spi: spi-xilinx: Use DT information for bits_per_word value
Subsystems (3)
PATCH v2 1/1 spi: spi-xilinx: Use DT information for bits_per_word value
This patch overrides the default value of bits_per_word with the actual value of "xlnx,num-transfer-bits" from the DTS file to allow for 16 and 32 bit word lengths. In case of a non-existing entry this will be ignored.
---
Changes in v2:
- use of_property_read_u32() instead of of_get_property()
- added some documentation
- original patch v1 #2124911
Grant Likely - March 2, 2013, 9:22 p.m.
Quoted 13 lines · Jens Renner (EFE)
From: Jens Renner <[email protected]>
This patch overrides the default value of
bits_per_wordwith the actual value of "xlnx,num-transfer-bits" from the DTS file to allow for 16 and 32 bit word lengths.Signed-off-by Jens Renner <[email protected]>---
drivers/spi/spi-xilinx.c +0
-0
drivers/spi/spi-xilinx.c static int xilinx_spi_probe(struct platform_device *dev) · line 495
Quoted 9 lines
drivers/spi/spi-xilinx.c +6
-0@@ -487,6 +487,12 @@ static int xilinx_spi_probe(struct platform_device *dev) &len);if (prop && len >=sizeof (*prop)) num_cs =__be32_to_cpup (prop); + +/* override default number of bits per word */ + prop =of_get_property (dev->dev.of_node, +"xlnx,num-transfer-bits" , &len); +if (prop && len >=sizeof (*prop)) + bits_per_word =__be32_to_cpup (prop);
Hi Jens,
Please remember to update documentation when modifying a DT binding.
Also, if you use of_property_read_u32() the code will be a lot simpler.
g.
drivers/spi/spi-xilinx.c | 13 ++++++------- Documentation/devicetree/bindings/spi/spi-xilinx.txt | 32 ++++++++++++++++++++ 2 files changed, 38 insertions(+), 7 deletions(-)
drivers/spi/spi-xilinx.c +6 -7
@@ -479,14 +479,13 @@ static int xilinx_spi_probe(struct platform_device *dev)#ifdef CONFIG_OF if (dev->dev.of_node) { -const __be32 *prop; -int len; -/* number of slave select bits is required */ - prop =of_get_property (dev->dev.of_node,"xlnx,num-ss-bits" , - &len); -if (prop && len >=sizeof (*prop)) - num_cs =__be32_to_cpup (prop); +of_property_read_u32 (dev->dev.of_node,"xlnx,num-ss-bits" , + &num_cs); + +/* override default number of bits per word */ +of_property_read_u32 (dev->dev.of_node,"xlnx,num-transfer-bits" , + &bits_per_word); }#endif
Documentation/devicetree/bindings/spi/spi-xilinx.txt new file +32 -0
@@ -0,0 +1,32 @@ +Xilinx SPI controller: + +Required properties: +- compatible : Must be "xlnx,axi-1.02.a" or "xlnx,xps-spi-2.00.a" +- interrupt-parent : reference to parent interrupt controller +- interrupts : SPI controller interrupt +- reg : SPI register location and length + +Optional properties: +- xlnx,num-ss-bits : # of slave select bits +- xlnx,num-transfer_bits : # of data transfer bits (defaults to 8) +- xlnx,... : not considered by kernel module +- #address-cells = <1> : if child nodes are defined +- #size-cells = <0> : if child nodes are defined +- Child nodes conforming to SPI bus binding + +Example with 3 slave select bits and 32 bit transfer size: + + axi_spi_0: spi@40a00000 { + compatible = "xlnx,axi-spi-1.02.a", "xlnx,xps-spi-2.00.a"; + interrupt-parent = <&axi_intc_0>; + interrupts = < 2 2 >; + reg = < 0x40a00000 0x10000 >; + xlnx,family = "spartan6"; + xlnx,fifo-exist = <0x1>; + xlnx,instance = "axi_spi_0"; + xlnx,num-ss-bits = <0x3>; + xlnx,num-transfer-bits = <0x20>; + xlnx,sck-ratio = <0x4>; + #address-cells = <1>; + #size-cells = <0>; + } ;
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