linux-kernel - [PATCH v5] i2c: imx: make bus recovery through pinctrl optional

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Date:   Fri, 19 Aug 2016 17:05:22 -0500
From:   Li Yang <leoyang.li@....com>
To:     Wolfram Sang <wsa@...-dreams.de>, <linux-i2c@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>
CC:     Li Yang <leoyang.li@....com>, Gao Pan <pandy.gao@....com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>
Subject: [PATCH v5] i2c: imx: make bus recovery through pinctrl optional

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 with this controller such as ls1021a
and ls1043a, and the device tree binding also mentioned this gpio based
recovery mechanism as optional.  The patch makes it really optional that
the probe function won't bailout but just disable the bus recovery function
when pinctrl is not available.

Signed-off-by: Li Yang <leoyang.li@....com>
Cc: Gao Pan <pandy.gao@....com>
Cc: Uwe Kleine-König <u.kleine-koenig@...gutronix.de>
Acked-by: Linus Walleij <linus.walleij@...aro.org>
---
v5:
Revert the last minute change of recovery info initialization timing, it
will cause problem if initialized after i2c_add_numbered_adapter()

v4:
Remove the use of IS_ERR_OR_NULL
Move the condition judgement to i2c_imx_init_recovery_info()
Change the timing of recovery initialization to be after bus registration

v3:
Rebased to Wolfram's for-next branch
Added acked-by from Linus Walleij
Update to use new nxp email addresses due to company merge

 drivers/i2c/busses/i2c-imx.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 1844bc9..7ae7992 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -989,6 +989,15 @@ static void i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
 {
 	struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;
 
+	/* if pinctrl is not supported on the system */
+	if (IS_ERR(i2c_imx->pinctrl))
+		i2c_imx->pinctrl = NULL;
+
+	if (!i2c_imx->pinctrl) {
+		dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
+		return;
+	}
+
 	i2c_imx->pinctrl_pins_default = pinctrl_lookup_state(i2c_imx->pinctrl,
 			PINCTRL_STATE_DEFAULT);
 	i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx->pinctrl,
@@ -1081,8 +1090,11 @@ 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;
 	}
@@ -1125,6 +1137,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
 			i2c_imx, IMX_I2C_I2CR);
 	imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
 
+	/* Init bus recovery info if supported */
 	i2c_imx_init_recovery_info(i2c_imx, pdev);
 
 	/* Add I2C adapter */
-- 
1.9.0