* [PATCH net-next] net: dsa: xrs700x: Correctly address device over I2C
@ 2021-02-02 19:16 Tobias Waldekranz
2021-02-02 20:05 ` George McCollister
0 siblings, 1 reply; 3+ messages in thread
From: Tobias Waldekranz @ 2021-02-02 19:16 UTC (permalink / raw)
To: davem, kuba
Cc: george.mccollister, andrew, vivien.didelot, f.fainelli, olteanv, netdev
On read, master should send 31 MSB of the register (only even values
are ever used), followed by a 1 to indicate read. Then, reading two
bytes, the device will output the register's value.
On write, master sends 31 MSB of the register, followed by a 0 to
indicate write, followed by two bytes containing the register value.
Flexibilis' documentation (version 1.3) specifies the opposite
polarity (#read/write), but the scope indicates that it is, in fact,
read/#write.
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
---
George, have you used the chip in I2C mode with the code that is on
net-next now? I was not able to get the driver to even read the ID
register correctly.
drivers/net/dsa/xrs700x/xrs700x_i2c.c | 31 ++++++++++++---------------
1 file changed, 14 insertions(+), 17 deletions(-)
diff --git a/drivers/net/dsa/xrs700x/xrs700x_i2c.c b/drivers/net/dsa/xrs700x/xrs700x_i2c.c
index a5f8883af829..16a46a78a037 100644
--- a/drivers/net/dsa/xrs700x/xrs700x_i2c.c
+++ b/drivers/net/dsa/xrs700x/xrs700x_i2c.c
@@ -10,33 +10,34 @@
#include "xrs700x.h"
#include "xrs700x_reg.h"
+struct xrs700x_i2c_cmd {
+ __be32 reg;
+ __be16 val;
+} __packed;
+
static int xrs700x_i2c_reg_read(void *context, unsigned int reg,
unsigned int *val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
- unsigned char buf[4];
+ struct xrs700x_i2c_cmd cmd;
int ret;
- buf[0] = reg >> 23 & 0xff;
- buf[1] = reg >> 15 & 0xff;
- buf[2] = reg >> 7 & 0xff;
- buf[3] = (reg & 0x7f) << 1;
+ cmd.reg = cpu_to_be32(reg | 1);
- ret = i2c_master_send(i2c, buf, sizeof(buf));
+ ret = i2c_master_send(i2c, (char *)&cmd.reg, sizeof(cmd.reg));
if (ret < 0) {
dev_err(dev, "xrs i2c_master_send returned %d\n", ret);
return ret;
}
- ret = i2c_master_recv(i2c, buf, 2);
+ ret = i2c_master_recv(i2c, (char *)&cmd.val, sizeof(cmd.val));
if (ret < 0) {
dev_err(dev, "xrs i2c_master_recv returned %d\n", ret);
return ret;
}
- *val = buf[0] << 8 | buf[1];
-
+ *val = be16_to_cpu(cmd.val);
return 0;
}
@@ -45,17 +46,13 @@ static int xrs700x_i2c_reg_write(void *context, unsigned int reg,
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
- unsigned char buf[6];
+ struct xrs700x_i2c_cmd cmd;
int ret;
- buf[0] = reg >> 23 & 0xff;
- buf[1] = reg >> 15 & 0xff;
- buf[2] = reg >> 7 & 0xff;
- buf[3] = (reg & 0x7f) << 1 | 1;
- buf[4] = val >> 8 & 0xff;
- buf[5] = val & 0xff;
+ cmd.reg = cpu_to_be32(reg);
+ cmd.val = cpu_to_be16(val);
- ret = i2c_master_send(i2c, buf, sizeof(buf));
+ ret = i2c_master_send(i2c, (char *)&cmd, sizeof(cmd));
if (ret < 0) {
dev_err(dev, "xrs i2c_master_send returned %d\n", ret);
return ret;
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] net: dsa: xrs700x: Correctly address device over I2C
2021-02-02 19:16 [PATCH net-next] net: dsa: xrs700x: Correctly address device over I2C Tobias Waldekranz
@ 2021-02-02 20:05 ` George McCollister
2021-02-05 3:11 ` Jakub Kicinski
0 siblings, 1 reply; 3+ messages in thread
From: George McCollister @ 2021-02-02 20:05 UTC (permalink / raw)
To: Tobias Waldekranz
Cc: David S. Miller, Jakub Kicinski, Andrew Lunn, Vivien Didelot,
Florian Fainelli, Vladimir Oltean, netdev
On Tue, Feb 2, 2021 at 1:17 PM Tobias Waldekranz <tobias@waldekranz.com> wrote:
[snip]
>
> George, have you used the chip in I2C mode with the code that is on
> net-next now? I was not able to get the driver to even read the ID
> register correctly.
I wrote the i2c driver before I had any hardware in hand thinking I
was going to get a board with the switch connected via i2c. When the
board arrived it turned out it was connected via mdio so I wrote that
driver as well. I looked it over quite carefully but I guess the
documentation was wrong and I had the register addresses shifted off
by one. I never ended up with hardware to test the i2c.
>
> drivers/net/dsa/xrs700x/xrs700x_i2c.c | 31 ++++++++++++---------------
> 1 file changed, 14 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/net/dsa/xrs700x/xrs700x_i2c.c b/drivers/net/dsa/xrs700x/xrs700x_i2c.c
> index a5f8883af829..16a46a78a037 100644
> --- a/drivers/net/dsa/xrs700x/xrs700x_i2c.c
> +++ b/drivers/net/dsa/xrs700x/xrs700x_i2c.c
> @@ -10,33 +10,34 @@
> #include "xrs700x.h"
> #include "xrs700x_reg.h"
>
> +struct xrs700x_i2c_cmd {
> + __be32 reg;
> + __be16 val;
> +} __packed;
> +
> static int xrs700x_i2c_reg_read(void *context, unsigned int reg,
> unsigned int *val)
> {
> struct device *dev = context;
> struct i2c_client *i2c = to_i2c_client(dev);
> - unsigned char buf[4];
> + struct xrs700x_i2c_cmd cmd;
> int ret;
>
> - buf[0] = reg >> 23 & 0xff;
> - buf[1] = reg >> 15 & 0xff;
> - buf[2] = reg >> 7 & 0xff;
> - buf[3] = (reg & 0x7f) << 1;
> + cmd.reg = cpu_to_be32(reg | 1);
>
> - ret = i2c_master_send(i2c, buf, sizeof(buf));
> + ret = i2c_master_send(i2c, (char *)&cmd.reg, sizeof(cmd.reg));
> if (ret < 0) {
> dev_err(dev, "xrs i2c_master_send returned %d\n", ret);
> return ret;
> }
>
> - ret = i2c_master_recv(i2c, buf, 2);
> + ret = i2c_master_recv(i2c, (char *)&cmd.val, sizeof(cmd.val));
> if (ret < 0) {
> dev_err(dev, "xrs i2c_master_recv returned %d\n", ret);
> return ret;
> }
>
> - *val = buf[0] << 8 | buf[1];
> -
> + *val = be16_to_cpu(cmd.val);
> return 0;
> }
>
> @@ -45,17 +46,13 @@ static int xrs700x_i2c_reg_write(void *context, unsigned int reg,
> {
> struct device *dev = context;
> struct i2c_client *i2c = to_i2c_client(dev);
> - unsigned char buf[6];
> + struct xrs700x_i2c_cmd cmd;
> int ret;
>
> - buf[0] = reg >> 23 & 0xff;
> - buf[1] = reg >> 15 & 0xff;
> - buf[2] = reg >> 7 & 0xff;
> - buf[3] = (reg & 0x7f) << 1 | 1;
> - buf[4] = val >> 8 & 0xff;
> - buf[5] = val & 0xff;
> + cmd.reg = cpu_to_be32(reg);
> + cmd.val = cpu_to_be16(val);
>
> - ret = i2c_master_send(i2c, buf, sizeof(buf));
> + ret = i2c_master_send(i2c, (char *)&cmd, sizeof(cmd));
> if (ret < 0) {
> dev_err(dev, "xrs i2c_master_send returned %d\n", ret);
> return ret;
> --
> 2.17.1
>
Reviewed-by: George McCollister <george.mccollister@gmail.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] net: dsa: xrs700x: Correctly address device over I2C
2021-02-02 20:05 ` George McCollister
@ 2021-02-05 3:11 ` Jakub Kicinski
0 siblings, 0 replies; 3+ messages in thread
From: Jakub Kicinski @ 2021-02-05 3:11 UTC (permalink / raw)
To: George McCollister, Tobias Waldekranz
Cc: David S. Miller, Andrew Lunn, Vivien Didelot, Florian Fainelli,
Vladimir Oltean, netdev
On Tue, 2 Feb 2021 14:05:20 -0600 George McCollister wrote:
> On Tue, Feb 2, 2021 at 1:17 PM Tobias Waldekranz <tobias@waldekranz.com> wrote:
> [snip]
> >
> > George, have you used the chip in I2C mode with the code that is on
> > net-next now? I was not able to get the driver to even read the ID
> > register correctly.
>
> I wrote the i2c driver before I had any hardware in hand thinking I
> was going to get a board with the switch connected via i2c. When the
> board arrived it turned out it was connected via mdio so I wrote that
> driver as well. I looked it over quite carefully but I guess the
> documentation was wrong and I had the register addresses shifted off
> by one. I never ended up with hardware to test the i2c.
> Reviewed-by: George McCollister <george.mccollister@gmail.com>
Applied, thanks!
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-02-02 20:05 ` George McCollister
2021-02-05 3:11 ` Jakub Kicinski
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