path: root/README
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authorChris Packham <judge.packham@gmail.com>2010-12-19 10:12:13 +0000
committerHeiko Schocher <hs@denx.de>2011-01-10 07:53:00 +0100
commit5dec49ca2273bcf181071bc1c97a9901b155ebc1 (patch)
tree2b00e45e8f268dcd9b872525591d8460d434462f /README
parent89c95f0cd3f8140f3b8a82a22a6a144c148d09c6 (diff)
pca953x: support 16-pin devices
This adds support for for the PCA9535/PCA9539 family of gpio devices which have 16 output pins. To let the driver know which devices are 16-pin it is necessary to define CONFIG_SYS_I2C_PCA953X_WIDTH in your board config file. This is used to create an array of {chip, ngpio} tuples that are used to determine the width of a particular chip. For backwards compatibility it is assumed that any chip not defined in CONFIG_SYS_I2C_PCA953X_WIDTH has 8 pins. Acked-by: Peter Tyser <ptyser@xes-inc.com> Tested-by: Peter Tyser <ptyser@xes-inc.com> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Diffstat (limited to 'README')
1 files changed, 4 insertions, 0 deletions
diff --git a/README b/README
index 68f5fb091..831c5af15 100644
--- a/README
+++ b/README
@@ -746,6 +746,10 @@ The following options need to be configured:
CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO
CONFIG_PCA953X_INFO - enable pca953x info command
+ The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of
+ chip-ngpio pairs that tell the PCA953X driver the number of
+ pins supported by a particular chip.
Note that if the GPIO device uses I2C, then the I2C interface
must also be configured. See I2C Support, below.