Add device tree probe support for atmel at_hdmac DMA driver. Bindings are added to specify the number of channels that the implementation of the controller actually has. They also allow to tell if the peripherals/DMA transfer is supported by the IP.
Signed-off-by: Nicolas Ferre <[email protected]> --- .../devicetree/bindings/dma/atmel-hdmac.txt | 23 +++++++++ drivers/dma/at_hdmac.c | 51 ++++++++++++++++---- 2 files changed, 65 insertions(+), 9 deletions(-) create mode 100644 Documentation/devicetree/bindings/dma/atmel-hdmac.txt diff --git a/Documentation/devicetree/bindings/dma/atmel-hdmac.txt b/Documentation/devicetree/bindings/dma/atmel-hdmac.txt new file mode 100644 index 0000000..0e48553 --- /dev/null +++ b/Documentation/devicetree/bindings/dma/atmel-hdmac.txt @@ -0,0 +1,23 @@ +* Atmel Direct Memory Access Controller + +Required properties: +- compatible: Should be "atmel,<chip>-hdmac" +- reg: Should contain DMA registers location and length +- interrupts: Should contain DMA interrupt +- atmel,hdmac-nr-channels: Should contain number of channels + available in the controller + +Optional properties: +- atmel,hdmac-cap-memcpy: Chip can do memory to memory transfers +- atmel,hdmac-cap-slave: Chip can do peripherals/memory transfers + +Examples: + +dma@ffffec00 { + compatible = "atmel,at91sam9g45-hdmac"; + reg = <0xffffec00 0x200>; + interrupts = <21>; + atmel,hdmac-nr-channels = <8>; + atmel,hdmac-cap-memcpy; + atmel,hdmac-cap-slave; +}; diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 8f1d2ee..4a0cefe 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -23,6 +23,8 @@ #include <linux/module.h> #include <linux/platform_device.h> #include <linux/slab.h> +#include <linux/of.h> +#include <linux/of_device.h> #include "at_hdmac_regs.h" @@ -1167,6 +1169,18 @@ static void atc_free_chan_resources(struct dma_chan *chan) /*-- Module Management -----------------------------------------------*/ +#if defined(CONFIG_OF) +static const struct of_device_id atmel_dma_dt_ids[] = { + { .compatible = "atmel,at91sam9rl-hdmac" }, + { .compatible = "atmel,at91sam9g45-hdmac" }, + { /* sentinel */ } +}; + +MODULE_DEVICE_TABLE(of, atmel_dma_dt_ids); +#else +#define atmel_dma_dt_ids NULL +#endif + /** * at_dma_off - disable DMA controller * @atdma: the Atmel HDAMC device @@ -1185,17 +1199,36 @@ static void at_dma_off(struct at_dma *atdma) static int __init at_dma_probe(struct platform_device *pdev) { - struct at_dma_platform_data *pdata; + const struct of_device_id *of_id = + of_match_device(atmel_dma_dt_ids, &pdev->dev); + struct device_node *np = pdev->dev.of_node; + struct at_dma_platform_data *pdata = pdev->dev.platform_data; struct resource *io; struct at_dma *atdma; size_t size; int irq; int err; int i; + u32 nr_channels; + dma_cap_mask_t cap_mask = {}; + + /* get DMA Controller parameters */ + if (of_id) { + if (of_property_read_u32(np, "atmel,hdmac-nr-channels", + &nr_channels)) + return -EINVAL; + if (of_find_property(np, "atmel,hdmac-cap-memcpy", NULL)) + dma_cap_set(DMA_MEMCPY, cap_mask); + if (of_find_property(np, "atmel,hdmac-cap-slave", NULL)) + dma_cap_set(DMA_SLAVE, cap_mask); + } else if (pdata) { + nr_channels = pdata->nr_channels; + cap_mask = pdata->cap_mask; + } else { + return -EINVAL; + } - /* get DMA Controller parameters from platform */ - pdata = pdev->dev.platform_data; - if (!pdata || pdata->nr_channels > AT_DMA_MAX_NR_CHANNELS) + if (!nr_channels || nr_channels > AT_DMA_MAX_NR_CHANNELS) return -EINVAL; io = platform_get_resource(pdev, IORESOURCE_MEM, 0); @@ -1207,14 +1240,13 @@ static int __init at_dma_probe(struct platform_device *pdev) return irq; size = sizeof(struct at_dma); - size += pdata->nr_channels * sizeof(struct at_dma_chan); + size += nr_channels * sizeof(struct at_dma_chan); atdma = kzalloc(size, GFP_KERNEL); if (!atdma) return -ENOMEM; - /* discover transaction capabilites from the platform data */ - atdma->dma_common.cap_mask = pdata->cap_mask; - atdma->all_chan_mask = (1 << pdata->nr_channels) - 1; + atdma->dma_common.cap_mask = cap_mask; + atdma->all_chan_mask = (1 << nr_channels) - 1; size = io->end - io->start + 1; if (!request_mem_region(io->start, size, pdev->dev.driver->name)) { @@ -1260,7 +1292,7 @@ static int __init at_dma_probe(struct platform_device *pdev) /* initialize channels related values */ INIT_LIST_HEAD(&atdma->dma_common.channels); - for (i = 0; i < pdata->nr_channels; i++, atdma->dma_common.chancnt++) { + for (i = 0; i < nr_channels; i++, atdma->dma_common.chancnt++) { struct at_dma_chan *atchan = &atdma->chan[i]; atchan->chan_common.device = &atdma->dma_common; @@ -1406,6 +1438,7 @@ static struct platform_driver at_dma_driver = { .driver = { .name = "at_hdmac", .pm = &at_dma_dev_pm_ops, + .of_match_table = atmel_dma_dt_ids, }, }; -- 1.7.4.1 _______________________________________________ devicetree-discuss mailing list [email protected] https://lists.ozlabs.org/listinfo/devicetree-discuss
