From: Jean Delvare Date: Tue, 11 Oct 2016 11:13:27 +0000 (+0200) Subject: i2c: i801: Fix I2C Block Read on 8-Series/C220 and later X-Git-Tag: v4.9-rc3~27^2~2 X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=ba9ad2af7019956b990ad654c56da5bac1e8b71b i2c: i801: Fix I2C Block Read on 8-Series/C220 and later Starting with the 8-Series/C220 PCH (Lynx Point), the SMBus controller includes a SPD EEPROM protection mechanism. Once the SPD Write Disable bit is set, only reads are allowed to slave addresses 0x50-0x57. However the legacy implementation of I2C Block Read since the ICH5 looks like a write, and is therefore blocked by the SPD protection mechanism. This causes the eeprom and at24 drivers to fail. So assume that I2C Block Read is implemented as an actual read on these chipsets. I tested it on my Q87 chipset and it seems to work just fine. Signed-off-by: Jean Delvare Tested-by: Jarkko Nikula [wsa: rebased to v4.9-rc2] Signed-off-by: Wolfram Sang --- diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index 08847e8b8998..eb3627f35d12 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -146,6 +146,7 @@ #define SMBHSTCFG_HST_EN 1 #define SMBHSTCFG_SMB_SMI_EN 2 #define SMBHSTCFG_I2C_EN 4 +#define SMBHSTCFG_SPD_WD 0x10 /* TCO configuration bits for TCOCTL */ #define TCOCTL_EN 0x0100 @@ -865,9 +866,16 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr, block = 1; break; case I2C_SMBUS_I2C_BLOCK_DATA: - /* NB: page 240 of ICH5 datasheet shows that the R/#W - * bit should be cleared here, even when reading */ - outb_p((addr & 0x7f) << 1, SMBHSTADD(priv)); + /* + * NB: page 240 of ICH5 datasheet shows that the R/#W + * bit should be cleared here, even when reading. + * However if SPD Write Disable is set (Lynx Point and later), + * the read will fail if we don't set the R/#W bit. + */ + outb_p(((addr & 0x7f) << 1) | + ((priv->original_hstcfg & SMBHSTCFG_SPD_WD) ? + (read_write & 0x01) : 0), + SMBHSTADD(priv)); if (read_write == I2C_SMBUS_READ) { /* NB: page 240 of ICH5 datasheet also shows * that DATA1 is the cmd field when reading */ @@ -1573,6 +1581,8 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id) /* Disable SMBus interrupt feature if SMBus using SMI# */ priv->features &= ~FEATURE_IRQ; } + if (temp & SMBHSTCFG_SPD_WD) + dev_info(&dev->dev, "SPD Write Disable is set\n"); /* Clear special mode bits */ if (priv->features & (FEATURE_SMBUS_PEC | FEATURE_BLOCK_BUFFER))