Re: [Patch v4 06/10] dmaengine: Add dma router for pl08x in LPC32XX SoC

[Krzysztof Kozlowski <krzk@xxxxxxxxxx>]

On 20/06/2024 19:56, Piotr Wojtaszczyk wrote:
> LPC32XX connects few of its peripherals to pl08x DMA thru a multiplexer,
> this driver allows to route a signal request line thru the multiplexer for
> given peripheral.
> 
> Signed-off-by: Piotr Wojtaszczyk <piotr.wojtaszczyk@xxxxxxxxxxx>
> ---
> Changes for v4:
> - This patch is new in v4
> 
>  MAINTAINERS                  |   1 +
>  drivers/dma/Kconfig          |   9 ++
>  drivers/dma/Makefile         |   1 +
>  drivers/dma/lpc32xx-dmamux.c | 195 +++++++++++++++++++++++++++++++++++
>  4 files changed, 206 insertions(+)
>  create mode 100644 drivers/dma/lpc32xx-dmamux.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fadf1baafd89..5ffe988ee282 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2403,6 +2403,7 @@ R:	Vladimir Zapolskiy <vz@xxxxxxxxx>
>  L:	linux-arm-kernel@xxxxxxxxxxxxxxxxxxx (moderated for non-subscribers)
>  S:	Maintained
>  F:	Documentation/devicetree/bindings/dma/nxp,lpc3220-dmamux.yaml
> +F:	drivers/dma/lpc32xx-dmamux.c
>  N:	lpc32xx
>  
>  ARM/Marvell Dove/MV78xx0/Orion SOC support
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index 002a5ec80620..aeace3d7e066 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -378,6 +378,15 @@ config LPC18XX_DMAMUX
>  	  Enable support for DMA on NXP LPC18xx/43xx platforms
>  	  with PL080 and multiplexed DMA request lines.
>  
> +config LPC32XX_DMAMUX
> +	bool "NXP LPC32xx DMA MUX for PL080"
> +	depends on ARCH_LPC32XX || COMPILE_TEST
> +	depends on OF && AMBA_PL08X
> +	select MFD_SYSCON
> +	help
> +	  Support for PL080 multiplexed DMA request lines on
> +	  LPC32XX platrofm.
> +
>  config LS2X_APB_DMA
>  	tristate "Loongson LS2X APB DMA support"
>  	depends on LOONGARCH || COMPILE_TEST
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index 802ca916f05f..6f1350b62e7f 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -50,6 +50,7 @@ obj-$(CONFIG_INTEL_IOATDMA) += ioat/
>  obj-y += idxd/
>  obj-$(CONFIG_K3_DMA) += k3dma.o
>  obj-$(CONFIG_LPC18XX_DMAMUX) += lpc18xx-dmamux.o
> +obj-$(CONFIG_LPC32XX_DMAMUX) += lpc32xx-dmamux.o
>  obj-$(CONFIG_LS2X_APB_DMA) += ls2x-apb-dma.o
>  obj-$(CONFIG_MILBEAUT_HDMAC) += milbeaut-hdmac.o
>  obj-$(CONFIG_MILBEAUT_XDMAC) += milbeaut-xdmac.o
> diff --git a/drivers/dma/lpc32xx-dmamux.c b/drivers/dma/lpc32xx-dmamux.c
> new file mode 100644
> index 000000000000..4e6ce6026164
> --- /dev/null
> +++ b/drivers/dma/lpc32xx-dmamux.c
> @@ -0,0 +1,195 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +//
> +// Copyright 2024 Timesys Corporation <piotr.wojtaszczyk@xxxxxxxxxxx>
> +//
> +// Based on TI DMA Crossbar driver by:
> +//   Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
> +//   Author: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> +
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/of.h>
> +#include <linux/of_dma.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/spinlock.h>
> +
> +#define LPC32XX_SSP_CLK_CTRL 0x78
> +#define LPC32XX_I2S_CLK_CTRL 0x7c
> +
> +struct lpc32xx_dmamux {
> +	int signal;
> +	char *name_sel0;
> +	char *name_sel1;
> +	int muxval;
> +	int muxreg;
> +	int bit;
> +	bool busy;
> +};
> +
> +/* From LPC32x0 User manual "3.2.1 DMA request signals" */
> +static struct lpc32xx_dmamux lpc32xx_muxes[] = {
> +	{
> +		.signal = 3,
> +		.name_sel0 = "spi2-rx-tx",
> +		.name_sel1 = "ssp1-rx",
> +		.muxreg = LPC32XX_SSP_CLK_CTRL,
> +		.bit = 5,
> +	},
> +	{
> +		.signal = 10,
> +		.name_sel0 = "uart7-rx",
> +		.name_sel1 = "i2s1-dma1",
> +		.muxreg = LPC32XX_I2S_CLK_CTRL,
> +		.bit = 4,
> +	},
> +	{
> +		.signal = 11,
> +		.name_sel0 = "spi1-rx-tx",
> +		.name_sel1 = "ssp1-tx",
> +		.muxreg = LPC32XX_SSP_CLK_CTRL,
> +		.bit = 4,
> +	},
> +	{
> +		.signal = 14,
> +		.name_sel0 = "none",
> +		.name_sel1 = "ssp0-rx",
> +		.muxreg = LPC32XX_SSP_CLK_CTRL,
> +		.bit = 3,
> +	},
> +	{
> +		.signal = 15,
> +		.name_sel0 = "none",
> +		.name_sel1 = "ssp0-tx",
> +		.muxreg = LPC32XX_SSP_CLK_CTRL,
> +		.bit = 2,
> +	},
> +};
> +
> +struct lpc32xx_dmamux_data {
> +	struct dma_router dmarouter;
> +	struct regmap *reg;
> +	spinlock_t lock; /* protects busy status flag */
> +};

Please keep declarations of structures before definitions, so this
should go before lpc32xx_muxes.

> +

...

> +	dmamux->reg = syscon_node_to_regmap(np->parent);
> +	if (IS_ERR(dmamux->reg)) {
> +		dev_err(&pdev->dev, "syscon lookup failed\n");
> +		return PTR_ERR(dmamux->reg);

This should be rather:
return dev_err_probe().


Best regards,
Krzysztof