imx-weim on 6sololite using 3.14.28 kernel

[jayakumar2]

Hi,

I'm working on getting a userspace EIM application working on a 6sololite board using the 3.14.28 kernel. I had modified my devicetree dts to add the weim interface. While trying to figure that part out, I noticed that drivers/bus/imx-weim.c on 3.14.28 only lists the following:

static const struct of_device_id weim_id_table[] = {

        /* i.MX1/21 */

        { .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },

        /* i.MX25/27/31/35 */

        { .compatible = "fsl,imx27-weim", .data = &imx27_weim_devtype, },

        /* i.MX50/53/6Q */

        { .compatible = "fsl,imx50-weim", .data = &imx50_weim_devtype, },

        { .compatible = "fsl,imx6q-weim", .data = &imx50_weim_devtype, },

        /* i.MX51 */

        { .compatible = "fsl,imx51-weim", .data = &imx51_weim_devtype, },

        { }

};

Searching for imx6sl-weim gets no hits. Does that mean the imx-weim driver is not compatible with imx6sl? My guess is that it is not. It looks like I would need to add some 6sl specific handling for the clock setup. Also:

static const struct imx_weim_devtype imx50_weim_devtype = {

        .cs_count       = 4,

        .cs_regs_count  = 6,

        .cs_stride      = 0x18,

};

If I'm mistaken, please help point me to a 6sl example that uses imx-weim in its device tree config.

Thanks!

ps: Igor, if you reply, please do NOT mark as Assumed Answered until I have a chance to reply! At least give me 2-3 days to try any suggestions rather than assuming that your "answer" is the solution. Thanks for understanding!

[igorpadykov]

"fsl,imx6q-weim" is included in imx6sx.dtsi


linux-2.6-imx.git - Freescale i.MX Linux Tree

Best regards

igor

[jayakumar2]

Hi Igor,

Thanks for your reply. Now I understand your meaning.

Ok, in my case, when I test, I'm getting:

io scheduler deadline registered

io scheduler cfq registered (default)

imx-weim: probe of 21b8000.weim failed with error -2

After adding debug to imx-weim, I found the error is actually due to the clock setup.

imx-weim 21b8000.weim: fail on clk get.                                       

imx-weim: probe of 21b8000.weim failed with error -2 

Which is from the following code in imx-weim:

        clk = devm_clk_get(&pdev->dev, NULL);

        if (IS_ERR(clk)) {

                dev_err(&pdev->dev, "fail on clk get.\n");

So it looks like the root cause is my clock setup in the dts.

Previously on 3.0.35, in my board setup I was setting my EMI clock to 66MHz using:

        /* CLKCTL_CCGR6: Set emi_slow_clock to be on in all modes */

        printk(KERN_ERR "setting EMI slow clock to always be on\n");

        reg = readl(ccm_reg + 0x80);

        reg |= 0x00000C00;

        writel(reg, ccm_reg + 0x80);

        printk(KERN_ERR "setting CLKCTL_CCGR6 to be 0x%x\n", reg);

        clk = clk_get(NULL, "emi_slow_clk");

        if (IS_ERR(clk))

                printk(KERN_ERR "emi_slow_clk not found\n");

...

                ret = clk_set_rate(clk, clk_round_rate(clk, 66000000));

It looks like I'll need to figure out arch/arm/mach-imx/clk-imx6sl.c to add a suitable clock for EIM there.

Thanks!

[jayakumar2]

I added the following patch:

--- a/include/dt-bindings/clock/imx6sl-clock.h

+++ b/include/dt-bindings/clock/imx6sl-clock.h

@@ -175,7 +175,8 @@

#define IMX6SL_CLK_SSI3_IPG            162

#define IMX6SL_CLK_UART_OSC_4M         163

#define IMX6SL_CLK_SPDIF_GCLK          164

-#define IMX6SL_CLK_END                 165

+#define IMX6SL_CLK_EIM_SLOW            165

+#define IMX6SL_CLK_END                 166

--- a/arch/arm/mach-imx/clk-imx6sl.c

+++ b/arch/arm/mach-imx/clk-imx6sl.c

@@ -415,6 +415,7 @@ static void __init imx6sl_clocks_init(struct device_node *ccm_node)

        clks[IMX6SL_CLK_USDHC2]       = imx_clk_gate2("usdhc2",       "usdhc2_podf",       base + 0x80, 4);

        clks[IMX6SL_CLK_USDHC3]       = imx_clk_gate2("usdhc3",       "usdhc3_podf",       base + 0x80, 6);

        clks[IMX6SL_CLK_USDHC4]       = imx_clk_gate2("usdhc4",       "usdhc4_podf",       base + 0x80, 8);

+       clks[IMX6SL_CLK_EIM_SLOW]     = imx_clk_gate2("eim",          "perclk",            base + 0x80, 10);

        for (i = 0; i < ARRAY_SIZE(clks); i++)

                if (IS_ERR(clks[i]))

--- a/arch/arm/boot/dts/imx6sl.dtsi

+++ b/arch/arm/boot/dts/imx6sl.dtsi

@@ -903,8 +903,9 @@

                        };

                        weim: weim@021b8000 {

+                               compatible = "fsl,imx6sx-weim", "fsl,imx6q-weim";

                                reg = <0x021b8000 0x4000>;

-                               interrupts = <0 14 IRQ_TYPE_LEVEL_HIGH>;

+                               clocks = <&clks IMX6SL_CLK_EIM_SLOW>;

                        };

                        ocotp: ocotp-ctrl@021bc000 {

Seems to bootup but no EIM transactions working yet.

I was expecting clock rate to be 66MHz but looks like it is 24MHz.

root@imx6slevk:~# cat /sys/kernel/debug/clk/osc/perclk_sel/perclk/eim/clk_rate

24000000

[igorpadykov]

Hi Jaya

i.MX6SL weim module is the same as in i.MX6SX,UL

so one can look for example working configuration for

imx6sx-19x19-arm2.dts:

linux-2.6-imx.git - Freescale i.MX Linux Tree

Best regards

igor

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[jayakumar2]

Hi Igor,

Thanks for your reply. But I'm confused. I'm asking about the imx-weim driver specifically, whereas the imx6sx-19x19-arm2.dts example uses the nor driver. This is the section of code in the imx6sx dts that is relevant:

	nor@0,0 {
		compatible = "cfi-flash";

Whereas what I was saying is that if we put compatible = "imx-weim", then it would not work on 6sl because the imx-weim driver doesn't have a 6sl id included.

static const struct of_device_id weim_id_table[] = {

        /* i.MX1/21 */

        { .compatible = "fsl,imx1-weim", .data = &imx1_weim_devtype, },

        /* i.MX25/27/31/35 */

        { .compatible = "fsl,imx27-weim", .data = &imx27_weim_devtype, },

        /* i.MX50/53/6Q */

        { .compatible = "fsl,imx50-weim", .data = &imx50_weim_devtype, },

        { .compatible = "fsl,imx6q-weim", .data = &imx50_weim_devtype, },

        /* i.MX51 */

        { .compatible = "fsl,imx51-weim", .data = &imx51_weim_devtype, },

        { }

};

Thanks,

jaya

[igorpadykov]

Hi Jaya

mentioned i.MX6SX example also has not "6sx id included", however it works.

Seems "fsl,imx6q-weim", .compatible = "fsl,imx6q-weim" records are sufficient for correct operation.

Best regards

igor

[jayakumar2]

Hi Igor,

I'm not sure why you're saying "it works". I thought I gave an explanation of the difference above. The imx6sx example does not use the imx-weim driver, it uses cfi-flash which is a different driver (it is only for nor flash) than imx-weim which is what the subject of this is. The reason for using imx-weim is that I'm interfacing with an fpga in userspace, not a flash chip.

Thanks!

[igorpadykov]

Hi Jaya

I believe i.MX6SX uses  imx-weim driver,  for interfacing fpga

one can use "nor flash" configuration or reuse it.

Best regards

igor

[jayakumar2]

Igor,

"I believe i.MX6SX uses  imx-weim driver"

I'm not able to follow this logic. You mentioned compatible = "fsl,imx6q-weim" which does not exist in that dts or any dts in the arch/arm/boot/dts directory. Could you check where you got that from because it is not in imx6sx-19x19-arm2.dts.

Eg:

linux-imx/3.14.28-r0/git$ egrep "imx6q-weim" arch/arm/boot/dts/*

linux-imx/3.14.28-r0/git$

The only place where "imx6q-weim" is mentioned is in Documentation/devicetree/bindings/bus/imx-weim.txt.

Thanks!