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i2c: mv64xxx: add software delays 

As stated in Marvell's Functional Specifications in MV-S107021-U0 Rev. A
on page 420 ff. software delays are needed. "SW delay represent a delay
of at least 2 internal clock cycles". These delays are hereby
implemented.

The original kernel driver compensates the needed software delays with
the time the interrupts take.

Signed-off-by: Bastian Stender <bst@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Bastian Stender 2017-02-23 17:34:49 +01:00 committed by Sascha Hauer
parent 222078a38c
commit 8d38b5205c
1 changed files with 10 additions and 2 deletions
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12
drivers/i2c/busses/i2c-mv64xxx.c
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@ -270,6 +270,7 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
}
/* FALLTHRU */
case STATUS_MAST_RD_DATA_ACK: /* 0x50 */
udelay(2);
if (status != STATUS_MAST_RD_DATA_ACK)
drv_data->action = ACTION_CONTINUE;
else {
@ -280,6 +281,7 @@ mv64xxx_i2c_fsm(struct mv64xxx_i2c_data *drv_data, u32 status)
if (drv_data->bytes_left == 1)
drv_data->cntl_bits &= ~REG_CONTROL_ACK;
udelay(2);
break;
case STATUS_MAST_RD_DATA_NO_ACK: /* 0x58 */
@ -318,6 +320,8 @@ static void mv64xxx_i2c_send_start(struct mv64xxx_i2c_data *drv_data)
mv64xxx_i2c_prepare_for_io(drv_data, drv_data->msgs);
mv64xxx_write(drv_data, drv_data->cntl_bits | REG_CONTROL_START,
drv_data->reg_offsets.control);
udelay(2);
}
static void
@ -333,7 +337,7 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
mv64xxx_i2c_send_start(drv_data);
if (drv_data->errata_delay)
udelay(5);
udelay(3);
/*
* We're never at the start of the message here, and by this
@ -349,6 +353,7 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
break;
case ACTION_SEND_ADDR_1:
udelay(2);
mv64xxx_write(drv_data, drv_data->addr1,
drv_data->reg_offsets.data);
mv64xxx_write(drv_data, drv_data->cntl_bits,
@ -360,9 +365,11 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
drv_data->reg_offsets.data);
mv64xxx_write(drv_data, drv_data->cntl_bits,
drv_data->reg_offsets.control);
udelay(2);
break;
case ACTION_SEND_DATA:
udelay(2);
mv64xxx_write(drv_data, drv_data->msg->buf[drv_data->byte_posn++],
drv_data->reg_offsets.data);
mv64xxx_write(drv_data, drv_data->cntl_bits,
@ -383,8 +390,9 @@ mv64xxx_i2c_do_action(struct mv64xxx_i2c_data *drv_data)
mv64xxx_write(drv_data, drv_data->cntl_bits | REG_CONTROL_STOP,
drv_data->reg_offsets.control);
drv_data->block = false;
udelay(2);
if (drv_data->errata_delay)
udelay(5);
udelay(3);
break;