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Diffstat (limited to 'drivers/mfd/atmel-flexcom.c')
-rw-r--r--drivers/mfd/atmel-flexcom.c123
1 files changed, 123 insertions, 0 deletions
diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
new file mode 100644
index 0000000000..b52f7ffdad
--- /dev/null
+++ b/drivers/mfd/atmel-flexcom.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Atmel Flexcom
+ *
+ * Copyright (C) 2015 Atmel Corporation
+ *
+ * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <dt-bindings/mfd/atmel-flexcom.h>
+
+/* I/O register offsets */
+#define FLEX_MR 0x0 /* Mode Register */
+#define FLEX_VERSION 0xfc /* Version Register */
+
+/* Mode Register bit fields */
+#define FLEX_MR_OPMODE_OFFSET (0) /* Operating Mode */
+#define FLEX_MR_OPMODE_MASK (0x3 << FLEX_MR_OPMODE_OFFSET)
+#define FLEX_MR_OPMODE(opmode) (((opmode) << FLEX_MR_OPMODE_OFFSET) & \
+ FLEX_MR_OPMODE_MASK)
+
+struct atmel_flexcom {
+ void __iomem *base;
+ u32 opmode;
+ struct clk *clk;
+};
+
+static int atmel_flexcom_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct atmel_flexcom *ddata;
+ int err;
+
+ ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
+ if (!ddata)
+ return -ENOMEM;
+
+ platform_set_drvdata(pdev, ddata);
+
+ err = of_property_read_u32(np, "atmel,flexcom-mode", &ddata->opmode);
+ if (err)
+ return err;
+
+ if (ddata->opmode < ATMEL_FLEXCOM_MODE_USART ||
+ ddata->opmode > ATMEL_FLEXCOM_MODE_TWI)
+ return -EINVAL;
+
+ ddata->base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
+ if (IS_ERR(ddata->base))
+ return PTR_ERR(ddata->base);
+
+ ddata->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(ddata->clk))
+ return PTR_ERR(ddata->clk);
+
+ err = clk_prepare_enable(ddata->clk);
+ if (err)
+ return err;
+
+ /*
+ * Set the Operating Mode in the Mode Register: only the selected device
+ * is clocked. Hence, registers of the other serial devices remain
+ * inaccessible and are read as zero. Also the external I/O lines of the
+ * Flexcom are muxed to reach the selected device.
+ */
+ writel(FLEX_MR_OPMODE(ddata->opmode), ddata->base + FLEX_MR);
+
+ clk_disable_unprepare(ddata->clk);
+
+ return devm_of_platform_populate(&pdev->dev);
+}
+
+static const struct of_device_id atmel_flexcom_of_match[] = {
+ { .compatible = "atmel,sama5d2-flexcom" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, atmel_flexcom_of_match);
+
+static int __maybe_unused atmel_flexcom_resume_noirq(struct device *dev)
+{
+ struct atmel_flexcom *ddata = dev_get_drvdata(dev);
+ int err;
+ u32 val;
+
+ err = clk_prepare_enable(ddata->clk);
+ if (err)
+ return err;
+
+ val = FLEX_MR_OPMODE(ddata->opmode),
+ writel(val, ddata->base + FLEX_MR);
+
+ clk_disable_unprepare(ddata->clk);
+
+ return 0;
+}
+
+static const struct dev_pm_ops __maybe_unused atmel_flexcom_pm_ops = {
+ .resume_noirq = atmel_flexcom_resume_noirq,
+};
+
+static struct platform_driver atmel_flexcom_driver = {
+ .probe = atmel_flexcom_probe,
+ .driver = {
+ .name = "atmel_flexcom",
+ .pm = pm_ptr(&atmel_flexcom_pm_ops),
+ .of_match_table = atmel_flexcom_of_match,
+ },
+};
+
+module_platform_driver(atmel_flexcom_driver);
+
+MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
+MODULE_DESCRIPTION("Atmel Flexcom MFD driver");
+MODULE_LICENSE("GPL v2");