[patch v5 1/1] i2c: add master driver for mellanox systems

From: vadimp
Date: Mon Nov 07 2016 - 00:48:59 EST

From: Vadim Pasternak <vadimp@xxxxxxxxxxxx>

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@xxxxxxxxxxxx>
Signed-off-by: Vadim Pasternak <vadimp@xxxxxxxxxxxx>
Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxxxx>
Reviewed-by: Vladimir Zapolskiy <vz@xxxxxxxxx>
---
v4->v5:
Comments pointed out by Vladimir:
- Remove "default n" from Kconfig;
- Fix the comments for timeout and pool time;
- Optimize error flow in mlxcpld_i2c_probe;
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 | 11 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-mlxcpld.c | 551 +++++++++++++++++++++++++++++++++++
5 files changed, 618 insertions(+)
create mode 100644 Documentation/i2c/busses/i2c-mlxcpld
create mode 100644 drivers/i2c/busses/i2c-mlxcpld.c

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@xxxxxxxxxxxx>
+
+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@xxxxxxxxxxxx>
+M: Michael Shych <michaelsh@xxxxxxxxxxxx>
+L: linux-i2c@xxxxxxxxxxxxxxx
+S: Supported
+F: drivers/i2c/busses/i2c-mlxcpld.c
+F: Documentation/i2c/busses/i2c-mlxcpld
+
MELLANOX MLXCPLD LED DRIVER
M: Vadim Pasternak <vadimp@xxxxxxxxxxxx>
L: linux-leds@xxxxxxxxxxxxxxx
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index d252276..6399cea 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -1150,6 +1150,17 @@ 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
+ 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..f7a6f3a
--- /dev/null
+++ b/drivers/i2c/busses/i2c-mlxcpld.c
@@ -0,0 +1,551 @@
+/*
+ * drivers/i2c/busses/i2c-mlxcpld.c
+ * Copyright (c) 2016 Mellanox Technologies. All rights reserved.
+ * Copyright (c) 2016 Michael Shych <michaels@xxxxxxxxxxxx>
+ *
+ * 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 /* usec */
+#define MLXCPLD_I2C_POLL_TIME 2000 /* usec */
+
+/* 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)
+ 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@xxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Mellanox I2C-CPLD controller driver");
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("platform:i2c-mlxcpld");
--
2.1.4