Intelligent Plaform Management Interface (IPMI) requires I2C driver
to support block read, where the first byte received from slave is
the length of following data:-
Added length check if the read type is block read (I2C_M_RECV_LEN)
Send NACK/STOP bits before last byte is received
Signed-off-by: Garrett Ding <g-d...@ti.com>
Signed-off-by: Murali Karicheri <m-kariche...@ti.com>
Tested-by: Garrett Ding <g-d...@ti.com>
CC: Sekhar Nori <nsek...@ti.com>
CC: Kevin Hilman <khil...@deeprootsystems.com>
CC: Wolfram Sang <w...@the-dreams.de>
CC: Santosh Shilimkar <santosh.shilim...@ti.com>
---
Tested on a customer board based on K2HK SoC
drivers/i2c/busses/i2c-davinci.c | 42 +++++++++++++++++++++++++++++++++-----
1 file changed, 37 insertions(+), 5 deletions(-)
diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index 389bc68..cd97920 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -97,6 +97,10 @@
#define DAVINCI_I2C_IMR_NACK BIT(1)
#define DAVINCI_I2C_IMR_AL BIT(0)
+/* capabilities */
+#define I2C_CAPABILITIES (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | \
+ I2C_FUNC_SMBUS_READ_BLOCK_DATA)
+
struct davinci_i2c_dev {
struct device *dev;
void __iomem *base;
@@ -318,7 +322,13 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct
i2c_msg *msg, int stop)
davinci_i2c_write_reg(dev, DAVINCI_I2C_SAR_REG, msg->addr);
dev->buf = msg->buf;
- dev->buf_len = msg->len;
+
+ /* if first received byte is length, set buf_len = 0xffff as flag */
+ if (msg->flags & I2C_M_RECV_LEN)
+ dev->buf_len = 0xffff;
+ else
+ dev->buf_len = msg->len;
+
dev->stop = stop;
davinci_i2c_write_reg(dev, DAVINCI_I2C_CNT_REG, dev->buf_len);
@@ -456,7 +466,7 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg
msgs[], int num)
static u32 i2c_davinci_func(struct i2c_adapter *adap)
{
- return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+ return I2C_CAPABILITIES;
}
static void terminate_read(struct davinci_i2c_dev *dev)
@@ -528,10 +538,32 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void
*dev_id)
case DAVINCI_I2C_IVR_RDR:
if (dev->buf_len) {
- *dev->buf++ =
- davinci_i2c_read_reg(dev,
- DAVINCI_I2C_DRR_REG);
+ *dev->buf++ = davinci_i2c_read_reg(dev,
+ DAVINCI_I2C_DRR_REG);
+ /*
+ * check if the first received byte is message
+ * length, i.e, I2C_M_RECV_LEN
+ */
+ if (dev->buf_len == 0xffff)
+ dev->buf_len = *(dev->buf - 1) + 1;
+
dev->buf_len--;
+ /*
+ * send NACK/STOP bits BEFORE last byte is
+ * received
+ */
+ if (dev->buf_len == 1) {
+ w = davinci_i2c_read_reg(dev,
+ DAVINCI_I2C_MDR_REG);
+ w |= DAVINCI_I2C_MDR_NACK;
+ davinci_i2c_write_reg(dev,
+ DAVINCI_I2C_MDR_REG, w);
+
+ w |= DAVINCI_I2C_MDR_STP;
+ davinci_i2c_write_reg(dev,
+ DAVINCI_I2C_MDR_REG, w);
+ }
+
if (dev->buf_len)
continue;
--
1.7.9.5
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