[PATCH] i2c: designware: fix slave not acknowledge when address matched

[<liao.zenghui@zte.com.cn>]

From: liao zenghui <liao.zenghui@zte.com.cn>

According to Chapter 5.1.31 of the databook "DesignWare DW_apb_i2c
Databook (2.03a)", the bit[19] of the IC_ENABLE register defaults to
one when the configuration parameter of the controller is
"IC_MULTI_SAR_EN == 1". This bit controls whether the slave send
acknowledge signal to the master after an address match. Because
setting the IC_ENABLE register using "1" and "0" directly in function
"__i2c_dw_enabl" and function "__i2c_dw_disable_nowait", results in the
bit[19] of this register being zero, no acknowledge signal is generated
when address matched.
Therefore, the two functions are modified.Restore the reset value of the
IC_ENABLE register in the function "__i2c_dw_disable_nowait". Only
bit[0] is set in the function "__i2c_dw_enable" and the other bits
remain unchanged. In addition, the code for determining whether the i2c
controller is enabled using the value of the IC_ENABLE register is
modified. Otherwise, when "C_MULTI_SAR_EN==1" and the bit[19] of the
IC_ENABLE register is 1, the determination of the variable "enable"
will be not work.

Signed-off-by: liao zenghui <liao.zenghui@zte.com.cn>
---
drivers/i2c/busses/i2c-designware-core.h | 13 +++++++++++--
drivers/i2c/busses/i2c-designware-master.c | 2 +-
drivers/i2c/busses/i2c-designware-slave.c | 3 ++-
3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 050d8c63ad3c..49b2f8819952 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -113,6 +113,9 @@
#define DW_IC_STATUS_MASTER_ACTIVITY BIT(5)
#define DW_IC_STATUS_SLAVE_ACTIVITY BIT(6)

+#define DW_IC_ENABLE_ENABLE BIT(0)
+#define DW_IC_ENABLE_SAR_EN BIT(19)
+
#define DW_IC_SDA_HOLD_RX_SHIFT 16
#define DW_IC_SDA_HOLD_RX_MASK GENMASK(23, 16)

@@ -333,13 +336,19 @@ void i2c_dw_disable(struct dw_i2c_dev *dev);

static inline void __i2c_dw_enable(struct dw_i2c_dev *dev)
{
+ u32 enabled;
+
dev->status |= STATUS_ACTIVE;
- regmap_write(dev->map, DW_IC_ENABLE, 1);
+ regmap_read(dev->map, DW_IC_ENABLE, &enabled);
+ regmap_write(dev->map, DW_IC_ENABLE, enabled | DW_IC_ENABLE_ENABLE);
}

static inline void __i2c_dw_disable_nowait(struct dw_i2c_dev *dev)
{
- regmap_write(dev->map, DW_IC_ENABLE, 0);
+ u32 enabled;
+
+ regmap_read(dev->map, DW_IC_ENABLE, &enabled);
+ regmap_write(dev->map, DW_IC_ENABLE, enabled & DW_IC_ENABLE_SAR_EN);
dev->status &= ~STATUS_ACTIVE;
}

diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index 55ea91a63382..f2cc25f1c3c7 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -719,7 +719,7 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)

regmap_read(dev->map, DW_IC_ENABLE, &enabled);
regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &stat);
- if (!enabled || !(stat & ~DW_IC_INTR_ACTIVITY))
+ if (!(enabled & DW_IC_ENABLE_ENABLE) || !(stat & ~DW_IC_INTR_ACTIVITY))
return IRQ_NONE;
if (pm_runtime_suspended(dev->dev) || stat == GENMASK(31, 0))
return IRQ_NONE;
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index cec25054bb24..0da1e0291001 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -158,7 +158,8 @@ static irqreturn_t i2c_dw_isr_slave(int this_irq, void *dev_id)
regmap_read(dev->map, DW_IC_STATUS, &tmp);
slave_activity = ((tmp & DW_IC_STATUS_SLAVE_ACTIVITY) >> 6);

- if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY) || !dev->slave)
+ if (!(enabled & DW_IC_ENABLE_ENABLE) ||
+ !(raw_stat & ~DW_IC_INTR_ACTIVITY) || !dev->slave)
return IRQ_NONE;

stat = i2c_dw_read_clear_intrbits_slave(dev);
--
2.25.1