	(0 << 8)
+#define MMIO_74XX_DIR_OUT	(1 << 8)
+#define MMIO_74XX_BIT_CNT(x)	((x) & 0xff)
+
+struct mmio_74xx_gpio_priv {
+	struct bgpio_chip	bgc;
+	unsigned		flags;
+};
+
+static const struct of_device_id mmio_74xx_gpio_ids[] = {
+	{
+		.compatible	= "ti,74ahc1g125",
+		.data		= (const void *)(MMIO_74XX_DIR_IN | 1),
+	},
+	{
+		.compatible	= "ti,74lvc2g125",
+		.data		= (const void *)(MMIO_74XX_DIR_IN | 2),
+	},
+	{
+		.compatible	= "ti,74hc125",
+		.data		= (const void *)(MMIO_74XX_DIR_IN | 4),
+	},
+	{
+		.compatible	= "ti,74hc365",
+		.data		= (const void *)(MMIO_74XX_DIR_IN | 6),
+	},
+	{
+		.compatible	= "ti,74hc244",
+		.data		= (const void *)(MMIO_74XX_DIR_IN | 8),
+	},
+	{
+		.compatible	= "ti,74ac1624",
+		.data		= (const void *)(MMIO_74XX_DIR_IN | 16),
+	},
+	{
+		.compatible	= "ti,74auc1g74",
+		.data		= (const void *)(MMIO_74XX_DIR_OUT | 1),
+	},
+	{
+		.compatible	= "ti,74hc74",
+		.data		= (const void *)(MMIO_74XX_DIR_OUT | 2),
+	},
+	{
+		.compatible	= "ti,74hc175",
+		.data		= (const void *)(MMIO_74XX_DIR_OUT | 4),
+	},
+	{
+		.compatible	= "ti,74hc174",
+		.data		= (const void *)(MMIO_74XX_DIR_OUT | 6),
+	},
+	{
+		.compatible	= "ti,74hc273",
+		.data		= (const void *)(MMIO_74XX_DIR_OUT | 8),
+	},
+	{
+		.compatible	= "ti,74ac16374",
+		.data		= (const void *)(MMIO_74XX_DIR_OUT | 16),
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mmio_74xx_gpio_ids);
+
+static inline struct mmio_74xx_gpio_priv *to_74xx_gpio(struct gpio_chip *gc)
+{
+	struct bgpio_chip *bgc = to_bgpio_chip(gc);
+
+	return container_of(bgc, struct mmio_74xx_gpio_priv, bgc);
+}
+
+static int mmio_74xx_get_direction(struct gpio_chip *gc, unsigned offset)
+{
+	struct mmio_74xx_gpio_priv *priv = to_74xx_gpio(gc);
+
+	return (priv->flags & MMIO_74XX_DIR_OUT) ? GPIOF_DIR_OUT : GPIOF_DIR_IN;
+}
+
+static int mmio_74xx_dir_in(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct mmio_74xx_gpio_priv *priv = to_74xx_gpio(gc);
+
+	return (priv->flags & MMIO_74XX_DIR_OUT) ? -ENOTSUPP : 0;
+}
+
+static int mmio_74xx_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct mmio_74xx_gpio_priv *priv = to_74xx_gpio(gc);
+
+	if (priv->flags & MMIO_74XX_DIR_OUT) {
+		gc->set(gc, gpio, val);
+		return 0;
+	}
+
+	return -ENOTSUPP;
+}
+
+static int mmio_74xx_gpio_probe(struct platform_device *pdev)
+{
+	const struct of_device_id *of_id =
+		of_match_device(mmio_74xx_gpio_ids, &pdev->dev);
+	struct mmio_74xx_gpio_priv *priv;
+	struct resource *res;
+	void __iomem *dat;
+	int err;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	dat = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(dat))
+		return PTR_ERR(dat);
+
+	priv->flags = (unsigned)of_id->data;
+
+	err = bgpio_init(&priv->bgc, &pdev->dev,
+			 DIV_ROUND_UP(MMIO_74XX_BIT_CNT(priv->flags), 8),
+			 dat, NULL, NULL, NULL, NULL, 0);
+	if (err)
+		return err;
+
+	priv->bgc.gc.direction_input = mmio_74xx_dir_in;
+	priv->bgc.gc.direction_output = mmio_74xx_dir_out;
+	priv->bgc.gc.get_direction = mmio_74xx_get_direction;
+	priv->bgc.gc.ngpio = MMIO_74XX_BIT_CNT(priv->flags);
+	priv->bgc.gc.owner = THIS_MODULE;
+
+	platform_set_drvdata(pdev, priv);
+
+	return gpiochip_add(&priv->bgc.gc);
+}
+
+static int mmio_74xx_gpio_remove(struct platform_device *pdev)
+{
+	struct mmio_74xx_gpio_priv *priv = platform_get_drvdata(pdev);
+
+	return bgpio_remove(&priv->bgc);
+}
+
+static struct platform_driver mmio_74xx_gpio_driver = {
+	.driver	= {
+		.name		= "74xx-mmio-gpio",
+		.of_match_table	= mmio_74xx_gpio_ids,
+	},
+	.probe	= mmio_74xx_gpio_probe,
+	.remove	= mmio_74xx_gpio_remove,
+};
+module_platform_driver(mmio_74xx_gpio_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Alexander Shiyan <shc_work@mail.ru>");
+MODULE_DESCRIPTION("74xx MMIO GPIO driver");
-- 
1.8.5.5

Re: [PATCH 1/2] GPIO: Add driver for 74xx-ICs with MMIO access

[Linus Walleij]

On Fri, Sep 19, 2014 at 9:40 AM, Alexander Shiyan <shc_work@mail.ru> wrote:

> This patch adds driver to support GPIO functionality for 74xx-compatible
> ICs with MMIO access. Compatible models include:
>  1 bit:   74AHC1G125 (Input), 74AUC1G74 (Output)
>  2 bits:  74LVC2G125 (Input), 74HC74 (Output)
>  4 bits:  74HC125 (Input), 74HC175 (Output)
>  6 bits:  74HC365 (Input), 74HC174 (Output)
>  8 bits:  74HC244 (Input), 74HC273 (Output)
>  16 bits: 74AC1624 (Input), 74AC16374 (Output)
>
> Signed-off-by: Alexander Shiyan <shc_work@mail.ru>

Looking good, if you fix up the DT bindings to not include
technology as indicated in reply to patch 2/2 I'll be happy to
apply this patch.

Sorry for the delay.

Yours,
Linus Walleij

Re: [PATCH 1/2] GPIO: Add driver for 74xx-ICs with MMIO access

[Alexander Shiyan]

Mon, 29 Sep 2014 14:04:47 +0200 от Linus Walleij <linus.walleij@linaro.org>:
> On Fri, Sep 19, 2014 at 9:40 AM, Alexander Shiyan <shc_work@mail.ru> wrote:
> 
> > This patch adds driver to support GPIO functionality for 74xx-compatible
> > ICs with MMIO access. Compatible models include:
> >  1 bit:   74AHC1G125 (Input), 74AUC1G74 (Output)
> >  2 bits:  74LVC2G125 (Input), 74HC74 (Output)
> >  4 bits:  74HC125 (Input), 74HC175 (Output)
> >  6 bits:  74HC365 (Input), 74HC174 (Output)
> >  8 bits:  74HC244 (Input), 74HC273 (Output)
> >  16 bits: 74AC1624 (Input), 74AC16374 (Output)
> >
> > Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
> 
> Looking good, if you fix up the DT bindings to not include
> technology as indicated in reply to patch 2/2 I'll be happy to
> apply this patch.

Hello.

Change affects both parts of the patch, so I will send complete patch as a v2.

Thanks!
---

[PATCH 2/2] GPIO: 74xx-mmio: Add DT bindings documentation

[Alexander Shiyan]

This patch adds DT binding documentation for the 74xx-mmio GPIO driver.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
---
 .../devicetree/bindings/gpio/gpio-74xx-mmio.txt    | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-74xx-mmio.txt

diff --git a/Documentation/devicetree/bindings/gpio/gpio-74xx-mmio.txt b/Documentation/devicetree/bindings/gpio/gpio-74xx-mmio.txt
new file mode 100644
index 0000000..202dce7
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-74xx-mmio.txt
@@ -0,0 +1,30 @@
+* 74XX MMIO GPIO driver
+
+Required properties:
+- compatible: Should contain one of the following:
+   "ti,74ahc1g125": for 74AHC1G125 (1-bit Input),
+   "ti,74auc1g174": for 74AUC1G74 (1-bit Output),
+   "ti,74lvc2g125": for 74LVC2G125 (2-bit Input),
+   "ti,74hc74":     for 74HC74 (2-bit Output),
+   "ti,74hc125":    for 74HC125 (4-bit Input),
+   "ti,74hc175":    for 74HC175 (4-bit Output),
+   "ti,74hc365":    for 74HC365 (6-bit Input),
+   "ti,74hc174":    for 74HC174 (6-bit Output),
+   "ti,74hc244":    for 74HC244 (8-bit Input),
+   "ti,74hc273":    for 74HC273 (8-bit Output),
+   "ti,74ac1624":   for 74AC1624 (16-bit Input),
+   "ti,74ac16374":  for 74AC16374 (16-bit Output).
+- reg: Physical base address and length where IC resides.
+- gpio-controller: Marks the device node as a gpio controller.
+- #gpio-cells: Should be two. The first cell is the pin number and
+   the second cell is used to specify the GPIO polarity:
+    0 = Active High,
+    1 = Active Low.
+
+Example:
+	ctrl: gpio@30008004 {
+		compatible = "ti,74hc174";
+		reg = <0x30008004 0x1>;
+		gpio-controller;
+		#gpio-cells = <2>;
+	};
-- 
1.8.5.5

Re: [PATCH 2/2] GPIO: 74xx-mmio: Add DT bindings documentation

[Geert Uytterhoeven]

On Fri, Sep 19, 2014 at 9:40 AM, Alexander Shiyan <shc_work@mail.ru> wrote:
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-74xx-mmio.txt
> @@ -0,0 +1,30 @@
> +* 74XX MMIO GPIO driver
> +
> +Required properties:
> +- compatible: Should contain one of the following:
> +   "ti,74ahc1g125": for 74AHC1G125 (1-bit Input),
> +   "ti,74auc1g174": for 74AUC1G74 (1-bit Output),
> +   "ti,74lvc2g125": for 74LVC2G125 (2-bit Input),
> +   "ti,74hc74":     for 74HC74 (2-bit Output),
> +   "ti,74hc125":    for 74HC125 (4-bit Input),
> +   "ti,74hc175":    for 74HC175 (4-bit Output),
> +   "ti,74hc365":    for 74HC365 (6-bit Input),
> +   "ti,74hc174":    for 74HC174 (6-bit Output),
> +   "ti,74hc244":    for 74HC244 (8-bit Input),
> +   "ti,74hc273":    for 74HC273 (8-bit Output),
> +   "ti,74ac1624":   for 74AC1624 (16-bit Input),
> +   "ti,74ac16374":  for 74AC16374 (16-bit Output).

As the actual implementation technology doesn't matter, I think you
should use the base name where appropriate.
E.g. "ti,7474" instead of "ti,74hc74".

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH 2/2] GPIO: 74xx-mmio: Add DT bindings documentation

[Alexander Shiyan]

Mon, 22 Sep 2014 13:39:26 +0200 от Geert Uytterhoeven <geert@linux-m68k.org>:
> On Fri, Sep 19, 2014 at 9:40 AM, Alexander Shiyan <shc_work@mail.ru> wrote:
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/gpio/gpio-74xx-mmio.txt
> > @@ -0,0 +1,30 @@
> > +* 74XX MMIO GPIO driver
> > +
> > +Required properties:
> > +- compatible: Should contain one of the following:
> > +   "ti,74ahc1g125": for 74AHC1G125 (1-bit Input),
> > +   "ti,74auc1g174": for 74AUC1G74 (1-bit Output),
> > +   "ti,74lvc2g125": for 74LVC2G125 (2-bit Input),
> > +   "ti,74hc74":     for 74HC74 (2-bit Output),
> > +   "ti,74hc125":    for 74HC125 (4-bit Input),
> > +   "ti,74hc175":    for 74HC175 (4-bit Output),
> > +   "ti,74hc365":    for 74HC365 (6-bit Input),
> > +   "ti,74hc174":    for 74HC174 (6-bit Output),
> > +   "ti,74hc244":    for 74HC244 (8-bit Input),
> > +   "ti,74hc273":    for 74HC273 (8-bit Output),
> > +   "ti,74ac1624":   for 74AC1624 (16-bit Input),
> > +   "ti,74ac16374":  for 74AC16374 (16-bit Output).
> 
> As the actual implementation technology doesn't matter, I think you
> should use the base name where appropriate.
> E.g. "ti,7474" instead of "ti,74hc74".

Make sense.

Linus, what you think overall about this driver?

---

Re: [PATCH 2/2] GPIO: 74xx-mmio: Add DT bindings documentation

[Linus Walleij]

On Tue, Sep 23, 2014 at 6:51 PM, Alexander Shiyan <shc_work@mail.ru> wrote:
> Mon, 22 Sep 2014 13:39:26 +0200 от Geert Uytterhoeven <geert@linux-m68k.org>:
>> On Fri, Sep 19, 2014 at 9:40 AM, Alexander Shiyan <shc_work@mail.ru> wrote:
>> > --- /dev/null
>> > +++ b/Documentation/devicetree/bindings/gpio/gpio-74xx-mmio.txt
>> > @@ -0,0 +1,30 @@
>> > +* 74XX MMIO GPIO driver
>> > +
>> > +Required properties:
>> > +- compatible: Should contain one of the following:
>> > +   "ti,74ahc1g125": for 74AHC1G125 (1-bit Input),
>> > +   "ti,74auc1g174": for 74AUC1G74 (1-bit Output),
>> > +   "ti,74lvc2g125": for 74LVC2G125 (2-bit Input),
>> > +   "ti,74hc74":     for 74HC74 (2-bit Output),
>> > +   "ti,74hc125":    for 74HC125 (4-bit Input),
>> > +   "ti,74hc175":    for 74HC175 (4-bit Output),
>> > +   "ti,74hc365":    for 74HC365 (6-bit Input),
>> > +   "ti,74hc174":    for 74HC174 (6-bit Output),
>> > +   "ti,74hc244":    for 74HC244 (8-bit Input),
>> > +   "ti,74hc273":    for 74HC273 (8-bit Output),
>> > +   "ti,74ac1624":   for 74AC1624 (16-bit Input),
>> > +   "ti,74ac16374":  for 74AC16374 (16-bit Output).
>>
>> As the actual implementation technology doesn't matter, I think you
>> should use the base name where appropriate.
>> E.g. "ti,7474" instead of "ti,74hc74".
>
> Make sense.
>
> Linus, what you think overall about this driver?

That's a question about patch 1/2, and I haven't gotten to it
yet. High incoming patch rate.

Yours,
Linus Walleij
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