Hi! Some comments inline. Cheers, Peter On 2016-11-17 09:30, vadimp@xxxxxxxxxxxx wrote: > 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> > --- > v5->v6: > Comments pointed out by Vladimir: > - Drop the line with module path from the header; > - In description of mlxcpld_i2c_priv remove lpc_gen_dec_reg asnd dev_id; > - In mlxcpld_i2c_priv change type of the filed base_addr to u16 for > the alignment with in/out and remove unused dev_id; > - Fix misspelling in comment for mlxcpld_i2c_invalid_len; > - Remove comment regarding EBUSY return in mlxcpld_i2c_check_busy; > - Use sizeof of the target storage in allocation in probe routine; > 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 | 544 +++++++++++++++++++++++++++++++++++ > 5 files changed, 611 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 Grammar: "This is a <what> for Mellanox..."? > +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. lsb? Why is lsb in bit 7? Isn't bit 7 msb per definition? Are you referring to the fact that this bit is the lsb on-the-wire? I.e. are you trying to say that the fields in this register are reversed compared to the on-wire byte format? I assume so... > + Bits [6:0] - the 7bit Address of the I2C device. > + It should be written last as it triggers an I2C transaction. ...but it make me wonder if the byte is bit-reversed or if it is just fields that are out of order? Probably not, but, odd! > +NUM_DATA 0x7 - data size reg. > + Number of address bytes to write in read transaction s/address/data/ ??? > +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 s/address is send in/the address is sent in a/ > + specified in four first bytes (DATA0 - DATA3). Data is reading s/in four/in the four/ s/reading/read/ > + starting from DATA0. > diff --git a/MAINTAINERS b/MAINTAINERS > index 411e3b8..26d05f8 100644 > --- a/MAINTAINERS > +++ b/MAINTAINERS > @@ -7881,6 +7881,14 @@ 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..07d5657 > --- /dev/null > +++ b/drivers/i2c/busses/i2c-mlxcpld.c > @@ -0,0 +1,544 @@ > +/* > + * 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: "xfer" seems to be a more common abbreviation of "transfer". > + * @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 { Dito. > + u8 cmd; > + u8 addr_width; > + u8 data_len; > + u8 msg_num; > + struct i2c_msg *msg; > +}; > + > +/** > + * struct mlxcpld_i2c_priv - private controller data: > + * @adap: i2c adapter; > + * @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; > + u32 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); > +} I find the below easier to read (untested): static void mlxcpld_i2c_lpc_write_buf(u8 *data, u8 len, u32 addr) { int i; for (i = 0; i < len - len % 4; i += 4) outl(*(u32 *)(data + i), addr + i); for (; i < len; ++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); > +} Similar to the above, of course. > + > +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 common length of all i2c messages in transfer. > + */ Multiline comments should start with a /* on a line on its own, to form symmetry with the trailing */. > +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 > + */ Dito. > +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. > + */ Dito. > +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. > + */ Dito, and I see more below... > + *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. */ > +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(*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"); > -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
