diff options
| author | Tobias Waldekranz <tobias@waldekranz.com> | 2021-02-02 22:16:45 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2021-02-05 06:09:47 +0300 |
| commit | add285bce37720675af5b1873f71af8561d0e2fe (patch) | |
| tree | 310c81935e04b68c396c93aa4a76f6abf31b9e54 /drivers/net/dsa/xrs700x | |
| parent | b53014f0791cbc4925f52d7c46220845e42d0a91 (diff) | |
| download | linux-add285bce37720675af5b1873f71af8561d0e2fe.tar.xz | |
net: dsa: xrs700x: Correctly address device over I2C
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>
Reviewed-by: George McCollister <george.mccollister@gmail.com>
Link: https://lore.kernel.org/r/20210202191645.439-1-tobias@waldekranz.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/dsa/xrs700x')
| -rw-r--r-- | drivers/net/dsa/xrs700x/xrs700x_i2c.c | 31 |
1 files 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; |