diff options
Diffstat (limited to 'meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0029-i2c-mux-pca954x-fix-i2c-mux-selection-caching.patch')
| -rw-r--r-- | meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0029-i2c-mux-pca954x-fix-i2c-mux-selection-caching.patch | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0029-i2c-mux-pca954x-fix-i2c-mux-selection-caching.patch b/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0029-i2c-mux-pca954x-fix-i2c-mux-selection-caching.patch new file mode 100644 index 0000000..1640b51 --- /dev/null +++ b/meta-rcar-gen3-adas/recipes-kernel/linux/linux-renesas/0029-i2c-mux-pca954x-fix-i2c-mux-selection-caching.patch @@ -0,0 +1,51 @@ +From 7f638c1cb0a1112dbe0b682a42db30521646686b Mon Sep 17 00:00:00 2001 +From: Russell King <rmk+kernel@armlinux.org.uk> +Date: Sat, 17 Dec 2016 12:10:56 +0000 +Subject: [PATCH] i2c: mux: pca954x: fix i2c mux selection caching + +smbus functions return -ve on error, 0 on success. However, +__i2c_transfer() have a different return signature - -ve on error, or +number of buffers transferred (which may be zero or greater.) + +The upshot of this is that the sense of the test is reversed when using +the mux on a bus supporting the master_xfer method: we cache the value +and never retry if we fail to transfer any buffers, but if we succeed, +we clear the cached value. + +Fix this by making pca954x_reg_write() return a negative error code for +all failure cases. + +Fixes: 463e8f845cbf ("i2c: mux: pca954x: retry updating the mux selection on failure") +Acked-by: Peter Rosin <peda@axentia.se> +Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk> +Signed-off-by: Wolfram Sang <wsa@the-dreams.de> +--- + drivers/i2c/muxes/i2c-mux-pca954x.c | 5 ++++- + 1 file changed, 4 insertions(+), 1 deletion(-) + +diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c +index 9a348ee..dd18b9c 100644 +--- a/drivers/i2c/muxes/i2c-mux-pca954x.c ++++ b/drivers/i2c/muxes/i2c-mux-pca954x.c +@@ -167,6 +167,9 @@ static int pca954x_reg_write(struct i2c_adapter *adap, + buf[0] = val; + msg.buf = buf; + ret = __i2c_transfer(adap, &msg, 1); ++ ++ if (ret >= 0 && ret != 1) ++ ret = -EREMOTEIO; + } else { + union i2c_smbus_data data; + ret = adap->algo->smbus_xfer(adap, client->addr, +@@ -195,7 +198,7 @@ static int pca954x_select_chan(struct i2c_mux_core *muxc, u32 chan) + /* Only select the channel if its different from the last channel */ + if (data->last_chan != regval) { + ret = pca954x_reg_write(muxc->parent, client, regval); +- data->last_chan = ret ? 0 : regval; ++ data->last_chan = ret < 0 ? 0 : regval; + } + + return ret; +-- +1.9.1 + |