i2c: MPC8349E-mITX Power Management and GPIO expander driver

On MPC8349E-mITX, MPC8315E-RDB and MPC837x-RDB boards there is a
Freescale MC9S08QG8 (MCU) chip with the custom firmware
pre-programmed. The chip is used to power-off the board by the
software, and to control some GPIO pins.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

diff --git a/drivers/i2c/chips/Kconfig b/drivers/i2c/chips/Kconfig
index a95cb94..1735682 100644 (file)
--- a/drivers/i2c/chips/Kconfig
+++ b/drivers/i2c/chips/Kconfig
@@ -172,4 +172,15 @@ config MENELAUS
          and other features that are often used in portable devices like
          cell phones and PDAs.
 
+config MCU_MPC8349EMITX
+       tristate "MPC8349E-mITX MCU driver"
+       depends on I2C && PPC_83xx
+       select GENERIC_GPIO
+       select ARCH_REQUIRE_GPIOLIB
+       help
+         Say Y here to enable soft power-off functionality on the Freescale
+         boards with the MPC8349E-mITX-compatible MCU chips. This driver will
+         also register MCU GPIOs with the generic GPIO API, so you'll able
+         to use MCU pins as GPIOs.
+
 endmenu

diff --git a/drivers/i2c/chips/Makefile b/drivers/i2c/chips/Makefile
index 39e3e69..ca520fa 100644 (file)
--- a/drivers/i2c/chips/Makefile
+++ b/drivers/i2c/chips/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_ISP1301_OMAP)    += isp1301_omap.o
 obj-$(CONFIG_TPS65010)         += tps65010.o
 obj-$(CONFIG_MENELAUS)         += menelaus.o
 obj-$(CONFIG_SENSORS_TSL2550)  += tsl2550.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 (file)
index 0000000..82a9bcb
--- /dev/null
+++ b/drivers/i2c/chips/mcu_mpc8349emitx.c
@@ -0,0 +1,209 @@
+/*
+ * Power Management and GPIO expander driver for MPC8349E-mITX-compatible MCU
+ *
+ * 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/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/i2c.h>
+#include <linux/gpio.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+
+/*
+ * I don't have specifications for the MCU firmware, 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 {
+       struct mutex 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");
+       mutex_lock(&mcu->lock);
+       i2c_smbus_write_byte_data(glob_mcu->client, MCU_REG_CTRL,
+                                 mcu->reg_ctrl | MCU_CTRL_POFF);
+       mutex_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);
+
+       mutex_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);
+       mutex_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;
+       int ret;
+
+       np = of_find_compatible_node(NULL, NULL, "fsl,mcu-mpc8349emitx");
+       if (!np)
+               return -ENODEV;
+
+       gc->owner = THIS_MODULE;
+       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 = 2;
+       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, if succeeded, we don't put the node here.
+        */
+       ret = gpiochip_add(gc);
+       if (ret)
+               of_node_put(np);
+       return ret;
+}
+
+static int mcu_gpiochip_remove(struct mcu *mcu)
+{
+       int ret;
+
+       ret = gpiochip_remove(&mcu->of_gc.gc);
+       if (ret)
+               return ret;
+       of_node_put(mcu->np);
+
+       return 0;
+}
+
+static int __devinit mcu_probe(struct i2c_client *client,
+                              const struct i2c_device_id *id)
+{
+       struct mcu *mcu;
+       int ret;
+
+       mcu = kzalloc(sizeof(*mcu), GFP_KERNEL);
+       if (!mcu)
+               return -ENOMEM;
+
+       mutex_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;
+       mcu->reg_ctrl = ret;
+
+       ret = mcu_gpiochip_add(mcu);
+       if (ret)
+               goto err;
+
+       /* XXX: this is potentially racy, but there is no lock for ppc_md */
+       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:
+       kfree(mcu);
+       return ret;
+}
+
+static int __devexit mcu_remove(struct i2c_client *client)
+{
+       struct mcu *mcu = i2c_get_clientdata(client);
+       int ret;
+
+       if (glob_mcu == mcu) {
+               ppc_md.power_off = NULL;
+               glob_mcu = NULL;
+       }
+
+       ret = mcu_gpiochip_remove(mcu);
+       if (ret)
+               return ret;
+       i2c_set_clientdata(client, NULL);
+       kfree(mcu);
+       return 0;
+}
+
+static const struct i2c_device_id mcu_ids[] = {
+       { "mcu-mpc8349emitx", },
+       {},
+};
+MODULE_DEVICE_TABLE(i2c, mcu_ids);
+
+static struct i2c_driver mcu_driver = {
+       .driver = {
+               .name = "mcu-mpc8349emitx",
+               .owner = THIS_MODULE,
+       },
+       .probe = mcu_probe,
+       .remove = __devexit_p(mcu_remove),
+       .id_table = mcu_ids,
+};
+
+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("Power Management and GPIO expander driver for "
+                  "MPC8349E-mITX-compatible MCU");
+MODULE_AUTHOR("Anton Vorontsov <avorontsov@ru.mvista.com>");
+MODULE_LICENSE("GPL");