From e95a1cd2cfe722dc8434db6de33958035853aa05 Mon Sep 17 00:00:00 2001 From: Serge Semin Date: Sat, 25 Jun 2022 00:06:23 +0300 Subject: [PATCH] spi: dw: Add deferred DMA-channels setup support Currently if the source DMA device isn't ready to provide the channels capable of the SPI DMA transfers, the DW SSI controller will be registered with no DMA support. It isn't right since all what the driver needs to do is to postpone the probe procedure until the DMA device is ready. Let's fix that in the framework of the DWC SSI generic DMA implementation. First we need to use the dma_request_chan() method instead of the dma_request_slave_channel() function, because the later one is deprecated and most importantly doesn't return the failure cause but the NULL-pointer. Second we need to stop the DW SSI controller probe procedure if the -EPROBE_DEFER error is returned on the DMA initialization. The procedure will resume later when the channels are ready to be requested. Signed-off-by: Serge Semin Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/20220624210623.6383-1-Sergey.Semin@baikalelectronics.ru Signed-off-by: Mark Brown --- drivers/spi/spi-dw-core.c | 5 ++++- drivers/spi/spi-dw-dma.c | 25 ++++++++++++++++++------- 2 files changed, 22 insertions(+), 8 deletions(-) diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c index ecea471..911ea9b 100644 --- a/drivers/spi/spi-dw-core.c +++ b/drivers/spi/spi-dw-core.c @@ -942,7 +942,9 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws) if (dws->dma_ops && dws->dma_ops->dma_init) { ret = dws->dma_ops->dma_init(dev, dws); - if (ret) { + if (ret == -EPROBE_DEFER) { + goto err_free_irq; + } else if (ret) { dev_warn(dev, "DMA init failed\n"); } else { master->can_dma = dws->dma_ops->can_dma; @@ -963,6 +965,7 @@ err_dma_exit: if (dws->dma_ops && dws->dma_ops->dma_exit) dws->dma_ops->dma_exit(dws); dw_spi_enable_chip(dws, 0); +err_free_irq: free_irq(dws->irq, master); err_free_master: spi_controller_put(master); diff --git a/drivers/spi/spi-dw-dma.c b/drivers/spi/spi-dw-dma.c index 63e5260..1322b8c 100644 --- a/drivers/spi/spi-dw-dma.c +++ b/drivers/spi/spi-dw-dma.c @@ -139,15 +139,20 @@ err_exit: static int dw_spi_dma_init_generic(struct device *dev, struct dw_spi *dws) { - dws->rxchan = dma_request_slave_channel(dev, "rx"); - if (!dws->rxchan) - return -ENODEV; + int ret; - dws->txchan = dma_request_slave_channel(dev, "tx"); - if (!dws->txchan) { - dma_release_channel(dws->rxchan); + dws->rxchan = dma_request_chan(dev, "rx"); + if (IS_ERR(dws->rxchan)) { + ret = PTR_ERR(dws->rxchan); dws->rxchan = NULL; - return -ENODEV; + goto err_exit; + } + + dws->txchan = dma_request_chan(dev, "tx"); + if (IS_ERR(dws->txchan)) { + ret = PTR_ERR(dws->txchan); + dws->txchan = NULL; + goto free_rxchan; } dws->master->dma_rx = dws->rxchan; @@ -160,6 +165,12 @@ static int dw_spi_dma_init_generic(struct device *dev, struct dw_spi *dws) dw_spi_dma_sg_burst_init(dws); return 0; + +free_rxchan: + dma_release_channel(dws->rxchan); + dws->rxchan = NULL; +err_exit: + return ret; } static void dw_spi_dma_exit(struct dw_spi *dws) -- 2.7.4