diff mbox

[v4,1/1] i2c: add master driver for mellanox systems

Message ID 1478250907-147450-1-git-send-email-vadimp@mellanox.com
State Superseded
Headers show

Commit Message

Vadim Pasternak Nov. 4, 2016, 9:15 a.m. UTC
From: Vadim Pasternak <vadimp@mellanox.com>

Device driver for Mellanox I2C controller logic, implemented in Lattice
CPLD device.
Device supports:
 - Master mode
 - One physical bus
 - Polling mode

The Kconfig currently controlling compilation of this code is:
drivers/i2c/busses/Kconfig:config I2C_MLXCPLD

Signed-off-by: Michael Shych <michaelsh@mellanox.com>
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
---
v3->v4:
 Comments pointed out by Vladimir:
 - Set default to no in Kconfig;
 - Make mlxcpld_i2c_plat_dev static and add empty line before the
   declaration;
 - In function mlxcpld_i2c_invalid_len remove (msg->len < 0), since len is
   unsigned;
 - Remove unused symbol mlxcpld_i2c_plat_dev;
 - Remove extra spaces in comments to mlxcpld_i2c_check_msg_params;
 - Remove unnecessary round braces in mlxcpld_i2c_set_transf_data;
 - Remove the assignment of 'i' variable in mlxcpld_i2c_wait_for_tc;
 - Add extra line in mlxcpld_i2c_xfer;
 - Move assignment of the adapter's fields retries and nr inside
   mlxcpld_i2c_adapter declaration;
v2->v3:
 Comments pointed out by Vladimir:
 - Use tab symbol as indentation in Kconfig
 - Add the Kconfig section preserving the alphabetical order - added
   within "Other I2C/SMBus bus drivers" after I2C_ELEKTOR (but after this
   sections others are not follow alphabetical);
 - Change license to dual;
 - Replace ADRR with ADDR in macros;
 - Remove unused macros: MLXCPLD_LPCI2C_LPF_DFLT,
   MLXCPLD_LPCI2C_HALF_CYC_100, MLXCPLD_LPCI2C_I2C_HOLD_100,
   MLXCPLD_LPCI2C_HALF_CYC_REG, MLXCPLD_LPCI2C_I2C_HOLD_REG;
 - Fix checkpatch warnings (**/ and the end of comment);
 - Add empty line before structures mlxcpld_i2c_regs,
   mlxcpld_i2c_curr_transf, mlxcpld_i2c_priv;
 - Remove unused structure mlxcpld_i2c_regs;
 - Remove from mlxcpld_i2c_priv the next fields:
   retr_num, poll_time, block_sz, xfer_to; use instead macros
   respectively: MLXCPLD_I2C_RETR_NUM, MLXCPLD_I2C_POLL_TIME,
   MLXCPLD_I2C_DATA_REG_SZ, MLXCPLD_I2C_XFER_TO;
 - In mlxcpld_i2c_invalid_len remove unnecessary else;
 - Optimize mlxcpld_i2c_set_transf_data;
 - mlxcpld_i2c_reset - add empty lines after/before mutex
   lock/unlock;
 - mlxcpld_i2c_wait_for_free - cover case timeout is equal
   MLXCPLD_I2C_XFER_TO;
 - mlxcpld_i2c_wait_for_tc:
   - Do not assign err in declaration (also err is removed);
   - Insert empty line before case MLXCPLD_LPCI2C_ACK_IND;
   - inside case MLXCPLD_LPCI2C_ACK_IND - avoid unnecessary
     indentation;
   - Remove case MLXCPLD_LPCI2C_ERR_IND and remove this macro;
 - Add empty lines in mlxcpld_i2c_xfer before/after mutex_lock/
   mutex_unlock;
 - In mlxcpld_i2c_probe add emtpy line after platform_set_drvdata;
 - Replace platfrom handle pdev in mlxcpld_i2c_priv with the pointer
   to the structure device;
 - Place assignment of base_addr near the others;
 - Enclose e-mail with <>;
 Fixes added by Vadim:
 - Change structure description format according to
   Documentation/kernel-documentation.rst guideline;
 - mlxcpld_i2c_wait_for_tc: return error if status reaches default case;
v1->v2
 Fixes added by Vadim:
 - Put new record in Makefile in alphabetic order;
 - Remove http://www.mellanox.com from MAINTAINERS record;
---
 Documentation/i2c/busses/i2c-mlxcpld |  47 +++
 MAINTAINERS                          |   8 +
 drivers/i2c/busses/Kconfig           |  12 +
 drivers/i2c/busses/Makefile          |   1 +
 drivers/i2c/busses/i2c-mlxcpld.c     | 558 +++++++++++++++++++++++++++++++++++
 5 files changed, 626 insertions(+)
 create mode 100644 Documentation/i2c/busses/i2c-mlxcpld
 create mode 100644 drivers/i2c/busses/i2c-mlxcpld.c

Comments

Vladimir Zapolskiy Nov. 7, 2016, 12:47 a.m. UTC | #1
Hi Vadim,

please find below some more nitpickings.

On 11/04/2016 11:15 AM, vadimp@mellanox.com wrote:
> From: Vadim Pasternak <vadimp@mellanox.com>
>

[snip]

> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index d252276..b9e1c4c 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -1150,6 +1150,18 @@ config I2C_ELEKTOR
>  	  This support is also available as a module.  If so, the module
>  	  will be called i2c-elektor.
>
> +config I2C_MLXCPLD
> +	tristate "Mellanox I2C driver"
> +	depends on X86_64
> +	default n

Please just remove 'default n' line, unset default value in Kconfig
is the same as 'default n'.

[snip]

> +/* General defines */
> +#define MLXPLAT_CPLD_LPC_I2C_BASE_ADDR	0x2000
> +#define MLXCPLD_I2C_DEVICE_NAME		"i2c_mlxcpld"
> +#define MLXCPLD_I2C_VALID_FLAG		(I2C_M_RECV_LEN | I2C_M_RD)
> +#define MLXCPLD_I2C_BUS_NUM		1
> +#define MLXCPLD_I2C_DATA_REG_SZ		36
> +#define MLXCPLD_I2C_MAX_ADDR_LEN	4
> +#define MLXCPLD_I2C_RETR_NUM		2
> +#define MLXCPLD_I2C_XFER_TO		500000 /* msec */
> +#define MLXCPLD_I2C_POLL_TIME		2000   /* msec */

Two lines above define macro values with the microsecond unit, its
short form is denoted as "usec" and "msec" or "ms" is used to
denote milliseconds. Please correct it, transfer timeout of "500
seconds" is confusing.

[snip]

> +
> +static int mlxcpld_i2c_probe(struct platform_device *pdev)
> +{
> +	struct mlxcpld_i2c_priv *priv;
> +	int err;
> +
> +	priv = devm_kzalloc(&pdev->dev, sizeof(struct mlxcpld_i2c_priv),
> +			    GFP_KERNEL);
> +	if (!priv)
> +		return -ENOMEM;
> +
> +	mutex_init(&priv->lock);
> +	platform_set_drvdata(pdev, priv);
> +
> +	priv->dev = &pdev->dev;
> +
> +	/* Register with i2c layer */
> +	mlxcpld_i2c_adapter.timeout = usecs_to_jiffies(MLXCPLD_I2C_XFER_TO);
> +	priv->adap = mlxcpld_i2c_adapter;
> +	priv->adap.dev.parent = &pdev->dev;
> +	priv->base_addr = MLXPLAT_CPLD_LPC_I2C_BASE_ADDR;
> +	i2c_set_adapdata(&priv->adap, priv);
> +
> +	err = i2c_add_numbered_adapter(&priv->adap);
> +	if (err) {
> +		dev_err(&pdev->dev, "Failed to add %s adapter (%d)\n",
> +			MLXCPLD_I2C_DEVICE_NAME, err);
> +		goto fail_adapter;
> +	}
> +
> +	return 0;
> +
> +fail_adapter:
> +	mutex_destroy(&priv->lock);
> +	return err;

Here you can save some more lines of code by changing it to

	err = i2c_add_numbered_adapter(&priv->adap);
	if (err)
		mutex_destroy(&priv->lock);

	return err;

Note, dev_err() is not needed here, because printing of the error
message is delegated to the I2C core.

> +}
> +

Please feel free to add a tag to the next version:

Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>

--
With best wishes,
Vladimir
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Vadim Pasternak Nov. 7, 2016, 5:49 a.m. UTC | #2
Hi Vladimir,

Thank you very much for reviews.

Thanks,
Vadim.

> -----Original Message-----

> From: Vladimir Zapolskiy [mailto:vz@mleia.com]

> Sent: Monday, November 07, 2016 2:47 AM

> To: Vadim Pasternak <vadimp@mellanox.com>; wsa@the-dreams.de

> Cc: linux-i2c@vger.kernel.org; linux-kernel@vger.kernel.org; jiri@resnulli.us;

> Michael Shych <michaelsh@mellanox.com>

> Subject: Re: [patch v4 1/1] i2c: add master driver for mellanox systems

> 

> Hi Vadim,

> 

> please find below some more nitpickings.

> 

> On 11/04/2016 11:15 AM, vadimp@mellanox.com wrote:

> > From: Vadim Pasternak <vadimp@mellanox.com>

> >

> 

> [snip]

> 

> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig

> > index d252276..b9e1c4c 100644

> > --- a/drivers/i2c/busses/Kconfig

> > +++ b/drivers/i2c/busses/Kconfig

> > @@ -1150,6 +1150,18 @@ config I2C_ELEKTOR

> >  	  This support is also available as a module.  If so, the module

> >  	  will be called i2c-elektor.

> >

> > +config I2C_MLXCPLD

> > +	tristate "Mellanox I2C driver"

> > +	depends on X86_64

> > +	default n

> 

> Please just remove 'default n' line, unset default value in Kconfig is the same as

> 'default n'.

> 

> [snip]

> 

> > +/* General defines */

> > +#define MLXPLAT_CPLD_LPC_I2C_BASE_ADDR	0x2000

> > +#define MLXCPLD_I2C_DEVICE_NAME		"i2c_mlxcpld"

> > +#define MLXCPLD_I2C_VALID_FLAG		(I2C_M_RECV_LEN |

> I2C_M_RD)

> > +#define MLXCPLD_I2C_BUS_NUM		1

> > +#define MLXCPLD_I2C_DATA_REG_SZ		36

> > +#define MLXCPLD_I2C_MAX_ADDR_LEN	4

> > +#define MLXCPLD_I2C_RETR_NUM		2

> > +#define MLXCPLD_I2C_XFER_TO		500000 /* msec */

> > +#define MLXCPLD_I2C_POLL_TIME		2000   /* msec */

> 

> Two lines above define macro values with the microsecond unit, its short form is

> denoted as "usec" and "msec" or "ms" is used to denote milliseconds. Please

> correct it, transfer timeout of "500 seconds" is confusing.

> 

> [snip]

> 

> > +

> > +static int mlxcpld_i2c_probe(struct platform_device *pdev) {

> > +	struct mlxcpld_i2c_priv *priv;

> > +	int err;

> > +

> > +	priv = devm_kzalloc(&pdev->dev, sizeof(struct mlxcpld_i2c_priv),

> > +			    GFP_KERNEL);

> > +	if (!priv)

> > +		return -ENOMEM;

> > +

> > +	mutex_init(&priv->lock);

> > +	platform_set_drvdata(pdev, priv);

> > +

> > +	priv->dev = &pdev->dev;

> > +

> > +	/* Register with i2c layer */

> > +	mlxcpld_i2c_adapter.timeout =

> usecs_to_jiffies(MLXCPLD_I2C_XFER_TO);

> > +	priv->adap = mlxcpld_i2c_adapter;

> > +	priv->adap.dev.parent = &pdev->dev;

> > +	priv->base_addr = MLXPLAT_CPLD_LPC_I2C_BASE_ADDR;

> > +	i2c_set_adapdata(&priv->adap, priv);

> > +

> > +	err = i2c_add_numbered_adapter(&priv->adap);

> > +	if (err) {

> > +		dev_err(&pdev->dev, "Failed to add %s adapter (%d)\n",

> > +			MLXCPLD_I2C_DEVICE_NAME, err);

> > +		goto fail_adapter;

> > +	}

> > +

> > +	return 0;

> > +

> > +fail_adapter:

> > +	mutex_destroy(&priv->lock);

> > +	return err;

> 

> Here you can save some more lines of code by changing it to

> 

> 	err = i2c_add_numbered_adapter(&priv->adap);

> 	if (err)

> 		mutex_destroy(&priv->lock);

> 

> 	return err;

> 

> Note, dev_err() is not needed here, because printing of the error message is

> delegated to the I2C core.

> 

> > +}

> > +

> 

> Please feel free to add a tag to the next version:

> 

> Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>

> 

> --

> With best wishes,

> Vladimir
diff mbox

Patch

diff --git a/Documentation/i2c/busses/i2c-mlxcpld b/Documentation/i2c/busses/i2c-mlxcpld
new file mode 100644
index 0000000..0f8678a
--- /dev/null
+++ b/Documentation/i2c/busses/i2c-mlxcpld
@@ -0,0 +1,47 @@ 
+Driver i2c-mlxcpld
+
+Author: Michael Shych <michaelsh@mellanox.com>
+
+This is a for Mellanox I2C controller logic, implemented in Lattice CPLD
+device.
+Device supports:
+ - Master mode.
+ - One physical bus.
+ - Polling mode.
+
+This controller is equipped within the next Mellanox systems:
+"msx6710", "msx6720", "msb7700", "msn2700", "msx1410", "msn2410", "msb7800",
+"msn2740", "msn2100".
+
+The next transaction types are supported:
+ - Receive Byte/Block.
+ - Send Byte/Block.
+ - Read Byte/Block.
+ - Write Byte/Block.
+
+Registers:
+CTRL		0x1 - control reg.
+			Resets all the registers.
+HALF_CYC	0x4 - cycle reg.
+			Configure the width of I2C SCL half clock cycle (in 4 LPC_CLK
+			units).
+I2C_HOLD	0x5 - hold reg.
+			OE (output enable) is delayed by value set to this register
+			(in LPC_CLK units)
+CMD			0x6 - command reg.
+			Bit 7(lsb), 0 = write, 1 = read.
+			Bits [6:0] - the 7bit Address of the I2C device.
+			It should be written last as it triggers an I2C transaction.
+NUM_DATA	0x7 - data size reg.
+			Number of address bytes to write in read transaction
+NUM_ADDR	0x8 - address reg.
+			Number of address bytes to write in read transaction.
+STATUS		0x9 - status reg.
+			Bit 0 - transaction is completed.
+			Bit 4 - ACK/NACK.
+DATAx		0xa - 0x54  - 68 bytes data buffer regs.
+			For write transaction address is specified in four first bytes
+			(DATA1 - DATA4), data starting from DATA4.
+			For read transactions address is send in separate transaction and
+			specified in four first bytes (DATA0 - DATA3). Data is reading
+			starting from DATA0.
diff --git a/MAINTAINERS b/MAINTAINERS
index 3d838cf..dfc6a0a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7876,6 +7876,14 @@  W:	http://www.mellanox.com
 Q:	http://patchwork.ozlabs.org/project/netdev/list/
 F:	drivers/net/ethernet/mellanox/mlxsw/
 
+MELLANOX MLXCPLD I2C DRIVER
+M:	Vadim Pasternak <vadimp@mellanox.com>
+M:	Michael Shych <michaelsh@mellanox.com>
+L:	linux-i2c@vger.kernel.org
+S:	Supported
+F:	drivers/i2c/busses/i2c-mlxcpld.c
+F:	Documentation/i2c/busses/i2c-mlxcpld
+
 MELLANOX MLXCPLD LED DRIVER
 M:	Vadim Pasternak <vadimp@mellanox.com>
 L:	linux-leds@vger.kernel.org
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index d252276..b9e1c4c 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1150,6 +1150,18 @@  config I2C_ELEKTOR
 	  This support is also available as a module.  If so, the module
 	  will be called i2c-elektor.
 
+config I2C_MLXCPLD
+	tristate "Mellanox I2C driver"
+	depends on X86_64
+	default n
+	help
+	  This exposes the Mellanox platform I2C busses to the linux I2C layer
+	  for X86 based systems.
+	  Controller is implemented as CPLD logic.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called as i2c-mlxcpld.
+
 config I2C_PCA_ISA
 	tristate "PCA9564/PCA9665 on an ISA bus"
 	depends on ISA
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 29764cc..645bf08 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -116,6 +116,7 @@  obj-$(CONFIG_I2C_BCM_KONA)	+= i2c-bcm-kona.o
 obj-$(CONFIG_I2C_BRCMSTB)	+= i2c-brcmstb.o
 obj-$(CONFIG_I2C_CROS_EC_TUNNEL)	+= i2c-cros-ec-tunnel.o
 obj-$(CONFIG_I2C_ELEKTOR)	+= i2c-elektor.o
+obj-$(CONFIG_I2C_MLXCPLD)	+= i2c-mlxcpld.o
 obj-$(CONFIG_I2C_OPAL)		+= i2c-opal.o
 obj-$(CONFIG_I2C_PCA_ISA)	+= i2c-pca-isa.o
 obj-$(CONFIG_I2C_SIBYTE)	+= i2c-sibyte.o
diff --git a/drivers/i2c/busses/i2c-mlxcpld.c b/drivers/i2c/busses/i2c-mlxcpld.c
new file mode 100644
index 0000000..6c9e022
--- /dev/null
+++ b/drivers/i2c/busses/i2c-mlxcpld.c
@@ -0,0 +1,558 @@ 
+/*
+ * drivers/i2c/busses/i2c-mlxcpld.c
+ * Copyright (c) 2016 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2016 Michael Shych <michaels@mellanox.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the names of the copyright holders nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * Alternatively, this software may be distributed under the terms of the
+ * GNU General Public License ("GPL") version 2 as published by the Free
+ * Software Foundation.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+
+/* General defines */
+#define MLXPLAT_CPLD_LPC_I2C_BASE_ADDR	0x2000
+#define MLXCPLD_I2C_DEVICE_NAME		"i2c_mlxcpld"
+#define MLXCPLD_I2C_VALID_FLAG		(I2C_M_RECV_LEN | I2C_M_RD)
+#define MLXCPLD_I2C_BUS_NUM		1
+#define MLXCPLD_I2C_DATA_REG_SZ		36
+#define MLXCPLD_I2C_MAX_ADDR_LEN	4
+#define MLXCPLD_I2C_RETR_NUM		2
+#define MLXCPLD_I2C_XFER_TO		500000 /* msec */
+#define MLXCPLD_I2C_POLL_TIME		2000   /* msec */
+
+/* LPC I2C registers */
+#define MLXCPLD_LPCI2C_LPF_REG		0x0
+#define MLXCPLD_LPCI2C_CTRL_REG		0x1
+#define MLXCPLD_LPCI2C_HALF_CYC_REG	0x4
+#define MLXCPLD_LPCI2C_I2C_HOLD_REG	0x5
+#define MLXCPLD_LPCI2C_CMD_REG		0x6
+#define MLXCPLD_LPCI2C_NUM_DAT_REG	0x7
+#define MLXCPLD_LPCI2C_NUM_ADDR_REG	0x8
+#define MLXCPLD_LPCI2C_STATUS_REG	0x9
+#define MLXCPLD_LPCI2C_DATA_REG		0xa
+
+/* LPC I2C masks and parametres */
+#define MLXCPLD_LPCI2C_RST_SEL_MASK	0x1
+#define MLXCPLD_LPCI2C_TRANS_END	0x1
+#define MLXCPLD_LPCI2C_STATUS_NACK	0x10
+#define MLXCPLD_LPCI2C_NO_IND		0
+#define MLXCPLD_LPCI2C_ACK_IND		1
+#define MLXCPLD_LPCI2C_NACK_IND		2
+
+/**
+ * struct mlxcpld_i2c_curr_transf - current transaction parameters:
+ * @cmd: command;
+ * @addr_width: address width;
+ * @data_len: data length;
+ * @cmd: command register;
+ * @msg_num: message number;
+ * @msg: pointer to message buffer;
+ */
+
+struct mlxcpld_i2c_curr_transf {
+	u8 cmd;
+	u8 addr_width;
+	u8 data_len;
+	u8 msg_num;
+	struct i2c_msg *msg;
+};
+
+/**
+ * struct mlxcpld_i2c_priv - private controller data:
+ * @lpc_gen_dec_reg: register space;
+ * @adap: i2c adapter;
+ * @dev_id: device id;
+ * @base_addr: base IO address;
+ * @lock: bus access lock;
+ * @xfer: current i2c transfer block;
+ * @dev: device handle;
+ */
+
+struct mlxcpld_i2c_priv {
+	struct i2c_adapter adap;
+	u16 dev_id;
+	u16 base_addr;
+	struct mutex lock;
+	struct mlxcpld_i2c_curr_transf xfer;
+	struct device *dev;
+};
+
+static void mlxcpld_i2c_lpc_write_buf(u8 *data, u8 len, u32 addr)
+{
+	int i, nbyte, ndword;
+
+	nbyte = len % 4;
+	ndword = len / 4;
+	for (i = 0; i < ndword; i++)
+		outl(*((u32 *)data + i), addr + i * 4);
+	ndword *= 4;
+	addr += ndword;
+	data += ndword;
+	for (i = 0; i < nbyte; i++)
+		outb(*(data + i), addr + i);
+}
+
+static void mlxcpld_i2c_lpc_read_buf(u8 *data, u8 len, u32 addr)
+{
+	int i, nbyte, ndword;
+
+	nbyte = len % 4;
+	ndword = len / 4;
+	for (i = 0; i < ndword; i++)
+		*((u32 *)data + i) = inl(addr + i * 4);
+	ndword *= 4;
+	addr += ndword;
+	data += ndword;
+	for (i = 0; i < nbyte; i++)
+		*(data + i) = inb(addr + i);
+}
+
+static void mlxcpld_i2c_read_comm(struct mlxcpld_i2c_priv *priv, u8 offs,
+				  u8 *data, u8 datalen)
+{
+	u32 addr = priv->base_addr + offs;
+
+	switch (datalen) {
+	case 1:
+		*(data) = inb(addr);
+		break;
+	case 2:
+		*((u16 *)data) = inw(addr);
+		break;
+	case 3:
+		*((u16 *)data) = inw(addr);
+		*(data + 2) = inb(addr + 2);
+		break;
+	case 4:
+		*((u32 *)data) = inl(addr);
+		break;
+	default:
+		mlxcpld_i2c_lpc_read_buf(data, datalen, addr);
+		break;
+	}
+}
+
+static void mlxcpld_i2c_write_comm(struct mlxcpld_i2c_priv *priv, u8 offs,
+				   u8 *data, u8 datalen)
+{
+	u32 addr = priv->base_addr + offs;
+
+	switch (datalen) {
+	case 1:
+		outb(*(data), addr);
+		break;
+	case 2:
+		outw(*((u16 *)data), addr);
+		break;
+	case 3:
+		outw(*((u16 *)data), addr);
+		outb(*(data + 2), addr + 2);
+		break;
+	case 4:
+		outl(*((u32 *)data), addr);
+		break;
+	default:
+		mlxcpld_i2c_lpc_write_buf(data, datalen, addr);
+		break;
+	}
+}
+
+/* Check validity of current i2c message and all transfer.
+ * Calculate also coomon length of all i2c messages in transfer.
+ */
+static int mlxcpld_i2c_invalid_len(struct mlxcpld_i2c_priv *priv,
+				   const struct i2c_msg *msg, u8 *comm_len)
+{
+	u8 max_len = msg->flags == I2C_M_RD ? MLXCPLD_I2C_DATA_REG_SZ -
+		     MLXCPLD_I2C_MAX_ADDR_LEN : MLXCPLD_I2C_DATA_REG_SZ;
+
+	if (msg->len > max_len)
+		return -EINVAL;
+
+	*comm_len += msg->len;
+	if (*comm_len > MLXCPLD_I2C_DATA_REG_SZ)
+		return -EINVAL;
+
+	return 0;
+}
+
+/* Check validity of received i2c messages parameters.
+ * Returns 0 if OK, other - in case of invalid parameters
+ * or common length of data that should be passed to CPLD
+ */
+static int mlxcpld_i2c_check_msg_params(struct mlxcpld_i2c_priv *priv,
+					struct i2c_msg *msgs, int num,
+					u8 *comm_len)
+{
+	int i;
+
+	if (!num) {
+		dev_err(priv->dev, "Incorrect 0 num of messages\n");
+		return -EINVAL;
+	}
+
+	if (unlikely(msgs[0].addr > 0x7f)) {
+		dev_err(priv->dev, "Invalid address 0x%03x\n",
+			msgs[0].addr);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < num; ++i) {
+		if (unlikely(!msgs[i].buf)) {
+			dev_err(priv->dev, "Invalid buf in msg[%d]\n",
+				i);
+			return -EINVAL;
+		}
+		if (unlikely(msgs[0].addr != msgs[i].addr)) {
+			dev_err(priv->dev, "Invalid addr in msg[%d]\n",
+				i);
+			return -EINVAL;
+		}
+		if (unlikely(mlxcpld_i2c_invalid_len(priv, &msgs[i],
+						     comm_len))) {
+			dev_err(priv->dev, "Invalid len %d msg[%d], addr 0x%x, lag %u\n",
+				msgs[i].len, i, msgs[i].addr, msgs[i].flags);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+/* Check if transfer is completed and status of operation.
+ * Returns 0 - transfer completed (both ACK or NACK),
+ * negative - transfer isn't finished.
+ */
+static int mlxcpld_i2c_check_status(struct mlxcpld_i2c_priv *priv, int *status)
+{
+	u8 val;
+
+	mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_STATUS_REG, &val, 1);
+
+	if (val & MLXCPLD_LPCI2C_TRANS_END) {
+		if (val & MLXCPLD_LPCI2C_STATUS_NACK)
+			/* The slave is unable to accept the data. No such
+			 * slave, command not understood, or unable to accept
+			 * any more data.
+			 */
+			*status = MLXCPLD_LPCI2C_NACK_IND;
+		else
+			*status = MLXCPLD_LPCI2C_ACK_IND;
+		return 0;
+	}
+	*status = MLXCPLD_LPCI2C_NO_IND;
+
+	return -EIO;
+}
+
+static void mlxcpld_i2c_set_transf_data(struct mlxcpld_i2c_priv *priv,
+					struct i2c_msg *msgs, int num,
+					u8 comm_len)
+{
+	priv->xfer.msg = msgs;
+	priv->xfer.msg_num = num;
+
+	/*
+	 * All upper layers currently are never use transfer with more than
+	 * 2 messages. Actually, it's also not so relevant in Mellanox systems
+	 * because of HW limitation. Max size of transfer is o more than 20B
+	 * in current x86 LPCI2C bridge.
+	 */
+	priv->xfer.cmd = msgs[num - 1].flags & I2C_M_RD;
+
+	if (priv->xfer.cmd == I2C_M_RD && comm_len != msgs[0].len) {
+		priv->xfer.addr_width = msgs[0].len;
+		priv->xfer.data_len = comm_len - priv->xfer.addr_width;
+	} else {
+		priv->xfer.addr_width = 0;
+		priv->xfer.data_len = comm_len;
+	}
+}
+
+/* Reset CPLD LPCI2C block */
+static void mlxcpld_i2c_reset(struct mlxcpld_i2c_priv *priv)
+{
+	u8 val;
+
+	mutex_lock(&priv->lock);
+
+	mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_CTRL_REG, &val, 1);
+	val &= ~MLXCPLD_LPCI2C_RST_SEL_MASK;
+	mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_CTRL_REG, &val, 1);
+
+	mutex_unlock(&priv->lock);
+}
+
+/* Make sure the CPLD is ready to start transmitting.
+ * Return 0 if it is, -EBUSY if it is not.
+ */
+static int mlxcpld_i2c_check_busy(struct mlxcpld_i2c_priv *priv)
+{
+	u8 val;
+
+	mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_STATUS_REG, &val, 1);
+
+	if (val & MLXCPLD_LPCI2C_TRANS_END)
+		return 0;
+
+	return -EIO;
+}
+
+static int mlxcpld_i2c_wait_for_free(struct mlxcpld_i2c_priv *priv)
+{
+	int timeout = 0;
+
+	do {
+		if (!mlxcpld_i2c_check_busy(priv))
+			break;
+		usleep_range(MLXCPLD_I2C_POLL_TIME / 2, MLXCPLD_I2C_POLL_TIME);
+		timeout += MLXCPLD_I2C_POLL_TIME;
+	} while (timeout <= MLXCPLD_I2C_XFER_TO);
+
+	if (timeout > MLXCPLD_I2C_XFER_TO)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+/*
+ * Wait for master transfer to complete.
+ * It puts current process to sleep until we get interrupt or timeout expires.
+ * Returns the number of transferred or read bytes or error (<0).
+ */
+static int mlxcpld_i2c_wait_for_tc(struct mlxcpld_i2c_priv *priv)
+{
+	int status, i, timeout = 0;
+	u8 datalen;
+
+	do {
+		usleep_range(MLXCPLD_I2C_POLL_TIME / 2, MLXCPLD_I2C_POLL_TIME);
+		if (!mlxcpld_i2c_check_status(priv, &status))
+			break;
+		timeout += MLXCPLD_I2C_POLL_TIME;
+	} while (status == 0 && timeout < MLXCPLD_I2C_XFER_TO);
+
+	switch (status) {
+	case MLXCPLD_LPCI2C_NO_IND:
+		return -ETIMEDOUT;
+
+	case MLXCPLD_LPCI2C_ACK_IND:
+		if (priv->xfer.cmd != I2C_M_RD)
+			return (priv->xfer.addr_width + priv->xfer.data_len);
+
+		if (priv->xfer.msg_num == 1)
+			i = 0;
+		else
+			i = 1;
+
+		if (!priv->xfer.msg[i].buf)
+			return -EINVAL;
+
+		/*
+		 * Actual read data len will be always the same as
+		 * requested len. 0xff (line pull-up) will be returned
+		 * if slave has no data to return. Thus don't read
+		 * MLXCPLD_LPCI2C_NUM_DAT_REG reg from CPLD.
+		 */
+		datalen = priv->xfer.data_len;
+
+		mlxcpld_i2c_read_comm(priv, MLXCPLD_LPCI2C_DATA_REG,
+				      priv->xfer.msg[i].buf, datalen);
+
+		return datalen;
+
+	case MLXCPLD_LPCI2C_NACK_IND:
+		return -EAGAIN;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static void mlxcpld_i2c_xfer_msg(struct mlxcpld_i2c_priv *priv)
+{
+	int i, len = 0;
+	u8 cmd;
+
+	mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_NUM_DAT_REG,
+			       &priv->xfer.data_len, 1);
+	mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_NUM_ADDR_REG,
+			       &priv->xfer.addr_width, 1);
+
+	for (i = 0; i < priv->xfer.msg_num; i++) {
+		if ((priv->xfer.msg[i].flags & I2C_M_RD) != I2C_M_RD) {
+			/* Don't write to CPLD buffer in read transaction */
+			mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_DATA_REG +
+					       len, priv->xfer.msg[i].buf,
+					       priv->xfer.msg[i].len);
+			len += priv->xfer.msg[i].len;
+		}
+	}
+
+	/* Set target slave address with command for master transfer.
+	 * It should be latest executed function before CPLD transaction.
+	 */
+	cmd = (priv->xfer.msg[0].addr << 1) | priv->xfer.cmd;
+	mlxcpld_i2c_write_comm(priv, MLXCPLD_LPCI2C_CMD_REG, &cmd, 1);
+}
+
+/* Generic lpc-i2c transfer.
+ * Returns the number of processed messages or error (<0).
+ */
+static int mlxcpld_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
+			    int num)
+{
+	struct mlxcpld_i2c_priv *priv = i2c_get_adapdata(adap);
+	u8 comm_len = 0;
+	int err;
+
+	err = mlxcpld_i2c_check_msg_params(priv, msgs, num, &comm_len);
+	if (err) {
+		dev_err(priv->dev, "Incorrect message\n");
+		return err;
+	}
+
+	/* Check bus state */
+	if (mlxcpld_i2c_wait_for_free(priv)) {
+		dev_err(priv->dev, "LPCI2C bridge is busy\n");
+
+		/*
+		 * Usually it means something serious has happened.
+		 * We can not have unfinished previous transfer
+		 * so it doesn't make any sense to try to stop it.
+		 * Probably we were not able to recover from the
+		 * previous error.
+		 * The only reasonable thing - is soft reset.
+		 */
+		mlxcpld_i2c_reset(priv);
+		if (mlxcpld_i2c_check_busy(priv)) {
+			dev_err(priv->dev, "LPCI2C bridge is busy after reset\n");
+			return -EIO;
+		}
+	}
+
+	mlxcpld_i2c_set_transf_data(priv, msgs, num, comm_len);
+
+	mutex_lock(&priv->lock);
+
+	/* Do real transfer. Can't fail */
+	mlxcpld_i2c_xfer_msg(priv);
+
+	/* Wait for transaction complete */
+	err = mlxcpld_i2c_wait_for_tc(priv);
+
+	mutex_unlock(&priv->lock);
+
+	return err < 0 ? err : num;
+}
+
+static u32 mlxcpld_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm mlxcpld_i2c_algo = {
+	.master_xfer	= mlxcpld_i2c_xfer,
+	.functionality	= mlxcpld_i2c_func
+};
+
+static struct i2c_adapter mlxcpld_i2c_adapter = {
+	.owner          = THIS_MODULE,
+	.name           = "i2c-mlxcpld",
+	.class          = I2C_CLASS_HWMON | I2C_CLASS_SPD,
+	.algo           = &mlxcpld_i2c_algo,
+	.retries	= MLXCPLD_I2C_RETR_NUM,
+	.nr		= MLXCPLD_I2C_BUS_NUM,
+};
+
+static int mlxcpld_i2c_probe(struct platform_device *pdev)
+{
+	struct mlxcpld_i2c_priv *priv;
+	int err;
+
+	priv = devm_kzalloc(&pdev->dev, sizeof(struct mlxcpld_i2c_priv),
+			    GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	mutex_init(&priv->lock);
+	platform_set_drvdata(pdev, priv);
+
+	priv->dev = &pdev->dev;
+
+	/* Register with i2c layer */
+	mlxcpld_i2c_adapter.timeout = usecs_to_jiffies(MLXCPLD_I2C_XFER_TO);
+	priv->adap = mlxcpld_i2c_adapter;
+	priv->adap.dev.parent = &pdev->dev;
+	priv->base_addr = MLXPLAT_CPLD_LPC_I2C_BASE_ADDR;
+	i2c_set_adapdata(&priv->adap, priv);
+
+	err = i2c_add_numbered_adapter(&priv->adap);
+	if (err) {
+		dev_err(&pdev->dev, "Failed to add %s adapter (%d)\n",
+			MLXCPLD_I2C_DEVICE_NAME, err);
+		goto fail_adapter;
+	}
+
+	return 0;
+
+fail_adapter:
+	mutex_destroy(&priv->lock);
+	return err;
+}
+
+static int mlxcpld_i2c_remove(struct platform_device *pdev)
+{
+	struct mlxcpld_i2c_priv *priv = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&priv->adap);
+	mutex_destroy(&priv->lock);
+
+	return 0;
+}
+
+static struct platform_driver mlxcpld_i2c_driver = {
+	.probe		= mlxcpld_i2c_probe,
+	.remove		= mlxcpld_i2c_remove,
+	.driver = {
+		.name = MLXCPLD_I2C_DEVICE_NAME,
+	},
+};
+
+module_platform_driver(mlxcpld_i2c_driver);
+
+MODULE_AUTHOR("Michael Shych <michaels@mellanox.com>");
+MODULE_DESCRIPTION("Mellanox I2C-CPLD controller driver");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("platform:i2c-mlxcpld");