static int rk3x_i2c_probe()

in busses/i2c-rk3x.c [1222:1364]

• 108 lines of code
• 17 McCabe index (conditional complexity)

static int rk3x_i2c_probe(struct platform_device *pdev)
{
	struct device_node *np = pdev->dev.of_node;
	const struct of_device_id *match;
	struct rk3x_i2c *i2c;
	int ret = 0;
	int bus_nr;
	u32 value;
	int irq;
	unsigned long clk_rate;

	i2c = devm_kzalloc(&pdev->dev, sizeof(struct rk3x_i2c), GFP_KERNEL);
	if (!i2c)
		return -ENOMEM;

	match = of_match_node(rk3x_i2c_match, np);
	i2c->soc_data = match->data;

	/* use common interface to get I2C timing properties */
	i2c_parse_fw_timings(&pdev->dev, &i2c->t, true);

	strlcpy(i2c->adap.name, "rk3x-i2c", sizeof(i2c->adap.name));
	i2c->adap.owner = THIS_MODULE;
	i2c->adap.algo = &rk3x_i2c_algorithm;
	i2c->adap.retries = 3;
	i2c->adap.dev.of_node = np;
	i2c->adap.algo_data = i2c;
	i2c->adap.dev.parent = &pdev->dev;

	i2c->dev = &pdev->dev;

	spin_lock_init(&i2c->lock);
	init_waitqueue_head(&i2c->wait);

	i2c->regs = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(i2c->regs))
		return PTR_ERR(i2c->regs);

	/* Try to set the I2C adapter number from dt */
	bus_nr = of_alias_get_id(np, "i2c");

	/*
	 * Switch to new interface if the SoC also offers the old one.
	 * The control bit is located in the GRF register space.
	 */
	if (i2c->soc_data->grf_offset >= 0) {
		struct regmap *grf;

		grf = syscon_regmap_lookup_by_phandle(np, "rockchip,grf");
		if (IS_ERR(grf)) {
			dev_err(&pdev->dev,
				"rk3x-i2c needs 'rockchip,grf' property\n");
			return PTR_ERR(grf);
		}

		if (bus_nr < 0) {
			dev_err(&pdev->dev, "rk3x-i2c needs i2cX alias");
			return -EINVAL;
		}

		/* 27+i: write mask, 11+i: value */
		value = BIT(27 + bus_nr) | BIT(11 + bus_nr);

		ret = regmap_write(grf, i2c->soc_data->grf_offset, value);
		if (ret != 0) {
			dev_err(i2c->dev, "Could not write to GRF: %d\n", ret);
			return ret;
		}
	}

	/* IRQ setup */
	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	ret = devm_request_irq(&pdev->dev, irq, rk3x_i2c_irq,
			       0, dev_name(&pdev->dev), i2c);
	if (ret < 0) {
		dev_err(&pdev->dev, "cannot request IRQ\n");
		return ret;
	}

	platform_set_drvdata(pdev, i2c);

	if (i2c->soc_data->calc_timings == rk3x_i2c_v0_calc_timings) {
		/* Only one clock to use for bus clock and peripheral clock */
		i2c->clk = devm_clk_get(&pdev->dev, NULL);
		i2c->pclk = i2c->clk;
	} else {
		i2c->clk = devm_clk_get(&pdev->dev, "i2c");
		i2c->pclk = devm_clk_get(&pdev->dev, "pclk");
	}

	if (IS_ERR(i2c->clk))
		return dev_err_probe(&pdev->dev, PTR_ERR(i2c->clk),
				     "Can't get bus clk\n");

	if (IS_ERR(i2c->pclk))
		return dev_err_probe(&pdev->dev, PTR_ERR(i2c->pclk),
				     "Can't get periph clk\n");

	ret = clk_prepare(i2c->clk);
	if (ret < 0) {
		dev_err(&pdev->dev, "Can't prepare bus clk: %d\n", ret);
		return ret;
	}
	ret = clk_prepare(i2c->pclk);
	if (ret < 0) {
		dev_err(&pdev->dev, "Can't prepare periph clock: %d\n", ret);
		goto err_clk;
	}

	i2c->clk_rate_nb.notifier_call = rk3x_i2c_clk_notifier_cb;
	ret = clk_notifier_register(i2c->clk, &i2c->clk_rate_nb);
	if (ret != 0) {
		dev_err(&pdev->dev, "Unable to register clock notifier\n");
		goto err_pclk;
	}

	ret = clk_enable(i2c->clk);
	if (ret < 0) {
		dev_err(&pdev->dev, "Can't enable bus clk: %d\n", ret);
		goto err_clk_notifier;
	}

	clk_rate = clk_get_rate(i2c->clk);
	rk3x_i2c_adapt_div(i2c, clk_rate);
	clk_disable(i2c->clk);

	ret = i2c_add_adapter(&i2c->adap);
	if (ret < 0)
		goto err_clk_notifier;

	return 0;

err_clk_notifier:
	clk_notifier_unregister(i2c->clk, &i2c->clk_rate_nb);
err_pclk:
	clk_unprepare(i2c->pclk);
err_clk:
	clk_unprepare(i2c->clk);
	return ret;
}