i2c: ocores: fix clock-frequency binding usage

- compatible      : "opencores,i2c-ocores" or "aeroflexgaisler,i2cmst"

- reg             : bus address start and address range size of device

- interrupts      : interrupt number

- clock-frequency : frequency of bus clock in Hz

- opencores,ip-clock-frequency: frequency of the controller clock in Hz;

                    see the note below

- #address-cells  : should be <1>

- #size-cells     : should be <0>

Optional properties:

- clock-frequency : frequency of bus clock in Hz; see the note below.

                    Defaults to 100 KHz when the property is not specified

- reg-shift       : device register offsets are shifted by this value

- reg-io-width    : io register width in bytes (1, 2 or 4)

- regstep         : deprecated, use reg-shift above

Note

clock-frequency property is meant to control the bus frequency for i2c bus

drivers, but it was incorrectly used to specify i2c controller input clock

frequency. So the following rules are set to fix this situation:

- if clock-frequency is present and opencores,ip-clock-frequency is not,

  then clock-frequency specifies i2c controller clock frequency. This is

  to keep backwards compatibility with setups using old DTB. i2c bus

  frequency is fixed at 100 KHz.

- if opencores,ip-clock-frequency is present it specifies i2c controller

  clock frequency. clock-frequency property specifies i2c bus frequency.

Example:

	i2c0: ocores@a0000000 {

		compatible = "opencores,i2c-ocores";

		reg = <0xa0000000 0x8>;

		interrupts = <10>;

		clock-frequency = <20000000>;

		opencores,ip-clock-frequency = <20000000>;

		reg-shift = <0>;	/* 8 bit registers */

		reg-io-width = <1>;	/* 8 bit read/write */

	int pos;

	int nmsgs;

	int state; /* see STATE_ */

	int clock_khz;

	int ip_clock_khz;

	int bus_clock_khz;

	void (*setreg)(struct ocores_i2c *i2c, int reg, u8 value);

	u8 (*getreg)(struct ocores_i2c *i2c, int reg);

};

		return -ETIMEDOUT;

}

static void ocores_init(struct ocores_i2c *i2c)

static int ocores_init(struct device *dev, struct ocores_i2c *i2c)

{

	int prescale;

	int diff;

	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);

	/* make sure the device is disabled */

	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));

	prescale = (i2c->clock_khz / (5*100)) - 1;

	prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;

	prescale = clamp(prescale, 0, 0xffff);

	diff = i2c->ip_clock_khz / (5 * (prescale + 1)) - i2c->bus_clock_khz;

	if (abs(diff) > i2c->bus_clock_khz / 10) {

		dev_err(dev,

			"Unsupported clock settings: core: %d KHz, bus: %d KHz\n",

			i2c->ip_clock_khz, i2c->bus_clock_khz);

		return -EINVAL;

	}

	oc_setreg(i2c, OCI2C_PRELOW, prescale & 0xff);

	oc_setreg(i2c, OCI2C_PREHIGH, prescale >> 8);

	/* Init the device */

	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);

	oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);

	return 0;

}

	struct device_node *np = pdev->dev.of_node;

	const struct of_device_id *match;

	u32 val;

	u32 clock_frequency;

	bool clock_frequency_present;

	if (of_property_read_u32(np, "reg-shift", &i2c->reg_shift)) {

		/* no 'reg-shift', check for deprecated 'regstep' */

		}

	}

	if (of_property_read_u32(np, "clock-frequency", &val)) {

	clock_frequency_present = !of_property_read_u32(np, "clock-frequency",

							&clock_frequency);

	i2c->bus_clock_khz = 100;

	if (of_property_read_u32(np, "opencores,ip-clock-frequency", &val)) {

		if (!clock_frequency_present) {

			dev_err(&pdev->dev,

			"Missing required parameter 'clock-frequency'\n");

				"Missing required parameter 'opencores,ip-clock-frequency'\n");

			return -ENODEV;

		}

	i2c->clock_khz = val / 1000;

		i2c->ip_clock_khz = clock_frequency / 1000;

		dev_warn(&pdev->dev,

			 "Deprecated usage of the 'clock-frequency' property, please update to 'opencores,ip-clock-frequency'\n");

	} else {

		i2c->ip_clock_khz = val / 1000;

		if (clock_frequency_present)

			i2c->bus_clock_khz = clock_frequency / 1000;

	}

	of_property_read_u32(pdev->dev.of_node, "reg-io-width",

				&i2c->reg_io_width);

	if (pdata) {

		i2c->reg_shift = pdata->reg_shift;

		i2c->reg_io_width = pdata->reg_io_width;

		i2c->clock_khz = pdata->clock_khz;

		i2c->ip_clock_khz = pdata->clock_khz;

		i2c->bus_clock_khz = 100;

	} else {

		ret = ocores_i2c_of_probe(pdev, i2c);

		if (ret)

		}

	}

	ocores_init(i2c);

	ret = ocores_init(&pdev->dev, i2c);

	if (ret)

		return ret;

	init_waitqueue_head(&i2c->wait);

	ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,

{

	struct ocores_i2c *i2c = dev_get_drvdata(dev);

	ocores_init(i2c);

	return 0;

	return ocores_init(dev, i2c);

}

static SIMPLE_DEV_PM_OPS(ocores_i2c_pm, ocores_i2c_suspend, ocores_i2c_resume);