linux-kernel - Re: [PATCH v1 1/2] i2c:busses:Register PCI1XXXX adapter to I2C subsystem

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Date:   Thu, 7 Oct 2021 19:40:04 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     LakshmiPraveen Kopparthi <LakshmiPraveen.Kopparthi@...rochip.com>,
        wsa@...nel.org, andriy.shevchenko@...ux.intel.com,
        treding@...dia.com, mirq-linux@...e.qmqm.pl, s.shtylyov@....ru,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     UNGLinuxDriver@...rochip.com
Subject: Re: [PATCH v1 1/2] i2c:busses:Register PCI1XXXX adapter to I2C
 subsystem

29.09.2021 09:22, LakshmiPraveen Kopparthi пишет:
> +static int pci1xxxx_i2c_suspend(struct device *dev)
> +{
> +	struct pci1xxxx_i2c *i2c = dev_get_drvdata(dev);
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	u32 regval;
> +
> +	i2c_mark_adapter_suspended(&i2c->adap);
> +
> +	pci1xxxx_ack_high_level_intr(i2c, ALL_HIGH_LAYER_INTR);
> +	pci1xxxx_i2c_config_high_level_intr(i2c, ALL_HIGH_LAYER_INTR, false);
> +
> +	/*
> +	 * Enable the PERST_DIS bit to mask the PERST from
> +	 * resetting the core regs
> +	 */
> +	regval = readl(i2c->i2c_base + SMBUS_RESET_REG);
> +	regval |= PERI_SMBUS_D3_RESET_DIS;
> +	writel(regval, i2c->i2c_base + SMBUS_RESET_REG);
> +
> +	return 0;
> +}
> +
> +static int pci1xxxx_i2c_resume(struct device *dev)
> +{
> +	struct pci1xxxx_i2c *i2c = dev_get_drvdata(dev);
> +	struct pci_dev *pdev = to_pci_dev(dev);
> +	u32 regval;
> +
> +	i2c_mark_adapter_resumed(&i2c->adap);
> +
> +	regval = readl(i2c->i2c_base + SMBUS_RESET_REG);
> +	regval &= ~PERI_SMBUS_D3_RESET_DIS;
> +	writel(regval, i2c->i2c_base + SMBUS_RESET_REG);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(pci1xxxx_i2c_pm_ops, pci1xxxx_i2c_suspend,
> +			 pci1xxxx_i2c_resume);

Can you move suspend/resume to NOIRQ level? Device drivers may require
to access I2C early on resume (or late on suspend), it's a common
trouble for bus drivers.