linux-kernel - [PATCH] i2c: imx: Defer probing if EDMA not available

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Date:   Wed, 27 Nov 2019 07:12:09 +0000
From:   Peng Ma <peng.ma@....com>
To:     "linux@...pel-privat.de" <linux@...pel-privat.de>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>
CC:     "festevam@...il.com" <festevam@...il.com>,
        dl-linux-imx <linux-imx@....com>,
        "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Peng Ma <peng.ma@....com>
Subject: [PATCH] i2c: imx: Defer probing if EDMA not available

EDMA may be not available or defered due to dependencies on
other modules, If these scenarios is encountered, we should
defer probing.

Signed-off-by: Peng Ma <peng.ma@....com>
---
 drivers/i2c/busses/i2c-imx.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c
index 40111a3..c2b0693 100644
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -369,8 +369,8 @@ static void i2c_imx_reset_regs(struct imx_i2c_struct *i2c_imx)
 }
 
 /* Functions for DMA support */
-static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
-						dma_addr_t phy_addr)
+static int i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
+			       dma_addr_t phy_addr)
 {
 	struct imx_i2c_dma *dma;
 	struct dma_slave_config dma_sconfig;
@@ -379,7 +379,7 @@ static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
 
 	dma = devm_kzalloc(dev, sizeof(*dma), GFP_KERNEL);
 	if (!dma)
-		return;
+		return -ENOMEM;
 
 	dma->chan_tx = dma_request_chan(dev, "tx");
 	if (IS_ERR(dma->chan_tx)) {
@@ -424,7 +424,7 @@ static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
 	dev_info(dev, "using %s (tx) and %s (rx) for DMA transfers\n",
 		dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
 
-	return;
+	return 0;
 
 fail_rx:
 	dma_release_channel(dma->chan_rx);
@@ -432,6 +432,8 @@ static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
 	dma_release_channel(dma->chan_tx);
 fail_al:
 	devm_kfree(dev, dma);
+
+	return ret;
 }
 
 static void i2c_imx_dma_callback(void *arg)
@@ -1605,10 +1607,14 @@ static int i2c_imx_probe(struct platform_device *pdev)
 	dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
 
 	/* Init DMA config if supported */
-	i2c_imx_dma_request(i2c_imx, phy_addr);
+	ret = i2c_imx_dma_request(i2c_imx, phy_addr);
+	if (ret == -EPROBE_DEFER)
+		goto i2c_adapter_remove;
 
 	return 0;   /* Return OK */
 
+i2c_adapter_remove:
+	i2c_del_adapter(&i2c_imx->adapter);
 clk_notifier_unregister:
 	clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
 rpm_disable:
-- 
2.9.5