diff options
Diffstat (limited to 'drivers/net/sfc/i2c-direct.c')
| -rw-r--r-- | drivers/net/sfc/i2c-direct.c | 381 |
1 files changed, 0 insertions, 381 deletions
diff --git a/drivers/net/sfc/i2c-direct.c b/drivers/net/sfc/i2c-direct.c deleted file mode 100644 index b6c62d0..0000000 --- a/drivers/net/sfc/i2c-direct.c +++ /dev/null @@ -1,381 +0,0 @@ -/**************************************************************************** - * Driver for Solarflare Solarstorm network controllers and boards - * Copyright 2005 Fen Systems Ltd. - * Copyright 2006-2008 Solarflare Communications Inc. - * - * This program is free software; you can redistribute it and/or modify it - * under the terms of the GNU General Public License version 2 as published - * by the Free Software Foundation, incorporated herein by reference. - */ - -#include <linux/delay.h> -#include "net_driver.h" -#include "i2c-direct.h" - -/* - * I2C data (SDA) and clock (SCL) line read/writes with appropriate - * delays. - */ - -static inline void setsda(struct efx_i2c_interface *i2c, int state) -{ - udelay(i2c->op->udelay); - i2c->sda = state; - i2c->op->setsda(i2c); - udelay(i2c->op->udelay); -} - -static inline void setscl(struct efx_i2c_interface *i2c, int state) -{ - udelay(i2c->op->udelay); - i2c->scl = state; - i2c->op->setscl(i2c); - udelay(i2c->op->udelay); -} - -static inline int getsda(struct efx_i2c_interface *i2c) -{ - int sda; - - udelay(i2c->op->udelay); - sda = i2c->op->getsda(i2c); - udelay(i2c->op->udelay); - return sda; -} - -static inline int getscl(struct efx_i2c_interface *i2c) -{ - int scl; - - udelay(i2c->op->udelay); - scl = i2c->op->getscl(i2c); - udelay(i2c->op->udelay); - return scl; -} - -/* - * I2C low-level protocol operations - * - */ - -static inline void i2c_release(struct efx_i2c_interface *i2c) -{ - EFX_WARN_ON_PARANOID(!i2c->scl); - EFX_WARN_ON_PARANOID(!i2c->sda); - /* Devices may time out if operations do not end */ - setscl(i2c, 1); - setsda(i2c, 1); - EFX_BUG_ON_PARANOID(getsda(i2c) != 1); - EFX_BUG_ON_PARANOID(getscl(i2c) != 1); -} - -static inline void i2c_start(struct efx_i2c_interface *i2c) -{ - /* We may be restarting immediately after a {send,recv}_bit, - * so SCL will not necessarily already be high. - */ - EFX_WARN_ON_PARANOID(!i2c->sda); - setscl(i2c, 1); - setsda(i2c, 0); - setscl(i2c, 0); - setsda(i2c, 1); -} - -static inline void i2c_send_bit(struct efx_i2c_interface *i2c, int bit) -{ - EFX_WARN_ON_PARANOID(i2c->scl != 0); - setsda(i2c, bit); - setscl(i2c, 1); - setscl(i2c, 0); - setsda(i2c, 1); -} - -static inline int i2c_recv_bit(struct efx_i2c_interface *i2c) -{ - int bit; - - EFX_WARN_ON_PARANOID(i2c->scl != 0); - EFX_WARN_ON_PARANOID(!i2c->sda); - setscl(i2c, 1); - bit = getsda(i2c); - setscl(i2c, 0); - return bit; -} - -static inline void i2c_stop(struct efx_i2c_interface *i2c) -{ - EFX_WARN_ON_PARANOID(i2c->scl != 0); - setsda(i2c, 0); - setscl(i2c, 1); - setsda(i2c, 1); -} - -/* - * I2C mid-level protocol operations - * - */ - -/* Sends a byte via the I2C bus and checks for an acknowledgement from - * the slave device. - */ -static int i2c_send_byte(struct efx_i2c_interface *i2c, u8 byte) -{ - int i; - - /* Send byte */ - for (i = 0; i < 8; i++) { - i2c_send_bit(i2c, !!(byte & 0x80)); - byte <<= 1; - } - - /* Check for acknowledgement from slave */ - return (i2c_recv_bit(i2c) == 0 ? 0 : -EIO); -} - -/* Receives a byte via the I2C bus and sends ACK/NACK to the slave device. */ -static u8 i2c_recv_byte(struct efx_i2c_interface *i2c, int ack) -{ - u8 value = 0; - int i; - - /* Receive byte */ - for (i = 0; i < 8; i++) - value = (value << 1) | i2c_recv_bit(i2c); - - /* Send ACK/NACK */ - i2c_send_bit(i2c, (ack ? 0 : 1)); - - return value; -} - -/* Calculate command byte for a read operation */ -static inline u8 i2c_read_cmd(u8 device_id) -{ - return ((device_id << 1) | 1); -} - -/* Calculate command byte for a write operation */ -static inline u8 i2c_write_cmd(u8 device_id) -{ - return ((device_id << 1) | 0); -} - -int efx_i2c_check_presence(struct efx_i2c_interface *i2c, u8 device_id) -{ - int rc; - - /* If someone is driving the bus low we just give up. */ - if (getsda(i2c) == 0 || getscl(i2c) == 0) { - EFX_ERR(i2c->efx, "%s someone is holding the I2C bus low." - " Giving up.\n", __func__); - return -EFAULT; - } - - /* Pretend to initiate a device write */ - i2c_start(i2c); - rc = i2c_send_byte(i2c, i2c_write_cmd(device_id)); - if (rc) - goto out; - - out: - i2c_stop(i2c); - i2c_release(i2c); - - return rc; -} - -/* This performs a fast read of one or more consecutive bytes from an - * I2C device. Not all devices support consecutive reads of more than - * one byte; for these devices use efx_i2c_read() instead. - */ -int efx_i2c_fast_read(struct efx_i2c_interface *i2c, - u8 device_id, u8 offset, u8 *data, unsigned int len) -{ - int i; - int rc; - - EFX_WARN_ON_PARANOID(getsda(i2c) != 1); - EFX_WARN_ON_PARANOID(getscl(i2c) != 1); - EFX_WARN_ON_PARANOID(data == NULL); - EFX_WARN_ON_PARANOID(len < 1); - - /* Select device and starting offset */ - i2c_start(i2c); - rc = i2c_send_byte(i2c, i2c_write_cmd(device_id)); - if (rc) - goto out; - rc = i2c_send_byte(i2c, offset); - if (rc) - goto out; - - /* Read data from device */ - i2c_start(i2c); - rc = i2c_send_byte(i2c, i2c_read_cmd(device_id)); - if (rc) - goto out; - for (i = 0; i < (len - 1); i++) - /* Read and acknowledge all but the last byte */ - data[i] = i2c_recv_byte(i2c, 1); - /* Read last byte with no acknowledgement */ - data[i] = i2c_recv_byte(i2c, 0); - - out: - i2c_stop(i2c); - i2c_release(i2c); - - return rc; -} - -/* This performs a fast write of one or more consecutive bytes to an - * I2C device. Not all devices support consecutive writes of more - * than one byte; for these devices use efx_i2c_write() instead. - */ -int efx_i2c_fast_write(struct efx_i2c_interface *i2c, - u8 device_id, u8 offset, - const u8 *data, unsigned int len) -{ - int i; - int rc; - - EFX_WARN_ON_PARANOID(getsda(i2c) != 1); - EFX_WARN_ON_PARANOID(getscl(i2c) != 1); - EFX_WARN_ON_PARANOID(len < 1); - - /* Select device and starting offset */ - i2c_start(i2c); - rc = i2c_send_byte(i2c, i2c_write_cmd(device_id)); - if (rc) - goto out; - rc = i2c_send_byte(i2c, offset); - if (rc) - goto out; - - /* Write data to device */ - for (i = 0; i < len; i++) { - rc = i2c_send_byte(i2c, data[i]); - if (rc) - goto out; - } - - out: - i2c_stop(i2c); - i2c_release(i2c); - - return rc; -} - -/* I2C byte-by-byte read */ -int efx_i2c_read(struct efx_i2c_interface *i2c, - u8 device_id, u8 offset, u8 *data, unsigned int len) -{ - int rc; - - /* i2c_fast_read with length 1 is a single byte read */ - for (; len > 0; offset++, data++, len--) { - rc = efx_i2c_fast_read(i2c, device_id, offset, data, 1); - if (rc) - return rc; - } - - return 0; -} - -/* I2C byte-by-byte write */ -int efx_i2c_write(struct efx_i2c_interface *i2c, - u8 device_id, u8 offset, const u8 *data, unsigned int len) -{ - int rc; - - /* i2c_fast_write with length 1 is a single byte write */ - for (; len > 0; offset++, data++, len--) { - rc = efx_i2c_fast_write(i2c, device_id, offset, data, 1); - if (rc) - return rc; - mdelay(i2c->op->mdelay); - } - - return 0; -} - - -/* This is just a slightly neater wrapper round efx_i2c_fast_write - * in the case where the target doesn't take an offset - */ -int efx_i2c_send_bytes(struct efx_i2c_interface *i2c, - u8 device_id, const u8 *data, unsigned int len) -{ - return efx_i2c_fast_write(i2c, device_id, data[0], data + 1, len - 1); -} - -/* I2C receiving of bytes - does not send an offset byte */ -int efx_i2c_recv_bytes(struct efx_i2c_interface *i2c, u8 device_id, - u8 *bytes, unsigned int len) -{ - int i; - int rc; - - EFX_WARN_ON_PARANOID(getsda(i2c) != 1); - EFX_WARN_ON_PARANOID(getscl(i2c) != 1); - EFX_WARN_ON_PARANOID(len < 1); - - /* Select device */ - i2c_start(i2c); - - /* Read data from device */ - rc = i2c_send_byte(i2c, i2c_read_cmd(device_id)); - if (rc) - goto out; - - for (i = 0; i < (len - 1); i++) - /* Read and acknowledge all but the last byte */ - bytes[i] = i2c_recv_byte(i2c, 1); - /* Read last byte with no acknowledgement */ - bytes[i] = i2c_recv_byte(i2c, 0); - - out: - i2c_stop(i2c); - i2c_release(i2c); - - return rc; -} - -/* SMBus and some I2C devices will time out if the I2C clock is - * held low for too long. This is most likely to happen in virtualised - * systems (when the entire domain is descheduled) but could in - * principle happen due to preemption on any busy system (and given the - * potential length of an I2C operation turning preemption off is not - * a sensible option). The following functions deal with the failure by - * retrying up to a fixed number of times. - */ - -#define I2C_MAX_RETRIES (10) - -/* The timeout problem will result in -EIO. If the wrapped function - * returns any other error, pass this up and do not retry. */ -#define RETRY_WRAPPER(_f) \ - int retries = I2C_MAX_RETRIES; \ - int rc; \ - while (retries) { \ - rc = _f; \ - if (rc != -EIO) \ - return rc; \ - retries--; \ - } \ - return rc; \ - -int efx_i2c_check_presence_retry(struct efx_i2c_interface *i2c, u8 device_id) -{ - RETRY_WRAPPER(efx_i2c_check_presence(i2c, device_id)) -} - -int efx_i2c_read_retry(struct efx_i2c_interface *i2c, - u8 device_id, u8 offset, u8 *data, unsigned int len) -{ - RETRY_WRAPPER(efx_i2c_read(i2c, device_id, offset, data, len)) -} - -int efx_i2c_write_retry(struct efx_i2c_interface *i2c, - u8 device_id, u8 offset, const u8 *data, unsigned int len) -{ - RETRY_WRAPPER(efx_i2c_write(i2c, device_id, offset, data, len)) -} |