From: Alexander Stein alexander.stein@ew.tq-group.com
[ Upstream commit 4268254a39484fc11ba991ae148bacbe75d9cc0a ]
Instead of repeatedly calling clk_get_rate for each transfer, lock the clock rate and cache the value. A deadlock has been observed while adding tlv320aic32x4 audio codec to the system. When this clock provider adds its clock, the clk mutex is locked already, it needs to access i2c, which in return needs the mutex for clk_get_rate as well.
Signed-off-by: Alexander Stein alexander.stein@ew.tq-group.com Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Reviewed-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Andi Shyti andi.shyti@kernel.org [ Don't call devm_clk_rate_exclusive_get() for devm_clk_rate_exclusive_get() does not exist in v6.1. ] Signed-off-by: Bin Lan bin.lan.cn@windriver.com --- drivers/i2c/busses/i2c-imx-lpi2c.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/i2c/busses/i2c-imx-lpi2c.c b/drivers/i2c/busses/i2c-imx-lpi2c.c index ff12018bc206..270197ac995a 100644 --- a/drivers/i2c/busses/i2c-imx-lpi2c.c +++ b/drivers/i2c/busses/i2c-imx-lpi2c.c @@ -100,6 +100,7 @@ struct lpi2c_imx_struct { __u8 *rx_buf; __u8 *tx_buf; struct completion complete; + unsigned long rate_per; unsigned int msglen; unsigned int delivered; unsigned int block_data; @@ -208,7 +209,8 @@ static int lpi2c_imx_config(struct lpi2c_imx_struct *lpi2c_imx)
lpi2c_imx_set_mode(lpi2c_imx);
- clk_rate = clk_get_rate(lpi2c_imx->clks[0].clk); + clk_rate = lpi2c_imx->rate_per; + if (lpi2c_imx->mode == HS || lpi2c_imx->mode == ULTRA_FAST) filt = 0; else @@ -594,6 +596,11 @@ static int lpi2c_imx_probe(struct platform_device *pdev) if (ret) return ret;
+ lpi2c_imx->rate_per = clk_get_rate(lpi2c_imx->clks[0].clk); + if (!lpi2c_imx->rate_per) + return dev_err_probe(&pdev->dev, -EINVAL, + "can't get I2C peripheral clock rate\n"); + pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT); pm_runtime_use_autosuspend(&pdev->dev); pm_runtime_get_noresume(&pdev->dev);
On Fri, Dec 13, 2024 at 02:43:14PM +0800, bin.lan.cn@eng.windriver.com wrote:
From: Alexander Stein alexander.stein@ew.tq-group.com
[ Upstream commit 4268254a39484fc11ba991ae148bacbe75d9cc0a ]
Now deleted, please see: https://lore.kernel.org/r/2024121322-conjuror-gap-b542@gregkh for what you all need to do, TOGETHER, to get this fixed and so that I can accept patches from your company in the future.
thanks,
greg k-h
[ Sasha's backport helper bot ]
Hi,
The upstream commit SHA1 provided is correct: 4268254a39484fc11ba991ae148bacbe75d9cc0a
WARNING: Author mismatch between patch and upstream commit: Backport author: bin.lan.cn@eng.windriver.com Commit author: Alexander Stein alexander.stein@ew.tq-group.com
Status in newer kernel trees: 6.12.y | Present (exact SHA1) 6.6.y | Present (different SHA1: d038693e08ad) 6.1.y | Not found
Note: The patch differs from the upstream commit: --- 1: 4268254a39484 ! 1: 3d20023e353b7 i2c: lpi2c: Avoid calling clk_get_rate during transfer @@ Metadata ## Commit message ## i2c: lpi2c: Avoid calling clk_get_rate during transfer
+ [ Upstream commit 4268254a39484fc11ba991ae148bacbe75d9cc0a ] + Instead of repeatedly calling clk_get_rate for each transfer, lock the clock rate and cache the value. A deadlock has been observed while adding tlv320aic32x4 audio codec to @@ Commit message Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Reviewed-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Andi Shyti andi.shyti@kernel.org + [ Don't call devm_clk_rate_exclusive_get() for devm_clk_rate_exclusive_get() + does not exist in v6.1. ] + Signed-off-by: Bin Lan bin.lan.cn@windriver.com
## drivers/i2c/busses/i2c-imx-lpi2c.c ## @@ drivers/i2c/busses/i2c-imx-lpi2c.c: struct lpi2c_imx_struct { @@ drivers/i2c/busses/i2c-imx-lpi2c.c: static int lpi2c_imx_config(struct lpi2c_imx lpi2c_imx_set_mode(lpi2c_imx);
- clk_rate = clk_get_rate(lpi2c_imx->clks[0].clk); -- if (!clk_rate) -- return -EINVAL; + clk_rate = lpi2c_imx->rate_per; - ++ if (lpi2c_imx->mode == HS || lpi2c_imx->mode == ULTRA_FAST) filt = 0; + else @@ drivers/i2c/busses/i2c-imx-lpi2c.c: static int lpi2c_imx_probe(struct platform_device *pdev) if (ret) return ret;
-+ /* -+ * Lock the parent clock rate to avoid getting parent clock upon -+ * each transfer -+ */ -+ ret = devm_clk_rate_exclusive_get(&pdev->dev, lpi2c_imx->clks[0].clk); -+ if (ret) -+ return dev_err_probe(&pdev->dev, ret, -+ "can't lock I2C peripheral clock rate\n"); -+ + lpi2c_imx->rate_per = clk_get_rate(lpi2c_imx->clks[0].clk); + if (!lpi2c_imx->rate_per) + return dev_err_probe(&pdev->dev, -EINVAL, ---
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-6.1.y | Success | Success |
linux-stable-mirror@lists.linaro.org
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bin.lan.cn＠eng.windriver.com -
Greg KH -
Sasha Levin