Re: [PATCH] i2c/synquacer: Deal with optional PCLK correctly

From: Marion & Christophe JAILLET
Date: Thu Sep 12 2024 - 13:12:12 EST


(trying to merge t and cc fields from Ard's and Andy's messages)


Le 12/09/2024 à 12:46, Ard Biesheuvel a écrit :
From: Ard Biesheuvel <ardb@xxxxxxxxxx>

ACPI boot does not provide clocks and regulators, but instead, provides
the PCLK rate directly, and enables the clock in firmware. So deal
gracefully with this.

Fixes: 55750148e559 ("i2c: synquacer: Fix an error handling path in synquacer_i2c_probe()")

Hi,

If that matters, I'm not sure that the Fixes tag is correct.

IIUC, either it is a new functionally that is added (now it works with ACPI...), or if considered as a fix, then I think that it is linked to commit 0d676a6c4390 ("i2c: add support for Socionext SynQuacer I2C controller").

I don't think that 55750148e559 introduced a regression. The issue seems to be there since the beginning. Agreed?

If yes, then it may be needed to backport it in older kernels too.

CJ

Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Andi Shyti <andi.shyti@xxxxxxxxxx>
Cc: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
https://lore.kernel.org/all/CAMj1kXFH+zB_YuUS+vaEpguhuVGLYbQw55VNDCxnBfSPe6b-nw@xxxxxxxxxxxxxx/T/#u

drivers/i2c/busses/i2c-synquacer.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-synquacer.c b/drivers/i2c/busses/i2c-synquacer.c
index 4eccbcd0fbfc..bbb9062669e4 100644
--- a/drivers/i2c/busses/i2c-synquacer.c
+++ b/drivers/i2c/busses/i2c-synquacer.c
@@ -550,12 +550,13 @@ static int synquacer_i2c_probe(struct platform_device *pdev)
device_property_read_u32(&pdev->dev, "socionext,pclk-rate",
&i2c->pclkrate);
- pclk = devm_clk_get_enabled(&pdev->dev, "pclk");
+ pclk = devm_clk_get_optional_enabled(&pdev->dev, "pclk");
if (IS_ERR(pclk))
return dev_err_probe(&pdev->dev, PTR_ERR(pclk),
"failed to get and enable clock\n");
- i2c->pclkrate = clk_get_rate(pclk);
+ if (pclk)
+ i2c->pclkrate = clk_get_rate(pclk);
if (i2c->pclkrate < SYNQUACER_I2C_MIN_CLK_RATE ||
i2c->pclkrate > SYNQUACER_I2C_MAX_CLK_RATE)