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i2c: imx-lpi2c: reset controller in probe stage

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Reset I2C controller in probe stage to avoid unexpected LPI2C controller
state left from previous stages and hang system boot.

Per the LPI2C reference manual, section 7.1.4 "Controller Control (MCR)"
and 7.1.20 Target Control (SCR), the RST bit (bit 1) description states:

  "The reset takes effect immediately and remains asserted until negated
  by software. There is no minimum delay required before clearing the
  software reset."

Therefore, it is safe to write 0 to MCR and SCR immediately after
asserting the RST bit without any additional delay.

Signed-off-by: Carlos Song <carlos.song@nxp.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Link: https://lore.kernel.org/r/20260716071957.2670263-3-carlos.song@oss.nxp.com
This commit is contained in:
Carlos Song
2026-07-16 15:19:57 +08:00
committed by Andi Shyti
parent cbd043b00e
commit a4c419356a
1 changed files with 14 additions and 5 deletions
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19
drivers/i2c/busses/i2c-imx-lpi2c.c
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@@ -1510,11 +1510,6 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
if (ret)
lpi2c_imx->bitrate = I2C_MAX_STANDARD_MODE_FREQ;
ret = devm_request_irq(&pdev->dev, lpi2c_imx->irq, lpi2c_imx_isr, IRQF_NO_SUSPEND,
pdev->name, lpi2c_imx);
if (ret)
return ret;
i2c_set_adapdata(&lpi2c_imx->adapter, lpi2c_imx);
platform_set_drvdata(pdev, lpi2c_imx);
@@ -1550,6 +1545,20 @@ static int lpi2c_imx_probe(struct platform_device *pdev)
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
/*
* Reset all internal controller registers of both Master and Target
* to avoid effects of previous status.
*/
writel(MCR_RST, lpi2c_imx->base + LPI2C_MCR);
writel(SCR_RST, lpi2c_imx->base + LPI2C_SCR);
writel(0, lpi2c_imx->base + LPI2C_MCR);
writel(0, lpi2c_imx->base + LPI2C_SCR);
ret = devm_request_irq(&pdev->dev, lpi2c_imx->irq, lpi2c_imx_isr, IRQF_NO_SUSPEND,
pdev->name, lpi2c_imx);
if (ret)
goto rpm_disable;
temp = readl(lpi2c_imx->base + LPI2C_PARAM);
lpi2c_imx->txfifosize = 1 << (temp & 0x0f);
lpi2c_imx->rxfifosize = 1 << ((temp >> 8) & 0x0f);