From 1b2dbfa2cd6e49362a93451320b9f1cee6021514 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Sat, 26 Jun 2004 09:43:15 +0000 Subject: [PATCH] Implement read error handling (backport from 2.6). git-svn-id: http://lm-sensors.org/svn/lm-sensors/trunk@2610 7894878c-1315-0410-8ee3-d5d059ff63e0 --- kernel/chips/w83l785ts.c | 47 ++++++++++++++++++++++++++++++++++------ 1 file changed, 40 insertions(+), 7 deletions(-) diff --git a/kernel/chips/w83l785ts.c b/kernel/chips/w83l785ts.c index a8afa9a1..fdd32719 100644 --- a/kernel/chips/w83l785ts.c +++ b/kernel/chips/w83l785ts.c @@ -9,6 +9,9 @@ * Winbond's website at: * http://www.winbond-usa.com/products/winbond_products/pdfs/PCIC/W83L785TS-S.pdf * + * Thanks to James Bolt for benchmarking the read + * error handling mechanism. + * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or @@ -29,12 +32,16 @@ #include #include #include +#include #include "version.h" #ifndef I2C_DRIVERID_W83L785TS #define I2C_DRIVERID_W83L785TS 1047 #endif +/* How many retries on register read error */ +#define MAX_RETRIES 5 + /* * Address to scan * Address is fully defined internally and cannot be changed. @@ -79,6 +86,7 @@ static int w83l785ts_attach_adapter(struct i2c_adapter *adapter); static int w83l785ts_detect(struct i2c_adapter *adapter, int address, unsigned short flags, int kind); static int w83l785ts_detach_client(struct i2c_client *client); +static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval); static void w83l785ts_update_client(struct i2c_client *client); static void w83l785ts_temp(struct i2c_client *client, int operation, int ctl_name, int *nrels_mag, long *results); @@ -199,8 +207,10 @@ static int w83l785ts_detect(struct i2c_adapter *adapter, int address, */ if (kind < 0) { /* detection */ - if (((i2c_smbus_read_byte_data(new_client, W83L785TS_REG_CONFIG) & 0x80) != 0x00) - || ((i2c_smbus_read_byte_data(new_client, W83L785TS_REG_TYPE) & 0xFC) != 0x00)) { + if (((w83l785ts_read_value(new_client, W83L785TS_REG_CONFIG, 0) + & 0x80) != 0x00) + || ((w83l785ts_read_value(new_client, W83L785TS_REG_TYPE, 0) + & 0xFC) != 0x00)) { #ifdef DEBUG printk(KERN_DEBUG "w83l785ts.o: Detection failed at " "0x%02x.\n", address); @@ -213,9 +223,9 @@ static int w83l785ts_detect(struct i2c_adapter *adapter, int address, u16 man_id; u8 chip_id; - man_id = (i2c_smbus_read_byte_data(new_client, W83L785TS_REG_MAN_ID1) << 8) - + i2c_smbus_read_byte_data(new_client, W83L785TS_REG_MAN_ID2); - chip_id = i2c_smbus_read_byte_data(new_client, W83L785TS_REG_CHIP_ID); + man_id = (w83l785ts_read_value(new_client, W83L785TS_REG_MAN_ID1, 0) << 8) + + w83l785ts_read_value(new_client, W83L785TS_REG_MAN_ID2, 0); + chip_id = w83l785ts_read_value(new_client, W83L785TS_REG_CHIP_ID, 0); if (man_id == 0x5CA3) { /* Winbond */ if (chip_id == 0x70) kind = w83l785ts; @@ -299,6 +309,27 @@ static int w83l785ts_detach_client(struct i2c_client *client) return 0; } +static u8 w83l785ts_read_value(struct i2c_client *client, u8 reg, u8 defval) +{ + int value, i; + + /* Frequent read errors have been reported on Asus boards, so we + * retry on read errors. If it still fails (unlikely), return the + * default value requested by the caller. */ + for (i = 1; i <= MAX_RETRIES; i++) { + value = i2c_smbus_read_byte_data(client, reg); + if (value >= 0) + return value; + printk(KERN_WARNING "w83l785ts.o: Read failed, will retry " + "in %d.\n", i); + mdelay(i); + } + + printk(KERN_ERR "w83l785ts.o: Couldn't read value from register. " + "Please report.\n"); + return defval; +} + static void w83l785ts_update_client(struct i2c_client *client) { struct w83l785ts_data *data = client->data; @@ -311,8 +342,10 @@ static void w83l785ts_update_client(struct i2c_client *client) #ifdef DEBUG printk(KERN_DEBUG "w83l785ts.o: Updating data.\n"); #endif - data->temp = i2c_smbus_read_byte_data(client, W83L785TS_REG_TEMP); - data->temp_over = i2c_smbus_read_byte_data(client, W83L785TS_REG_TEMP_OVER); + data->temp = w83l785ts_read_value(client, W83L785TS_REG_TEMP, + data->temp); + data->temp_over = w83l785ts_read_value(client, + W83L785TS_REG_TEMP_OVER, data->temp_over); data->last_updated = jiffies; data->valid = 1; }