[PATCH v2] i2c: imx: make bus recovery through pinctrl optional

[PATCH v2] i2c: imx: make bus recovery through pinctrl optional

[Li Yang]

Since commit 1c4b6c3bcf30 ("i2c: imx: implement bus recovery") the driver
starts to use gpio/pinctrl to do i2c bus recovery.  But pinctrl is not
always available for platforms using this driver such as ls1021a and
ls1043a, and the device tree binding also mentioned this gpio based
recovery mechanism as optional.  The patch make it really optional that
the probe function won't bailout when pinctrl is not available and it
won't try to register recovery functions if pinctrl is NULL when the
PINCTRL is not enabled at all.

Signed-off-by: Li Yang <leoli@freescale.com>
Cc: Gao Pan <b54642@freescale.com>
---
v2: bailout on -ENOMEM and -EPROBE_DEFER

 drivers/i2c/busses/i2c-imx.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 9bb0b05..41289f8 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -1087,8 +1087,11 @@ static int i2c_imx_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/* optional bus recovery feature through pinctrl */
 	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
-	if (IS_ERR(i2c_imx->pinctrl)) {
+	/* bailout on -ENOMEM or -EPROBE_DEFER, continue for other errors */
+	if (PTR_ERR(i2c_imx->pinctrl) == -ENOMEM ||
+			PTR_ERR(i2c_imx->pinctrl) == -EPROBE_DEFER) {
 		ret = PTR_ERR(i2c_imx->pinctrl);
 		goto clk_disable;
 	}
@@ -1126,7 +1129,10 @@ static int i2c_imx_probe(struct platform_device *pdev)
 		goto clk_disable;
 	}
 
-	i2c_imx_init_recovery_info(i2c_imx, pdev);
+	if (IS_ERR_OR_NULL(i2c_imx->pinctrl))
+		dev_info(&pdev->dev, "can't get pinctrl, bus recovery feature disabled\n");
+	else
+		i2c_imx_init_recovery_info(i2c_imx, pdev);
 
 	/* Set up platform driver data */
 	platform_set_drvdata(pdev, i2c_imx);
-- 
2.3.3

Re: [PATCH v2] i2c: imx: make bus recovery through pinctrl optional

[Linus Walleij]

On Fri, Nov 20, 2015 at 10:45 PM, Li Yang <leoli@freescale.com> wrote:

> -       if (IS_ERR(i2c_imx->pinctrl)) {
> +       /* bailout on -ENOMEM or -EPROBE_DEFER, continue for other errors */
> +       if (PTR_ERR(i2c_imx->pinctrl) == -ENOMEM ||
> +                       PTR_ERR(i2c_imx->pinctrl) == -EPROBE_DEFER) {

This is one of the evils of deferred probe: you never know if
something will eventually turn up. It feels wrong to bail out
on deferred probe...

I have no better idea though.
Acked-by

Yours,
Linus Walleij

Re: [PATCH v2] i2c: imx: make bus recovery through pinctrl optional

[Wolfram Sang]

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On Mon, Nov 30, 2015 at 01:55:19PM +0100, Linus Walleij wrote:
> On Fri, Nov 20, 2015 at 10:45 PM, Li Yang <leoli@freescale.com> wrote:
> 
> > -       if (IS_ERR(i2c_imx->pinctrl)) {
> > +       /* bailout on -ENOMEM or -EPROBE_DEFER, continue for other errors */
> > +       if (PTR_ERR(i2c_imx->pinctrl) == -ENOMEM ||
> > +                       PTR_ERR(i2c_imx->pinctrl) == -EPROBE_DEFER) {
> 
> This is one of the evils of deferred probe: you never know if
> something will eventually turn up. It feels wrong to bail out
> on deferred probe...
> 
> I have no better idea though.
> Acked-by

Linus, proper ack next time please, so patchwork will pick it up
automatically.

Li Yang: There have been some other changes to the imx driver. Could you
rebase against my for-next or for-4.5 and add Linus' ack? Thanks!


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