[PATCH] mmc: pwrseq: simplify alloc/free hooks

[Alexandre Courbot <acourbot@nvidia.com>]

The alloc() and free() hooks required each pwrseq implementation to set
host->pwrseq themselves. This is error-prone and could be done at a
higher level if alloc() was changed to return a pointer to a struct
mmc_pwrseq instead of an error code.

This patch performs this change and moves the burden of maintaining
host->pwrseq from the power sequence hooks to the pwrseq code.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
---
It occured to me that after this change, none of the alloc()
implementations ever uses the host parameter. I have kept it in case
it could be useful for other purposes, but can remove it in a v2 if
this is deemed better by the MMC maintainers.

 drivers/mmc/core/pwrseq.c        | 16 ++++++++++++----
 drivers/mmc/core/pwrseq.h        |  6 ++++--
 drivers/mmc/core/pwrseq_emmc.c   | 11 +++++------
 drivers/mmc/core/pwrseq_simple.c | 11 +++++------
 4 files changed, 26 insertions(+), 18 deletions(-)

diff --git a/drivers/mmc/core/pwrseq.c b/drivers/mmc/core/pwrseq.c
index 862356123d78..ab2129781161 100644
--- a/drivers/mmc/core/pwrseq.c
+++ b/drivers/mmc/core/pwrseq.c
@@ -19,7 +19,7 @@
 
 struct mmc_pwrseq_match {
 	const char *compatible;
-	int (*alloc)(struct mmc_host *host, struct device *dev);
+	struct mmc_pwrseq *(*alloc)(struct mmc_host *host, struct device *dev);
 };
 
 static struct mmc_pwrseq_match pwrseq_match[] = {
@@ -52,6 +52,7 @@ 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;
 
 	np = of_parse_phandle(host->parent->of_node, "mmc-pwrseq", 0);
@@ -70,9 +71,14 @@ int mmc_pwrseq_alloc(struct mmc_host *host)
 		goto err;
 	}
 
-	ret = match->alloc(host, &pdev->dev);
-	if (!ret)
-		dev_info(host->parent, "allocated mmc-pwrseq\n");
+	pwrseq = match->alloc(host, &pdev->dev);
+	if (IS_ERR(pwrseq)) {
+		ret = PTR_ERR(host->pwrseq);
+		goto err;
+	}
+
+	host->pwrseq = pwrseq;
+	dev_info(host->parent, "allocated mmc-pwrseq\n");
 
 err:
 	of_node_put(np);
@@ -109,4 +115,6 @@ void mmc_pwrseq_free(struct mmc_host *host)
 
 	if (pwrseq && pwrseq->ops && pwrseq->ops->free)
 		pwrseq->ops->free(host);
+
+	host->pwrseq = NULL;
 }
diff --git a/drivers/mmc/core/pwrseq.h b/drivers/mmc/core/pwrseq.h
index aba3409e8d6e..096da48c6a7e 100644
--- a/drivers/mmc/core/pwrseq.h
+++ b/drivers/mmc/core/pwrseq.h
@@ -27,8 +27,10 @@ void mmc_pwrseq_post_power_on(struct mmc_host *host);
 void mmc_pwrseq_power_off(struct mmc_host *host);
 void mmc_pwrseq_free(struct mmc_host *host);
 
-int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev);
-int mmc_pwrseq_emmc_alloc(struct mmc_host *host, struct device *dev);
+struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
+					   struct device *dev);
+struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
+					 struct device *dev);
 
 #else
 
diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c
index a2d545904fbf..9d6d2fb21796 100644
--- a/drivers/mmc/core/pwrseq_emmc.c
+++ b/drivers/mmc/core/pwrseq_emmc.c
@@ -49,7 +49,6 @@ static void mmc_pwrseq_emmc_free(struct mmc_host *host)
 	unregister_restart_handler(&pwrseq->reset_nb);
 	gpiod_put(pwrseq->reset_gpio);
 	kfree(pwrseq);
-	host->pwrseq = NULL;
 }
 
 static struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
@@ -67,14 +66,15 @@ static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
 	return NOTIFY_DONE;
 }
 
-int mmc_pwrseq_emmc_alloc(struct mmc_host *host, struct device *dev)
+struct mmc_pwrseq *mmc_pwrseq_emmc_alloc(struct mmc_host *host,
+					 struct device *dev)
 {
 	struct mmc_pwrseq_emmc *pwrseq;
 	int ret = 0;
 
 	pwrseq = kzalloc(sizeof(struct mmc_pwrseq_emmc), GFP_KERNEL);
 	if (!pwrseq)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	pwrseq->reset_gpio = gpiod_get_index(dev, "reset", 0, GPIOD_OUT_LOW);
 	if (IS_ERR(pwrseq->reset_gpio)) {
@@ -92,10 +92,9 @@ int mmc_pwrseq_emmc_alloc(struct mmc_host *host, struct device *dev)
 	register_restart_handler(&pwrseq->reset_nb);
 
 	pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
-	host->pwrseq = &pwrseq->pwrseq;
 
-	return 0;
+	return &pwrseq->pwrseq;
 free:
 	kfree(pwrseq);
-	return ret;
+	return ERR_PTR(ret);
 }
diff --git a/drivers/mmc/core/pwrseq_simple.c b/drivers/mmc/core/pwrseq_simple.c
index e9f1d8d84613..5c0667af8dd6 100644
--- a/drivers/mmc/core/pwrseq_simple.c
+++ b/drivers/mmc/core/pwrseq_simple.c
@@ -85,7 +85,6 @@ static void mmc_pwrseq_simple_free(struct mmc_host *host)
 		clk_put(pwrseq->ext_clk);
 
 	kfree(pwrseq);
-	host->pwrseq = NULL;
 }
 
 static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
@@ -95,7 +94,8 @@ static struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
 	.free = mmc_pwrseq_simple_free,
 };
 
-int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
+struct mmc_pwrseq *mmc_pwrseq_simple_alloc(struct mmc_host *host,
+					   struct device *dev)
 {
 	struct mmc_pwrseq_simple *pwrseq;
 	int i, nr_gpios, ret = 0;
@@ -107,7 +107,7 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
 	pwrseq = kzalloc(sizeof(struct mmc_pwrseq_simple) + nr_gpios *
 			 sizeof(struct gpio_desc *), GFP_KERNEL);
 	if (!pwrseq)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
 	pwrseq->ext_clk = clk_get(dev, "ext_clock");
 	if (IS_ERR(pwrseq->ext_clk) &&
@@ -133,13 +133,12 @@ int mmc_pwrseq_simple_alloc(struct mmc_host *host, struct device *dev)
 
 	pwrseq->nr_gpios = nr_gpios;
 	pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
-	host->pwrseq = &pwrseq->pwrseq;
 
-	return 0;
+	return &pwrseq->pwrseq;
 clk_put:
 	if (!IS_ERR(pwrseq->ext_clk))
 		clk_put(pwrseq->ext_clk);
 free:
 	kfree(pwrseq);
-	return ret;
+	return ERR_PTR(ret);
 }
-- 
2.3.0