Re: [PATCH 2/5] mmc: pwrseq_simple: Extend to support more pins

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Hi Javier,

You are in a lead of 3 hrs from me..
Surprisingly I send very much same patch just few Mins ago :-)
May be we can merge goods in both :-)

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@xxxxxxxxxxxxxxx>
---
  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..

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


+	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);
}


  }

  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?
Probably you should do of_gpio_named_count before allocating memory.

+		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])


		
+				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.

Thanks,
srini
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