mmc: pwrseq: convert to proper platform device

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 solve 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.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 49 insertions, 59 deletions

diff --git a/drivers/mmc/core/pwrseq.c b/drivers/mmc/core/pwrseq.c
index 4c1d175..9386c47 100644
--- a/drivers/mmc/core/pwrseq.c
+++ b/drivers/mmc/core/pwrseq.c
@@ -8,88 +8,55 @@
  *  MMC power sequence management
  */
 #include <linux/kernel.h>
-#include <linux/platform_device.h>
 #include <linux/err.h>
+#include <linux/module.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)
-{
-	struct mmc_pwrseq_match *match = ERR_PTR(-ENODEV);
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(pwrseq_match); i++) {
-		if (of_device_is_compatible(np,	pwrseq_match[i].compatible)) {
-			match = &pwrseq_match[i];
-			break;
-		}
-	}
-
-	return match;
-}
+static DEFINE_MUTEX(pwrseq_list_mutex);
+static LIST_HEAD(pwrseq_list);
 
 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;
+	struct mmc_pwrseq *p;
 
 	np = of_parse_phandle(host->parent->of_node, "mmc-pwrseq", 0);
 	if (!np)
 		return 0;
 
-	pdev = of_find_device_by_node(np);
-	if (!pdev) {
-		ret = -ENODEV;
-		goto err;
-	}
+	mutex_lock(&pwrseq_list_mutex);
+	list_for_each_entry(p, &pwrseq_list, pwrseq_node) {
+		if (p->dev->of_node == np) {
+			if (!try_module_get(p->owner))
+				dev_err(host->parent,
+					"increasing module refcount failed\n");
+			else
+				host->pwrseq = p;
 
-	match = mmc_pwrseq_find(np);
-	if (IS_ERR(match)) {
-		ret = PTR_ERR(match);
-		goto err;
+			break;
+		}
 	}
 
-	pwrseq = match->alloc(host, &pdev->dev);
-	if (IS_ERR(pwrseq)) {
-		ret = PTR_ERR(pwrseq);
-		goto err;
-	}
+	of_node_put(np);
+	mutex_unlock(&pwrseq_list_mutex);
+
+	if (!host->pwrseq)
+		return -EPROBE_DEFER;
 
-	host->pwrseq = pwrseq;
 	dev_info(host->parent, "allocated mmc-pwrseq\n");
 
-err:
-	of_node_put(np);
-	return ret;
+	return 0;
 }
 
 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 +64,7 @@ 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 +72,7 @@ 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 +80,31 @@ 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) {
+		module_put(pwrseq->owner);
+		host->pwrseq = NULL;
+	}
+}
+
+int mmc_pwrseq_register(struct mmc_pwrseq *pwrseq)
+{
+	if (!pwrseq || !pwrseq->ops || !pwrseq->dev)
+		return -EINVAL;
 
-	host->pwrseq = NULL;
+	mutex_lock(&pwrseq_list_mutex);
+	list_add(&pwrseq->pwrseq_node, &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->pwrseq_node);
+		mutex_unlock(&pwrseq_list_mutex);
+	}
 }
+EXPORT_SYMBOL_GPL(mmc_pwrseq_unregister);