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Diffstat (limited to 'drivers/mfd/atmel-flexcom.c')
-rw-r--r--drivers/mfd/atmel-flexcom.c74
1 files changed, 74 insertions, 0 deletions
diff --git a/drivers/mfd/atmel-flexcom.c b/drivers/mfd/atmel-flexcom.c
new file mode 100644
index 0000000000..58e94c4889
--- /dev/null
+++ b/drivers/mfd/atmel-flexcom.c
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0-only
+// SPDX-FileCopyrightText: (C) 2015 Atmel Corporation
+/*
+ * Driver for Atmel Flexcom
+ * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
+ */
+
+#include <common.h>
+#include <of.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)
+
+static int atmel_flexcom_probe(struct device *dev)
+{
+ struct resource *res;
+ struct clk *clk;
+ u32 opmode;
+ int err;
+
+ err = of_property_read_u32(dev->of_node,
+ "atmel,flexcom-mode", &opmode);
+ if (err)
+ return err;
+
+ if (opmode < ATMEL_FLEXCOM_MODE_USART || opmode > ATMEL_FLEXCOM_MODE_TWI)
+ return -EINVAL;
+
+ res = dev_request_mem_resource(dev, 0);
+ if (IS_ERR(res))
+ return PTR_ERR(res);
+
+ clk = clk_get(dev, NULL);
+ if (IS_ERR(clk))
+ return PTR_ERR(clk);
+
+ err = clk_enable(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(opmode), IOMEM(res->start) + FLEX_MR);
+
+ clk_disable(clk);
+
+ return of_platform_populate(dev->of_node, NULL, 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 struct driver atmel_flexcom_driver = {
+ .probe = atmel_flexcom_probe,
+ .name = "atmel_flexcom",
+ .of_compatible = atmel_flexcom_of_match,
+};
+coredevice_platform_driver(atmel_flexcom_driver);