[PATCH 3/6] mfd: 88pm860x: enhance lock on i2c transaction

Haojian Zhuang
2011-05-06T09:30:29Z

Accessing test page in 88pm860x is a sequence of read/write on i2c bus.
Bus lock is used in each small i2c transaction. But it may result the
whole sequence interrupted by other i2c client transaction.

Use i2c_lock_adapter()/i2c_unlock_adapter() to protect the sequence and
use master_xfer() to send i2c message.

Signed-off-by: Haojian Zhuang <haojian.zhuang@marvell.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Jean Delvare <khali@linux-fr.org>
Cc: Ben Dooks <ben-linux@fluff.org>
---
drivers/mfd/88pm860x-i2c.c | 112 +++++++++++++++++++++++++++++++------------
1 files changed, 81 insertions(+), 31 deletions(-)

diff --git a/drivers/mfd/88pm860x-i2c.c b/drivers/mfd/88pm860x-i2c.c
index e017dc8..67a34f4 100644
--- a/drivers/mfd/88pm860x-i2c.c
+++ b/drivers/mfd/88pm860x-i2c.c
@@ -126,6 +126,51 @@ out:
}
EXPORT_SYMBOL(pm860x_set_bits);

+static int read_device(struct i2c_client *i2c, int reg,
+ int bytes, void *dest)
+{
+ unsigned char msgbuf0[I2C_SMBUS_BLOCK_MAX + 3];
+ unsigned char msgbuf1[I2C_SMBUS_BLOCK_MAX + 2];
+ struct i2c_adapter *adap = i2c->adapter;
+ struct i2c_msg msg[2] = {{i2c->addr, i2c->flags, 1, msgbuf0},
+ {i2c->addr, i2c->flags | I2C_M_RD, 0, msgbuf1},
+ };
+ int num = 1, ret = 0;
+
+ if (dest == NULL)
+ return -EINVAL;
+ msgbuf0[0] = (unsigned char)reg; /* command */
+ msg[1].len = bytes;
+
+ /* if data needs to read back, num should be 2 */
+ if (bytes > 0)
+ num = 2;
+ ret = adap->algo->master_xfer(adap, msg, num);
+ memcpy(dest, msgbuf1, bytes);
+ return ret;
+}
+
+static int write_device(struct i2c_client *i2c, int reg,
+ int bytes, void *src)
+{
+ unsigned char buf[bytes + 1];
+ struct i2c_adapter *adap = i2c->adapter;
+ struct i2c_msg msg;
+ int ret;
+
+ buf[0] = (unsigned char)reg;
+ memcpy(&buf[1], src, bytes);
+ msg.addr = i2c->addr;
+ msg.flags = i2c->flags;
+ msg.len = bytes + 1;
+ msg.buf = buf;
+
+ ret = adap->algo->master_xfer(adap, &msg, 1);
+ if (ret < 0)
+ return ret;
+ return 0;
+}
+
int pm860x_page_reg_read(struct i2c_client *i2c, int reg)
{
struct pm860x_chip *chip = i2c_get_clientdata(i2c);
@@ -134,14 +179,15 @@ int pm860x_page_reg_read(struct i2c_client *i2c, int reg)
int ret;

mutex_lock(&chip->io_lock);
- pm860x_write_device(i2c, 0xFA, 0, &zero);
- pm860x_write_device(i2c, 0xFB, 0, &zero);
- pm860x_write_device(i2c, 0xFF, 0, &zero);
- ret = pm860x_read_device(i2c, reg, 1, &data);
+ i2c_lock_adapter(i2c->adapter);
+ read_device(i2c, 0xFA, 0, &zero);
+ read_device(i2c, 0xFB, 0, &zero);
+ read_device(i2c, 0xFF, 0, &zero);
+ ret = read_device(i2c, reg, 1, &data);
if (ret >= 0)
ret = (int)data;
- pm860x_write_device(i2c, 0xFE, 0, &zero);
- pm860x_write_device(i2c, 0xFC, 0, &zero);
+ read_device(i2c, 0xFC, 0, &zero);
+ i2c_unlock_adapter(i2c->adapter);
mutex_unlock(&chip->io_lock);
return ret;
}
@@ -155,12 +201,13 @@ int pm860x_page_reg_write(struct i2c_client *i2c, int reg,
int ret;

mutex_lock(&chip->io_lock);
- pm860x_write_device(i2c, 0xFA, 0, &zero);
- pm860x_write_device(i2c, 0xFB, 0, &zero);
- pm860x_write_device(i2c, 0xFF, 0, &zero);
- ret = pm860x_write_device(i2c, reg, 1, &data);
- pm860x_write_device(i2c, 0xFE, 0, &zero);
- pm860x_write_device(i2c, 0xFC, 0, &zero);
+ i2c_lock_adapter(i2c->adapter);
+ read_device(i2c, 0xFA, 0, &zero);
+ read_device(i2c, 0xFB, 0, &zero);
+ read_device(i2c, 0xFF, 0, &zero);
+ ret = write_device(i2c, reg, 1, &data);
+ read_device(i2c, 0xFC, 0, &zero);
+ i2c_unlock_adapter(i2c->adapter);
mutex_unlock(&chip->io_lock);
return ret;
}
@@ -174,12 +221,13 @@ int pm860x_page_bulk_read(struct i2c_client *i2c, int reg,
int ret;

mutex_lock(&chip->io_lock);
- pm860x_write_device(i2c, 0xFA, 0, &zero);
- pm860x_write_device(i2c, 0xFB, 0, &zero);
- pm860x_write_device(i2c, 0xFF, 0, &zero);
- ret = pm860x_read_device(i2c, reg, count, buf);
- pm860x_write_device(i2c, 0xFE, 0, &zero);
- pm860x_write_device(i2c, 0xFC, 0, &zero);
+ i2c_lock_adapter(i2c->adapter);
+ read_device(i2c, 0xFA, 0, &zero);
+ read_device(i2c, 0xFB, 0, &zero);
+ read_device(i2c, 0xFF, 0, &zero);
+ ret = read_device(i2c, reg, count, buf);
+ read_device(i2c, 0xFC, 0, &zero);
+ i2c_unlock_adapter(i2c->adapter);
mutex_unlock(&chip->io_lock);
return ret;
}
@@ -193,12 +241,13 @@ int pm860x_page_bulk_write(struct i2c_client *i2c, int reg,
int ret;

mutex_lock(&chip->io_lock);
- pm860x_write_device(i2c, 0xFA, 0, &zero);
- pm860x_write_device(i2c, 0xFB, 0, &zero);
- pm860x_write_device(i2c, 0xFF, 0, &zero);
- ret = pm860x_write_device(i2c, reg, count, buf);
- pm860x_write_device(i2c, 0xFE, 0, &zero);
- pm860x_write_device(i2c, 0xFC, 0, &zero);
+ i2c_lock_adapter(i2c->adapter);
+ read_device(i2c, 0xFA, 0, &zero);
+ read_device(i2c, 0xFB, 0, &zero);
+ read_device(i2c, 0xFF, 0, &zero);
+ ret = write_device(i2c, reg, count, buf);
+ read_device(i2c, 0xFC, 0, &zero);
+ i2c_unlock_adapter(i2c->adapter);
mutex_unlock(&chip->io_lock);
return ret;
}
@@ -213,18 +262,19 @@ int pm860x_page_set_bits(struct i2c_client *i2c, int reg,
int ret;

mutex_lock(&chip->io_lock);
- pm860x_write_device(i2c, 0xFA, 0, &zero);
- pm860x_write_device(i2c, 0xFB, 0, &zero);
- pm860x_write_device(i2c, 0xFF, 0, &zero);
- ret = pm860x_read_device(i2c, reg, 1, &value);
+ i2c_lock_adapter(i2c->adapter);
+ read_device(i2c, 0xFA, 0, &zero);
+ read_device(i2c, 0xFB, 0, &zero);
+ read_device(i2c, 0xFF, 0, &zero);
+ ret = read_device(i2c, reg, 1, &value);
if (ret < 0)
goto out;
value &= ~mask;
value |= data;
- ret = pm860x_write_device(i2c, reg, 1, &value);
+ ret = write_device(i2c, reg, 1, &value);
out:
- pm860x_write_device(i2c, 0xFE, 0, &zero);
- pm860x_write_device(i2c, 0xFC, 0, &zero);
+ read_device(i2c, 0xFC, 0, &zero);
+ i2c_unlock_adapter(i2c->adapter);
mutex_unlock(&chip->io_lock);
return ret;
}
--
1.5.6.5