Re: [RFC PATCH 3/3] mmc: pwrseq: convert to proper platform device

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 19/01/16 13:01, Ulf Hansson wrote:
> On 19 January 2016 at 11:59, Srinivas Kandagatla
> <srinivas.kandagatla@linaro.org> wrote:
>> simple-pwrseq and emmc-pwrseq drivers rely on platform_device
>> structure from of_find_device_by_node(), this works mostly. But, as there
>> is no driver associated with this devices, cases like default/init pinctrl
>> setup would never be performed by pwrseq. This becomes problem when the
>> gpios used in pwrseq require pinctrl setup.
>>
>> Currently most of the common pinctrl setup is done in
>> drivers/base/pinctrl.c by pinctrl_bind_pins().
>>
>> There are two ways to slove this issue on either convert pwrseq drivers
>> to a proper platform drivers or copy the exact code from
>> pcintrl_bind_pins(). I prefer converting pwrseq to proper drivers so that
>> other cases like setting up clks/parents from dt would also be possible.
>
> Overall I like the approach, thanks for posting this!
>
> I have browsed through the patch, it looks okay, besides one issue...
>
> There is a possibility that the pwrseq drivers haven't been probed
> before mmc_pwrseq_alloc() gets called. This leads to that the
> pwrseq_list may be empty, which means that we would silently fail to
> find a corresponding pwrseq type even if the device node would say
> there should be one.
>
> Perhaps you should do a pre-validation of the device node in
> mmc_pwrseq_alloc(), to see if there is a pwrseq handle. If so, but no
> corresponding pwrseq method registerd (because the driver hasn’t been
> probed yet), you could return -EPROBE_DEFER. Or perhaps there are
> other alternatives to solved this issue!?
That's a good point.

Doing EPROBE_DEFER sounds more correct to me, we could return this error 
in cases where the phandle for "mmc-pwrseq" exists and unable to find 
the pwrseq in the list.

This would go well with mmc_of_parse() return types.

Will spin v2 with this fix.

thanks,
srini

>
> Kind regards
> Uffe
>
>>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>> ---
>>   drivers/mmc/core/pwrseq.c        | 99 ++++++++++++++++++++--------------------
>>   drivers/mmc/core/pwrseq.h        | 13 ++++--
>>   drivers/mmc/core/pwrseq_emmc.c   | 65 ++++++++++++++++----------
>>   drivers/mmc/core/pwrseq_simple.c | 71 ++++++++++++++++++----------
>>   4 files changed, 145 insertions(+), 103 deletions(-)
>>
>> diff --git a/drivers/mmc/core/pwrseq.c b/drivers/mmc/core/pwrseq.c
>> index 4c1d175..669608e 100644
>> --- a/drivers/mmc/core/pwrseq.c
>> +++ b/drivers/mmc/core/pwrseq.c
>> @@ -8,50 +8,30 @@
>>    *  MMC power sequence management
>>    */
>>   #include <linux/kernel.h>
>> -#include <linux/platform_device.h>
>>   #include <linux/err.h>
>>   #include <linux/of.h>
>> -#include <linux/of_platform.h>
>>
>>   #include <linux/mmc/host.h>
>>
>>   #include "pwrseq.h"
>>
>> -struct mmc_pwrseq_match {
>> -       const char *compatible;
>> -       struct mmc_pwrseq *(*alloc)(struct mmc_host *host, struct device *dev);
>> -};
>> -
>> -static struct mmc_pwrseq_match pwrseq_match[] = {
>> -       {
>> -               .compatible = "mmc-pwrseq-simple",
>> -               .alloc = mmc_pwrseq_simple_alloc,
>> -       }, {
>> -               .compatible = "mmc-pwrseq-emmc",
>> -               .alloc = mmc_pwrseq_emmc_alloc,
>> -       },
>> -};
>> -
>> -static struct mmc_pwrseq_match *mmc_pwrseq_find(struct device_node *np)
>> +static DEFINE_MUTEX(pwrseq_list_mutex);
>> +static LIST_HEAD(pwrseq_list);
>> +
>> +static struct mmc_pwrseq *of_find_mmc_pwrseq(struct device_node *np)
>>   {
>> -       struct mmc_pwrseq_match *match = ERR_PTR(-ENODEV);
>> -       int i;
>> +       struct mmc_pwrseq *p;
>>
>> -       for (i = 0; i < ARRAY_SIZE(pwrseq_match); i++) {
>> -               if (of_device_is_compatible(np, pwrseq_match[i].compatible)) {
>> -                       match = &pwrseq_match[i];
>> -                       break;
>> -               }
>> -       }
>> +       list_for_each_entry(p, &pwrseq_list, list)
>> +               if (p->dev->of_node == np)
>> +                       return p;
>>
>> -       return match;
>> +       return NULL;
>>   }
>>
>>   int mmc_pwrseq_alloc(struct mmc_host *host)
>>   {
>> -       struct platform_device *pdev;
>>          struct device_node *np;
>> -       struct mmc_pwrseq_match *match;
>>          struct mmc_pwrseq *pwrseq;
>>          int ret = 0;
>>
>> @@ -59,25 +39,18 @@ int mmc_pwrseq_alloc(struct mmc_host *host)
>>          if (!np)
>>                  return 0;
>>
>> -       pdev = of_find_device_by_node(np);
>> -       if (!pdev) {
>> -               ret = -ENODEV;
>> -               goto err;
>> -       }
>> +       pwrseq = of_find_mmc_pwrseq(np);
>>
>> -       match = mmc_pwrseq_find(np);
>> -       if (IS_ERR(match)) {
>> -               ret = PTR_ERR(match);
>> -               goto err;
>> -       }
>> +       if (pwrseq && pwrseq->ops && pwrseq->ops->alloc) {
>> +               host->pwrseq = pwrseq;
>> +               ret = pwrseq->ops->alloc(host);
>> +               if (IS_ERR_VALUE(ret)) {
>> +                       host->pwrseq = NULL;
>> +                       goto err;
>> +               }
>>
>> -       pwrseq = match->alloc(host, &pdev->dev);
>> -       if (IS_ERR(pwrseq)) {
>> -               ret = PTR_ERR(pwrseq);
>> -               goto err;
>>          }
>>
>> -       host->pwrseq = pwrseq;
>>          dev_info(host->parent, "allocated mmc-pwrseq\n");
>>
>>   err:
>> @@ -89,7 +62,7 @@ void mmc_pwrseq_pre_power_on(struct mmc_host *host)
>>   {
>>          struct mmc_pwrseq *pwrseq = host->pwrseq;
>>
>> -       if (pwrseq && pwrseq->ops && pwrseq->ops->pre_power_on)
>> +       if (pwrseq && pwrseq->ops->pre_power_on)
>>                  pwrseq->ops->pre_power_on(host);
>>   }
>>
>> @@ -97,7 +70,7 @@ void mmc_pwrseq_post_power_on(struct mmc_host *host)
>>   {
>>          struct mmc_pwrseq *pwrseq = host->pwrseq;
>>
>> -       if (pwrseq && pwrseq->ops && pwrseq->ops->post_power_on)
>> +       if (pwrseq && pwrseq->ops->post_power_on)
>>                  pwrseq->ops->post_power_on(host);
>>   }
>>
>> @@ -105,7 +78,7 @@ void mmc_pwrseq_power_off(struct mmc_host *host)
>>   {
>>          struct mmc_pwrseq *pwrseq = host->pwrseq;
>>
>> -       if (pwrseq && pwrseq->ops && pwrseq->ops->power_off)
>> +       if (pwrseq && pwrseq->ops->power_off)
>>                  pwrseq->ops->power_off(host);
>>   }
>>
>> @@ -113,8 +86,34 @@ void mmc_pwrseq_free(struct mmc_host *host)
>>   {
>>          struct mmc_pwrseq *pwrseq = host->pwrseq;
>>
>> -       if (pwrseq && pwrseq->ops && pwrseq->ops->free)
>> -               pwrseq->ops->free(host);
>> +       if (pwrseq) {
>> +               if (pwrseq->ops->free)
>> +                       pwrseq->ops->free(host);
>> +
>> +               host->pwrseq = NULL;
>> +       }
>>
>> -       host->pwrseq = NULL;
>>   }
>> +
>> +int mmc_pwrseq_register(struct mmc_pwrseq *pwrseq)
>> +{
>> +       if (!pwrseq || !pwrseq->ops || !pwrseq->dev)
>> +               return -EINVAL;
>> +
>> +       mutex_lock(&pwrseq_list_mutex);
>> +       list_add(&pwrseq->list, &pwrseq_list);
>> +       mutex_unlock(&pwrseq_list_mutex);
>> +
>> +       return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(mmc_pwrseq_register);
>> +
>> +void mmc_pwrseq_unregister(struct mmc_pwrseq *pwrseq)
>> +{
>> +       if (pwrseq) {
>> +               mutex_lock(&pwrseq_list_mutex);
>> +               list_del(&pwrseq->list);
>> +               mutex_unlock(&pwrseq_list_mutex);
>> +       }
>> +}
>> +EXPORT_SYMBOL_GPL(mmc_pwrseq_unregister);
>> diff --git a/drivers/mmc/core/pwrseq.h b/drivers/mmc/core/pwrseq.h
>> index 096da48..08a7d2d 100644
>> --- a/drivers/mmc/core/pwrseq.h
>> +++ b/drivers/mmc/core/pwrseq.h
>> @@ -8,7 +8,10 @@
>>   #ifndef _MMC_CORE_PWRSEQ_H
>>   #define _MMC_CORE_PWRSEQ_H
>>
>> +#include <linux/mmc/host.h>
>> +
>>   struct mmc_pwrseq_ops {
>> +       int (*alloc)(struct mmc_host *host);
>>          void (*pre_power_on)(struct mmc_host *host);
>>          void (*post_power_on)(struct mmc_host *host);
>>          void (*power_off)(struct mmc_host *host);
>> @@ -17,21 +20,21 @@ struct mmc_pwrseq_ops {
>>
>>   struct mmc_pwrseq {
>>          struct mmc_pwrseq_ops *ops;
>> +       struct device *dev;
>> +       struct list_head list;
>>   };
>>
>>   #ifdef CONFIG_OF
>>
>> +int mmc_pwrseq_register(struct mmc_pwrseq *pwrseq);
>> +void mmc_pwrseq_unregister(struct mmc_pwrseq *pwrseq);
>> +
>>   int mmc_pwrseq_alloc(struct mmc_host *host);
>>   void mmc_pwrseq_pre_power_on(struct mmc_host *host);
>>   void mmc_pwrseq_post_power_on(struct mmc_host *host);
>>   void mmc_pwrseq_power_off(struct mmc_host *host);
>>   void mmc_pwrseq_free(struct mmc_host *host);
>>
>> -struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
>> -                                          struct device *dev);
>> -struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
>> -                                        struct device *dev);
>> -
>>   #else
>>
>>   static inline int mmc_pwrseq_alloc(struct mmc_host *host) { return 0; }
>> diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c
>> index 7978fb7..75f7423 100644
>> --- a/drivers/mmc/core/pwrseq_emmc.c
>> +++ b/drivers/mmc/core/pwrseq_emmc.c
>> @@ -9,6 +9,7 @@
>>    */
>>   #include <linux/delay.h>
>>   #include <linux/kernel.h>
>> +#include <linux/platform_device.h>
>>   #include <linux/slab.h>
>>   #include <linux/device.h>
>>   #include <linux/err.h>
>> @@ -48,14 +49,8 @@ static void mmc_pwrseq_emmc_free(struct mmc_host *host)
>>
>>          unregister_restart_handler(&pwrseq->reset_nb);
>>          gpiod_put(pwrseq->reset_gpio);
>> -       kfree(pwrseq);
>>   }
>>
>> -static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
>> -       .post_power_on = mmc_pwrseq_emmc_reset,
>> -       .free = mmc_pwrseq_emmc_free,
>> -};
>> -
>>   static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
>>                                      unsigned long mode, void *cmd)
>>   {
>> @@ -66,21 +61,14 @@ static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
>>          return NOTIFY_DONE;
>>   }
>>
>> -struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
>> -                                        struct device *dev)
>> +static int mmc_pwrseq_emmc_alloc(struct mmc_host *host)
>>   {
>> -       struct mmc_pwrseq_emmc *pwrseq;
>> -       int ret = 0;
>> -
>> -       pwrseq = kzalloc(sizeof(struct mmc_pwrseq_emmc), GFP_KERNEL);
>> -       if (!pwrseq)
>> -               return ERR_PTR(-ENOMEM);
>> +       struct mmc_pwrseq_emmc *pwrseq =  to_pwrseq_emmc(host->pwrseq);
>>
>> -       pwrseq->reset_gpio = gpiod_get(dev, "reset", GPIOD_OUT_LOW);
>> -       if (IS_ERR(pwrseq->reset_gpio)) {
>> -               ret = PTR_ERR(pwrseq->reset_gpio);
>> -               goto free;
>> -       }
>> +       pwrseq->reset_gpio = gpiod_get(host->pwrseq->dev,
>> +                                       "reset", GPIOD_OUT_LOW);
>> +       if (IS_ERR(pwrseq->reset_gpio))
>> +               return PTR_ERR(pwrseq->reset_gpio);
>>
>>          /*
>>           * register reset handler to ensure emmc reset also from
>> @@ -91,10 +79,41 @@ struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
>>          pwrseq->reset_nb.priority = 255;
>>          register_restart_handler(&pwrseq->reset_nb);
>>
>> +       return 0;
>> +}
>> +
>> +static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
>> +       .alloc = mmc_pwrseq_emmc_alloc,
>> +       .post_power_on = mmc_pwrseq_emmc_reset,
>> +       .free = mmc_pwrseq_emmc_free,
>> +};
>> +
>> +static int mmc_pwrseq_emmc_probe(struct platform_device *pdev)
>> +{
>> +       struct mmc_pwrseq_emmc *pwrseq;
>> +       struct device *dev = &pdev->dev;
>> +
>> +       pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
>> +       if (!pwrseq)
>> +               return -ENOMEM;
>> +
>>          pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
>> +       pwrseq->pwrseq.dev = dev;
>>
>> -       return &pwrseq->pwrseq;
>> -free:
>> -       kfree(pwrseq);
>> -       return ERR_PTR(ret);
>> +       return mmc_pwrseq_register(&pwrseq->pwrseq);
>>   }
>> +
>> +static const struct of_device_id mmc_pwrseq_emmc_of_match[] = {
>> +       { .compatible = "mmc-pwrseq-emmc",},
>> +       {/* sentinel */},
>> +};
>> +
>> +static struct platform_driver mmc_pwrseq_emmc_driver = {
>> +       .probe = mmc_pwrseq_emmc_probe,
>> +       .driver = {
>> +               .name = "pwrseq_emmc",
>> +               .of_match_table = mmc_pwrseq_emmc_of_match,
>> +       },
>> +};
>> +
>> +builtin_platform_driver(mmc_pwrseq_emmc_driver);
>> diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
>> index c091f98..b04cc2d 100644
>> --- a/drivers/mmc/core/pwrseq_simple.c
>> +++ b/drivers/mmc/core/pwrseq_simple.c
>> @@ -9,6 +9,7 @@
>>    */
>>   #include <linux/clk.h>
>>   #include <linux/kernel.h>
>> +#include <linux/platform_device.h>
>>   #include <linux/slab.h>
>>   #include <linux/device.h>
>>   #include <linux/err.h>
>> @@ -82,46 +83,66 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
>>          if (!IS_ERR(pwrseq->ext_clk))
>>                  clk_put(pwrseq->ext_clk);
>>
>> -       kfree(pwrseq);
>>   }
>>
>> -static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
>> -       .pre_power_on = mmc_pwrseq_simple_pre_power_on,
>> -       .post_power_on = mmc_pwrseq_simple_post_power_on,
>> -       .power_off = mmc_pwrseq_simple_power_off,
>> -       .free = mmc_pwrseq_simple_free,
>> -};
>> -
>> -struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
>> -                                          struct device *dev)
>> +int mmc_pwrseq_simple_alloc(struct mmc_host *host)
>>   {
>> -       struct mmc_pwrseq_simple *pwrseq;
>> +       struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);
>> +       struct device *dev = host->pwrseq->dev;
>>          int ret = 0;
>>
>> -       pwrseq = kzalloc(sizeof(*pwrseq), GFP_KERNEL);
>> -       if (!pwrseq)
>> -               return ERR_PTR(-ENOMEM);
>> -
>>          pwrseq->ext_clk = clk_get(dev, "ext_clock");
>>          if (IS_ERR(pwrseq->ext_clk) &&
>>              PTR_ERR(pwrseq->ext_clk) != -ENOENT) {
>> -               ret = PTR_ERR(pwrseq->ext_clk);
>> -               goto free;
>> +               return PTR_ERR(pwrseq->ext_clk);
>> +
>>          }
>>
>>          pwrseq->reset_gpios = gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
>>          if (IS_ERR(pwrseq->reset_gpios)) {
>>                  ret = PTR_ERR(pwrseq->reset_gpios);
>> -               goto clk_put;
>> +               clk_put(pwrseq->ext_clk);
>> +               return ret;
>>          }
>>
>> +       return 0;
>> +}
>> +
>> +static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
>> +       .alloc = mmc_pwrseq_simple_alloc,
>> +       .pre_power_on = mmc_pwrseq_simple_pre_power_on,
>> +       .post_power_on = mmc_pwrseq_simple_post_power_on,
>> +       .power_off = mmc_pwrseq_simple_power_off,
>> +       .free = mmc_pwrseq_simple_free,
>> +};
>> +
>> +static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
>> +       { .compatible = "mmc-pwrseq-simple",},
>> +       {/* sentinel */},
>> +};
>> +
>> +static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
>> +{
>> +       struct mmc_pwrseq_simple *pwrseq;
>> +       struct device *dev = &pdev->dev;
>> +
>> +       pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
>> +       if (!pwrseq)
>> +               return ERR_PTR(-ENOMEM);
>> +
>> +       pwrseq->pwrseq.dev = dev;
>>          pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
>>
>> -       return &pwrseq->pwrseq;
>> -clk_put:
>> -       if (!IS_ERR(pwrseq->ext_clk))
>> -               clk_put(pwrseq->ext_clk);
>> -free:
>> -       kfree(pwrseq);
>> -       return ERR_PTR(ret);
>> +       return mmc_pwrseq_register(&pwrseq->pwrseq);
>>   }
>> +
>> +
>> +static struct platform_driver mmc_pwrseq_simple_driver = {
>> +       .probe = mmc_pwrseq_simple_probe,
>> +       .driver = {
>> +               .name = "pwrseq_simple",
>> +               .of_match_table = mmc_pwrseq_simple_of_match,
>> +       },
>> +};
>> +
>> +builtin_platform_driver(mmc_pwrseq_simple_driver);
>> --
>> 1.9.1
>>