[devel] [PATCH 16/35] Added TF307/TF306 board management controller driver

[asheplyakov@yandex.ru]

From: Alexey Sheplyakov <asheplyakov@altlinux.org>

The board management controller (BMC) device is responsible for CPU
kick-starting, controlling power button, and a full board poweroff.
X-feature-Baikal-M
---
 drivers/misc/Kconfig  |  18 +
 drivers/misc/Makefile |   1 +
 drivers/misc/tp_bmc.c | 747 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 766 insertions(+)
 create mode 100644 drivers/misc/tp_bmc.c

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 0f5a49fc7c9e..42a679533cb0 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -470,6 +470,24 @@ config HISI_HIKEY_USB
 	  switching between the dual-role USB-C port and the USB-A host ports
 	  using only one USB controller.
 
+config TP_BMC
+	tristate "TF307/TF306 board management controller"
+	depends on I2C
+	depends on OF
+	select PINCTRL
+	select GENERIC_PINCONF
+	select SERIO
+	default y if ARCH_BAIKAL
+	help
+	  Say Y here if you want to build a driver for BMC devices embedded into
+          some boards with Baikal BE-M1000 and BE-T1000 processors. The device main
+	  purpose is the CPU kick-starting as well as some additional side-way
+	  functionality like power on/off buttons state tracing and full device
+	  powering off.
+
+	  If you choose to build module, its name will be tp-bmc. If unsure,
+	  say N here.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index a086197af544..ae7bd2a8c813 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_UACCE)		+= uacce/
 obj-$(CONFIG_XILINX_SDFEC)	+= xilinx_sdfec.o
 obj-$(CONFIG_HISI_HIKEY_USB)	+= hisi_hikey_usb.o
 obj-$(CONFIG_HI6421V600_IRQ)	+= hi6421v600-irq.o
+obj-$(CONFIG_TP_BMC)		+= tp_bmc.o
diff --git a/drivers/misc/tp_bmc.c b/drivers/misc/tp_bmc.c
new file mode 100644
index 000000000000..0b320d3ffae4
--- /dev/null
+++ b/drivers/misc/tp_bmc.c
@@ -0,0 +1,747 @@
+#include <linux/i2c.h>
+#include <linux/bcd.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/input.h>
+#include <linux/regmap.h>
+#include <linux/delay.h>
+#include <linux/kthread.h>
+#include <linux/pm.h>
+#include <linux/rtc.h>
+#include <linux/serio.h>
+#include <linux/platform_device.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinconf-generic.h>
+
+enum I2C_REGS {
+	R_ID1 = 0,
+	R_ID2,
+	R_ID3,
+	R_ID4,
+	R_SOFTOFF_RQ,
+	R_PWROFF_RQ,
+	R_PWRBTN_STATE,
+	R_VERSION1,
+	R_VERSION2,
+	R_BOOTREASON,
+	R_BOOTREASON_ARG,
+	R_SCRATCH1,
+	R_SCRATCH2,
+	R_SCRATCH3,
+	R_SCRATCH4,
+	R_CAP,
+	R_GPIODIR0,
+	R_GPIODIR1,
+	R_GPIODIR2,
+	R_COUNT
+};
+
+#define BMC_ID1_VAL 0x49
+#define BMC_ID2_VAL 0x54
+#define BMC_ID3_VAL 0x58
+#define BMC_ID4_VAL0 0x32
+#define BMC_ID4_VAL1 0x2
+
+#define BMC_VERSION1	0
+#define BMC_VERSION2	2
+#define BMC_VERSION2_3	3
+
+#define BMC_CAP_PWRBTN		0x1
+#define BMC_CAP_TOUCHPAD	0x2
+#define BMC_CAP_RTC		0x4
+#define BMC_CAP_FRU		0x8
+#define BMC_CAP_GPIODIR		0x10
+
+#define BMC_SERIO_BUFSIZE	7
+
+#define POLL_JIFFIES 100
+
+struct bmc_poll_data {
+	struct i2c_client *c;
+};
+
+static struct i2c_client *bmc_i2c;
+static struct i2c_client *rtc_i2c;
+static struct i2c_driver mitx2_bmc_i2c_driver;
+static struct input_dev *button_dev;
+static struct bmc_poll_data poll_data;
+static struct task_struct *polling_task;
+#ifdef CONFIG_SERIO
+static struct i2c_client *serio_i2c;
+static struct task_struct *touchpad_task;
+#endif
+static u8 bmc_proto_version[3];
+static u8 bmc_bootreason[2];
+static u8 bmc_scratch[4];
+static int bmc_cap;
+static const char input_name[] = "BMC input dev";
+static u8 prev_ret;
+
+/* BMC RTC */
+static int
+bmc_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	uint8_t rtc_buf[8];
+	struct i2c_msg msg;
+	int t;
+	int rc;
+
+	msg.addr = client->addr;
+	msg.flags = I2C_M_RD;
+	msg.len = 8;
+	msg.buf = rtc_buf;
+	rc = i2c_transfer(client->adapter, &msg, 1);
+	if (rc != 1) {
+		dev_err(dev, "rtc_read_time: i2c_transfer error %d\n", rc);
+		return rc;
+	}
+
+	tm->tm_sec = bcd2bin(rtc_buf[0] & 0x7f);
+	tm->tm_min = bcd2bin(rtc_buf[1] & 0x7f);
+	tm->tm_hour = bcd2bin(rtc_buf[2] & 0x3f);
+	if (rtc_buf[3] & (1 << 6)) /* PM */
+		tm->tm_hour += 12;
+	tm->tm_mday  = bcd2bin(rtc_buf[4] & 0x3f);
+	tm->tm_mon = bcd2bin(rtc_buf[5] & 0x1f);
+	t = rtc_buf[5] >> 5;
+	tm->tm_wday = (t == 7) ? 0 : t;
+	tm->tm_year = bcd2bin(rtc_buf[6]) + 100; /* year since 1900 */
+	tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
+	tm->tm_isdst = 0;
+
+	return rtc_valid_tm(tm);
+}
+
+static int
+bmc_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	uint8_t rtc_buf[8];
+	struct i2c_msg msg;
+	int rc;
+	uint8_t seconds, minutes, hours, wday, mday, month, years;
+
+	seconds = bin2bcd(tm->tm_sec);
+	minutes = bin2bcd(tm->tm_min);
+	hours = bin2bcd(tm->tm_hour);
+	wday = tm->tm_wday ? tm->tm_wday : 0x7;
+	mday = bin2bcd(tm->tm_mday);
+	month = bin2bcd(tm->tm_mon);
+	years = bin2bcd(tm->tm_year % 100);
+
+	/* Need sanity check??? */
+	rtc_buf[0] = seconds;
+	rtc_buf[1] = minutes;
+	rtc_buf[2] = hours;
+	rtc_buf[3] = 0;
+	rtc_buf[4] = mday;
+	rtc_buf[5] = month | (wday << 5);
+	rtc_buf[6] = years;
+	rtc_buf[7] = 0;
+
+	msg.addr = client->addr;
+	msg.flags = 0;
+	msg.len = 8;
+	msg.buf = rtc_buf;
+	dev_dbg(dev, "rtc_set_time: %08x-%08x\n", *(uint32_t *)&rtc_buf[0],
+		*(uint32_t *)&rtc_buf[4]);
+	rc = i2c_transfer(client->adapter, &msg, 1);
+	if (rc != 1)
+		dev_err(dev, "i2c write: %d\n", rc);
+
+	return (rc == 1) ? 0 : -EIO;
+}
+
+static const struct rtc_class_ops
+bmc_rtc_ops = {
+	.read_time = bmc_rtc_read_time,
+	.set_time = bmc_rtc_set_time,
+};
+
+#ifdef CONFIG_SERIO
+/* BMC serio (PS/2 touchpad) interface */
+
+static int bmc_serio_write(struct serio *id, unsigned char val)
+{
+	struct i2c_client *client = id->port_data;
+	uint8_t buf[4];
+	struct i2c_msg msg;
+	int rc;
+
+	buf[0] = val;
+	msg.addr = client->addr;
+	msg.flags = 0;
+	msg.len = 1;
+	msg.buf = buf;
+	dev_dbg(&client->dev, "bmc_serio_write: %02x\n", val);
+	rc = i2c_transfer(client->adapter, &msg, 1);
+	if (rc != 1)
+		dev_err(&client->dev, "i2c write: %d\n", rc);
+
+	return (rc == 1) ? 0 : -EIO;
+}
+
+/* returns: -1 on error, +1 if more data available, 0 otherwise */
+static int bmc_serio_read(struct i2c_client *client)
+{
+	struct serio *serio = dev_get_drvdata(&client->dev);
+	int i, rc, cnt;
+	uint8_t buf[BMC_SERIO_BUFSIZE];
+	struct i2c_msg msg;
+
+	msg.addr = client->addr;
+	msg.flags = I2C_M_RD;
+	msg.len = BMC_SERIO_BUFSIZE;
+	msg.buf = buf;
+	rc = i2c_transfer(client->adapter, &msg, 1);
+	if (rc != 1) {
+		dev_err(&client->dev, "bmc_serio_read: i2c_transfer error %d\n", rc);
+		return -1;
+	}
+
+	cnt = buf[0];
+	rc = 0;
+	if (cnt > BMC_SERIO_BUFSIZE - 1) {
+		cnt = BMC_SERIO_BUFSIZE - 1;
+		rc = 1;
+	}
+
+	for (i = 0; i < cnt; i++) {
+		serio_interrupt(serio, buf[i + 1], 0);
+	}
+
+	return 0;
+}
+
+int
+touchpad_poll_fn(void *data) {
+	int ret;
+
+	while (1) {
+		if (kthread_should_stop())
+			break;
+		while ((ret = bmc_serio_read(serio_i2c)) > 0)
+			;
+		if (ret < 0) {
+			msleep_interruptible(10000);
+		}
+		msleep_interruptible(10);
+	}
+	return 0;
+}
+#endif /* CONFIG_SERIO */
+
+#ifdef CONFIG_PINCTRL
+static uint8_t bmc_pincf_state [3];
+#define BMC_NPINS	(sizeof(bmc_pincf_state) * 8)
+
+static struct pinctrl_pin_desc bmc_pin_desc[BMC_NPINS] = {
+	PINCTRL_PIN(0, "P0"),
+	PINCTRL_PIN(1, "P1"),
+	PINCTRL_PIN(2, "P2"),
+	PINCTRL_PIN(3, "P3"),
+	PINCTRL_PIN(4, "P4"),
+	PINCTRL_PIN(5, "P5"),
+	PINCTRL_PIN(6, "P6"),
+	PINCTRL_PIN(7, "P7"),
+	PINCTRL_PIN(8, "P8"),
+	PINCTRL_PIN(9, "P9"),
+	PINCTRL_PIN(10, "P10"),
+	PINCTRL_PIN(11, "P11"),
+	PINCTRL_PIN(12, "P12"),
+	PINCTRL_PIN(13, "P13"),
+	PINCTRL_PIN(14, "P14"),
+	PINCTRL_PIN(15, "P15"),
+	PINCTRL_PIN(16, "P16"),
+	PINCTRL_PIN(17, "P17"),
+	PINCTRL_PIN(18, "P18"),
+	PINCTRL_PIN(19, "P19"),
+	PINCTRL_PIN(20, "P20"),
+	PINCTRL_PIN(21, "P21"),
+	PINCTRL_PIN(22, "P22"),
+	PINCTRL_PIN(23, "P23"),
+};
+
+#define PCTRL_DEV	"bmc_pinctrl"
+
+static int bmc_pin_config_get(struct pinctrl_dev *pctldev,
+			      unsigned pin,
+			      unsigned long *config)
+{
+	int idx, bit;
+
+	if (pin > BMC_NPINS)
+		return -EINVAL;
+
+	idx = pin >> 3;
+	bit = pin & 7;
+
+	*config = !!(bmc_pincf_state[idx] & (1 << bit));
+	return 0;
+}
+
+static int bmc_pin_config_set(struct pinctrl_dev *pctldev,
+			      unsigned pin,
+			      unsigned long *config,
+			      unsigned nc)
+{
+	int idx, bit;
+	enum pin_config_param param;
+	int arg;
+
+	if (pin > BMC_NPINS)
+		return -EINVAL;
+
+	idx = pin >> 3;
+	bit = pin & 7;
+
+	param = pinconf_to_config_param (*config);
+	arg = pinconf_to_config_argument (*config);
+	if (param != PIN_CONFIG_OUTPUT)
+		return -EINVAL;
+
+	if (arg)
+		bmc_pincf_state[idx] |= (1 << bit);
+	else
+		bmc_pincf_state[idx] &= ~(1 << bit);
+dev_dbg(&bmc_i2c->dev, "bmc_pin_config_set: pin %u, dir %lu\n", pin, *config);
+
+	return i2c_smbus_write_byte_data(bmc_i2c, R_GPIODIR0 + idx, bmc_pincf_state[idx]);
+}
+
+void pinconf_generic_dump_config(struct pinctrl_dev *pctldev,
+				 struct seq_file *s, unsigned long config);
+
+void pinctrl_utils_free_map(struct pinctrl_dev *pctldev,
+			    struct pinctrl_map *map, unsigned num_maps);
+
+static const struct pinconf_ops bmc_confops = {
+	.pin_config_get = bmc_pin_config_get,
+	.pin_config_set = bmc_pin_config_set,
+	.pin_config_config_dbg_show = pinconf_generic_dump_config,
+};
+
+static int bmc_groups_count(struct pinctrl_dev *pctldev)
+{
+	return 0;
+}
+
+static const char *bmc_group_name(struct pinctrl_dev *pctldev,
+				   unsigned selector)
+{
+	return NULL;
+}
+
+static const struct pinctrl_ops bmc_ctrl_ops = {
+	.get_groups_count = bmc_groups_count,
+	.get_group_name = bmc_group_name,
+	.dt_node_to_map = pinconf_generic_dt_node_to_map_pin,
+	.dt_free_map = pinctrl_utils_free_map,
+};
+
+static struct pinctrl_desc bmc_pincrtl_desc = {
+	.name = PCTRL_DEV,
+	.pins = bmc_pin_desc,
+	.pctlops = &bmc_ctrl_ops,
+	.npins = BMC_NPINS,
+	.confops = &bmc_confops,
+};
+
+static struct pinctrl_dev *bmc_pinctrl_dev;
+
+static int bmc_pinctrl_register(struct device *dev)
+{
+	struct pinctrl_dev *pctrl_dev;
+	struct platform_device *pbdev;
+
+	pbdev = platform_device_alloc(PCTRL_DEV, -1);
+	pbdev->dev.parent = dev;
+	pbdev->dev.of_node = of_find_node_by_name(dev->of_node, "bmc_pinctrl");
+	platform_device_add(pbdev);
+	pctrl_dev = devm_pinctrl_register(&pbdev->dev, &bmc_pincrtl_desc, NULL);
+	if (IS_ERR(pctrl_dev)) {
+		dev_err(&pbdev->dev, "Can't register pinctrl (%ld)\n", PTR_ERR(pctrl_dev));
+		return PTR_ERR(pctrl_dev);
+	} else {
+		dev_info(&pbdev->dev, "BMC pinctrl registered\n");
+		bmc_pinctrl_dev = pctrl_dev;
+	}
+	/* reset all pins to default state */
+	i2c_smbus_write_byte_data(to_i2c_client(dev), R_GPIODIR0, 0);
+	i2c_smbus_write_byte_data(to_i2c_client(dev), R_GPIODIR1, 0);
+	i2c_smbus_write_byte_data(to_i2c_client(dev), R_GPIODIR2, 0);
+	return 0;
+}
+
+static void bmc_pinctrl_unregister(void)
+{
+	if (bmc_pinctrl_dev)
+		devm_pinctrl_unregister(&bmc_i2c->dev, bmc_pinctrl_dev);
+}
+
+#endif
+
+void
+bmc_pwroff_rq(void) {
+	int ret = 0;
+
+	dev_info(&bmc_i2c->dev, "Write reg R_PWROFF_RQ\n");
+	ret = i2c_smbus_write_byte_data(bmc_i2c, R_PWROFF_RQ, 0x01);
+	dev_info(&bmc_i2c->dev, "ret: %i\n", ret);
+}
+
+int
+pwroff_rq_poll_fn(void *data) {
+	int ret;
+
+	while (1) {
+		if (kthread_should_stop())
+			break;
+		dev_dbg(&poll_data.c->dev, "Polling\n");
+		ret = i2c_smbus_read_byte_data(poll_data.c, R_SOFTOFF_RQ);
+		dev_dbg(&poll_data.c->dev, "Polling returned: %i\n", ret);
+		if (prev_ret != ret) {
+			dev_info(&poll_data.c->dev, "key change [%i]\n", ret);
+			if (ret < 0) {
+				dev_err(&poll_data.c->dev,
+					"Could not read register %x\n",
+					R_SOFTOFF_RQ);
+				return -EIO;
+			} else if (ret != 0) {
+				dev_info(&poll_data.c->dev,
+					 "PWROFF \"irq\" detected [%i]\n", ret);
+				input_event(button_dev, EV_KEY, KEY_POWER, 1);
+			} else {
+				input_event(button_dev, EV_KEY, KEY_POWER, 0);
+			}
+			input_sync(button_dev);
+		}
+		prev_ret = ret;
+
+		msleep_interruptible(100);
+	}
+	do_exit(1);
+	return 0;
+}
+
+static int
+mitx2_bmc_validate(struct i2c_client *client) {
+	int ret = 0;
+	int i = 0;
+	static const u8 regs[] = {R_ID1, R_ID2, R_ID3};
+	static const u8 vals[] = {BMC_ID1_VAL, BMC_ID2_VAL, BMC_ID3_VAL};
+
+	bmc_proto_version[0] = 0;
+	bmc_proto_version[1] = 0;
+	bmc_proto_version[2] = 0;
+
+	for (i = 0; i < ARRAY_SIZE(regs); i++) {
+		ret = i2c_smbus_read_byte_data(client, regs[i]);
+		if (ret < 0) {
+			dev_err(&client->dev, "Could not read register %x\n",
+				regs[i]);
+			return -EIO;
+		}
+		if (ret != vals[i]) {
+			dev_err(&client->dev,
+				"Bad value [0x%02x] in register 0x%02x, should be [0x%02x]\n",
+				 ret, regs[i], vals[i]);
+
+			return -ENODEV;
+		}
+	}
+	ret = i2c_smbus_read_byte_data(client, R_ID4);
+	if (ret < 0) {
+		dev_err(&client->dev, "Could not read register %x\n", R_ID4);
+		return -EIO;
+	}
+	if (ret == BMC_ID4_VAL0) {
+		bmc_proto_version[0] = 0;
+	} else if (ret == BMC_ID4_VAL1) {
+		bmc_proto_version[0] = 2;
+		ret = i2c_smbus_read_byte_data(client, R_VERSION1);
+		if (ret < 0) {
+			dev_err(&client->dev, "Could not read register %x\n",
+				R_VERSION1);
+			return -EIO;
+		}
+		bmc_proto_version[1] = ret;
+		ret = i2c_smbus_read_byte_data(client, R_VERSION2);
+		if (ret < 0) {
+			dev_err(&client->dev, "Could not read register %x\n",
+				R_VERSION2);
+			return -EIO;
+		}
+		bmc_proto_version[2] = ret;
+		ret = i2c_smbus_read_byte_data(client, R_BOOTREASON);
+		if (ret < 0) {
+			dev_err(&client->dev, "Could not read register %x\n",
+				R_BOOTREASON);
+			return -EIO;
+		}
+		bmc_bootreason[0] = ret;
+		dev_info(&client->dev, "BMC bootreason[0]->%i\n", ret);
+		ret = i2c_smbus_read_byte_data(client, R_BOOTREASON_ARG);
+		if (ret < 0) {
+			dev_err(&client->dev, "Could not read register %x\n",
+				R_BOOTREASON_ARG);
+			return -EIO;
+		}
+		bmc_bootreason[1] = ret;
+		dev_info(&client->dev, "BMC bootreason[1]->%i\n", ret);
+		for (i = R_SCRATCH1; i <= R_SCRATCH4; i++) {
+			ret = i2c_smbus_read_byte_data(client, i);
+			if (ret < 0) {
+				dev_err(&client->dev,
+					"Could not read register %x\n", i);
+				return -EIO;
+			}
+			bmc_scratch[i - R_SCRATCH1] = ret;
+		}
+		if (bmc_proto_version[2] >= BMC_VERSION2_3) {
+			ret = i2c_smbus_read_byte_data(client, R_CAP);
+			if (ret >= 0)
+				bmc_cap = ret;
+			dev_info(&client->dev,
+				 "BMC extended capabilities %x\n", bmc_cap);
+		} else {
+			bmc_cap = BMC_CAP_PWRBTN;
+		}
+	} else {
+		dev_err(&client->dev, "Bad value [0x%02x] in register 0x%02x\n",
+			ret, R_ID4);
+		return -ENODEV;
+	}
+	dev_info(&client->dev, "BMC seems to be valid\n");
+	return 0;
+}
+
+static int
+bmc_create_client_devices(struct device *bmc_dev)
+{
+	int ret = 0;
+	struct rtc_device *rtc_dev;
+	struct i2c_client *client = to_i2c_client(bmc_dev);
+	int client_addr = client->addr + 1;
+
+	if (bmc_cap & BMC_CAP_TOUCHPAD) {
+#ifdef CONFIG_SERIO
+		struct serio *serio;
+		serio_i2c = i2c_new_ancillary_device(client,
+						     "bmc_serio", client_addr);
+		if (IS_ERR(serio_i2c)) {
+			dev_err(&client->dev, "Can't get serio secondary\n");
+			serio_i2c = NULL;
+			ret = -ENOMEM;
+			goto fail;
+		}
+		serio = devm_kzalloc(&serio_i2c->dev, sizeof(struct serio), GFP_KERNEL);
+		if (!serio) {
+			dev_err(&serio_i2c->dev, "Can't allocate serio\n");
+			ret = -ENOMEM;
+			i2c_unregister_device(serio_i2c);
+			serio_i2c = NULL;
+			goto skip_tp;
+		}
+		serio->write = bmc_serio_write;
+		serio->port_data = serio_i2c;
+		serio->id.type = SERIO_PS_PSTHRU;
+		serio_register_port(serio);
+		dev_set_drvdata(&serio_i2c->dev, serio);
+		touchpad_task = kthread_run(touchpad_poll_fn, NULL, "BMC serio poll task");
+
+skip_tp:
+#endif
+		client_addr++;
+	}
+
+	if (bmc_cap & BMC_CAP_RTC) {
+		rtc_i2c = i2c_new_ancillary_device(client,
+						   "bmc_rtc", client_addr);
+		if (IS_ERR(rtc_i2c)) {
+			dev_err(&client->dev, "Can't get RTC secondary\n");
+			rtc_i2c = NULL;
+			ret = -ENOMEM;
+			goto fail;
+		}
+
+		rtc_dev = devm_rtc_device_register(&rtc_i2c->dev, "bmc_rtc",
+						   &bmc_rtc_ops, THIS_MODULE);
+		if (IS_ERR(rtc_dev)) {
+			ret = PTR_ERR(rtc_dev);
+			dev_err(&client->dev, "Failed to register RTC device: %d\n",
+				ret);
+			i2c_unregister_device(rtc_i2c);
+			rtc_i2c = NULL;
+		}
+fail:
+		client_addr++;
+	}
+
+#ifdef CONFIG_PINCTRL
+	if (bmc_cap & BMC_CAP_GPIODIR || 1 /*vvv*/)
+		bmc_pinctrl_register(bmc_dev);
+#endif
+
+	return ret;
+}
+
+static int
+mitx2_bmc_i2c_probe(struct i2c_client *client,
+		    const struct i2c_device_id *id)
+{
+	int err = 0;
+	int i = 0;
+
+	dev_info(&client->dev, "mitx2 bmc probe\n");
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
+		return -ENODEV;
+
+	for (i = 0; i < 10; i++) {
+		err = mitx2_bmc_validate(client);
+		if (!err)
+			break;
+		msleep_interruptible(20);
+	}
+	if (err)
+		return err;
+
+	if (bmc_cap & BMC_CAP_PWRBTN) {
+		button_dev = input_allocate_device();
+		if (!button_dev) {
+			dev_err(&client->dev, "Not enough memory\n");
+			return -ENOMEM;
+		}
+
+		button_dev->id.bustype = BUS_I2C;
+		button_dev->dev.parent = &client->dev;
+		button_dev->name = input_name;
+		button_dev->phys = "bmc-input0";
+		button_dev->evbit[0] = BIT_MASK(EV_KEY);
+		button_dev->keybit[BIT_WORD(KEY_POWER)] = BIT_MASK(KEY_POWER);
+
+		err = input_register_device(button_dev);
+		if (err) {
+			dev_err(&client->dev, "Failed to register device\n");
+			input_free_device(button_dev);
+			return err;
+		}
+
+		dev_info(&client->dev, "Starting polling thread\n");
+		poll_data.c = client;
+		polling_task = kthread_run(pwroff_rq_poll_fn, NULL, "BMC poll task");
+	}
+
+	if (bmc_cap || 1 /*vvv*/)
+		err = bmc_create_client_devices(&client->dev);
+
+	bmc_i2c = client;
+	/* register as poweroff handler */
+	pm_power_off = bmc_pwroff_rq;
+
+	return 0;
+}
+
+static int
+mitx2_bmc_i2c_remove(struct i2c_client *client)
+{
+#ifdef CONFIG_SERIO
+	struct serio *serio;
+#endif
+
+	if (button_dev) {
+		kthread_stop(polling_task);
+		input_unregister_device(button_dev);
+	}
+#ifdef CONFIG_SERIO
+	if (serio_i2c) {
+		kthread_stop(touchpad_task);
+		serio = dev_get_drvdata(&serio_i2c->dev);
+		serio_unregister_port(serio);
+		i2c_unregister_device(serio_i2c);
+	}
+#endif
+	if (rtc_i2c)
+		i2c_unregister_device(rtc_i2c);
+#ifdef CONFIG_PINCTRL
+	bmc_pinctrl_unregister();
+#endif
+
+	return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id mitx2_bmc_of_match[] = {
+	{ .compatible = "tp,mitx2-bmc" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mitx2_bmc_of_match);
+#endif
+
+static const struct i2c_device_id mitx2_bmc_i2c_id[] = {
+	{ "mitx2_bmc", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mitx2_bmc_i2c_id);
+
+static ssize_t
+version_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%i.%i.%i\n", bmc_proto_version[0],
+			bmc_proto_version[1], bmc_proto_version[2]);
+}
+
+static struct kobj_attribute version_attribute =
+	__ATTR(version, 0664, version_show, NULL);
+
+static ssize_t
+bootreason_show(struct kobject *kobj,
+		struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%i\n", (bmc_bootreason[0] |
+			(bmc_bootreason[1] << 8)));
+}
+
+static struct kobj_attribute bootreason_attribute =
+	__ATTR(bootreason, 0664, bootreason_show, NULL);
+
+static ssize_t
+scratch_show(struct kobject *kobj,
+	     struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%i\n", (bmc_scratch[0] | (bmc_scratch[1] << 8) |
+			(bmc_scratch[2] << 16) | (bmc_scratch[3] << 24)));
+}
+
+static struct kobj_attribute scratch_attribute =
+	__ATTR(scratch, 0664, scratch_show, NULL);
+
+static struct attribute *bmc_attrs[] = {
+	&version_attribute.attr,
+	&bootreason_attribute.attr,
+	&scratch_attribute.attr,
+	NULL,
+};
+
+ATTRIBUTE_GROUPS(bmc);
+
+static struct i2c_driver mitx2_bmc_i2c_driver = {
+	.driver		= {
+		.name	= "mitx2-bmc",
+		.of_match_table = of_match_ptr(mitx2_bmc_of_match),
+		.groups = bmc_groups,
+	},
+	.probe		= mitx2_bmc_i2c_probe,
+	.remove	  = mitx2_bmc_i2c_remove,
+	.id_table	= mitx2_bmc_i2c_id,
+};
+module_i2c_driver(mitx2_bmc_i2c_driver);
+
+MODULE_AUTHOR("Konstantin Kirik");
+MODULE_DESCRIPTION("mITX2 BMC driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("serial:bmc");
-- 
2.32.0