i2c: designware: Move SDA hold time configuration to common code

SDA hold time configuration is common to both master and slave code. It
is also something that can be done once during probe and do only
register write when HW needs to be reinitialized.

Remove duplication and move SDA hold time configuration to common code.
It will be called from slave probe and for master code from a new
i2c_dw_set_timings_master() to where we will populate more probe time
timing parameter setting.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-designware-common.c b/drivers/i2c/busses/i2c-designware-common.c
index 59156046f2d0afeeff1fd58d8037e5c0221f51cf..6f1c773c0417684ddca9ec90a4271a329af1777c 100644 (file)
--- a/drivers/i2c/busses/i2c-designware-common.c
+++ b/drivers/i2c/busses/i2c-designware-common.c
@@ -184,6 +184,43 @@ u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset)
        return ((ic_clk * (tLOW + tf) + 500000) / 1000000) - 1 + offset;
 }
 
+int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev)
+{
+       u32 reg;
+       int ret;
+
+       ret = i2c_dw_acquire_lock(dev);
+       if (ret)
+               return ret;
+
+       /* 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;
+       } else if (dev->sda_hold_time) {
+               dev_warn(dev->dev,
+                       "Hardware too old to adjust SDA hold time.\n");
+               dev->sda_hold_time = 0;
+       }
+
+       i2c_dw_release_lock(dev);
+
+       return 0;
+}
+
 void __i2c_dw_disable(struct dw_i2c_dev *dev)
 {
        int timeout = 100;

diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 5d54f70710adf323fc77dabd60f0906fb6d47b10..29b92f05bb2b08a938e7fb8bce2675892e345983 100644 (file)
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -298,6 +298,7 @@ void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset);
 int i2c_dw_set_reg_access(struct dw_i2c_dev *dev);
 u32 i2c_dw_scl_hcnt(u32 ic_clk, u32 tSYMBOL, u32 tf, int cond, int offset);
 u32 i2c_dw_scl_lcnt(u32 ic_clk, u32 tLOW, u32 tf, int offset);
+int i2c_dw_set_sda_hold(struct dw_i2c_dev *dev);
 unsigned long i2c_dw_clk_rate(struct dw_i2c_dev *dev);
 int i2c_dw_prepare_clk(struct dw_i2c_dev *dev, bool prepare);
 int i2c_dw_acquire_lock(struct dw_i2c_dev *dev);

diff --git a/drivers/i2c/busses/i2c-designware-master.c b/drivers/i2c/busses/i2c-designware-master.c
index cb3ac1f39cb67c9c17c20a8a71068dbe8405f6f9..6b64e3d01fd9b521cb4a64e6c9f666879ce2012d 100644 (file)
--- a/drivers/i2c/busses/i2c-designware-master.c
+++ b/drivers/i2c/busses/i2c-designware-master.c
@@ -45,6 +45,11 @@ static void i2c_dw_configure_fifo_master(struct dw_i2c_dev *dev)
        dw_writel(dev, dev->master_cfg, DW_IC_CON);
 }
 
+static int i2c_dw_set_timings_master(struct dw_i2c_dev *dev)
+{
+       return i2c_dw_set_sda_hold(dev);
+}
+
 /**
  * i2c_dw_init() - Initialize the designware I2C master hardware
  * @dev: device private data
@@ -57,7 +62,7 @@ static int i2c_dw_init_master(struct dw_i2c_dev *dev)
 {
        u32 ic_clk = i2c_dw_clk_rate(dev);
        u32 hcnt, lcnt;
-       u32 reg, comp_param1;
+       u32 comp_param1;
        u32 sda_falling_time, scl_falling_time;
        int ret;
 
@@ -133,27 +138,9 @@ 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;
+       /* Write SDA hold time if supported */
+       if (dev->sda_hold_time)
                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_configure_fifo_master(dev);
        i2c_dw_release_lock(dev);
@@ -672,6 +659,10 @@ int i2c_dw_probe(struct dw_i2c_dev *dev)
        if (ret)
                return ret;
 
+       ret = i2c_dw_set_timings_master(dev);
+       if (ret)
+               return ret;
+
        ret = dev->init(dev);
        if (ret)
                return ret;

diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index a1f802001e1f45c0f46a2339f62d4d1b1444b8f4..8af4c978938e79a13d37cd9c5f4ae1755b53271b 100644 (file)
--- a/drivers/i2c/busses/i2c-designware-slave.c
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -51,7 +51,6 @@ static void i2c_dw_configure_fifo_slave(struct dw_i2c_dev *dev)
  */
 static int i2c_dw_init_slave(struct dw_i2c_dev *dev)
 {
-       u32 reg;
        int ret;
 
        ret = i2c_dw_acquire_lock(dev);
@@ -61,27 +60,9 @@ 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;
+       /* Write SDA hold time if supported */
+       if (dev->sda_hold_time)
                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_configure_fifo_slave(dev);
        i2c_dw_release_lock(dev);
@@ -287,6 +268,10 @@ int i2c_dw_probe_slave(struct dw_i2c_dev *dev)
        if (ret)
                return ret;
 
+       ret = i2c_dw_set_sda_hold(dev);
+       if (ret)
+               return ret;
+
        ret = dev->init(dev);
        if (ret)
                return ret;