A common requirement is to find the clock ID for a peripheral. This is the second cell of the 'clocks' property (the first being the phandle itself).
Signed-off-by: Simon Glass sjg@chromium.org --- Changes in v4: - Add fdtdec function to return peripheral ID
include/fdtdec.h | 13 +++++++++++++ lib/fdtdec.c | 13 +++++++++++++ 2 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/include/fdtdec.h b/include/fdtdec.h index 6c0a2d1..f3115a6 100644 --- a/include/fdtdec.h +++ b/include/fdtdec.h @@ -272,3 +272,16 @@ int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error */ int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); + +/** + * Decode a peripheral ID from a device tree node. This may be a temporary + * function depending on what happens with clocks in the Linux fdt. + * + * This works by looking up the peripheral's 'clocks' node and reading out + * the second cell, which is the clock number / peripheral ID. + * + * @param blob FDT blob to use + * @param node Node to look at + * @return + */ +int fdtdec_decode_periph_id(const void *blob, int node); diff --git a/lib/fdtdec.c b/lib/fdtdec.c index c748cac..f999ed0 100644 --- a/lib/fdtdec.c +++ b/lib/fdtdec.c @@ -415,3 +415,16 @@ int fdtdec_setup_gpio(struct fdt_gpio_state *gpio) return -1; return 0; } + +int fdtdec_decode_periph_id(const void *blob, int node) +{ + u32 cell[2]; + int err; + + err = fdtdec_get_int_array(blob, node, "clocks", cell, + ARRAY_SIZE(cell)); + if (err) + return -1; + + return cell[1]; +}