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| author |   Carlos Song <carlos.song@nxp.com> | 2024-12-26 14:25:21 +0800 |
|---|---|---|
| committer |   Andi Shyti <andi.shyti@kernel.org> | 2025-01-07 23:46:10 +0100 |
| commit | d9a13c08f88d696218a44658f290b1b433e787b6 (patch) | |
| tree | 9d7bd30873988ddfcf7af0ce6e7b2144fc80bd57 | |
| parent | i2c: npcm: Enable slave in eob interrupt (diff) | |
| download | wireguard-linux-d9a13c08f88d696218a44658f290b1b433e787b6.tar.xz wireguard-linux-d9a13c08f88d696218a44658f290b1b433e787b6.zip | |
i2c: imx: support DMA defer probing
Return -EPROBE_DEFER when dma_request_slave_channel() because DMA driver
have not ready yet.
Move i2c_imx_dma_request() before registering I2C adapter to avoid
infinite loop of .probe() calls to the same driver, see "e8c220fac415
Revert "i2c: imx: improve the error handling in i2c_imx_dma_request()""
and "Documentation/driver-api/driver-model/driver.rst".
Use CPU mode to avoid stuck registering i2c adapter when DMA resources
are unavailable.
Signed-off-by: Carlos Song <carlos.song@nxp.com>
Signed-off-by: Clark Wang <xiaoning.wang@nxp.com>
Acked-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Acked-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://lore.kernel.org/r/20241226062521.1004809-1-carlos.song@nxp.com
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Diffstat (limited to '')
| -rw-r--r-- | drivers/i2c/busses/i2c-imx.c | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 1f441227bfdc..ee0d25b498cb 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -397,17 +397,16 @@ 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; - struct device *dev = &i2c_imx->adapter.dev; + struct device *dev = i2c_imx->adapter.dev.parent; int ret; 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)) { @@ -452,7 +451,7 @@ 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); @@ -460,6 +459,8 @@ fail_tx: dma_release_channel(dma->chan_tx); fail_al: devm_kfree(dev, dma); + + return ret; } static void i2c_imx_dma_callback(void *arg) @@ -1802,6 +1803,22 @@ static int i2c_imx_probe(struct platform_device *pdev) if (ret == -EPROBE_DEFER) goto clk_notifier_unregister; + /* + * DMA mode should be optional for I2C, when encountering DMA errors, + * no need to exit I2C probe. Only print warning to show DMA error and + * use PIO mode directly to ensure I2C bus available as much as possible. + */ + ret = i2c_imx_dma_request(i2c_imx, phy_addr); + if (ret) { + if (ret == -EPROBE_DEFER) + goto clk_notifier_unregister; + else if (ret == -ENODEV) + dev_dbg(&pdev->dev, "Only use PIO mode\n"); + else + dev_warn(&pdev->dev, "Failed to setup DMA (%pe), only use PIO mode\n", + ERR_PTR(ret)); + } + /* Add I2C adapter */ ret = i2c_add_numbered_adapter(&i2c_imx->adapter); if (ret < 0) @@ -1816,9 +1833,6 @@ static int i2c_imx_probe(struct platform_device *pdev) i2c_imx->adapter.name); dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n"); - /* Init DMA config if supported */ - i2c_imx_dma_request(i2c_imx, phy_addr); - return 0; /* Return OK */ clk_notifier_unregister: |