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sfc: SFN4111T: Fix GPIO sharing between I2C and FLASH_CFG_1

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Change sfn4111t_reset() to change only GPIO output enables so that it
doesn't break subsequent I2C operations.

Update comments to explain exactly what we're doing.

Add a short sleep to make sure the FLASH_CFG_1 value is latched before
any subsequent I2C operations.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Ben Hutchings 2009-01-29 17:49:29 +00:00 committed by David S. Miller
parent 8b9dc8dd44
commit 2f08575389
1 changed files with 9 additions and 6 deletions
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15
drivers/net/sfc/sfe4001.c
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@ -186,19 +186,22 @@ static int sfn4111t_reset(struct efx_nic *efx)
{
efx_oword_t reg;
/* GPIO pins are also used for I2C, so block that temporarily */
/* GPIO 3 and the GPIO register are shared with I2C, so block that */
mutex_lock(&efx->i2c_adap.bus_lock);
/* Pull RST_N (GPIO 2) low then let it up again, setting the
* FLASH_CFG_1 strap (GPIO 3) appropriately. Only change the
* output enables; the output levels should always be 0 (low)
* and we rely on external pull-ups. */
falcon_read(efx, &reg, GPIO_CTL_REG_KER);
EFX_SET_OWORD_FIELD(reg, GPIO2_OEN, true);
EFX_SET_OWORD_FIELD(reg, GPIO2_OUT, false);
falcon_write(efx, &reg, GPIO_CTL_REG_KER);
msleep(1000);
EFX_SET_OWORD_FIELD(reg, GPIO2_OUT, true);
EFX_SET_OWORD_FIELD(reg, GPIO3_OEN, true);
EFX_SET_OWORD_FIELD(reg, GPIO3_OUT,
!(efx->phy_mode & PHY_MODE_SPECIAL));
EFX_SET_OWORD_FIELD(reg, GPIO2_OEN, false);
EFX_SET_OWORD_FIELD(reg, GPIO3_OEN,
!!(efx->phy_mode & PHY_MODE_SPECIAL));
falcon_write(efx, &reg, GPIO_CTL_REG_KER);
msleep(1);
mutex_unlock(&efx->i2c_adap.bus_lock);