Re: [PATCH v2 4/6] mmc: pwrseq_simple: Add optional reference clock support

2015-01-29 Thread Javier Martinez Canillas 
Hello Ulf,

Thanks a lot for your feedback.

On 01/29/2015 02:05 PM, Ulf Hansson wrote:
>>
>>  struct mmc_pwrseq_simple {
>> struct mmc_pwrseq pwrseq;
>> +   struct clk *ext_clk;
> 
> You need to add a bool, maybe call it clk_enabled;  See why below.
>

Ok
 
>> int nr_gpios;
>> struct gpio_desc *reset_gpios[0];
>>  };
>> @@ -39,6 +41,9 @@ 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);
>>
>> +   if (!IS_ERR(pwrseq->ext_clk))
>> +   clk_prepare_enable(pwrseq->ext_clk);
>> +
> 
> There are no guarantee that the ->mmc_pwrseq_simple_pre_power_on()
> will be invoked prior ->mmc_pwrseq_simple_power_off().
>

Got it, I didn't know that mmc_pwrseq_simple_power_off() could be invoked.
without mmc_pwrseq_simple_pre_power_on() not being called before.

> That means you need to keep track of if you have gated/ungated the
> clock. In other words check pwrseq->clk_enabled. That will prevent
> potential clk unbalance issues.

Yes, I'll change to check for the boolean in _simple_power_off() and
_post_power_on() then.

>> @@ -85,6 +104,14 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, 
>> struct device *dev)
>> if (!pwrseq)
>> return -ENOMEM;
>>
>> +   pwrseq->ext_clk = clk_get(dev, "ext_clock");
>> +   if (IS_ERR(pwrseq->ext_clk) &&
>> +   PTR_ERR(pwrseq->ext_clk) != -ENOENT &&
>> +   PTR_ERR(pwrseq->ext_clk) != -ENOSYS) {
> 
> I don't think you can get -ENOSYS.
> 

You are right, I'll remove that.

Best regards,
Javier
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v2 4/6] mmc: pwrseq_simple: Add optional reference clock support

2015-01-29 Thread Ulf Hansson 
On 28 January 2015 at 19:15, Javier Martinez Canillas
 wrote:
> Some WLAN chips attached to a SDIO interface, need a reference clock.
>
> Since this is very common, extend the prseq_simple driver to support
> an optional clock that is enabled prior the card power up procedure.
>
> Note: the external clock is optional. Thus an error is not returned
> if the clock is not found.
>
> Signed-off-by: Javier Martinez Canillas 
> ---
>
> Changes since v1:
>  - Rebase on top of latest changes.
>  - Use IS_ERR() instead of checking for NULL to see if the clock exists.
> ---
>  drivers/mmc/core/pwrseq_simple.c | 34 --
>  1 file changed, 32 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/pwrseq_simple.c 
> b/drivers/mmc/core/pwrseq_simple.c
> index e53d3c7e059c..5e34c77efa5e 100644
> --- a/drivers/mmc/core/pwrseq_simple.c
> +++ b/drivers/mmc/core/pwrseq_simple.c
> @@ -7,6 +7,7 @@
>   *
>   *  Simple MMC power sequence management
>   */
> +#include 
>  #include 
>  #include 
>  #include 
> @@ -20,6 +21,7 @@
>
>  struct mmc_pwrseq_simple {
> struct mmc_pwrseq pwrseq;
> +   struct clk *ext_clk;

You need to add a bool, maybe call it clk_enabled;  See why below.

> int nr_gpios;
> struct gpio_desc *reset_gpios[0];
>  };
> @@ -39,6 +41,9 @@ 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);
>
> +   if (!IS_ERR(pwrseq->ext_clk))
> +   clk_prepare_enable(pwrseq->ext_clk);
> +

There are no guarantee that the ->mmc_pwrseq_simple_pre_power_on()
will be invoked prior ->mmc_pwrseq_simple_power_off().

That means you need to keep track of if you have gated/ungated the
clock. In other words check pwrseq->clk_enabled. That will prevent
potential clk unbalance issues.

> mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
>  }
>
> @@ -50,6 +55,17 @@ static void mmc_pwrseq_simple_post_power_on(struct 
> mmc_host *host)
> mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
>  }
>
> +static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
> +{
> +   struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
> +   struct mmc_pwrseq_simple, pwrseq);
> +
> +   mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
> +
> +   if (!IS_ERR(pwrseq->ext_clk))
> +   clk_disable_unprepare(pwrseq->ext_clk);

Same comment as above.

> +}
> +
>  static void mmc_pwrseq_simple_free(struct mmc_host *host)
>  {
> struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
> @@ -60,6 +76,9 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
> if (!IS_ERR(pwrseq->reset_gpios[i]))
> gpiod_put(pwrseq->reset_gpios[i]);
>
> +   if (!IS_ERR(pwrseq->ext_clk))
> +   clk_put(pwrseq->ext_clk);
> +
> kfree(pwrseq);
> host->pwrseq = NULL;
>  }
> @@ -67,7 +86,7 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
>  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_pre_power_on,
> +   .power_off = mmc_pwrseq_simple_power_off,
> .free = mmc_pwrseq_simple_free,
>  };
>
> @@ -85,6 +104,14 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct 
> device *dev)
> if (!pwrseq)
> return -ENOMEM;
>
> +   pwrseq->ext_clk = clk_get(dev, "ext_clock");
> +   if (IS_ERR(pwrseq->ext_clk) &&
> +   PTR_ERR(pwrseq->ext_clk) != -ENOENT &&
> +   PTR_ERR(pwrseq->ext_clk) != -ENOSYS) {

I don't think you can get -ENOSYS.

> +   ret = PTR_ERR(pwrseq->ext_clk);
> +   goto free;
> +   }
> +
> for (i = 0; i < nr_gpios; i++) {
> pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
>  GPIOD_OUT_HIGH);
> @@ -96,7 +123,7 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct 
> device *dev)
> while (--i)
> gpiod_put(pwrseq->reset_gpios[i]);
>
> -   goto free;
> +   goto clk_put;
> }
> }
>
> @@ -105,6 +132,9 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct 
> device *dev)
> host->pwrseq = &pwrseq->pwrseq;
>
> return 0;
> +clk_put:
> +   if (!IS_ERR(pwrseq->ext_clk))
> +   clk_put(pwrseq->ext_clk);
>  free:
> kfree(pwrseq);
> return ret;
> --
> 2.1.3
>

Kind regards
Uffe
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[PATCH v2 4/6] mmc: pwrseq_simple: Add optional reference clock support

2015-01-28 Thread Javier Martinez Canillas 
Some WLAN chips attached to a SDIO interface, need a reference clock.

Since this is very common, extend the prseq_simple driver to support
an optional clock that is enabled prior the card power up procedure.

Note: the external clock is optional. Thus an error is not returned
if the clock is not found.

Signed-off-by: Javier Martinez Canillas 
---

Changes since v1:
 - Rebase on top of latest changes.
 - Use IS_ERR() instead of checking for NULL to see if the clock exists.
---
 drivers/mmc/core/pwrseq_simple.c | 34 --
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
index e53d3c7e059c..5e34c77efa5e 100644
--- a/drivers/mmc/core/pwrseq_simple.c
+++ b/drivers/mmc/core/pwrseq_simple.c
@@ -7,6 +7,7 @@
  *
  *  Simple MMC power sequence management
  */
+#include 
 #include 
 #include 
 #include 
@@ -20,6 +21,7 @@
 
 struct mmc_pwrseq_simple {
struct mmc_pwrseq pwrseq;
+   struct clk *ext_clk;
int nr_gpios;
struct gpio_desc *reset_gpios[0];
 };
@@ -39,6 +41,9 @@ 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);
 
+   if (!IS_ERR(pwrseq->ext_clk))
+   clk_prepare_enable(pwrseq->ext_clk);
+
mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
 }
 
@@ -50,6 +55,17 @@ static void mmc_pwrseq_simple_post_power_on(struct mmc_host 
*host)
mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
 }
 
+static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
+{
+   struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
+   struct mmc_pwrseq_simple, pwrseq);
+
+   mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
+
+   if (!IS_ERR(pwrseq->ext_clk))
+   clk_disable_unprepare(pwrseq->ext_clk);
+}
+
 static void mmc_pwrseq_simple_free(struct mmc_host *host)
 {
struct mmc_pwrseq_simple *pwrseq = container_of(host->pwrseq,
@@ -60,6 +76,9 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
if (!IS_ERR(pwrseq->reset_gpios[i]))
gpiod_put(pwrseq->reset_gpios[i]);
 
+   if (!IS_ERR(pwrseq->ext_clk))
+   clk_put(pwrseq->ext_clk);
+
kfree(pwrseq);
host->pwrseq = NULL;
 }
@@ -67,7 +86,7 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
 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_pre_power_on,
+   .power_off = mmc_pwrseq_simple_power_off,
.free = mmc_pwrseq_simple_free,
 };
 
@@ -85,6 +104,14 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct 
device *dev)
if (!pwrseq)
return -ENOMEM;
 
+   pwrseq->ext_clk = clk_get(dev, "ext_clock");
+   if (IS_ERR(pwrseq->ext_clk) &&
+   PTR_ERR(pwrseq->ext_clk) != -ENOENT &&
+   PTR_ERR(pwrseq->ext_clk) != -ENOSYS) {
+   ret = PTR_ERR(pwrseq->ext_clk);
+   goto free;
+   }
+
for (i = 0; i < nr_gpios; i++) {
pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
 GPIOD_OUT_HIGH);
@@ -96,7 +123,7 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct 
device *dev)
while (--i)
gpiod_put(pwrseq->reset_gpios[i]);
 
-   goto free;
+   goto clk_put;
}
}
 
@@ -105,6 +132,9 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct 
device *dev)
host->pwrseq = &pwrseq->pwrseq;
 
return 0;
+clk_put:
+   if (!IS_ERR(pwrseq->ext_clk))
+   clk_put(pwrseq->ext_clk);
 free:
kfree(pwrseq);
return ret;
-- 
2.1.3

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html