diff options
Diffstat (limited to 'drivers/i2c/busses')
| -rw-r--r-- | drivers/i2c/busses/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/i2c/busses/Makefile | 1 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-mlxcpld.c | 504 |
3 files changed, 516 insertions, 0 deletions
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index d252276feadf..6399ceab402b 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 29764cc20a44..645bf081bd6a 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 000000000000..d271e6a0954c --- /dev/null +++ b/drivers/i2c/busses/i2c-mlxcpld.c @@ -0,0 +1,504 @@ +/* + * 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 /* 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_xfer { + u8 cmd; + u8 addr_width; + u8 data_len; + u8 msg_num; + struct i2c_msg *msg; +}; + +struct mlxcpld_i2c_priv { + struct i2c_adapter adap; + u32 base_addr; + struct mutex lock; + struct mlxcpld_i2c_curr_xfer xfer; + struct device *dev; +}; + +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; + + for (i = 0; i < len - len % 4; i += 4) + *(u32 *)(data + i) = inl(addr + i); + for (; i < len; ++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 received i2c messages parameters. + * Returns 0 if OK, other - in case of invalid parameters. + */ +static int mlxcpld_i2c_check_msg_params(struct mlxcpld_i2c_priv *priv, + struct i2c_msg *msgs, int num) +{ + 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; + } + } + + 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 not more than 32 + * bytes in the 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 -ENXIO; + + 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 i, err; + + err = mlxcpld_i2c_check_msg_params(priv, msgs, num); + if (err) { + dev_err(priv->dev, "Incorrect message\n"); + return err; + } + + for (i = 0; i < num; ++i) + comm_len += msgs[i].len; + + /* 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_quirks mlxcpld_i2c_quirks = { + .flags = I2C_AQ_COMB_WRITE_THEN_READ, + .max_read_len = MLXCPLD_I2C_DATA_REG_SZ - MLXCPLD_I2C_MAX_ADDR_LEN, + .max_write_len = MLXCPLD_I2C_DATA_REG_SZ, + .max_comb_1st_msg_len = 4, +}; + +static struct i2c_adapter mlxcpld_i2c_adapter = { + .owner = THIS_MODULE, + .name = "i2c-mlxcpld", + .class = I2C_CLASS_HWMON | I2C_CLASS_SPD, + .algo = &mlxcpld_i2c_algo, + .quirks = &mlxcpld_i2c_quirks, + .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@mellanox.com>"); +MODULE_DESCRIPTION("Mellanox I2C-CPLD controller driver"); +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_ALIAS("platform:i2c-mlxcpld"); |