1 files changed, 225 insertions, 0 deletions

diff --git a/drivers/mfd/fsl-imx25-tsadc.c b/drivers/mfd/fsl-imx25-tsadc.c
new file mode 100644
index 000000000..5f1f6f3a0
--- /dev/null
+++ b/drivers/mfd/fsl-imx25-tsadc.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2014-2015 Pengutronix, Markus Pargmann <mpa@pengutronix.de>
+ */
+
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqdesc.h>
+#include <linux/irqdomain.h>
+#include <linux/irq.h>
+#include <linux/mfd/imx25-tsadc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+
+static struct regmap_config mx25_tsadc_regmap_config = {
+	.fast_io = true,
+	.max_register = 8,
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
+static void mx25_tsadc_irq_handler(struct irq_desc *desc)
+{
+	struct mx25_tsadc *tsadc = irq_desc_get_handler_data(desc);
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	u32 status;
+
+	chained_irq_enter(chip, desc);
+
+	regmap_read(tsadc->regs, MX25_TSC_TGSR, &status);
+
+	if (status & MX25_TGSR_GCQ_INT)
+		generic_handle_irq(irq_find_mapping(tsadc->domain, 1));
+
+	if (status & MX25_TGSR_TCQ_INT)
+		generic_handle_irq(irq_find_mapping(tsadc->domain, 0));
+
+	chained_irq_exit(chip, desc);
+}
+
+static int mx25_tsadc_domain_map(struct irq_domain *d, unsigned int irq,
+				 irq_hw_number_t hwirq)
+{
+	struct mx25_tsadc *tsadc = d->host_data;
+
+	irq_set_chip_data(irq, tsadc);
+	irq_set_chip_and_handler(irq, &dummy_irq_chip,
+				 handle_level_irq);
+	irq_modify_status(irq, IRQ_NOREQUEST, IRQ_NOPROBE);
+
+	return 0;
+}
+
+static const struct irq_domain_ops mx25_tsadc_domain_ops = {
+	.map = mx25_tsadc_domain_map,
+	.xlate = irq_domain_xlate_onecell,
+};
+
+static int mx25_tsadc_setup_irq(struct platform_device *pdev,
+				struct mx25_tsadc *tsadc)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	int irq;
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		return irq;
+
+	tsadc->domain = irq_domain_add_simple(np, 2, 0, &mx25_tsadc_domain_ops,
+					      tsadc);
+	if (!tsadc->domain) {
+		dev_err(dev, "Failed to add irq domain\n");
+		return -ENOMEM;
+	}
+
+	irq_set_chained_handler_and_data(irq, mx25_tsadc_irq_handler, tsadc);
+
+	return 0;
+}
+
+static int mx25_tsadc_unset_irq(struct platform_device *pdev)
+{
+	struct mx25_tsadc *tsadc = platform_get_drvdata(pdev);
+	int irq = platform_get_irq(pdev, 0);
+
+	if (irq >= 0) {
+		irq_set_chained_handler_and_data(irq, NULL, NULL);
+		irq_domain_remove(tsadc->domain);
+	}
+
+	return 0;
+}
+
+static void mx25_tsadc_setup_clk(struct platform_device *pdev,
+				 struct mx25_tsadc *tsadc)
+{
+	unsigned clk_div;
+
+	/*
+	 * According to the datasheet the ADC clock should never
+	 * exceed 1,75 MHz. Base clock is the IPG and the ADC unit uses
+	 * a funny clock divider. To keep the ADC conversion time constant
+	 * adapt the ADC internal clock divider to the IPG clock rate.
+	 */
+
+	dev_dbg(&pdev->dev, "Found master clock at %lu Hz\n",
+		clk_get_rate(tsadc->clk));
+
+	clk_div = DIV_ROUND_UP(clk_get_rate(tsadc->clk), 1750000);
+	dev_dbg(&pdev->dev, "Setting up ADC clock divider to %u\n", clk_div);
+
+	/* adc clock = IPG clock / (2 * div + 2) */
+	clk_div -= 2;
+	clk_div /= 2;
+
+	/*
+	 * the ADC clock divider changes its behaviour when values below 4
+	 * are used: it is fixed to "/ 10" in this case
+	 */
+	clk_div = max_t(unsigned, 4, clk_div);
+
+	dev_dbg(&pdev->dev, "Resulting ADC conversion clock at %lu Hz\n",
+		clk_get_rate(tsadc->clk) / (2 * clk_div + 2));
+
+	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR,
+			   MX25_TGCR_ADCCLKCFG(0x1f),
+			   MX25_TGCR_ADCCLKCFG(clk_div));
+}
+
+static int mx25_tsadc_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mx25_tsadc *tsadc;
+	struct resource *res;
+	int ret;
+	void __iomem *iomem;
+
+	tsadc = devm_kzalloc(dev, sizeof(*tsadc), GFP_KERNEL);
+	if (!tsadc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	iomem = devm_ioremap_resource(dev, res);
+	if (IS_ERR(iomem))
+		return PTR_ERR(iomem);
+
+	tsadc->regs = devm_regmap_init_mmio(dev, iomem,
+					    &mx25_tsadc_regmap_config);
+	if (IS_ERR(tsadc->regs)) {
+		dev_err(dev, "Failed to initialize regmap\n");
+		return PTR_ERR(tsadc->regs);
+	}
+
+	tsadc->clk = devm_clk_get(dev, "ipg");
+	if (IS_ERR(tsadc->clk)) {
+		dev_err(dev, "Failed to get ipg clock\n");
+		return PTR_ERR(tsadc->clk);
+	}
+
+	/* setup clock according to the datasheet */
+	mx25_tsadc_setup_clk(pdev, tsadc);
+
+	/* Enable clock and reset the component */
+	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_CLK_EN,
+			   MX25_TGCR_CLK_EN);
+	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_TSC_RST,
+			   MX25_TGCR_TSC_RST);
+
+	/* Setup powersaving mode, but enable internal reference voltage */
+	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_POWERMODE_MASK,
+			   MX25_TGCR_POWERMODE_SAVE);
+	regmap_update_bits(tsadc->regs, MX25_TSC_TGCR, MX25_TGCR_INTREFEN,
+			   MX25_TGCR_INTREFEN);
+
+	ret = mx25_tsadc_setup_irq(pdev, tsadc);
+	if (ret)
+		return ret;
+
+	platform_set_drvdata(pdev, tsadc);
+
+	ret = devm_of_platform_populate(dev);
+	if (ret)
+		goto err_irq;
+
+	return 0;
+
+err_irq:
+	mx25_tsadc_unset_irq(pdev);
+
+	return ret;
+}
+
+static int mx25_tsadc_remove(struct platform_device *pdev)
+{
+	mx25_tsadc_unset_irq(pdev);
+
+	return 0;
+}
+
+static const struct of_device_id mx25_tsadc_ids[] = {
+	{ .compatible = "fsl,imx25-tsadc" },
+	{ /* Sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mx25_tsadc_ids);
+
+static struct platform_driver mx25_tsadc_driver = {
+	.driver = {
+		.name = "mx25-tsadc",
+		.of_match_table = of_match_ptr(mx25_tsadc_ids),
+	},
+	.probe = mx25_tsadc_probe,
+	.remove = mx25_tsadc_remove,
+};
+module_platform_driver(mx25_tsadc_driver);
+
+MODULE_DESCRIPTION("MFD for ADC/TSC for Freescale mx25");
+MODULE_AUTHOR("Markus Pargmann <mpa@pengutronix.de>");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:mx25-tsadc");