Re: [PATCH] tmio_mmc: Optionally support using platform clock

[pHilipp Zabel <philipp.zabel@gmail.com>]

On Wed, Jul 29, 2009 at 5:20 PM, pHilipp Zabel<philipp.zabel@gmail.com> wrote:
> On Tue, Jul 28, 2009 at 9:51 AM, Guennadi
> Liakhovetski<g.liakhovetski@gmx.de> wrote:
>> If the platform device has a clock associated with the tmio-mmc device,
>> use it.
>>
>> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
>> Cc: Magnus Damm <damm@opensource.se>
>> ---
>>
>> Depends (at least logically) on
>> http://marc.info/?l=linux-kernel&m=124782904228865&w=2
>>
>> Sorry if I forgot anyone who volunteered to help out with MMC patches.
>>
>>  drivers/mmc/host/tmio_mmc.c |   21 +++++++++++++++++++++
>>  drivers/mmc/host/tmio_mmc.h |    3 +++
>>  include/linux/mfd/tmio.h    |    1 +
>>  3 files changed, 25 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c
>> index c246191..2a01572 100644
>> --- a/drivers/mmc/host/tmio_mmc.c
>> +++ b/drivers/mmc/host/tmio_mmc.c
>> @@ -32,6 +32,7 @@
>>  #include <linux/mmc/host.h>
>>  #include <linux/mfd/core.h>
>>  #include <linux/mfd/tmio.h>
>> +#include <linux/clk.h>
>>
>>  #include "tmio_mmc.h"
>>
>> @@ -57,10 +58,18 @@ static void tmio_mmc_clk_stop(struct tmio_mmc_host *host)
>>        sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, ~0x0100 &
>>                sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
>>        msleep(10);
>> +       if (!IS_ERR(host->clk) && host->clk_is_running) {
>> +               clk_disable(host->clk);
>> +               host->clk_is_running = false;
>> +       }
>>  }
>>
>>  static void tmio_mmc_clk_start(struct tmio_mmc_host *host)
>>  {
>> +       if (!IS_ERR(host->clk) && !host->clk_is_running &&
>> +           !clk_enable(host->clk))
>> +               host->clk_is_running = true;
>> +
>>        sd_ctrl_write16(host, CTL_SD_CARD_CLK_CTL, 0x0100 |
>>                sd_ctrl_read16(host, CTL_SD_CARD_CLK_CTL));
>>        msleep(10);
>> @@ -567,6 +576,11 @@ static int __devinit tmio_mmc_probe(struct platform_device *dev)
>>                        goto unmap_cnf;
>>        }
>>
>> +       host->clk = clk_get(&dev->dev, pdata->clk_name);
>
> Instead of pdata->clk_name, this should be either NULL or better
> "HCLK" (to differentiate from CLK32, not sure if we want to be able to
> toggle that, too, in the future).
> Passing the clock consumer ID via pdata is just wrong and shouldn't be
> needed with clkdev.
>
>> +
>> +       if (!IS_ERR(host->clk) && !clk_enable(host->clk))
>> +               host->clk_is_running = true;
>> +
>>        /* Enable the MMC/SD Control registers */
>>        sd_config_write16(host, CNF_CMD, SDCREN);
>>        sd_config_write32(host, CNF_CTL_BASE,
>> @@ -608,6 +622,11 @@ static int __devinit tmio_mmc_probe(struct platform_device *dev)
>>        return 0;
>>
>>  unmap_cnf:
>> +       if (!IS_ERR(host->clk)) {
>> +               clk_disable(host->clk);
>> +               host->clk_is_running = false;
>> +               clk_put(host->clk);
>> +       }
>>        if (host->cnf)
>>                iounmap(host->cnf);
>>  unmap_ctl:
>> @@ -632,6 +651,8 @@ static int __devexit tmio_mmc_remove(struct platform_device *dev)
>>                if (host->cnf)
>>                        iounmap(host->cnf);
>>                mmc_free_host(mmc);
>> +               if (!IS_ERR(host->clk))
>> +                       clk_put(host->clk);
>>        }
>>
>>        return 0;
>> diff --git a/drivers/mmc/host/tmio_mmc.h b/drivers/mmc/host/tmio_mmc.h
>> index 45f06aa..a76d237 100644
>> --- a/drivers/mmc/host/tmio_mmc.h
>> +++ b/drivers/mmc/host/tmio_mmc.h
>> @@ -108,6 +108,7 @@
>>                sd_ctrl_write32((host), CTL_STATUS, mask); \
>>        } while (0)
>>
>> +struct clk;
>>
>>  struct tmio_mmc_host {
>>        void __iomem *cnf;
>> @@ -117,6 +118,8 @@ struct tmio_mmc_host {
>>        struct mmc_request      *mrq;
>>        struct mmc_data         *data;
>>        struct mmc_host         *mmc;
>> +       struct clk              *clk;
>> +       bool                    clk_is_running;
>>        int                     irq;
>>
>>        /* pio related stuff */
>> diff --git a/include/linux/mfd/tmio.h b/include/linux/mfd/tmio.h
>> index 6b9c5d0..e405895 100644
>> --- a/include/linux/mfd/tmio.h
>> +++ b/include/linux/mfd/tmio.h
>> @@ -23,6 +23,7 @@
>>  */
>>  struct tmio_mmc_data {
>>        const unsigned int              hclk;
>> +       const char                      *clk_name;
>
> Drop that.

Actually, this struct can be dropped completely and the HCLK rate can
be determined with clk_get_rate.

>>  };
>>
>>  /*
>> --
>> 1.6.2.4
>>
>> --
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>>
>
> Otherwise that patch doesn't seem wrong to me?
> As soon as we have the possibility for MFD drivers to provide their
> own clk API implementation, this should also work with ASIC3/TMIO.
> I'll try to register my ASIC3 HCLK with clkdev and see if this patch
> works.
>
> regards
> Philipp
>