[PATCH 1/5] i2c: designware: factorize setting SDA hold time
From: Alexandre Belloni <alexandre.belloni@bootlin.com>
Date: 2018-07-17 11:49:11
Also in:
linux-i2c, linux-mips, lkml
Subsystem:
i2c subsystem, i2c subsystem host drivers, synopsys designware i2c driver, the rest · Maintainers:
Andi Shyti, Mika Westerberg, Linus Torvalds
Factorize setting the SDA hold time in a new function
i2c_dw_set_sda_hold_time() that is used for both master and slave mode.
This conveniently pulls the fix for the spurious warning from commit
7a20e707aae2 ("i2c: designware: suppress unneeded SDA hold time warnings")
in slave mode.
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
drivers/i2c/busses/i2c-designware-common.c | 27 ++++++++++++++++++++++
drivers/i2c/busses/i2c-designware-core.h | 1 +
drivers/i2c/busses/i2c-designware-master.c | 22 +-----------------
drivers/i2c/busses/i2c-designware-slave.c | 22 +-----------------
4 files changed, 30 insertions(+), 42 deletions(-)
diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index 48914dfc8ce8..9afc3e075b33 100644
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c@@ -293,5 +293,32 @@ u32 i2c_dw_read_comp_param(struct dw_i2c_dev *dev) } EXPORT_SYMBOL_GPL(i2c_dw_read_comp_param); +void i2c_dw_set_sda_hold_time(struct dw_i2c_dev *dev) +{ + u32 reg; + + /* Configure SDA Hold Time if required. */ + reg = dw_readl(dev, DW_IC_COMP_VERSION); + if (reg >= DW_IC_SDA_HOLD_MIN_VERS) { + if (!dev->sda_hold_time) { + /* Keep previous hold time setting if no one set it. */ + dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD); + } + /* + * Workaround for avoiding TX arbitration lost in case I2C + * slave pulls SDA down "too quickly" after falling egde of + * SCL by enabling non-zero SDA RX hold. Specification says it + * extends incoming SDA low to high transition while SCL is + * high but it apprears to help also above issue. + */ + if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK)) + dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT; + dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD); + } else if (dev->sda_hold_time) { + dev_warn(dev->dev, + "Hardware too old to adjust SDA hold time.\n"); + } +} + MODULE_DESCRIPTION("Synopsys DesignWare I2C bus adapter core"); MODULE_LICENSE("GPL");
diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index d690e648bc01..bc43fb9ac1cf 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h@@ -306,6 +306,7 @@ int i2c_dw_handle_tx_abort(struct dw_i2c_dev *dev); u32 i2c_dw_func(struct i2c_adapter *adap); void i2c_dw_disable(struct dw_i2c_dev *dev); void i2c_dw_disable_int(struct dw_i2c_dev *dev); +void i2c_dw_set_sda_hold_time(struct dw_i2c_dev *dev); static inline void __i2c_dw_enable(struct dw_i2c_dev *dev) {
diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index 27436a937492..826329f8e30b 100644
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c@@ -146,27 +146,7 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev) } } - /* Configure SDA Hold Time if required */ - reg = dw_readl(dev, DW_IC_COMP_VERSION); - if (reg >= DW_IC_SDA_HOLD_MIN_VERS) { - if (!dev->sda_hold_time) { - /* Keep previous hold time setting if no one set it */ - dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD); - } - /* - * Workaround for avoiding TX arbitration lost in case I2C - * slave pulls SDA down "too quickly" after falling egde of - * SCL by enabling non-zero SDA RX hold. Specification says it - * extends incoming SDA low to high transition while SCL is - * high but it apprears to help also above issue. - */ - if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK)) - dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT; - dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD); - } else if (dev->sda_hold_time) { - dev_warn(dev->dev, - "Hardware too old to adjust SDA hold time.\n"); - } + i2c_dw_set_sda_hold_time(dev); i2c_dw_configure_fifo_master(dev); i2c_dw_release_lock(dev);
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 8ce2cd368477..150e5edb064c 100644
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c@@ -77,27 +77,7 @@ static int i2c_dw_init_slave(struct dw_i2c_dev *dev) /* Disable the adapter. */ __i2c_dw_disable(dev); - /* Configure SDA Hold Time if required. */ - reg = dw_readl(dev, DW_IC_COMP_VERSION); - if (reg >= DW_IC_SDA_HOLD_MIN_VERS) { - if (!dev->sda_hold_time) { - /* Keep previous hold time setting if no one set it. */ - dev->sda_hold_time = dw_readl(dev, DW_IC_SDA_HOLD); - } - /* - * Workaround for avoiding TX arbitration lost in case I2C - * slave pulls SDA down "too quickly" after falling egde of - * SCL by enabling non-zero SDA RX hold. Specification says it - * extends incoming SDA low to high transition while SCL is - * high but it apprears to help also above issue. - */ - if (!(dev->sda_hold_time & DW_IC_SDA_HOLD_RX_MASK)) - dev->sda_hold_time |= 1 << DW_IC_SDA_HOLD_RX_SHIFT; - dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD); - } else { - dev_warn(dev->dev, - "Hardware too old to adjust SDA hold time.\n"); - } + i2c_dw_set_sda_hold_time(dev); i2c_dw_configure_fifo_slave(dev); i2c_dw_release_lock(dev);
--
2.18.0