diff options
Diffstat (limited to 'drivers/mfd/atmel-flexcom.c')
-rw-r--r-- | drivers/mfd/atmel-flexcom.c | 74 |
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); |