Re: [PATCH 3/5] MMC: mmci: Add generic Device Tree bindings to mmci core code

[Lee Jones <lee.jones@linaro.org>]

On 15/03/12 15:12, Per Forlin wrote:
> On Wed, Mar 14, 2012 at 3:20 PM, Lee Jones <lee.jones@linaro.org> wrote:
>> This adds the necessary bindings for collection of shared
>> attributes used in the mmci driver.
>>
>> Signed-off-by: Lee Jones <lee.jones@linaro.org>
>> ---
>>  drivers/mmc/host/mmci.c |   43 +++++++++++++++++++++++++++++++++++++++++++
>>  1 files changed, 43 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
>> index 23b41a5..9132ca8 100644
>> --- a/drivers/mmc/host/mmci.c
>> +++ b/drivers/mmc/host/mmci.c
>> @@ -30,6 +30,7 @@
>>  #include <linux/dma-mapping.h>
>>  #include <linux/amba/mmci.h>
>>  #include <linux/pm_runtime.h>
>> +#include <linux/of_gpio.h>
>>
>>  #include <asm/div64.h>
>>  #include <asm/io.h>
>> @@ -1056,11 +1057,47 @@ static const struct mmc_host_ops mmci_ops = {
>>        .get_cd         = mmci_get_cd,
>>  };
>>
>> +#ifdef CONFIG_OF
>> +static void mmci_dt_populate_generic_pdata(struct device_node *np,
>> +                                       struct mmci_platform_data *pdata)
>> +{
>> +       const void *prop;
>> +       int len;
>> +
>> +       of_property_read_u32(np, "wp-gpios", &pdata->gpio_wp);
>> +       if (!pdata->gpio_wp)
>> +               pdata->gpio_wp = -1;
>> +
>> +       of_property_read_u32(np, "cd-gpios", &pdata->gpio_cd);
>> +       if (!pdata->gpio_cd)
>> +               pdata->gpio_cd = -1;
>> +
>> +       if (of_get_property(np, "cd-invert", NULL))
>> +               pdata->cd_invert = true;
>> +       else
>> +               pdata->cd_invert = false;
>> +
>> +       of_property_read_u32(np, "clock_frequency", &pdata->f_max);
>> +       if (!pdata->f_max)
>> +               pr_warning("%s has no 'clock_frequency' property\n", np->full_name);
>> +
>> +       if (of_get_property(np, "mmc_cap_4_bit_data", NULL))
> I have no previous experience with DT. Could you please bring some
> light on this.
> Is it really necessary to represent each bit in the CAP with a string?

No, you can use a straight integer in the DT blob, but this makes it
much easier to read.

> To add CAP_ERASE for instance I need to change the code here and
> update the DT, right?

That's right, but no MMCI user makes use of it, so it would just be
unnecessary/unused code clogging up the core driver.

Kind regards,
Lee

-- 
Lee Jones
Linaro ST-Ericsson Landing Team Lead
M: +44 77 88 633 515
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