static int ti_tscadc_probe()

in ti_am335x_tscadc.c [115:300]

• 135 lines of code
• 23 McCabe index (conditional complexity)

static	int ti_tscadc_probe(struct platform_device *pdev)
{
	struct ti_tscadc_dev *tscadc;
	struct resource *res;
	struct clk *clk;
	struct device_node *node;
	struct mfd_cell *cell;
	struct property *prop;
	const __be32 *cur;
	bool use_tsc = false, use_mag = false;
	u32 val;
	int err;
	int tscmag_wires = 0, adc_channels = 0, cell_idx = 0, total_channels;
	int readouts = 0, mag_tracks = 0;

	/* Allocate memory for device */
	tscadc = devm_kzalloc(&pdev->dev, sizeof(*tscadc), GFP_KERNEL);
	if (!tscadc)
		return -ENOMEM;

	tscadc->dev = &pdev->dev;

	if (!pdev->dev.of_node) {
		dev_err(&pdev->dev, "Could not find valid DT data.\n");
		return -EINVAL;
	}

	tscadc->data = of_device_get_match_data(&pdev->dev);

	if (ti_adc_with_touchscreen(tscadc)) {
		node = of_get_child_by_name(pdev->dev.of_node, "tsc");
		of_property_read_u32(node, "ti,wires", &tscmag_wires);
		err = of_property_read_u32(node, "ti,coordinate-readouts",
					   &readouts);
		if (err < 0)
			of_property_read_u32(node, "ti,coordiante-readouts",
					     &readouts);

		of_node_put(node);

		if (tscmag_wires)
			use_tsc = true;
	} else {
		/*
		 * When adding support for the magnetic stripe reader, here is
		 * the place to look for the number of tracks used from device
		 * tree. Let's default to 0 for now.
		 */
		mag_tracks = 0;
		tscmag_wires = mag_tracks * 2;
		if (tscmag_wires)
			use_mag = true;
	}

	node = of_get_child_by_name(pdev->dev.of_node, "adc");
	of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
		adc_channels++;
		if (val > 7) {
			dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
				val);
			of_node_put(node);
			return -EINVAL;
		}
	}

	of_node_put(node);

	total_channels = tscmag_wires + adc_channels;
	if (total_channels > 8) {
		dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
		return -EINVAL;
	}

	if (total_channels == 0) {
		dev_err(&pdev->dev, "Need at least one channel.\n");
		return -EINVAL;
	}

	if (use_tsc && (readouts * 2 + 2 + adc_channels > 16)) {
		dev_err(&pdev->dev, "Too many step configurations requested\n");
		return -EINVAL;
	}

	err = platform_get_irq(pdev, 0);
	if (err < 0)
		return err;
	else
		tscadc->irq = err;

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

	tscadc->tscadc_phys_base = res->start;
	tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
					       tscadc->tscadc_base,
					       &tscadc_regmap_config);
	if (IS_ERR(tscadc->regmap)) {
		dev_err(&pdev->dev, "regmap init failed\n");
		return PTR_ERR(tscadc->regmap);
	}

	spin_lock_init(&tscadc->reg_lock);
	init_waitqueue_head(&tscadc->reg_se_wait);

	pm_runtime_enable(&pdev->dev);
	pm_runtime_get_sync(&pdev->dev);

	/*
	 * The TSC_ADC_Subsystem has 2 clock domains: OCP_CLK and ADC_CLK.
	 * ADCs produce a 12-bit sample every 15 ADC_CLK cycles.
	 * am33xx ADCs expect to capture 200ksps.
	 * am47xx ADCs expect to capture 867ksps.
	 * We need ADC clocks respectively running at 3MHz and 13MHz.
	 * These frequencies are valid since TSC_ADC_SS controller design
	 * assumes the OCP clock is at least 6x faster than the ADC clock.
	 */
	clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(clk)) {
		dev_err(&pdev->dev, "failed to get fck\n");
		err = PTR_ERR(clk);
		goto err_disable_clk;
	}

	tscadc->clk_div = (clk_get_rate(clk) / tscadc->data->target_clk_rate) - 1;
	regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);

	/*
	 * Set the control register bits. tscadc->ctrl stores the configuration
	 * of the CTRL register but not the subsystem enable bit which must be
	 * added manually when timely.
	 */
	tscadc->ctrl = CNTRLREG_STEPID;
	if (ti_adc_with_touchscreen(tscadc)) {
		tscadc->ctrl |= CNTRLREG_TSC_STEPCONFIGWRT;
		if (use_tsc) {
			tscadc->ctrl |= CNTRLREG_TSC_ENB;
			if (tscmag_wires == 5)
				tscadc->ctrl |= CNTRLREG_TSC_5WIRE;
			else
				tscadc->ctrl |= CNTRLREG_TSC_4WIRE;
		}
	} else {
		tscadc->ctrl |= CNTRLREG_MAG_PREAMP_PWRDOWN |
				CNTRLREG_MAG_PREAMP_BYPASS;
	}
	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);

	tscadc_idle_config(tscadc);

	/* Enable the TSC module enable bit */
	regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);

	/* TSC or MAG Cell */
	if (use_tsc || use_mag) {
		cell = &tscadc->cells[cell_idx++];
		cell->name = tscadc->data->secondary_feature_name;
		cell->of_compatible = tscadc->data->secondary_feature_compatible;
		cell->platform_data = &tscadc;
		cell->pdata_size = sizeof(tscadc);
	}

	/* ADC Cell */
	if (adc_channels > 0) {
		cell = &tscadc->cells[cell_idx++];
		cell->name = tscadc->data->adc_feature_name;
		cell->of_compatible = tscadc->data->adc_feature_compatible;
		cell->platform_data = &tscadc;
		cell->pdata_size = sizeof(tscadc);
	}

	err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
			      tscadc->cells, cell_idx, NULL, 0, NULL);
	if (err < 0)
		goto err_disable_clk;

	platform_set_drvdata(pdev, tscadc);
	return 0;

err_disable_clk:
	pm_runtime_put_sync(&pdev->dev);
	pm_runtime_disable(&pdev->dev);

	return err;
}