* [PATCH v2] HID: cp2112: support i2c write-read transfers in hid-cp2112
@ 2015-07-10 4:55 Ellen Wang
2015-07-10 9:21 ` Jiri Kosina
0 siblings, 1 reply; 3+ messages in thread
From: Ellen Wang @ 2015-07-10 4:55 UTC (permalink / raw)
To: borneo.antonio, dbarksdale, jkosina, linux-input, linux-i2c; +Cc: ellen
cp2112_i2c_xfer() only supports a single i2c_msg. More than
one message at a time just returns EIO. This breaks certain
important cases. For example, the at24 eeprom driver generates
paired write and read messages (for eeprom address and data).
Since the device doesn't support i2c repeated starts in general,
but does support a single write-repeated-start-read pair
(since hardware rev 1), we recognize the latter case and
implement only that.
Signed-off-by: Ellen Wang <ellen@cumulusnetworks.com>
---
drivers/hid/hid-cp2112.c | 74 +++++++++++++++++++++++++++++++++++-------------
1 file changed, 55 insertions(+), 19 deletions(-)
diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
index 75398cb..1d24a65 100644
--- a/drivers/hid/hid-cp2112.c
+++ b/drivers/hid/hid-cp2112.c
@@ -156,6 +156,7 @@ struct cp2112_device {
wait_queue_head_t wait;
u8 read_data[61];
u8 read_length;
+ u8 hwversion;
int xfer_status;
atomic_t read_avail;
atomic_t xfer_avail;
@@ -446,6 +447,24 @@ static int cp2112_i2c_write_req(void *buf, u8 slave_address, u8 *data,
return data_length + 3;
}
+static int cp2112_i2c_write_read_req(void *buf, u8 slave_address,
+ u8 *addr, int addr_length,
+ int read_length)
+{
+ struct cp2112_write_read_req_report *report = buf;
+
+ if (read_length < 1 || read_length > 512 ||
+ addr_length > sizeof(report->target_address))
+ return -EINVAL;
+
+ report->report = CP2112_DATA_WRITE_READ_REQUEST;
+ report->slave_address = slave_address << 1;
+ report->length = cpu_to_be16(read_length);
+ report->target_address_length = addr_length;
+ memcpy(report->target_address, addr, addr_length);
+ return addr_length + 5;
+}
+
static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
@@ -453,26 +472,46 @@ static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
struct hid_device *hdev = dev->hdev;
u8 buf[64];
ssize_t count;
+ ssize_t read_length = 0;
+ u8 *read_buf = NULL;
unsigned int retries;
int ret;
hid_dbg(hdev, "I2C %d messages\n", num);
- if (num != 1) {
+ if (num == 1) {
+ if (msgs->flags & I2C_M_RD) {
+ hid_dbg(hdev, "I2C read %#04x len %d\n",
+ msgs->addr, msgs->len);
+ read_length = msgs->len;
+ read_buf = msgs->buf;
+ count = cp2112_read_req(buf, msgs->addr, msgs->len);
+ } else {
+ hid_dbg(hdev, "I2C write %#04x len %d\n",
+ msgs->addr, msgs->len);
+ count = cp2112_i2c_write_req(buf, msgs->addr,
+ msgs->buf, msgs->len);
+ }
+ if (count < 0)
+ return count;
+ } else if (dev->hwversion > 1 && /* no repeated start in rev 1 */
+ num == 2 &&
+ msgs[0].addr == msgs[1].addr &&
+ !(msgs[0].flags & I2C_M_RD) && (msgs[1].flags & I2C_M_RD)) {
+ hid_dbg(hdev, "I2C write-read %#04x wlen %d rlen %d\n",
+ msgs[0].addr, msgs[0].len, msgs[1].len);
+ read_length = msgs[1].len;
+ read_buf = msgs[1].buf;
+ count = cp2112_i2c_write_read_req(buf, msgs[0].addr,
+ msgs[0].buf, msgs[0].len, msgs[1].len);
+ if (count < 0)
+ return count;
+ } else {
hid_err(hdev,
"Multi-message I2C transactions not supported\n");
return -EOPNOTSUPP;
}
- if (msgs->flags & I2C_M_RD)
- count = cp2112_read_req(buf, msgs->addr, msgs->len);
- else
- count = cp2112_i2c_write_req(buf, msgs->addr, msgs->buf,
- msgs->len);
-
- if (count < 0)
- return count;
-
ret = hid_hw_power(hdev, PM_HINT_FULLON);
if (ret < 0) {
hid_err(hdev, "power management error: %d\n", ret);
@@ -508,11 +547,8 @@ static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
goto power_normal;
}
- if (!(msgs->flags & I2C_M_RD))
- goto finish;
-
- for (count = 0; count < msgs->len;) {
- ret = cp2112_read(dev, msgs->buf + count, msgs->len - count);
+ for (count = 0; count < read_length;) {
+ ret = cp2112_read(dev, read_buf + count, read_length - count);
if (ret < 0)
goto power_normal;
if (ret == 0) {
@@ -521,7 +557,7 @@ static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
goto power_normal;
}
count += ret;
- if (count > msgs->len) {
+ if (count > read_length) {
/*
* The hardware returned too much data.
* This is mostly harmless because cp2112_read()
@@ -531,15 +567,14 @@ static int cp2112_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
* it shouldn't go unnoticed.
*/
hid_err(hdev, "long read: %d > %zd\n",
- ret, msgs->len - count + ret);
+ ret, read_length - count + ret);
ret = -EIO;
goto power_normal;
}
}
-finish:
/* return the number of transferred messages */
- ret = 1;
+ ret = num;
power_normal:
hid_hw_power(hdev, PM_HINT_NORMAL);
@@ -1047,6 +1082,7 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
dev->adap.dev.parent = &hdev->dev;
snprintf(dev->adap.name, sizeof(dev->adap.name),
"CP2112 SMBus Bridge on hiddev%d", hdev->minor);
+ dev->hwversion = buf[2];
init_waitqueue_head(&dev->wait);
hid_device_io_start(hdev);
--
1.9.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] HID: cp2112: support i2c write-read transfers in hid-cp2112
2015-07-10 4:55 [PATCH v2] HID: cp2112: support i2c write-read transfers in hid-cp2112 Ellen Wang
@ 2015-07-10 9:21 ` Jiri Kosina
2015-07-14 10:09 ` Antonio Borneo
0 siblings, 1 reply; 3+ messages in thread
From: Jiri Kosina @ 2015-07-10 9:21 UTC (permalink / raw)
To: Ellen Wang; +Cc: borneo.antonio, dbarksdale, linux-input, linux-i2c
On Thu, 9 Jul 2015, Ellen Wang wrote:
> cp2112_i2c_xfer() only supports a single i2c_msg. More than
> one message at a time just returns EIO. This breaks certain
> important cases. For example, the at24 eeprom driver generates
> paired write and read messages (for eeprom address and data).
>
> Since the device doesn't support i2c repeated starts in general,
> but does support a single write-repeated-start-read pair
> (since hardware rev 1), we recognize the latter case and
> implement only that.
>
> Signed-off-by: Ellen Wang <ellen@cumulusnetworks.com>
Applied to for-4.3/cp2112.
Thanks,
--
Jiri Kosina
SUSE Labs
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] HID: cp2112: support i2c write-read transfers in hid-cp2112
2015-07-10 9:21 ` Jiri Kosina
@ 2015-07-14 10:09 ` Antonio Borneo
0 siblings, 0 replies; 3+ messages in thread
From: Antonio Borneo @ 2015-07-14 10:09 UTC (permalink / raw)
To: Jiri Kosina; +Cc: Ellen Wang, David Barksdale, linux-input, linux-i2c
On Fri, Jul 10, 2015 at 5:21 PM, Jiri Kosina <jkosina@suse.com> wrote:
> On Thu, 9 Jul 2015, Ellen Wang wrote:
>
>> cp2112_i2c_xfer() only supports a single i2c_msg. More than
>> one message at a time just returns EIO. This breaks certain
>> important cases. For example, the at24 eeprom driver generates
>> paired write and read messages (for eeprom address and data).
>>
>> Since the device doesn't support i2c repeated starts in general,
>> but does support a single write-repeated-start-read pair
>> (since hardware rev 1), we recognize the latter case and
>> implement only that.
>>
>> Signed-off-by: Ellen Wang <ellen@cumulusnetworks.com>
>
> Applied to for-4.3/cp2112.
>
Good!
Either
Tested-by: Antonio Borneo <borneo.antonio@gmail.com>
and/or
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
By the way, while this patch extends the i2c functionality, it makes
clear that repeated start is always broken on HW rev 1, also for
SMBUS!
I'm testing a patch to restrict SMBUS on rev 1 to only those
transactions that don't require repeated start.
Will post it shortly.
Regards,
Antonio
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-07-10 4:55 [PATCH v2] HID: cp2112: support i2c write-read transfers in hid-cp2112 Ellen Wang
2015-07-10 9:21 ` Jiri Kosina
2015-07-14 10:09 ` Antonio Borneo
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