i2c-imx.c

			dev_dbg(&i2c_imx->adapter.dev,
				"<%s> repeated start\n", __func__);
			temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
			temp |= I2CR_RSTA;
			imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
			result = i2c_imx_bus_busy(i2c_imx, 1, atomic);
			if (result)
				goto fail0;
		}
		dev_dbg(&i2c_imx->adapter.dev,
			"<%s> transfer message: %d\n", __func__, i);
		/* write/read data */
#ifdef CONFIG_I2C_DEBUG_BUS
		temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
		dev_dbg(&i2c_imx->adapter.dev,
			"<%s> CONTROL: IEN=%d, IIEN=%d, MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n",
			__func__,
			(temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0),
			(temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0),
			(temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0));
		temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
		dev_dbg(&i2c_imx->adapter.dev,
			"<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n",
			__func__,
			(temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0),
			(temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0),
			(temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0),
			(temp & I2SR_RXAK ? 1 : 0));
#endif
		if (msgs[i].flags & I2C_M_RD) {
			result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg, atomic);
		} else {
			if (!atomic &&
			    i2c_imx->dma && msgs[i].len >= DMA_THRESHOLD)
				result = i2c_imx_dma_write(i2c_imx, &msgs[i]);
			else
				result = i2c_imx_write(i2c_imx, &msgs[i], atomic);
		}
		if (result)
			goto fail0;
	}

fail0:
	/* Stop I2C transfer */
	i2c_imx_stop(i2c_imx, atomic);

	dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
		(result < 0) ? "error" : "success msg",
			(result < 0) ? result : num);
	return (result < 0) ? result : num;
}

static int i2c_imx_xfer(struct i2c_adapter *adapter,
			struct i2c_msg *msgs, int num)
{
	struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
	bool enable_runtime_pm = false;
	int result;

	if (!pm_runtime_enabled(i2c_imx->adapter.dev.parent)) {
		pm_runtime_enable(i2c_imx->adapter.dev.parent);
		enable_runtime_pm = true;
	}

	result = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
	if (result < 0) {
		if (enable_runtime_pm)
			pm_runtime_disable(i2c_imx->adapter.dev.parent);
		return result;
	}

	result = i2c_imx_xfer_common(adapter, msgs, num, false);

	pm_runtime_mark_last_busy(i2c_imx->adapter.dev.parent);
	pm_runtime_put_autosuspend(i2c_imx->adapter.dev.parent);

	return result;
}

static int i2c_imx_xfer_atomic(struct i2c_adapter *adapter,
			       struct i2c_msg *msgs, int num)
{
	struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
	int result;

	result = clk_enable(i2c_imx->clk);
	if (result)
		return result;

	result = i2c_imx_xfer_common(adapter, msgs, num, true);

	clk_disable(i2c_imx->clk);

	return result;
}

static void i2c_imx_prepare_recovery(struct i2c_adapter *adap)
{
	struct imx_i2c_struct *i2c_imx;

	i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);

	pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_gpio);
}

static void i2c_imx_unprepare_recovery(struct i2c_adapter *adap)
{
	struct imx_i2c_struct *i2c_imx;

	i2c_imx = container_of(adap, struct imx_i2c_struct, adapter);

	pinctrl_select_state(i2c_imx->pinctrl, i2c_imx->pinctrl_pins_default);
}

/*
 * We switch SCL and SDA to their GPIO function and do some bitbanging
 * for bus recovery. These alternative pinmux settings can be
 * described in the device tree by a separate pinctrl state "gpio". If
 * this is missing this is not a big problem, the only implication is
 * that we can't do bus recovery.
 */
static int i2c_imx_init_recovery_info(struct imx_i2c_struct *i2c_imx,
		struct platform_device *pdev)
{
	struct i2c_bus_recovery_info *rinfo = &i2c_imx->rinfo;

	i2c_imx->pinctrl = devm_pinctrl_get(&pdev->dev);
	if (!i2c_imx->pinctrl || IS_ERR(i2c_imx->pinctrl)) {
		dev_info(&pdev->dev, "can't get pinctrl, bus recovery not supported\n");
		return PTR_ERR(i2c_imx->pinctrl);
	}

	i2c_imx->pinctrl_pins_default = pinctrl_lookup_state(i2c_imx->pinctrl,
			PINCTRL_STATE_DEFAULT);
	i2c_imx->pinctrl_pins_gpio = pinctrl_lookup_state(i2c_imx->pinctrl,
			"gpio");
	rinfo->sda_gpiod = devm_gpiod_get(&pdev->dev, "sda", GPIOD_IN);
	rinfo->scl_gpiod = devm_gpiod_get(&pdev->dev, "scl", GPIOD_OUT_HIGH_OPEN_DRAIN);

	if (PTR_ERR(rinfo->sda_gpiod) == -EPROBE_DEFER ||
	    PTR_ERR(rinfo->scl_gpiod) == -EPROBE_DEFER) {
		return -EPROBE_DEFER;
	} else if (IS_ERR(rinfo->sda_gpiod) ||
		   IS_ERR(rinfo->scl_gpiod) ||
		   IS_ERR(i2c_imx->pinctrl_pins_default) ||
		   IS_ERR(i2c_imx->pinctrl_pins_gpio)) {
		dev_dbg(&pdev->dev, "recovery information incomplete\n");
		return 0;
	}

	dev_dbg(&pdev->dev, "using scl%s for recovery\n",
		rinfo->sda_gpiod ? ",sda" : "");

	rinfo->prepare_recovery = i2c_imx_prepare_recovery;
	rinfo->unprepare_recovery = i2c_imx_unprepare_recovery;
	rinfo->recover_bus = i2c_generic_scl_recovery;
	i2c_imx->adapter.bus_recovery_info = rinfo;

	return 0;
}

static u32 i2c_imx_func(struct i2c_adapter *adapter)
{
	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
		| I2C_FUNC_SMBUS_READ_BLOCK_DATA;
}

static const struct i2c_algorithm i2c_imx_algo = {
	.master_xfer = i2c_imx_xfer,
	.master_xfer_atomic = i2c_imx_xfer_atomic,
	.functionality = i2c_imx_func,
};

static int i2c_imx_probe(struct platform_device *pdev)
{
	struct imx_i2c_struct *i2c_imx;
	struct resource *res;
	struct imxi2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
	void __iomem *base;
	int irq, ret;
	dma_addr_t phy_addr;
	const struct imx_i2c_hwdata *match;

	dev_dbg(&pdev->dev, "<%s>\n", __func__);

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(base))
		return PTR_ERR(base);

	phy_addr = (dma_addr_t)res->start;
	i2c_imx = devm_kzalloc(&pdev->dev, sizeof(*i2c_imx), GFP_KERNEL);
	if (!i2c_imx)
		return -ENOMEM;

	match = device_get_match_data(&pdev->dev);
	if (match)
		i2c_imx->hwdata = match;
	else
		i2c_imx->hwdata = (struct imx_i2c_hwdata *)
				platform_get_device_id(pdev)->driver_data;

	/* Setup i2c_imx driver structure */
	strlcpy(i2c_imx->adapter.name, pdev->name, sizeof(i2c_imx->adapter.name));
	i2c_imx->adapter.owner		= THIS_MODULE;
	i2c_imx->adapter.algo		= &i2c_imx_algo;
	i2c_imx->adapter.dev.parent	= &pdev->dev;
	i2c_imx->adapter.nr		= pdev->id;
	i2c_imx->adapter.dev.of_node	= pdev->dev.of_node;
	i2c_imx->base			= base;
	ACPI_COMPANION_SET(&i2c_imx->adapter.dev, ACPI_COMPANION(&pdev->dev));

	/* Get I2C clock */
	i2c_imx->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(i2c_imx->clk))
		return dev_err_probe(&pdev->dev, PTR_ERR(i2c_imx->clk),
				     "can't get I2C clock\n");

	ret = clk_prepare_enable(i2c_imx->clk);
	if (ret) {
		dev_err(&pdev->dev, "can't enable I2C clock, ret=%d\n", ret);
		return ret;
	}

	/* Init queue */
	init_waitqueue_head(&i2c_imx->queue);

	/* Set up adapter data */
	i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);

	/* Set up platform driver data */
	platform_set_drvdata(pdev, i2c_imx);

	pm_runtime_set_autosuspend_delay(&pdev->dev, I2C_PM_TIMEOUT);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_set_active(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	ret = pm_runtime_get_sync(&pdev->dev);
	if (ret < 0)
		goto rpm_disable;

	/* Request IRQ */
	ret = request_threaded_irq(irq, i2c_imx_isr, NULL,
				   IRQF_SHARED | IRQF_NO_SUSPEND,
				   pdev->name, i2c_imx);
	if (ret) {
		dev_err(&pdev->dev, "can't claim irq %d\n", irq);
		goto rpm_disable;
	}

	/* Set up clock divider */
	i2c_imx->bitrate = I2C_MAX_STANDARD_MODE_FREQ;
	ret = of_property_read_u32(pdev->dev.of_node,
				   "clock-frequency", &i2c_imx->bitrate);
	if (ret < 0 && pdata && pdata->bitrate)
		i2c_imx->bitrate = pdata->bitrate;
	i2c_imx->clk_change_nb.notifier_call = i2c_imx_clk_notifier_call;
	clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);
	i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));

	/*
	 * This limit caused by an i.MX7D hardware issue(e7805 in Errata).
	 * If there is no limit, when the bitrate set up to 400KHz, it will
	 * cause the SCK low level period less than 1.3us.
	 */
	if (is_imx7d_i2c(i2c_imx) && i2c_imx->bitrate > IMX_I2C_MAX_E_BIT_RATE)
		i2c_imx->bitrate = IMX_I2C_MAX_E_BIT_RATE;

	/* Set up chip registers to defaults */
	imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
			i2c_imx, IMX_I2C_I2CR);
	imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);

	/* Init optional bus recovery function */
	ret = i2c_imx_init_recovery_info(i2c_imx, pdev);
	/* Give it another chance if pinctrl used is not ready yet */
	if (ret == -EPROBE_DEFER)
		goto clk_notifier_unregister;

	/* Add I2C adapter */
	ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
	if (ret < 0)
		goto clk_notifier_unregister;

	pm_runtime_mark_last_busy(&pdev->dev);
	pm_runtime_put_autosuspend(&pdev->dev);

	dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", irq);
	dev_dbg(&i2c_imx->adapter.dev, "device resources: %pR\n", res);
	dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
		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:
	clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
	free_irq(irq, i2c_imx);
rpm_disable:
	pm_runtime_put_noidle(&pdev->dev);
	pm_runtime_disable(&pdev->dev);
	pm_runtime_set_suspended(&pdev->dev);
	pm_runtime_dont_use_autosuspend(&pdev->dev);
	clk_disable_unprepare(i2c_imx->clk);
	return ret;
}

static int i2c_imx_remove(struct platform_device *pdev)
{
	struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
	int irq, ret;

	ret = pm_runtime_get_sync(&pdev->dev);
	if (ret < 0)
		return ret;

	/* remove adapter */
	dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
	i2c_del_adapter(&i2c_imx->adapter);

	if (i2c_imx->dma)
		i2c_imx_dma_free(i2c_imx);

	/* setup chip registers to defaults */
	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);
	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IFDR);
	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2CR);
	imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);

	clk_notifier_unregister(i2c_imx->clk, &i2c_imx->clk_change_nb);
	irq = platform_get_irq(pdev, 0);
	if (irq >= 0)
		free_irq(irq, i2c_imx);
	clk_disable_unprepare(i2c_imx->clk);

	pm_runtime_put_noidle(&pdev->dev);
	pm_runtime_disable(&pdev->dev);

	return 0;
}

static int __maybe_unused i2c_imx_runtime_suspend(struct device *dev)
{
	struct imx_i2c_struct *i2c_imx = dev_get_drvdata(dev);

	clk_disable_unprepare(i2c_imx->clk);
	pinctrl_pm_select_sleep_state(dev);

	return 0;
}

static int __maybe_unused i2c_imx_runtime_resume(struct device *dev)
{
	struct imx_i2c_struct *i2c_imx = dev_get_drvdata(dev);
	int ret;

	pinctrl_pm_select_default_state(dev);
	ret = clk_prepare_enable(i2c_imx->clk);
	if (ret)
		dev_err(dev, "can't enable I2C clock, ret=%d\n", ret);

	return ret;
}

static int i2c_imx_suspend(struct device *dev)
{
	pinctrl_pm_select_sleep_state(dev);
	return 0;
}

static int i2c_imx_resume(struct device *dev)
{
	pinctrl_pm_select_default_state(dev);
	return 0;
}

static const struct dev_pm_ops i2c_imx_pm_ops = {
	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(i2c_imx_suspend, i2c_imx_resume)
	SET_RUNTIME_PM_OPS(i2c_imx_runtime_suspend,
			   i2c_imx_runtime_resume, NULL)
};

static struct platform_driver i2c_imx_driver = {
	.probe = i2c_imx_probe,
	.remove = i2c_imx_remove,
	.driver = {
		.name = DRIVER_NAME,
		.pm = &i2c_imx_pm_ops,
		.of_match_table = i2c_imx_dt_ids,
		.acpi_match_table = i2c_imx_acpi_ids,
	},
	.id_table = imx_i2c_devtype,
};

static int __init i2c_adap_imx_init(void)
{
	return platform_driver_register(&i2c_imx_driver);
}
subsys_initcall(i2c_adap_imx_init);

static void __exit i2c_adap_imx_exit(void)
{
	platform_driver_unregister(&i2c_imx_driver);
}
module_exit(i2c_adap_imx_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Darius Augulis");
MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
MODULE_ALIAS("platform:" DRIVER_NAME);