[PATCH v2 1/3] mmc: atmel-mci: add device tree support
Ludovic Desroches
ludovic.desroches at atmel.com
Wed Mar 28 05:04:39 EDT 2012
Hi Thomas,
On Wed, Mar 28, 2012 at 02:01:16PM +0530, Thomas Abraham wrote:
> On 28 March 2012 15:35, <ludovic.desroches at atmel.com> wrote:
> > From: Ludovic Desroches <ludovic.desroches at atmel.com>
> >
> > Signed-off-by: Ludovic Desroches <ludovic.desroches at atmel.com>
> > ---
> > .../devicetree/bindings/mmc/atmel-hsmci.txt | 67 ++++++++++++++++
> > drivers/mmc/host/atmel-mci.c | 80 ++++++++++++++++++++
> > 2 files changed, 147 insertions(+), 0 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/mmc/atmel-hsmci.txt
> >
> > diff --git a/Documentation/devicetree/bindings/mmc/atmel-hsmci.txt b/Documentation/devicetree/bindings/mmc/atmel-hsmci.txt
> > new file mode 100644
> > index 0000000..bd21e52
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/mmc/atmel-hsmci.txt
> > @@ -0,0 +1,67 @@
> > +* Atmel High Speed MultiMedia Card Interface
> > +
> > +This controller on atmel products provides an interface for MMC, SD and SDIO
> > +types of memory cards.
> > +
> > +1) MCI node
> > +
> > +Required properties:
> > +- compatible: no blank "atmel,hsmci"
> > +- reg: should contain HSMCI registers location and length
> > +- interrupts: should contain HSMCI interrupt number
> > +- #address-cells: should be one. The cell is the slot id.
> > +- #size-cells: should be zero.
> > +- at least one slot node
> > +
> > +The node contains child nodes for each slot that the platform uses
> > +
> > +Example MCI node:
> > +
> > +mmc0: mmc at f0008000 {
> > + compatible = "atmel,hsmci";
> > + reg = <0xf0008000 0x600>;
> > + interrupts = <12 4>;
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + [ child node definitions...]
> > +};
> > +
> > +2) slot nodes
> > +
> > +Required properties:
> > +- reg: should contain the slot id.
> > +
> > +Optional properties:
> > +- bus-width: number of data lines connected to the controller
> > +- cd-gpios: specify GPIOs for card detection
> > +- cd-invert: invert the value of external card detect gpio line
> > +- wp-gpios: specify GPIOs for write protection
>
> There is a push for common bindings for sd/mmc and other card
> controllers as suggested by Arnd here:
> http://www.mail-archive.com/linux-mmc@vger.kernel.org/msg13421.html
>
Thanks for the link, I have seen this discussion so I know that bindings
should change in order to have common ones.
Since I have seen no decision (or I missed it) about common bindings, I only
used existing bindings:
- cd-gpios and wp-gpios seem quite common
- bus-width is used by omap-hsmmc and samsung-sdhci
- cd-invert was into patches sent for mmci device tree support
I will change my bindings if needed.
> > +
> > +Example slot node:
> > +
> > +slot at 0 {
> > + reg = <0>;
> > + bus-width = <4>;
> > + cd-gpios = <&pioD 15 0>
> > + cd-invert;
> > +};
> > +
> > +Example full MCI node:
> > +mmc0: mmc at f0008000 {
> > + compatible = "atmel,hsmci";
> > + reg = <0xf0008000 0x600>;
> > + interrupts = <12 4>;
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > + slot at 0 {
> > + reg = <0>;
> > + bus-width = <4>;
> > + cd-gpios = <&pioD 15 0>
> > + cd-invert;
> > + };
> > + slot at 1 {
> > + reg = <1>;
> > + bus-width = <4>;
> > + };
> > +};
> > diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> > index b5693fd..b160be6 100644
> > --- a/drivers/mmc/host/atmel-mci.c
> > +++ b/drivers/mmc/host/atmel-mci.c
> > @@ -19,6 +19,9 @@
> > #include <linux/interrupt.h>
> > #include <linux/ioport.h>
> > #include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/of_gpio.h>
> > #include <linux/platform_device.h>
> > #include <linux/scatterlist.h>
> > #include <linux/seq_file.h>
> > @@ -477,6 +480,70 @@ err:
> > dev_err(&mmc->class_dev, "failed to initialize debugfs for slot\n");
> > }
> >
> > +#if defined(CONFIG_OF)
> > +static const struct of_device_id atmci_dt_ids[] = {
> > + { .compatible = "atmel,hsmci" },
> > + { /* sentinel */ }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, atmci_dt_ids);
> > +
> > +static int __devinit atmci_of_init(struct platform_device *pdev)
> > +{
> > + struct device_node *np = pdev->dev.of_node;
> > + struct device_node *cnp;
> > + struct mci_platform_data *pdata;
> > + unsigned int slot_id;
> > + const __be32 *reg;
> > +
> > + if (!np)
> > + return 0;
> > +
> > + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
> > + if (!pdata)
> > + return -ENOMEM;
> > +
> > + for_each_child_of_node(np, cnp) {
> > + reg = of_get_property(cnp, "reg", NULL);
> > + if (!reg) {
> > + dev_warn(&pdev->dev, "reg property is missing for %s\n",
> > + cnp->full_name);
> > + continue;
> > + }
> > +
> > + slot_id = be32_to_cpu(reg[0]);
> > +
> > + if (slot_id > (ATMCI_MAX_NR_SLOTS-1)) {
> > + dev_warn(&pdev->dev, "can't have more than %d slots\n",
> > + ATMCI_MAX_NR_SLOTS);
> > + break;
> > + }
> > +
> > + if (of_property_read_u32(cnp, "bus-width",
> > + &pdata->slot[slot_id].bus_width))
> > + pdata->slot[slot_id].bus_width = 1;
> > +
> > + pdata->slot[slot_id].detect_pin =
> > + of_get_named_gpio(cnp, "cd-gpios", 0);
> > +
> > + if (of_find_property(cnp, "cd-invert", NULL))
> > + pdata->slot[slot_id].detect_is_active_high = true;
> > +
> > + pdata->slot[slot_id].wp_pin =
> > + of_get_named_gpio(cnp, "wp-gpios", 0);
> > + }
> > +
> > + pdev->dev.platform_data = pdata;
>
> Assigning a pointer to pdev->dev.platform as done above is not
> allowed. The pointer to pdata obtained from dt should be stored as
> part of the driver's private data and used. (I used to do the same
> mistake until I learnt this lesson learnt from Grant).
>
Thanks for this lesson. It seems to be a usual error. I will correct it.
> > +
> > + return 0;
> > +}
> > +#else /* CONFIG_OF */
> > +static inline int atmci_of_init(struct platform_device *dev)
> > +{
> > + return 0;
> > +}
> > +#endif
> > +
> > static inline unsigned int atmci_ns_to_clocks(struct atmel_mci *host,
> > unsigned int ns)
> > {
> > @@ -1847,6 +1914,13 @@ static int __init atmci_init_slot(struct atmel_mci *host,
> > slot->sdc_reg = sdc_reg;
> > slot->sdio_irq = sdio_irq;
> >
> > + dev_dbg(&mmc->class_dev,
> > + "slot[%u]: bus_width=%u, detect_pin=%d, "
> > + "detect_is_active_high=%s, wp_pin=%d\n",
> > + id, slot_data->bus_width, slot_data->detect_pin,
> > + slot_data->detect_is_active_high ? "true" : "false",
> > + slot_data->wp_pin);
> > +
> > mmc->ops = &atmci_ops;
> > mmc->f_min = DIV_ROUND_UP(host->bus_hz, 512);
> > mmc->f_max = host->bus_hz / 2;
> > @@ -2047,6 +2121,11 @@ static int __init atmci_probe(struct platform_device *pdev)
> > regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > if (!regs)
> > return -ENXIO;
> > +
> > + ret = atmci_of_init(pdev);
> > + if (ret)
> > + return ret;
> > +
> > pdata = pdev->dev.platform_data;
> > if (!pdata)
> > return -ENXIO;
> > @@ -2242,6 +2321,7 @@ static struct platform_driver atmci_driver = {
> > .driver = {
> > .name = "atmel_mci",
> > .pm = ATMCI_PM_OPS,
> > + .of_match_table = of_match_ptr(atmci_dt_ids),
> > },
> > };
> >
> > --
> > 1.7.5.4
>
> Thanks,
> Thomas.
>
Thanks
Regards
Ludovic
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