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

Krzysztof Kozlowski
2024-06-21T06:25:57Z

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@timesys.com>
> ---
> 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@mleia.com>
> L: linux-arm-kernel@lists.infradead.org (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@timesys.com>
> +//
> +// Based on TI DMA Crossbar driver by:
> +// Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com
> +// Author: Peter Ujfalusi <peter.ujfalusi@ti.com>
> +
> +#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