>-----Original Message-----
>From: Karicheri, Muralidharan
>Sent: Thursday, May 01, 2014 2:50 PM
>To: davinci-linux-open-source@xxxxxxxxxxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; linux-
>kernel@xxxxxxxxxxxxxxx
>Cc: Karicheri, Muralidharan; Ding, Garrett; Nori, Sekhar; Kevin Hilman; Wolfram Sang;
>Shilimkar, Santosh
>Subject: [PATCH] i2c: davinci: Add block read functionality for IPMI
>
>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-ding@xxxxxx>
>Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
>Tested-by: Garrett Ding <g-ding@xxxxxx>
>CC: Sekhar Nori <nsekhar@xxxxxx>
>CC: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
>CC: Wolfram Sang <wsa@xxxxxxxxxxxxx>
>CC: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
>---
> 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
All,
Please review this when you get a chance.
Murali
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