The BYTECNT register holds the transfer size minus one. Setting it to
the correct value removes the need for a dummy read/write at the end of
each transfer. As zero-length transfers are not supported, do not
advertise I2C_FUNC_SMBUS_QUICK.
In other words, this patch makes the driver transfer the number of bytes
requested unless this is zero, which is not supported by the hardware
and is thus refused.
Signed-off-by: Mans Rullgard <[email protected]>
---
Changes:
- refuse zero-length transfers and stop advertising I2C_FUNC_SMBUS_QUICK
---
drivers/i2c/busses/i2c-xlr.c | 50 ++++++++++++++++++++++++--------------------
1 file changed, 27 insertions(+), 23 deletions(-)
diff --git a/drivers/i2c/busses/i2c-xlr.c b/drivers/i2c/busses/i2c-xlr.c
index 10fb916..2cfaba7 100644
--- a/drivers/i2c/busses/i2c-xlr.c
+++ b/drivers/i2c/busses/i2c-xlr.c
@@ -89,38 +89,43 @@ static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len,
unsigned long timeout, stoptime, checktime;
u32 i2c_status;
int pos, timedout;
- u8 offset, byte;
+ u8 offset;
+ u32 xfer;
+
+ if (!len)
+ return -EOPNOTSUPP;
offset = buf[0];
xlr_i2c_wreg(priv->iobase, XLR_I2C_ADDR, offset);
xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG,
XLR_I2C_CFG_ADDR | priv->cfg->cfg_extra);
- xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
stoptime = jiffies + timeout;
timedout = 0;
- pos = 1;
-retry:
+
if (len == 1) {
- xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
- XLR_I2C_STARTXFR_ND);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
+ xfer = XLR_I2C_STARTXFR_ND;
+ pos = 1;
} else {
- xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[pos]);
- xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR,
- XLR_I2C_STARTXFR_WR);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 2);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[1]);
+ xfer = XLR_I2C_STARTXFR_WR;
+ pos = 2;
}
+retry:
+ /* retry can only happen on the first byte */
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, xfer);
+
while (!timedout) {
checktime = jiffies;
i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
- if (i2c_status & XLR_I2C_SDOEMPTY) {
- pos++;
- /* need to do a empty dataout after the last byte */
- byte = (pos < len) ? buf[pos] : 0;
- xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, byte);
+ if ((i2c_status & XLR_I2C_SDOEMPTY) && pos < len) {
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT, buf[pos++]);
/* reset timeout on successful xmit */
stoptime = jiffies + timeout;
@@ -149,11 +154,13 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr)
u32 i2c_status;
unsigned long timeout, stoptime, checktime;
int nbytes, timedout;
- u8 byte;
+
+ if (!len)
+ return -EOPNOTSUPP;
xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG,
XLR_I2C_CFG_NOADDR | priv->cfg->cfg_extra);
- xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
@@ -167,14 +174,11 @@ retry:
checktime = jiffies;
i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
if (i2c_status & XLR_I2C_RXRDY) {
- if (nbytes > len)
+ if (nbytes >= len)
return -EIO; /* should not happen */
- /* we need to do a dummy datain when nbytes == len */
- byte = xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN);
- if (nbytes < len)
- buf[nbytes] = byte;
- nbytes++;
+ buf[nbytes++] =
+ xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN);
/* reset timeout on successful read */
stoptime = jiffies + timeout;
@@ -228,7 +232,7 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap,
static u32 xlr_func(struct i2c_adapter *adap)
{
/* Emulate SMBUS over I2C */
- return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_I2C;
+ return (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) | I2C_FUNC_I2C;
}
static struct i2c_algorithm xlr_i2c_algo = {
--
2.6.3
The Sigma Designs variant of this controller has the ability to generate
interrupts. This is controlled using two additional registers, oddly
enough overlapping with the defined but unused HDSTATIM.
This patch adds support for using this feature instead of busy-looping
if an IRQ is specified.
Signed-off-by: Mans Rullgard <[email protected]>
---
Changes:
- rebase onto v2 of previous patch
---
drivers/i2c/busses/i2c-xlr.c | 119 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 119 insertions(+)
diff --git a/drivers/i2c/busses/i2c-xlr.c b/drivers/i2c/busses/i2c-xlr.c
index 2cfaba7..613c3a4 100644
--- a/drivers/i2c/busses/i2c-xlr.c
+++ b/drivers/i2c/busses/i2c-xlr.c
@@ -19,6 +19,8 @@
#include <linux/platform_device.h>
#include <linux/of_device.h>
#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
/* XLR I2C REGISTERS */
#define XLR_I2C_CFG 0x00
@@ -32,6 +34,10 @@
#define XLR_I2C_BYTECNT 0x08
#define XLR_I2C_HDSTATIM 0x09
+/* Sigma Designs additional registers */
+#define XLR_I2C_INT_EN 0x09
+#define XLR_I2C_INT_STAT 0x0a
+
/* XLR I2C REGISTERS FLAGS */
#define XLR_I2C_BUS_BUSY 0x01
#define XLR_I2C_SDOEMPTY 0x02
@@ -65,7 +71,10 @@ static inline u32 xlr_i2c_rdreg(u32 __iomem *base, unsigned int reg)
return __raw_readl(base + reg);
}
+#define XLR_I2C_FLAG_IRQ 1
+
struct xlr_i2c_config {
+ u32 flags; /* optional feature support */
u32 status_busy; /* value of STATUS[0] when busy */
u32 cfg_extra; /* extra CFG bits to set */
};
@@ -73,7 +82,11 @@ struct xlr_i2c_config {
struct xlr_i2c_private {
struct i2c_adapter adap;
u32 __iomem *iobase;
+ int irq;
+ int pos;
+ struct i2c_msg *msg;
const struct xlr_i2c_config *cfg;
+ wait_queue_head_t wait;
struct clk *clk;
};
@@ -82,6 +95,74 @@ static int xlr_i2c_busy(struct xlr_i2c_private *priv, u32 status)
return (status & XLR_I2C_BUS_BUSY) == priv->cfg->status_busy;
}
+static int xlr_i2c_idle(struct xlr_i2c_private *priv)
+{
+ return !xlr_i2c_busy(priv, xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS));
+}
+
+static int xlr_i2c_wait(struct xlr_i2c_private *priv, unsigned long timeout)
+{
+ int status;
+ int t;
+
+ t = wait_event_timeout(priv->wait, xlr_i2c_idle(priv),
+ msecs_to_jiffies(timeout));
+ if (!t)
+ return -ETIMEDOUT;
+
+ status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
+
+ return status & XLR_I2C_ACK_ERR ? -EIO : 0;
+}
+
+static void xlr_i2c_tx_irq(struct xlr_i2c_private *priv, u32 status)
+{
+ struct i2c_msg *msg = priv->msg;
+
+ if (status & XLR_I2C_SDOEMPTY)
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_DATAOUT,
+ msg->buf[priv->pos++]);
+}
+
+static void xlr_i2c_rx_irq(struct xlr_i2c_private *priv, u32 status)
+{
+ struct i2c_msg *msg = priv->msg;
+
+ if (status & XLR_I2C_RXRDY)
+ msg->buf[priv->pos++] =
+ xlr_i2c_rdreg(priv->iobase, XLR_I2C_DATAIN);
+}
+
+static irqreturn_t xlr_i2c_irq(int irq, void *dev_id)
+{
+ struct xlr_i2c_private *priv = dev_id;
+ struct i2c_msg *msg = priv->msg;
+ u32 int_stat, status;
+
+ int_stat = xlr_i2c_rdreg(priv->iobase, XLR_I2C_INT_STAT);
+ if (!int_stat)
+ return IRQ_NONE;
+
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_STAT, int_stat);
+
+ if (!msg)
+ return IRQ_HANDLED;
+
+ status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
+
+ if (priv->pos < msg->len) {
+ if (msg->flags & I2C_M_RD)
+ xlr_i2c_rx_irq(priv, status);
+ else
+ xlr_i2c_tx_irq(priv, status);
+ }
+
+ if (!xlr_i2c_busy(priv, status))
+ wake_up(&priv->wait);
+
+ return IRQ_HANDLED;
+}
+
static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len,
u8 *buf, u16 addr)
{
@@ -116,10 +197,15 @@ static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len,
pos = 2;
}
+ priv->pos = pos;
+
retry:
/* retry can only happen on the first byte */
xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, xfer);
+ if (priv->irq > 0)
+ return xlr_i2c_wait(priv, XLR_I2C_TIMEOUT * len);
+
while (!timedout) {
checktime = jiffies;
i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
@@ -163,6 +249,8 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr)
xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);
xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
+ priv->pos = 0;
+
timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
stoptime = jiffies + timeout;
timedout = 0;
@@ -170,6 +258,9 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr)
retry:
xlr_i2c_wreg(priv->iobase, XLR_I2C_STARTXFR, XLR_I2C_STARTXFR_RD);
+ if (priv->irq > 0)
+ return xlr_i2c_wait(priv, XLR_I2C_TIMEOUT * len);
+
while (!timedout) {
checktime = jiffies;
i2c_status = xlr_i2c_rdreg(priv->iobase, XLR_I2C_STATUS);
@@ -214,8 +305,13 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap,
if (ret)
return ret;
+ if (priv->irq)
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0xf);
+
+
for (i = 0; ret == 0 && i < num; i++) {
msg = &msgs[i];
+ priv->msg = msg;
if (msg->flags & I2C_M_RD)
ret = xlr_i2c_rx(priv, msg->len, &msg->buf[0],
msg->addr);
@@ -224,7 +320,11 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap,
msg->addr);
}
+ if (priv->irq)
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0);
+
clk_disable(priv->clk);
+ priv->msg = NULL;
return (ret != 0) ? ret : num;
}
@@ -246,6 +346,7 @@ static const struct xlr_i2c_config xlr_i2c_config_default = {
};
static const struct xlr_i2c_config xlr_i2c_config_tangox = {
+ .flags = XLR_I2C_FLAG_IRQ,
.status_busy = 0,
.cfg_extra = 1 << 8,
};
@@ -267,6 +368,7 @@ static int xlr_i2c_probe(struct platform_device *pdev)
unsigned long clk_rate;
unsigned long clk_div;
u32 busfreq;
+ int irq;
int ret;
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
@@ -284,6 +386,23 @@ static int xlr_i2c_probe(struct platform_device *pdev)
if (IS_ERR(priv->iobase))
return PTR_ERR(priv->iobase);
+ irq = platform_get_irq(pdev, 0);
+
+ if (irq > 0 && (priv->cfg->flags & XLR_I2C_FLAG_IRQ)) {
+ priv->irq = irq;
+
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_EN, 0);
+ xlr_i2c_wreg(priv->iobase, XLR_I2C_INT_STAT, 0xf);
+
+ ret = devm_request_irq(&pdev->dev, priv->irq, xlr_i2c_irq,
+ IRQF_SHARED, dev_name(&pdev->dev),
+ priv);
+ if (ret)
+ return ret;
+
+ init_waitqueue_head(&priv->wait);
+ }
+
if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",
&busfreq))
busfreq = 100000;
--
2.6.3
On Tue, Dec 15, 2015 at 11:15:05PM +0000, Mans Rullgard wrote:
> The BYTECNT register holds the transfer size minus one. Setting it to
> the correct value removes the need for a dummy read/write at the end of
> each transfer. As zero-length transfers are not supported, do not
> advertise I2C_FUNC_SMBUS_QUICK.
>
> In other words, this patch makes the driver transfer the number of bytes
> requested unless this is zero, which is not supported by the hardware
> and is thus refused.
>
> Signed-off-by: Mans Rullgard <[email protected]>
Applied to for-next, thanks!
On Tue, Dec 15, 2015 at 11:15:06PM +0000, Mans Rullgard wrote:
> The Sigma Designs variant of this controller has the ability to generate
> interrupts. This is controlled using two additional registers, oddly
> enough overlapping with the defined but unused HDSTATIM.
>
> This patch adds support for using this feature instead of busy-looping
> if an IRQ is specified.
>
> Signed-off-by: Mans Rullgard <[email protected]>
Applied to for-next, thanks!