[PATCH v2 2/6] mmc: pwrseq_simple: Extend to support more pins

Javier Martinez Canillas
2015-01-28T18:15:49Z

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>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
---

Changes since v1:
- Many code cleanups suggested by Srinivas Kandagatla
* Rename reset_gpio array to reset_gpios.
* Use a zero length array for reset_gpios to avoid a kmalloc.
* Refactor GPIO assert and de-ssert logic into a common function.
* Simplify gpiod_put logic in case of gpiod_get error.
---
drivers/mmc/core/pwrseq_simple.c | 55 +++++++++++++++++++++++++++++-----------
1 file changed, 40 insertions(+), 15 deletions(-)

diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
index 0958c696137f..e53d3c7e059c 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>
@@ -19,16 +20,26 @@

struct mmc_pwrseq_simple {
struct mmc_pwrseq pwrseq;
- struct gpio_desc *reset_gpio;
+ int nr_gpios;
+ struct gpio_desc *reset_gpios[0];
};

+static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
+ int value)
+{
+ int i;
+
+ for (i = 0; i < pwrseq->nr_gpios; i++)
+ if (!IS_ERR(pwrseq->reset_gpios[i]))
+ gpiod_set_value_cansleep(pwrseq->reset_gpios[i], value);
+}
+
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->reset_gpio))
- gpiod_set_value_cansleep(pwrseq->reset_gpio, 1);
+ mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
}

static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
@@ -36,17 +47,18 @@ 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);

- if (!IS_ERR(pwrseq->reset_gpio))
- gpiod_set_value_cansleep(pwrseq->reset_gpio, 0);
+ mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);
}

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);
+ for (i = 0; i < pwrseq->nr_gpios; i++)
+ if (!IS_ERR(pwrseq->reset_gpios[i]))
+ gpiod_put(pwrseq->reset_gpios[i]);

kfree(pwrseq);
host->pwrseq = NULL;
@@ -62,20 +74,33 @@ static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
{
struct mmc_pwrseq_simple *pwrseq;
- int ret = 0;
+ int i, nr_gpios, ret = 0;

- pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple), GFP_KERNEL);
+ nr_gpios = of_gpio_named_count(dev->of_node, "reset-gpios");
+ if (nr_gpios < 0)
+ nr_gpios = 0;
+
+ pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple) + nr_gpios *
+ sizeof(struct gpio_desc *), 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;
+ for (i = 0; i < nr_gpios; i++) {
+ pwrseq->reset_gpios[i] = gpiod_get_index(dev, "reset", i,
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(pwrseq->reset_gpios[i]) &&
+ PTR_ERR(pwrseq->reset_gpios[i]) != -ENOENT &&
+ PTR_ERR(pwrseq->reset_gpios[i]) != -ENOSYS) {
+ ret = PTR_ERR(pwrseq->reset_gpios[i]);
+
+ while (--i)
+ gpiod_put(pwrseq->reset_gpios[i]);
+
+ goto free;
+ }
}

+ pwrseq->nr_gpios = nr_gpios;
pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
host->pwrseq = &pwrseq->pwrseq;

--
2.1.3