[PATCH 4/5] i2c: MPC837xRDB Power Management and GPIO expander driver

[PATCH 4/5] i2c: MPC837xRDB Power Management and GPIO expander driver

[Anton Vorontsov]

On the MPC837xRDB boards there is MC9S08QG8 (MCU) chip with the custom
firmware pre-programmed. This firmware offers to control some of the MCU
GPIO pins via I2C (two pins, connected to the LEDs, but also available
from the J28 and J43 headers, plus another (third) pin is a GPIO as well
but on this board it is reserved for Power-Off function). MCU have some
other functions, but these are not implemented yet.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
---

This patch depends on the not yet applied OF/PowerPC GPIO patches, so
please consider this for RFC only.

Thanks.

 drivers/i2c/chips/Kconfig          |    9 ++
 drivers/i2c/chips/Makefile         |    1 +
 drivers/i2c/chips/mcu_mpc837xrdb.c |  185 ++++++++++++++++++++++++++++++++++++
 3 files changed, 195 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/chips/mcu_mpc837xrdb.c

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index 09d4937..db81018 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -150,4 +150,13 @@ config OZ99X
 	  This driver can also be built as a module.  If so, the module
 	  will be called oz99x.
 
+config MCU_MPC837XRDB
+	tristate "MPC837XRDB MCU driver"
+	depends on I2C && MPC837x_RDB && OF_GPIO
+	help
+	  Say Y here to enable soft power-off functionality on the Freescale
+	  MPC837X-RDB boards, plus this driver will register MCU GPIOs as a
+	  generic GPIO API chip, so you'll able to use MCU1 and MCU2 as GPIOs
+	  and LEDs.
+
 endmenu
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index c69f891..bbe7495 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_TPS65010)		+= tps65010.o
 obj-$(CONFIG_MENELAUS)		+= menelaus.o
 obj-$(CONFIG_SENSORS_TSL2550)	+= tsl2550.o
 obj-$(CONFIG_OZ99X)		+= oz99x.o
+obj-$(CONFIG_MCU_MPC837XRDB)	+= mcu_mpc837xrdb.o
 
 ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/i2c/chips/mcu_mpc837xrdb.c b/drivers/i2c/chips/mcu_mpc837xrdb.c
new file mode 100644
index 0000000..a461c0e
--- /dev/null
+++ b/drivers/i2c/chips/mcu_mpc837xrdb.c
@@ -0,0 +1,190 @@
+/*
+ * MPC837xRDB Power Management and GPIO expander driver
+ *
+ * On the MPC837xRDB boards there is MC9S08QG8 (MCU) chip with the custom
+ * firmware pre-programmed. This firmware offers to control some of the MCU
+ * GPIO pins via I2C (two pins, connected to the LEDs, but also available
+ * from the J28 and J43 headers, plus another (third) pin is a GPIO as well
+ * but on this board it is reserved for Power-Off function). MCU have some
+ * other functions, but these are not implemented yet.
+ *
+ * Copyright (c) 2008  MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * 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/spinlock.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <asm/machdep.h>
+
+/*
+ * I don't have specifications for the MCU firmware that is used on the
+ * MPC837XRDB board, I found this register and bits positions by the
+ * trial&error method.
+ */
+#define MCU_REG_CTRL	0x20
+#define MCU_CTRL_POFF	0x40
+#define MCU_NUM_GPIO	2
+
+struct mcu {
+	spinlock_t lock;
+	struct device_node *np;
+	struct i2c_client *client;
+	struct of_gpio_chip of_gc;
+	u8 reg_ctrl;
+};
+
+static struct mcu *glob_mcu;
+
+static void mcu_power_off(void)
+{
+	struct mcu *mcu = glob_mcu;
+
+	pr_info("Sending power-off request to the MCU...\n");
+	spin_lock(&mcu->lock);
+	i2c_smbus_write_byte_data(glob_mcu->client, MCU_REG_CTRL,
+				  mcu->reg_ctrl | MCU_CTRL_POFF);
+	spin_unlock(&mcu->lock);
+}
+
+static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct of_gpio_chip *of_gc = to_of_gpio_chip(gc);
+	struct mcu *mcu = container_of(of_gc, struct mcu, of_gc);
+	u8 bit = 1 << (4 + gpio);
+
+	spin_lock(&mcu->lock);
+	if (val)
+		mcu->reg_ctrl |= bit;
+	else
+		mcu->reg_ctrl &= ~bit;
+
+	i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
+	spin_unlock(&mcu->lock);
+}
+
+static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	mcu_gpio_set(gc, gpio, val);
+	return 0;
+}
+
+static int mcu_gpiochip_add(struct mcu *mcu)
+{
+	struct device_node *np;
+	struct of_gpio_chip *of_gc = &mcu->of_gc;
+	struct gpio_chip *gc = &of_gc->gc;
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc837xrdb");
+	if (!np)
+		return -ENODEV;
+
+	gc->label = np->full_name;
+	gc->can_sleep = 1;
+	gc->ngpio = MCU_NUM_GPIO;
+	gc->base = -1;
+	gc->set = mcu_gpio_set;
+	gc->direction_output = mcu_gpio_dir_out;
+	of_gc->gpio_cells = 1;
+	of_gc->xlate = of_gpio_simple_xlate;
+
+	np->data = of_gc;
+	mcu->np = np;
+
+	/*
+	 * We don't want to lose the node, its ->data and ->full_name...
+	 * So, there is no of_node_put(np); here.
+	 */
+	return gpiochip_add(gc);
+}
+
+static void mcu_gpiochip_remove(struct mcu *mcu)
+{
+	gpiochip_remove(&mcu->of_gc.gc);
+	of_node_put(mcu->np);
+}
+
+static int mcu_probe(struct i2c_client *client)
+{
+	struct mcu *mcu;
+	int ret;
+
+	mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
+	if (!mcu)
+		return -ENOMEM;
+
+	spin_lock_init(&mcu->lock);
+	mcu->client = client;
+	i2c_set_clientdata(client, mcu);
+
+	ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
+	if (ret < 0)
+		goto err_iic_read;
+	mcu->reg_ctrl = ret;
+
+	/* XXX: this is potentionally racy, but there is no ppc_md lock */
+	if (!ppc_md.power_off) {
+		glob_mcu = mcu;
+		ppc_md.power_off = mcu_power_off;
+		dev_info(&client->dev, "will provide power-off service\n");
+	}
+
+	ret = mcu_gpiochip_add(mcu);
+	if (ret)
+		goto err_gpio;
+
+	return 0;
+err_gpio:
+	mcu_gpiochip_remove(mcu);
+err_iic_read:
+	kfree(mcu);
+	return ret;
+}
+
+static int mcu_remove(struct i2c_client *client)
+{
+	struct mcu *mcu = i2c_get_clientdata(client);
+
+	if (glob_mcu == mcu) {
+		ppc_md.power_off = NULL;
+		glob_mcu = NULL;
+	}
+
+	i2c_set_clientdata(client, NULL);
+	mcu_gpiochip_remove(mcu);
+	kfree(mcu);
+	return 0;
+}
+
+static struct i2c_driver mcu_driver = {
+	.driver = {
+		.name = "mcu-mpc837xrdb",
+		.owner = THIS_MODULE,
+	},
+	.probe = mcu_probe,
+	.remove	= mcu_remove,
+};
+
+static int __init mcu_init(void)
+{
+	return i2c_add_driver(&mcu_driver);
+}
+module_init(mcu_init);
+
+static void __exit mcu_exit(void)
+{
+	i2c_del_driver(&mcu_driver);
+}
+module_exit(mcu_exit);
+
+MODULE_DESCRIPTION("MPC837xRDB Power Management and GPIO expander driver");
+MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
+MODULE_LICENSE("GPL");
-- 
1.5.2.2

Re: [PATCH 4/5] i2c: MPC837xRDB Power Management and GPIO expander driver

[Timur Tabi]

Anton Vorontsov wrote:

> +config MCU_MPC837XRDB
> +	tristate "MPC837XRDB MCU driver"
> +	depends on I2C && MPC837x_RDB && OF_GPIO

The MPC8349E-mITX also has this chip.  Can you include support for that board as
well?

-- 
Timur Tabi
Linux kernel developer at Freescale

Re: [PATCH 4/5] i2c: MPC837xRDB Power Management and GPIO expander driver

[Anton Vorontsov]

On Wed, Mar 26, 2008 at 03:56:37PM -0500, Timur Tabi wrote:
> Anton Vorontsov wrote:
> 
> > +config MCU_MPC837XRDB
> > +	tristate "MPC837XRDB MCU driver"
> > +	depends on I2C && MPC837x_RDB && OF_GPIO
> 
> The MPC8349E-mITX also has this chip.  Can you include support for that board as
> well?

Well, only if it has the same (or compatible) firmware.. then yes.

Thanks for the info, I'll look into this.

-- 
Anton Vorontsov
email: cbouatmailru@gmail.com
irc://irc.freenode.net/bd2

Re: [PATCH 4/5] i2c: MPC837xRDB Power Management and GPIO expander driver

[Anton Vorontsov]

On Thu, Mar 27, 2008 at 01:56:11AM +0300, Anton Vorontsov wrote:
> On Wed, Mar 26, 2008 at 03:56:37PM -0500, Timur Tabi wrote:
> > Anton Vorontsov wrote:
> > 
> > > +config MCU_MPC837XRDB
> > > +	tristate "MPC837XRDB MCU driver"
> > > +	depends on I2C && MPC837x_RDB && OF_GPIO
> > 
> > The MPC8349E-mITX also has this chip.  Can you include support for that board as
> > well?
> 
> Well, only if it has the same (or compatible) firmware.. then yes.

Ok, they're the same and everything works fine. Except one mitx-specific
thing though... on the power-off call I can see that MCU is driving its
PTA1 pin low as expected, but the board doesn't turn off. PTA1 pin is
wired to the J19 jumper pin1, pin2 is PORESET# and pin3 is RESET#.
It doesn't work in both [1-2] and [2-3] positions...

This is surely not a software issue though. And just in case, on the
board I have the PWR button isn't functional, so this is hw issues (or
just need to find another jumper somewhere ;-).

Updated patch follows.

- - - -
From: Anton Vorontsov <avorontsov@ru.mvista.com>
Subject: [POWERPC] mpc8349emitx/mpc837xrdb: add support for MCU

MCU is an external Freescale MC9S08QG8 microcontroller, mainly used to
provide soft power-off function, but also exports two GPIOs (wired to
the LEDs, but also available from the external headers).

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
---
 arch/powerpc/boot/dts/mpc8349emitx.dts    |   39 ++++++++++++++++++++++++++++-
 arch/powerpc/boot/dts/mpc8377_rdb.dts     |   29 ++++++++++++++++++++-
 arch/powerpc/boot/dts/mpc8378_rdb.dts     |   29 ++++++++++++++++++++-
 arch/powerpc/boot/dts/mpc8379_rdb.dts     |   29 ++++++++++++++++++++-
 arch/powerpc/platforms/83xx/mpc834x_itx.c |    1 +
 arch/powerpc/platforms/83xx/mpc837x_rdb.c |    1 +
 arch/powerpc/sysdev/fsl_soc.c             |    1 +
 7 files changed, 125 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/boot/dts/mpc8349emitx.dts b/arch/powerpc/boot/dts/mpc8349emitx.dts
index 9426676..0ad85af 100644
--- a/arch/powerpc/boot/dts/mpc8349emitx.dts
+++ b/arch/powerpc/boot/dts/mpc8349emitx.dts
@@ -51,6 +51,8 @@
 	soc8349@e0000000 {
 		#address-cells = <1>;
 		#size-cells = <1>;
+		compatible = "fsl,immr-mpc8349e", "fsl,immr", "fsl,soc",
+			     "simple-bus";
 		device_type = "soc";
 		ranges = <0x0 0xe0000000 0x00100000>;
 		reg = <0xe0000000 0x00000200>;
@@ -66,11 +68,46 @@
 			#address-cells = <1>;
 			#size-cells = <0>;
 			cell-index = <0>;
-			compatible = "fsl-i2c";
+			compatible = "fsl-i2c", "simple-bus";
 			reg = <0x3000 0x100>;
 			interrupts = <14 0x8>;
 			interrupt-parent = <&ipic>;
 			dfsrr;
+
+			rtc@68 {
+				device_type = "rtc";
+				compatible = "dallas,ds1339";
+				reg = <0x68>;
+			};
+
+			mcu_pio: mcu@0a {
+				#address-cells = <0>;
+				#size-cells = <0>;
+				#gpio-cells = <1>;
+				compatible = "fsl,mc9s08qg8-mpc8349emitx",
+					     "fsl,mcu-mpc8349emitx",
+					     "simple-bus";
+				reg = <0x0a>;
+				gpio-controller;
+
+				led@0 {
+					compatible = "fsl,mcu-mpc8349emitx-led2",
+						     "gpio-led";
+					linux,name = "pwr";
+					linux,brightness = <1>;
+					linux,active-low;
+					gpios = <&mcu_pio 0>;
+				};
+
+				led@1 {
+					compatible = "fsl,mcu-mpc8349emitx-led1",
+						     "gpio-led";
+					linux,name = "hdd";
+					linux,default-trigger = "ide-disk";
+					linux,active-low;
+					gpios = <&mcu_pio 1>;
+				};
+			};
 		};
 
 		i2c@3100 {
diff --git a/arch/powerpc/boot/dts/mpc8377_rdb.dts b/arch/powerpc/boot/dts/mpc8377_rdb.dts
index 440aa4d..20d7e29 100644
--- a/arch/powerpc/boot/dts/mpc8377_rdb.dts
+++ b/arch/powerpc/boot/dts/mpc8377_rdb.dts
@@ -111,7 +111,7 @@
 			#address-cells = <1>;
 			#size-cells = <0>;
 			cell-index = <0>;
-			compatible = "fsl-i2c";
+			compatible = "fsl-i2c", "simple-bus";
 			reg = <0x3000 0x100>;
 			interrupts = <14 0x8>;
 			interrupt-parent = <&ipic>;
@@ -121,6 +121,33 @@
 				compatible = "dallas,ds1339";
 				reg = <0x68>;
 			};
+			mcu_pio: mcu@0a {
+				#address-cells = <0>;
+				#size-cells = <0>;
+				#gpio-cells = <1>;
+				compatible = "fsl,mc9s08qg8-mpc837xrdb",
+					     "fsl,mcu-mpc837xrdb",
+					     "fsl,mcu-mpc8349emitx",
+					     "simple-bus";
+				reg = <0x0a>;
+				gpio-controller;
+
+				led@0 {
+					compatible = "fsl,mcu-mpc837xrdb-led2",
+						     "gpio-led";
+					linux,name = "mcu2";
+					linux,active-low;
+					gpios = <&mcu_pio 0>;
+				};
+
+				led@1 {
+					compatible = "fsl,mcu-mpc837xrdb-led1",
+						     "gpio-led";
+					linux,name = "mcu1";
+					linux,active-low;
+					gpios = <&mcu_pio 1>;
+				};
+			};
 		};
 
 		i2c@3100 {
diff --git a/arch/powerpc/boot/dts/mpc8378_rdb.dts b/arch/powerpc/boot/dts/mpc8378_rdb.dts
index 9271153..fdd2e9b 100644
--- a/arch/powerpc/boot/dts/mpc8378_rdb.dts
+++ b/arch/powerpc/boot/dts/mpc8378_rdb.dts
@@ -111,7 +111,7 @@
 			#address-cells = <1>;
 			#size-cells = <0>;
 			cell-index = <0>;
-			compatible = "fsl-i2c";
+			compatible = "fsl-i2c", "simple-bus";
 			reg = <0x3000 0x100>;
 			interrupts = <14 0x8>;
 			interrupt-parent = <&ipic>;
@@ -121,6 +121,33 @@
 				compatible = "dallas,ds1339";
 				reg = <0x68>;
 			};
+			mcu_pio: mcu@0a {
+				#address-cells = <0>;
+				#size-cells = <0>;
+				#gpio-cells = <1>;
+				compatible = "fsl,mc9s08qg8-mpc837xrdb",
+					     "fsl,mcu-mpc837xrdb",
+					     "fsl,mcu-mpc8349emitx",
+					     "simple-bus";
+				reg = <0x0a>;
+				gpio-controller;
+
+				led@0 {
+					compatible = "fsl,mcu-mpc837xrdb-led2",
+						     "gpio-led";
+					linux,name = "mcu2";
+					linux,active-low;
+					gpios = <&mcu_pio 0>;
+				};
+
+				led@1 {
+					compatible = "fsl,mcu-mpc837xrdb-led1",
+						     "gpio-led";
+					linux,name = "mcu1";
+					linux,active-low;
+					gpios = <&mcu_pio 1>;
+				};
+			};
 		};
 
 		i2c@3100 {
diff --git a/arch/powerpc/boot/dts/mpc8379_rdb.dts b/arch/powerpc/boot/dts/mpc8379_rdb.dts
index 0dda2fc..c7a0152 100644
--- a/arch/powerpc/boot/dts/mpc8379_rdb.dts
+++ b/arch/powerpc/boot/dts/mpc8379_rdb.dts
@@ -111,7 +111,7 @@
 			#address-cells = <1>;
 			#size-cells = <0>;
 			cell-index = <0>;
-			compatible = "fsl-i2c";
+			compatible = "fsl-i2c", "simple-bus";
 			reg = <0x3000 0x100>;
 			interrupts = <14 0x8>;
 			interrupt-parent = <&ipic>;
@@ -121,6 +121,33 @@
 				compatible = "dallas,ds1339";
 				reg = <0x68>;
 			};
+			mcu_pio: mcu@0a {
+				#address-cells = <0>;
+				#size-cells = <0>;
+				#gpio-cells = <1>;
+				compatible = "fsl,mc9s08qg8-mpc837xrdb",
+					     "fsl,mcu-mpc837xrdb",
+					     "fsl,mcu-mpc8349emitx",
+					     "simple-bus";
+				reg = <0x0a>;
+				gpio-controller;
+
+				led@0 {
+					compatible = "fsl,mcu-mpc837xrdb-led2",
+						     "gpio-led";
+					linux,name = "mcu2";
+					linux,active-low;
+					gpios = <&mcu_pio 0>;
+				};
+
+				led@1 {
+					compatible = "fsl,mcu-mpc837xrdb-led1",
+						     "gpio-led";
+					linux,name = "mcu1";
+					linux,active-low;
+					gpios = <&mcu_pio 1>;
+				};
+			};
 		};
 
 		i2c@3100 {
diff --git a/arch/powerpc/platforms/83xx/mpc834x_itx.c b/arch/powerpc/platforms/83xx/mpc834x_itx.c
index 50e8f63..1b3451c 100644
--- a/arch/powerpc/platforms/83xx/mpc834x_itx.c
+++ b/arch/powerpc/platforms/83xx/mpc834x_itx.c
@@ -40,6 +40,7 @@
 
 static struct of_device_id __initdata mpc834x_itx_ids[] = {
 	{ .compatible = "fsl,pq2pro-localbus", },
+	{ .compatible = "simple-bus", },
 	{},
 };
 
diff --git a/arch/powerpc/platforms/83xx/mpc837x_rdb.c b/arch/powerpc/platforms/83xx/mpc837x_rdb.c
index 2293ae5..c00356b 100644
--- a/arch/powerpc/platforms/83xx/mpc837x_rdb.c
+++ b/arch/powerpc/platforms/83xx/mpc837x_rdb.c
@@ -46,6 +46,7 @@ static void __init mpc837x_rdb_setup_arch(void)
 static struct of_device_id mpc837x_ids[] = {
 	{ .type = "soc", },
 	{ .compatible = "soc", },
+	{ .compatible = "simple-bus", },
 	{},
 };
 
diff --git a/arch/powerpc/sysdev/fsl_soc.c b/arch/powerpc/sysdev/fsl_soc.c
index 7ad9bce..e8fe369 100644
--- a/arch/powerpc/sysdev/fsl_soc.c
+++ b/arch/powerpc/sysdev/fsl_soc.c
@@ -410,6 +410,7 @@ static struct i2c_driver_device i2c_devices[] __initdata = {
 	{"dallas,ds1340",  "rtc-ds1307",  "ds1340",},
 	{"stm,m41t00",     "rtc-ds1307",  "m41t00"},
 	{"dallas,ds1374",  "rtc-ds1374",  "rtc-ds1374",},
+	{"fsl,mcu-mpc8349emitx", "mcu-mpc8349emitx", "mcu-mpc8349emitx"},
 };
 
 static int __init of_find_i2c_driver(struct device_node *node,
-- 
1.5.2.2

Re: [PATCH 4/5] i2c: MPC837xRDB Power Management and GPIO expander driver

[Anton Vorontsov]

On Wed, Mar 26, 2008 at 11:25:11PM +0300, Anton Vorontsov wrote:
> On the MPC837xRDB boards there is MC9S08QG8 (MCU) chip with the custom
> firmware pre-programmed. This firmware offers to control some of the MCU
> GPIO pins via I2C (two pins, connected to the LEDs, but also available
> from the J28 and J43 headers, plus another (third) pin is a GPIO as well
> but on this board it is reserved for Power-Off function). MCU have some
> other functions, but these are not implemented yet.
> 
> Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
> ---
> 
> This patch depends on the not yet applied OF/PowerPC GPIO patches, so
> please consider this for RFC only.
> 
> Thanks.

Since the same chip with the identical firmware also found on the
MPC8349E-mITXE board (thanks to Timur Tabi for noticing) here is an updated
patch. MPC8349E-mITX board predates MPC837X-RDB boards, so I renamed this
driver to mcu_mpc8349emitx.

- - - -
From: Anton Vorontsov <avorontsov@ru.mvista.com>
Subject: i2c: MPC8349E-mITX/MPC837x-RDB Power Management and GPIO expander driver

On the MPC8349E-mITX and MPC837x-RDB boards there is MC9S08QG8 (MCU) chip
with the custom firmware pre-programmed. This firmware offers to control
some of the MCU GPIO pins (used for LEDs and soft power-off) via I2C. MCU
have some other functions, but these are not implemented yet.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
---
 drivers/i2c/chips/Kconfig            |   11 ++
 drivers/i2c/chips/Makefile           |    1 +
 drivers/i2c/chips/mcu_mpc8349emitx.c |  189 ++++++++++++++++++++++++++++++++++
 3 files changed, 201 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/chips/mcu_mpc8349emitx.c

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index 09d4937..d3e3bfb 100644
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -150,4 +150,15 @@ config OZ99X
 	  This driver can also be built as a module.  If so, the module
 	  will be called oz99x.
 
+config MCU_MPC8349EMITX
+	tristate "MPC8349E-mITX/MPC837X-RDB MCU driver"
+	depends on I2C && (MPC834x_ITX || MPC837x_RDB)
+	select GENERIC_GPIO
+	select HAVE_GPIO_LIB
+	help
+	  Say Y here to enable soft power-off functionality on the Freescale
+	  MPC8349E-mITX and MPC837X-RDB boards, plus this driver will register
+	  MCU GPIOs as a generic GPIO API chip, so you'll able to use some MCU
+	  pins as a GPIOs and LEDs.
+
 endmenu
diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index c69f891..89c92df 100644
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -14,6 +14,7 @@ obj-$(CONFIG_TPS65010)		+= tps65010.o
 obj-$(CONFIG_MENELAUS)		+= menelaus.o
 obj-$(CONFIG_SENSORS_TSL2550)	+= tsl2550.o
 obj-$(CONFIG_OZ99X)		+= oz99x.o
+obj-$(CONFIG_MCU_MPC8349EMITX)	+= mcu_mpc8349emitx.o
 
 ifeq ($(CONFIG_I2C_DEBUG_CHIP),y)
 EXTRA_CFLAGS += -DDEBUG
diff --git a/drivers/i2c/chips/mcu_mpc8349emitx.c b/drivers/i2c/chips/mcu_mpc8349emitx.c
new file mode 100644
index 0000000..b90dbe9
--- /dev/null
+++ b/drivers/i2c/chips/mcu_mpc8349emitx.c
@@ -0,0 +1,189 @@
+/*
+ * MPC8349E-mITX/MPC837x-RDB Power Management and GPIO expander driver
+ *
+ * On the MPC8349E-mITX and MPC837x-RDB boards there is MC9S08QG8 (MCU) chip
+ * with the custom firmware pre-programmed. This firmware offers to control
+ * some of the MCU GPIO pins (used for LEDs and soft power-off) via I2C. MCU
+ * have some other functions, but these are not implemented yet.
+ *
+ * Copyright (c) 2008  MontaVista Software, Inc.
+ *
+ * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
+ *
+ * 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/spinlock.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <asm/machdep.h>
+
+/*
+ * I don't have specifications for the MCU firmware that is used on the
+ * MPC8349E-mITX/MPC837XRDB boards, I found this register and bits positions
+ * by the trial&error method.
+ */
+#define MCU_REG_CTRL	0x20
+#define MCU_CTRL_POFF	0x40
+#define MCU_NUM_GPIO	2
+
+struct mcu {
+	spinlock_t lock;
+	struct device_node *np;
+	struct i2c_client *client;
+	struct of_gpio_chip of_gc;
+	u8 reg_ctrl;
+};
+
+static struct mcu *glob_mcu;
+
+static void mcu_power_off(void)
+{
+	struct mcu *mcu = glob_mcu;
+
+	pr_info("Sending power-off request to the MCU...\n");
+	spin_lock(&mcu->lock);
+	i2c_smbus_write_byte_data(glob_mcu->client, MCU_REG_CTRL,
+				  mcu->reg_ctrl | MCU_CTRL_POFF);
+	spin_unlock(&mcu->lock);
+}
+
+static void mcu_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct of_gpio_chip *of_gc = to_of_gpio_chip(gc);
+	struct mcu *mcu = container_of(of_gc, struct mcu, of_gc);
+	u8 bit = 1 << (4 + gpio);
+
+	spin_lock(&mcu->lock);
+	if (val)
+		mcu->reg_ctrl |= bit;
+	else
+		mcu->reg_ctrl &= ~bit;
+
+	i2c_smbus_write_byte_data(mcu->client, MCU_REG_CTRL, mcu->reg_ctrl);
+	spin_unlock(&mcu->lock);
+}
+
+static int mcu_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	mcu_gpio_set(gc, gpio, val);
+	return 0;
+}
+
+static int mcu_gpiochip_add(struct mcu *mcu)
+{
+	struct device_node *np;
+	struct of_gpio_chip *of_gc = &mcu->of_gc;
+	struct gpio_chip *gc = &of_gc->gc;
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
+	if (!np)
+		return -ENODEV;
+
+	gc->label = np->full_name;
+	gc->can_sleep = 1;
+	gc->ngpio = MCU_NUM_GPIO;
+	gc->base = -1;
+	gc->set = mcu_gpio_set;
+	gc->direction_output = mcu_gpio_dir_out;
+	of_gc->gpio_cells = 1;
+	of_gc->xlate = of_gpio_simple_xlate;
+
+	np->data = of_gc;
+	mcu->np = np;
+
+	/*
+	 * We don't want to lose the node, its ->data and ->full_name...
+	 * So, there is no of_node_put(np); here.
+	 */
+	return gpiochip_add(gc);
+}
+
+static void mcu_gpiochip_remove(struct mcu *mcu)
+{
+	gpiochip_remove(&mcu->of_gc.gc);
+	of_node_put(mcu->np);
+}
+
+static int mcu_probe(struct i2c_client *client)
+{
+	struct mcu *mcu;
+	int ret;
+
+	mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
+	if (!mcu)
+		return -ENOMEM;
+
+	spin_lock_init(&mcu->lock);
+	mcu->client = client;
+	i2c_set_clientdata(client, mcu);
+
+	ret = i2c_smbus_read_byte_data(mcu->client, MCU_REG_CTRL);
+	if (ret < 0)
+		goto err_iic_read;
+	mcu->reg_ctrl = ret;
+
+	ret = mcu_gpiochip_add(mcu);
+	if (ret)
+		goto err_gpio;
+
+	/* XXX: this is potentionally racy, but there is no ppc_md lock */
+	if (!ppc_md.power_off) {
+		glob_mcu = mcu;
+		ppc_md.power_off = mcu_power_off;
+		dev_info(&client->dev, "will provide power-off service\n");
+	}
+
+	return 0;
+err_gpio:
+	mcu_gpiochip_remove(mcu);
+err_iic_read:
+	kfree(mcu);
+	return ret;
+}
+
+static int mcu_remove(struct i2c_client *client)
+{
+	struct mcu *mcu = i2c_get_clientdata(client);
+
+	if (glob_mcu == mcu) {
+		ppc_md.power_off = NULL;
+		glob_mcu = NULL;
+	}
+
+	i2c_set_clientdata(client, NULL);
+	mcu_gpiochip_remove(mcu);
+	kfree(mcu);
+	return 0;
+}
+
+static struct i2c_driver mcu_driver = {
+	.driver = {
+		.name = "mcu-mpc8349emitx",
+		.owner = THIS_MODULE,
+	},
+	.probe = mcu_probe,
+	.remove	= mcu_remove,
+};
+
+static int __init mcu_init(void)
+{
+	return i2c_add_driver(&mcu_driver);
+}
+module_init(mcu_init);
+
+static void __exit mcu_exit(void)
+{
+	i2c_del_driver(&mcu_driver);
+}
+module_exit(mcu_exit);
+
+MODULE_DESCRIPTION("MPC8349E-mITX/MPC837x-RDB Power Management and GPIO "
+		   "expander driver");
+MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
+MODULE_LICENSE("GPL");
-- 
1.5.2.2

Re: [PATCH 4/5] i2c: MPC837xRDB Power Management and GPIO expander driver

[Anton Vorontsov]

Incidentally I used some weird .config without preemption and
CONFIG_ENABLE_MUST_CHECK. Heh.

[...]
> + * I don't have specifications for the MCU firmware that is used on the
> + * MPC8349E-mITX/MPC837XRDB boards, I found this register and bits positions
> + * by the trial&error method.
> + */
> +#define MCU_REG_CTRL	0x20
> +#define MCU_CTRL_POFF	0x40
> +#define MCU_NUM_GPIO	2
> +
> +struct mcu {
> +	spinlock_t lock;

This should be mutex of course, otherwise preemptable kernel
will complain.

[...]
> +	gpiochip_remove(&mcu->of_gc.gc);

Should check return value.

-- 
Anton Vorontsov
email: cboumailru@gmail.com
irc://irc.freenode.net/bd2