LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
To: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	Ulf Hansson <ulf.hansson@linaro.org>
Cc: devicetree@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
	linux-mmc@vger.kernel.org, Doug Anderson <dianders@chromium.org>,
	linux-kernel@vger.kernel.org, Kukjin Kim <kgene@kernel.org>,
	Olof Johansson <olof@lixom.net>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/5] mmc: pwrseq_simple: Extend to support more pins
Date: Wed, 28 Jan 2015 17:13:32 +0100	[thread overview]
Message-ID: <54C90AAC.3010907@collabora.co.uk> (raw)
In-Reply-To: <54C8EBB2.10101@linaro.org>

Hello Srinivas,

Thanks a lot for your feedback.

On 01/28/2015 03:01 PM, Srinivas Kandagatla wrote:
> Hi Javier,
> 
> You are in a lead of 3 hrs from me..
> Surprisingly I send very much same patch just few Mins ago :-)

:-)

I didn't find the posted patch you are referring too though, did you cc
linux-mmc?

> May be we can merge goods in both :-)
>

Sure, I want $subject to be generic enough to be useful for other platforms.

> On 28/01/15 10:10, Javier Martinez Canillas wrote:
>> Many WLAN attached to a SDIO/MMC interface, needs more than one pin for
>> their reset sequence. For example, is very common for chips to have two
>> pins: one for reset and one for power enable.
>>
>> This patch adds support for more reset pins to the pwrseq_simple driver
>> and instead hardcoding a fixed number, it uses the of_gpio_named_count()
>> since the MMC power sequence is only built when CONFIG_OF is enabled.
>>
>> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
>> ---
>>   drivers/mmc/core/pwrseq_simple.c | 54 ++++++++++++++++++++++++++++++----------
>>   1 file changed, 41 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
>> index 0958c696137f..9e51fe1051c5 100644
>> --- a/drivers/mmc/core/pwrseq_simple.c
>> +++ b/drivers/mmc/core/pwrseq_simple.c
>> @@ -11,6 +11,7 @@
>>   #include <linux/slab.h>
>>   #include <linux/device.h>
>>   #include <linux/err.h>
>> +#include <linux/of_gpio.h>
>>   #include <linux/gpio/consumer.h>
>>
>>   #include <linux/mmc/host.h>
>> @@ -19,34 +20,44 @@
>>
>>   struct mmc_pwrseq_simple {
>>   	struct mmc_pwrseq pwrseq;
>> -	struct gpio_desc *reset_gpio;
>> +	struct gpio_desc **reset_gpio;
> 
> May be renaming it to reset_gpios makes more sense..
>

Ok

> If you make this struct gpio_desc *reset_gpios[0]; You can aviod an 
> extra kmalloc and free ..
> 
>

That's a very good idea, thanks.

>> +	int nr_gpios;
>>   };
>>
>>   static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
>>   {
> 
> [...
>>   	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
>>   					struct mmc_pwrseq_simple, pwrseq);
>> +	int i;
>>
>> -	if (!IS_ERR(pwrseq->reset_gpio))
>> -		gpiod_set_value_cansleep(pwrseq->reset_gpio, 1);
>> +	for (i = 0; i < pwrseq->nr_gpios; i++)
>> +		if (!IS_ERR(pwrseq->reset_gpio[i]))
>> +			gpiod_set_value_cansleep(pwrseq->reset_gpio[i], 1);
> 
> ...]
> 
>>   }
>>
>>   static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
>>   {
> 
> [...
> 
>>   	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
>>   					struct mmc_pwrseq_simple, pwrseq);
>> +	int i;
>>
>> -	if (!IS_ERR(pwrseq->reset_gpio))
>> -		gpiod_set_value_cansleep(pwrseq->reset_gpio, 0);
>> +	for (i = 0; i < pwrseq->nr_gpios; i++)
>> +		if (!IS_ERR(pwrseq->reset_gpio[i]))
>> +			gpiod_set_value_cansleep(pwrseq->reset_gpio[i], 0);
> ...]
> 
> Now that we have more code in mmc_pwrseq_simple_post_power_on() and 
> mmc_pwrseq_simple_pre_power_on(), Just move most of them into a common 
> function like:
> 
> static void __mmc_pwrseq_simple_power_on_off(struct mmc_host *host,
> 						      bool on)
> {
> 	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
> 					struct mmc_pwrseq_simple, pwrseq);
> 	int i;
> 
> 	if (!IS_ERR(pwrseq->reset_gpios)) {
> 		for (i = 0; i < pwrseq->ngpios; i++)
> 			gpiod_set_value_cansleep(pwrseq->reset_gpios[i],
> 						 on ? : 0);
> 	}
> }
>
> static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
> {
> 	__mmc_pwrseq_simple_power_on_off(host, true);
> }
> 
> static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
> {
> 	__mmc_pwrseq_simple_power_on_off(host, false);
> }
> 
>

Sure, will do.

>>   }
>>
>>   static void mmc_pwrseq_simple_free(struct mmc_host *host)
>>   {
>>   	struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
>>   					struct mmc_pwrseq_simple, pwrseq);
>> +	int i;
>>
>> -	if (!IS_ERR(pwrseq->reset_gpio))
>> -		gpiod_put(pwrseq->reset_gpio);
>> +	if (pwrseq->nr_gpios > 0) {
>> +		for (i = 0; i < pwrseq->nr_gpios; i++)
>> +			if (!IS_ERR(pwrseq->reset_gpio[i]))
>> +				gpiod_put(pwrseq->reset_gpio[i]);
>> +		kfree(pwrseq->reset_gpio);
>> +	}
>>
>>   	kfree(pwrseq);
>>   	host->pwrseq = NULL;
>> @@ -63,17 +74,27 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
>>   {
>>   	struct mmc_pwrseq_simple *pwrseq;
>>   	int ret = 0;
>> +	int i;
>>
>>   	pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple), GFP_KERNEL);
>>   	if (!pwrseq)
>>   		return -ENOMEM;
>>
>> -	pwrseq->reset_gpio = gpiod_get_index(dev, "reset", 0, GPIOD_OUT_HIGH);
>> -	if (IS_ERR(pwrseq->reset_gpio) &&
>> -		PTR_ERR(pwrseq->reset_gpio) != -ENOENT &&
>> -		PTR_ERR(pwrseq->reset_gpio) != -ENOSYS) {
>> -		ret = PTR_ERR(pwrseq->reset_gpio);
>> -		goto free;
>> +	pwrseq->nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
>> +	if (pwrseq->nr_gpios > 0) {
> 
> What happens if there are no gpios? This fuction should return -ENOENT 
> and should not even try to allocate pwrseq?

Not quite, the DT binding states that the GPIOs are optional so it should
not fail if no GPIOs are defined. 

> Probably you should do of_gpio_named_count before allocating memory.
>

I didn't do that because patch #4 "mmc: pwrseq_simple: Add optional reference
clock support" will need the struct mmc_pwrseq_simple even if no GPIOs are
defined.

A SDIO attached chip could require only an external clock or someone could
extend the pwrseq_simple driver to support an external regulator for example.

>> +		pwrseq->reset_gpio = kzalloc(sizeof(struct gpio_desc *) *
>> +					     pwrseq->nr_gpios, GFP_KERNEL);
>> +
>> +		for (i = 0; i < pwrseq->nr_gpios; i++) {
>> +			pwrseq->reset_gpio[i] = gpiod_get_index(dev, "reset", i,
>> +								GPIOD_OUT_HIGH);
>> +			if (IS_ERR(pwrseq->reset_gpio[i]) &&
>> +			    PTR_ERR(pwrseq->reset_gpio[i]) != -ENOENT &&
>> +			    PTR_ERR(pwrseq->reset_gpio[i]) != -ENOSYS) {
>> +				ret = PTR_ERR(pwrseq->reset_gpio[i]);
> 
> is simple to add:
> 	while(--i)
> 		gpiod_put(pwrseq->reset_gpio[i])
> 
> 
>

That's true, will change.

>> +				goto free;
>> +			}
>> +		}
> 
> 
>>   	}
>>
>>   	pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
>> @@ -81,6 +102,13 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
>>
>>   	return 0;
>>   free:
>> +	if (pwrseq->nr_gpios > 0) {
>> +		for (i = 0; i < pwrseq->nr_gpios; i++)
>> +			if (!IS_ERR_OR_NULL(pwrseq->reset_gpio[i]))
>> +				gpiod_put(pwrseq->reset_gpio[i]);
>> +		kfree(pwrseq->reset_gpio);
>> +	}
>> +
>>   	kfree(pwrseq);
>>   	return ret;
>>   }
>>
> 
> I get a feeling that am just dumping my patch here.. If possible could 
> you have look at it too.
>

Of course, do you have a link archive since I can't find it on my inbox.

> Thanks,
> srini
>

Again, thanks a lot and best regards,
Javier


  reply	other threads:[~2015-01-29  2:02 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-28 10:10 [PATCH 0/5] Add multiple GPIO and external clock to MMC pwrseq_simple Javier Martinez Canillas
2015-01-28 10:10 ` [PATCH 1/5] mmc: pwrseq: Document that simple sequence support more than one GPIO Javier Martinez Canillas
2015-01-28 16:34   ` Srinivas Kandagatla
2015-01-28 16:35     ` Javier Martinez Canillas
2015-01-28 10:10 ` [PATCH 2/5] mmc: pwrseq_simple: Extend to support more pins Javier Martinez Canillas
2015-01-28 14:01   ` Srinivas Kandagatla
2015-01-28 16:13     ` Javier Martinez Canillas [this message]
2015-01-28 16:31       ` Srinivas Kandagatla
2015-01-28 10:10 ` [PATCH 3/5] mmc: pwrseq: Document optional clock for the simple power sequence Javier Martinez Canillas
2015-01-28 10:10 ` [PATCH 4/5] mmc: pwrseq_simple: Add optional reference clock support Javier Martinez Canillas
2015-01-28 10:10 ` [PATCH 5/5] ARM: dts: exynos5250-snow: Enable wifi power-on Javier Martinez Canillas
2015-01-28 14:03   ` Arend van Spriel
2015-01-28 15:57     ` Javier Martinez Canillas

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=54C90AAC.3010907@collabora.co.uk \
    --to=javier.martinez@collabora.co.uk \
    --cc=devicetree@vger.kernel.org \
    --cc=dianders@chromium.org \
    --cc=kgene@kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mmc@vger.kernel.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=olof@lixom.net \
    --cc=srinivas.kandagatla@linaro.org \
    --cc=ulf.hansson@linaro.org \
    --subject='Re: [PATCH 2/5] mmc: pwrseq_simple: Extend to support more pins' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).