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SubjectRe: [PATCH v7 3/6] mfd: at91-usart: added mfd driver for usart
On Wed, Jun 13, 2018 at 07:36:18PM +0300, Radu Pirea wrote:
> This mfd driver is just a wrapper over atmel_serial driver and
> spi-at91-usart driver. Selection of one of the drivers is based on a
> property from device tree. If the property is not specified, the default
> driver is atmel_serial.
>
> Signed-off-by: Radu Pirea <radu.pirea@microchip.com>
> Acked-by: Rob Herring <robh@kernel.org>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> Acked-for-MFD-by: Lee Jones <lee.jones@linaro.org>
> ---
> drivers/mfd/Kconfig | 9 ++++++
> drivers/mfd/Makefile | 1 +
> drivers/mfd/at91-usart.c | 69 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 79 insertions(+)
> create mode 100644 drivers/mfd/at91-usart.c
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index b860eb5aa194..a886672b960d 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -99,6 +99,15 @@ config MFD_AAT2870_CORE
> additional drivers must be enabled in order to use the
> functionality of the device.
>
> +config MFD_AT91_USART
> + tristate "AT91 USART Driver"
> + select MFD_CORE
> + help
> + Select this to get support for AT91 USART IP. This is a wrapper
> + over at91-usart-serial driver and usart-spi-driver. Only one function
> + can be used at a time. The choice is done at boot time by the probe
> + function of this MFD driver according to a device tree property.
> +
> config MFD_ATMEL_FLEXCOM
> tristate "Atmel Flexcom (Flexible Serial Communication Unit)"
> select MFD_CORE
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index d9d2cf0d32ef..db1332aa96db 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -185,6 +185,7 @@ obj-$(CONFIG_MFD_SPMI_PMIC) += qcom-spmi-pmic.o
> obj-$(CONFIG_TPS65911_COMPARATOR) += tps65911-comparator.o
> obj-$(CONFIG_MFD_TPS65090) += tps65090.o
> obj-$(CONFIG_MFD_AAT2870_CORE) += aat2870-core.o
> +obj-$(CONFIG_MFD_AT91_USART) += at91-usart.o
> obj-$(CONFIG_MFD_ATMEL_FLEXCOM) += atmel-flexcom.o
> obj-$(CONFIG_MFD_ATMEL_HLCDC) += atmel-hlcdc.o
> obj-$(CONFIG_MFD_ATMEL_SMC) += atmel-smc.o
> diff --git a/drivers/mfd/at91-usart.c b/drivers/mfd/at91-usart.c
> new file mode 100644
> index 000000000000..3014ce532644
> --- /dev/null
> +++ b/drivers/mfd/at91-usart.c
> @@ -0,0 +1,69 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Driver for AT91 USART
> + *
> + * Copyright (C) 2018 Microchip Technology
> + *
> + * Author: Radu Pirea <radu.pirea@microchip.com>
> + *
> + */
> +
> +#include <dt-bindings/mfd/at91-usart.h>
> +
> +#include <linux/module.h>
> +#include <linux/mfd/core.h>
> +#include <linux/property.h>
> +
> +static struct mfd_cell at91_usart_spi_subdev = {
> + .name = "at91_usart_spi",
> + .of_compatible = "microchip,at91sam9g45-usart-spi",
> + };
> +
> +static struct mfd_cell at91_usart_serial_subdev = {
> + .name = "atmel_usart_serial",
> + .of_compatible = "atmel,at91rm9200-usart-serial",
> + };
> +
> +static int at91_usart_mode_probe(struct platform_device *pdev)
> +{
> + struct mfd_cell cell;
> + u32 opmode = AT91_USART_MODE_SERIAL;
> +
> + device_property_read_u32(&pdev->dev, "atmel,usart-mode", &opmode);
> +
> + switch (opmode) {
> + case AT91_USART_MODE_SPI:
> + cell = at91_usart_spi_subdev;
> + break;
> + case AT91_USART_MODE_SERIAL:
> + cell = at91_usart_serial_subdev;
> + break;
> + default:
> + break;

If there is an invalid opmode from the DT, you will pass a non initialized cell
to mfd_add_device().

Regards

Ludovic

> + }
> +
> + return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, &cell, 1,
> + NULL, 0, NULL);
> +}
> +
> +static const struct of_device_id at91_usart_mode_of_match[] = {
> + { .compatible = "atmel,at91rm9200-usart" },
> + { .compatible = "atmel,at91sam9260-usart" },
> + { /* sentinel */ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, at91_flexcom_of_match);
> +
> +static struct platform_driver at91_usart_mfd = {
> + .probe = at91_usart_mode_probe,
> + .driver = {
> + .name = "at91_usart_mode",
> + .of_match_table = at91_usart_mode_of_match,
> + },
> +};
> +
> +module_platform_driver(at91_usart_mfd);
> +
> +MODULE_AUTHOR("Radu Pirea <radu.pirea@microchip.com>");
> +MODULE_DESCRIPTION("AT91 USART MFD driver");
> +MODULE_LICENSE("GPL v2");
> --
> 2.17.1
>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

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