topic Re: use SPI MCP23S17 in i.MX Processors

use SPI MCP23S17

tobias_mrs — Tue, 10 Jan 2017 08:15:52 GMT

Hello
I have problems to get the GPIO Port Expander MCP23S17 to run and to use the Driver gpio-mcp23s08.c on a i.MX6

I have add the following Kernel configs

CONFIG_GPIO_MCP23S08=y
CONFIG_SPI_IMX=y

I have change my Devicetree like following:

&ecspi1 {
   pinctrl-names = "default";
   pinctrl-0 = <&pinctrl_ecspi1>;
   fsl,spi-num-chipselects = <2>;
   cs-gpios = <
       &gpio2 30 GPIO_ACTIVE_HIGH
       &gpio3 19 GPIO_ACTIVE_HIGH
   >;
   status = "okay";

   gpiom0: gpio8@0 {
       compatible = "microchip,mcp23s17";
       gpio-controller;
       #gpio-cells = <2>;
       microchip,spi-present-mask = <0x01>;
       reg = <0>;
       spi-max-frequency = <1000000>;
        };

   spidev1: spi@1 {
       compatible = "spidev";
       reg = <1>;
       spi-max-frequency = <54000000>;
   };
};

With

dmesg | grep spi
I get

[ 3.751757] spi_imx 2008000.ecspi: registered master spi0
[ 3.756600] spi spi0.0: spi_imx_setup: mode 0, 8 bpw, 1000000 hz
[ 3.761616] spi spi0.0: setup mode 0, 8 bits/w, 1000000 Hz max --> 0
[ 3.770168] spi_imx 2008000.ecspi: registered child spi0.0
[ 3.780987] spi spi0.1: spi_imx_setup: mode 0, 8 bpw, 54000000 hz
[ 3.785848] spi spi0.1: setup mode 0, 8 bits/w, 54000000 Hz max --> 0

How do I load, test and use the gpio-mcp23s08 Driver?

regards

Tobias

Re: use SPI MCP23S17

igorpadykov — Tue, 10 Jan 2017 10:50:27 GMT

Hi Tobias

control registers of MCP23S17 should be programmed appropriately, please

check examples on

https://www.raspberrypi.org/forums/viewtopic.php?t=5987
http://www.retrosemi.co.uk/mcp23s17/Getting_started_with_the_mcp23s17.pdf

Best regards
igor
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Re: use SPI MCP23S17

tobias_mrs — Fri, 13 Jan 2017 10:54:04 GMT

Hello

thanks for the examples.
I have now finished the experiment with the Decivetree, I don't get it run.

I have now implement my own control for the mcp23s17 like the example.
But now I get on every transfer on the spi bus the following message:

mx51_ecspi_clkdiv: fin: 60000000, fspi: 50000000, post: 0, pre: 1

Whats wrong now?

regards

Tobias

Re: use SPI MCP23S17

igorpadykov — Sat, 14 Jan 2017 00:17:15 GMT

seems ratio between fin, fspi should be integer, please look at

Figure 18-1 i.MX6DQ Reference Manual

http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6DQRM.pdf

Best regards
igor

Re: use SPI MCP23S17

tobias_mrs — Mon, 16 Jan 2017 09:20:10 GMT

Hello
thanks for the answer

the Problem was that I have enabled the DEBUG messages from the kernel and the the driver spi-imx.c allays displays its frequency.

function: mx51_ecspi_clkdiv:
pr_debug("%s: fin: %u, fspi: %u, post: %u, pre: %u\n", __func__, fin, fspi, post, pre);

Best regards

Tobias