Hi Mark, On Thu, Jan 31, 2013 at 16:53:03, Mark Rutland wrote: > Hello, > > I have a few comments on the devicetree binding and the way it's parsed. > Thanks for review. > On Thu, Jan 31, 2013 at 10:33:06AM +0000, Manjunathappa, Prakash wrote: > > Adds device tree support for davinci_mmc. Also add > > binding documentation. > > Tested with non-dma PIO mode and without GPIO > > card_detect/write_protect option because of > > dependencies on EDMA and GPIO modules 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 > > --- > > .../devicetree/bindings/mmc/davinci_mmc.txt | 23 +++++++ > > drivers/mmc/host/davinci_mmc.c | 69 +++++++++++++++++++- > > 2 files changed, 91 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..144bee6 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/mmc/davinci_mmc.txt > > @@ -0,0 +1,23 @@ > > +* 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 differences between the core properties described > > +by mmc.txt and the properties used by the davinci_mmc driver. > > + > > +Required properties: > > +- compatible: > > + Should be "ti,davinci_mmc", for davinci controllers > > "ti,davinci-mmc" (with '-' rather than '_') would be preferable. > I agree, will correct it. > > + > > +Optional properties: > > +- bus-width: Number of data lines, can be <1>, <4>, or <8>, default <1> > > +- max-frequency: maximum operating clock frequency. > > You said you only described differences from mmc.txt, but this is listed in > mmc.txt. > Agreed, I will remove it from here. > > +- caps: Check for Host capabilities in <linux/mmc/host.h> > > Is this a set of binary flags? Also, is this Linux-specific? > > I really don't think this should be in the devicetree binding. Why do you need > this? > I was using this to specify the below controller capabilities: MMC_CAP_MMC_HIGHSPEED and MMC_CAP_SD_HIGHSPEED, Found from discussion[1] that this can be derived from max-frequency, That is above capabilities are supported when max-frequency >= 50MHz. [1] https://lkml.org/lkml/2012/10/15/231 > > +- version: version of controller. > > This should be encoded as part of the compatible string. > Agreed will make change accordingly to accommodate version info in compatible string. > > +Example: > > + mmc1: mmc@0x4809c000 { > > + compatible = "ti,omap4-hsmmc"; > > + reg = <0x4809c000 0x400>; > > + bus-width = <4>; > > + }; > > It would be nice if the example referred to this binding rather than another. > Agreed, I will change. > > diff --git a/drivers/mmc/host/davinci_mmc.c b/drivers/mmc/host/davinci_mmc.c > > index 382b79d..ce6730d 100644 > > --- a/drivers/mmc/host/davinci_mmc.c > > +++ b/drivers/mmc/host/davinci_mmc.c > > @@ -34,6 +34,7 @@ > > #include <linux/dma-mapping.h> > > #include <linux/edma.h> > > #include <linux/mmc/mmc.h> > > +#include <linux/of.h> > > > > #include <linux/platform_data/mmc-davinci.h> > > > > @@ -1156,16 +1157,75 @@ static void __init init_mmcsd_host(struct mmc_davinci_host *host) > > > > mmc_davinci_reset_ctrl(host, 0); > > } > > +#ifdef CONFIG_OF > > +static struct davinci_mmc_config > > + *mmc_of_get_pdata(struct platform_device *pdev) > > +{ > > + struct device_node *np; > > + struct davinci_mmc_config *pdata = NULL; > > + u32 data; > > + int ret; > > + > > + pdata = pdev->dev.platform_data; > > + if (!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; > > + } > > + } > > Why do you need to conditionally allocate this? This only seems to be called > once. > This is common function for DT and non-DT kernel(will be removing #ifdef CONFIG_OF), So above check is necessary for to allocate pdata for DT kernel. > > + > > + np = pdev->dev.of_node; > > + if (!np) > > + goto nodata; > > Why not just return immediately here? You do nothing special at nodata. > Following convention to not have more than 1 return from function and have Common exit point. May not be necessary now since we have devm_* calls now. Can I still prefer to keep this goto? > > + > > + ret = of_property_read_u32(np, "bus-width", &data); > > + if (ret) > > + dev_info(&pdev->dev, "wires not specified, defaulting to 4 bit mode\n"); > > + pdata->wires = data; > > That dev_info doesn't seem to match up with what the next line is doing (data > might not have been initialised). Also, unless I've misunderstood, it doesn't > match up with the default of 1 mentioned in the binding doc. > Yes with missing bus-width property module comes in 1 bit mode, I will correct it. > > + > > + ret = of_property_read_u32(np, "max-frequency", &data); > > + if (ret) > > + dev_info(&pdev->dev, "max-frequency not specified, defaulting to 25MHz\n"); > > + pdata->max_freq = data; > > Again, the dev_info doesn't match up with the line below it. I notice > the default's not one specified in the binding. Is this frequency chosen > from the hardware docs, or is it an arbitrary choice. If not arbitrary, > it might be worth specifying in the binding. > Agreed, I will make the changes for the default values. > > > + > > + ret = of_property_read_u32(np, "caps", &data); > > + if (ret) > > + dev_info(&pdev->dev, "card capability not specified\n"); > > + pdata->caps = data; > > Again, you may be using garbage data. > Ok I will correct it. > > + > > + ret = of_property_read_u32(np, "version", &data); > > + if (ret) > > + dev_err(&pdev->dev, "version not specified\n"); > > + pdata->version = data; > > And again, though I'd prefer to see this property go entirely. > Yes this is going to go away. > > + > > +nodata: > > + return pdata; > > +} > > + > > +#else > > +static struct davinci_mmc_config > > + *mmc_of_get_pdata(struct platform_device *pdev) > > +{ > > + return pdev->dev.platform_data; > > +} > > +#endif > > This is poorly named if it's required for !CONFIG_OF. > > Why not change this to something like mmc_parse_pdata, returning an > error code. For !CONFIG_OF, it can simply return 0, which should be less > surprising for anyone else reading this code. > I will remove #ifdef CONFIG_OF conditional compilation and consideration your suggestion to name function as mmc_parse_pdata. > > > > static int __init davinci_mmcsd_probe(struct platform_device *pdev) > > { > > - struct davinci_mmc_config *pdata = pdev->dev.platform_data; > > + 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_of_get_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 */ > > > > ret = -ENODEV; > > @@ -1403,11 +1463,18 @@ static const struct dev_pm_ops davinci_mmcsd_pm = { > > #define davinci_mmcsd_pm_ops NULL > > #endif > > > > +static const struct of_device_id davinci_mmc_of_match[] = { > > + {.compatible = "ti,davinci_mmc", }, > > + {}, > > +}; > > +MODULE_DEVICE_TABLE(of, davinci_mmc_of_match); > > For supporting multiple versions, you could either use some auxdata > here, or check each one in davince_mmcsd_probe. > I will consider keeping auxdata via compatible field. > > + > > static struct platform_driver davinci_mmcsd_driver = { > > .driver = { > > .name = "davinci_mmc", > > .owner = THIS_MODULE, > > .pm = davinci_mmcsd_pm_ops, > > + .of_match_table = of_match_ptr(davinci_mmc_of_match), > > }, > > .remove = __exit_p(davinci_mmcsd_remove), > > }; > > Where does davinci_mmcsd_probe get called from, and how is the > of_match_table used? Should it not be set as .probe on the driver? > Driver probe is registered in module_init. And are you suggesting me to use module_platform_driver? If yes can it not be taken separately as it is unrelated to DT support I am adding. of_match_table is used by device tree. (will point to NULL for !CONFIG_OF) 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
