Hi Mark, On Thu, Feb 07, 2013 at 16:16:56, Mark Rutland wrote: > Hello, > > I have a couple of comments on the dt bindings and the way it's parsed. > Thanks for your review comments. > On Thu, Feb 07, 2013 at 07:57:04AM +0000, Manjunathappa, Prakash wrote: > > Adds device tree support for davinci_mmc. Also add binding documentation. > > Tested in non-dma PIO mode and without GPIO card_detect/write_protect > > option because of dependencies on EDMA and GPIO module DT support. > > > > Signed-off-by: Manjunathappa, Prakash <prakash.pm@xxxxxx> > > Cc: linux-mmc@xxxxxxxxxxxxxxx > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > Cc: linux-kernel@xxxxxxxxxxxxxxx > > Cc: davinci-linux-open-source@xxxxxxxxxxxxxxxxxxxx > > Cc: devicetree-discuss@xxxxxxxxxxxxxxxx > > Cc: cjb@xxxxxxxxxx > > Cc: Sekhar Nori <nsekhar@xxxxxx> > > Cc: mporter@xxxxxx > > --- > > Since v1: > > Modified DT parse function to take default values and accomodate controller > > version in compatible field. > > > > .../devicetree/bindings/mmc/davinci_mmc.txt | 30 ++++++++ > > drivers/mmc/host/davinci_mmc.c | 70 +++++++++++++++++++- > > 2 files changed, 99 insertions(+), 1 deletions(-) > > create mode 100644 Documentation/devicetree/bindings/mmc/davinci_mmc.txt > > > > diff --git a/Documentation/devicetree/bindings/mmc/davinci_mmc.txt b/Documentation/devicetree/bindings/mmc/davinci_mmc.txt > > new file mode 100644 > > index 0000000..6717ab1 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/mmc/davinci_mmc.txt > > @@ -0,0 +1,30 @@ > > +* TI Highspeed MMC host controller for DaVinci > > + > > +The Highspeed MMC Host Controller on TI DaVinci family > > +provides an interface for MMC, SD and SDIO types of memory cards. > > + > > +This file documents the properties used by the davinci_mmc driver. > > + > > +Required properties: > > +- compatible: > > + Should be "ti,davinci-mmc-da830": for da830, da850, dm365 > > + Should be "ti,davinci-mmc-dm355": for dm355, dm644x > > + > > +Optional properties: > > +- bus-width: Number of data lines, can be <4>, or <8>, default <1> > > +- max-frequency: Maximum operating clock frequency, default 25MHz. > > +- mmc-cap-mmc-highspeed: Indicates support for MMC in high speed mode > > +- mmc-cap-sd-highspeed: Indicates support for SD in high speed mode > > I thought the last two were derivable from max-frequency? > Yes, but I see below comment that it doesnot support MMC/SD. arch/arm/mach-davinci/devices.c: davinci_setup_mmc " * FIXME dm6441 (no MMC/SD), dm357 (one), and dm335 (two) are * not handled right here ... */" I was wondering how do we support such platforms, so I thought it is necessary to have these. But I see that on da850-evm even on skipping above flags EVM is able to detect card, does it mean there is no way to specify "no SD/MMC" capability? I will remove these and decide highspeed capability based on max-frequency. > https://lkml.org/lkml/2012/10/15/231 > > [...] > > > +static struct davinci_mmc_config > > + *mmc_parse_pdata(struct platform_device *pdev) > > { > > + struct device_node *np; > > struct davinci_mmc_config *pdata = pdev->dev.platform_data; > > + const struct of_device_id *match = > > + of_match_device(of_match_ptr(davinci_mmc_dt_ids), &pdev->dev); > > + u32 data; > > + > > + np = pdev->dev.of_node; > > + if (!np) > > + return pdata; > > + > > + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); > > + if (!pdata) { > > + dev_err(&pdev->dev, "Failed to allocate memory for struct davinci_mmc_config\n"); > > + goto nodata; > > + } > > + > > + if (match->data) > > + pdata->version = (u8)((int)match->data); > > + > > + of_property_read_u32(np, "max-frequency", &pdata->max_freq); > > + if (!pdata->max_freq) > > + dev_info(&pdev->dev, "'max-frequency' property not specified, defaulting to 25MHz\n"); > > + > > + if (of_get_property(np, "mmc-cap-mmc-highspeed", NULL)) > > + pdata->caps |= MMC_CAP_MMC_HIGHSPEED; > > + if (of_get_property(np, "mmc-cap-sd-highspeed", NULL)) > > + pdata->caps |= MMC_CAP_SD_HIGHSPEED; > > If these aren't derivable from max-frequency, you could use > of_property_read_bool to make this clearer. > Correct, I will decide these based on max-frequency. > > + > > + of_property_read_u32(np, "bus-width", &data); > > + switch (data) { > > + case 0: > > Judging by the binding doc, should this be 1 rather than 0? > By default driver comes up in 4 bit mode when bus-width is not specified. Bus-width is set to 1 bit for invalid bus-widths. Below are the cases when bus-width 0 or 4, bus-width is set to 4bit mode When bus-width is 8, bus-width is set to 8 bit mode I thought that if somebody specifies bus-width as 2, 3, 5, 6, 7..., then it should be defaulted to 1 bit mode, so I specified it as 1 bit in binding doc. But I feel that a person who is editing dts file will not make such a mistake. I will change binding document to default as 4 bit mode. > > + case 4: > > + case 8: > > + pdata->wires = data; > > + break; > > + default: > > + pdata->wires = 1; > > + dev_info(&pdev->dev, "Unsupported buswidth, defaulting to 1 bit\n"); > > + } > > +nodata: > > + return pdata; > > +} > > + > > +static int __init davinci_mmcsd_probe(struct platform_device *pdev) > > +{ > > + struct davinci_mmc_config *pdata = NULL; > > struct mmc_davinci_host *host = NULL; > > struct mmc_host *mmc = NULL; > > struct resource *r, *mem = NULL; > > int ret = 0, irq = 0; > > size_t mem_size; > > > > + pdata = mmc_parse_pdata(pdev); > > + if (pdata == NULL) { > > + dev_err(&pdev->dev, "Can not get platform data\n"); > > + return -ENOENT; > > + } > > + > > /* REVISIT: when we're fully converted, fail if pdata is NULL */ > > This comment can presumably disappear judging by the lines above? > Agreed. I will remove it. Thanks, Prakash -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html