Re: [PATCH v3 2/3] mmc: sdhci-of-arasan: add phy support for sdhci-of-arasan
From: Shawn Lin
Date: Tue Oct 20 2015 - 05:20:10 EST
On 2015/10/20 16:39, Ulf Hansson wrote:
+ Kishon
On 20 October 2015 at 09:05, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
This patch adds Generic PHY access for sdhci-of-arasan. Driver
can get PHY handler from dt-binding, and power-on/init the PHY.
Also we add pm ops for PHY here if CONFIG_PM_SLEEP is enabled.
Currently, it's just mandatory for arasan,sdhci-5.1.
Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
Serise-changes: 3
- remove phy_init/exit for suspend/resume
- adjust phy_int/power_on seq to make code more reasonable
- simplify suspend/resume_phy
Serise-changes: 2
- Keep phy as a mandatory requirement for arasan,sdhci-5.1
---
Changes in v2: None
drivers/mmc/host/sdhci-of-arasan.c | 87 ++++++++++++++++++++++++++++++++++++++
1 file changed, 87 insertions(+)
diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
index 75379cb..85bd0f9d 100644
--- a/drivers/mmc/host/sdhci-of-arasan.c
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -21,6 +21,7 @@
#include <linux/module.h>
#include <linux/of_device.h>
+#include <linux/phy/phy.h>
#include "sdhci-pltfm.h"
#define SDHCI_ARASAN_CLK_CTRL_OFFSET 0x2c
@@ -35,6 +36,7 @@
*/
struct sdhci_arasan_data {
struct clk *clk_ahb;
+ struct phy *phy;
};
static unsigned int sdhci_arasan_get_timeout_clock(struct sdhci_host *host)
@@ -70,6 +72,42 @@ static struct sdhci_pltfm_data sdhci_arasan_pdata = {
#ifdef CONFIG_PM_SLEEP
/**
+ * sdhci_arasan_suspend_phy - Suspend phy method for the driver
+ * @phy: Handler of phy structure
+ * Returns 0 on success and error value on error
+ *
+ * Put the phy in a deactive state.
+ */
+static int sdhci_arasan_suspend_phy(struct phy *phy)
+{
+ int ret = 0;
+
+ ret = phy_power_off(phy);
+ if (ret)
This is an odd error handling, should you really do phy_power_on()?
Thanks for these helpful comments.
Michal also mentioned this odd error handling. Well, I can't say whether
it's okay, but at least large numbers of drivers which adopt generic phy
interfaces don't even test the return value of power_off/on.
Anyway, remove this err handling is okay to me.
I will do it.
+ phy_power_on(phy);
+
+ return ret;
+}
+
+/**
+ * sdhci_arasan_resume_phy - Resume phy method for the driver
+ * @phy: Handler of phy structure
+ * Returns 0 on success and error value on error
+ *
+ * Put the phy in a active state.
+ */
+static int sdhci_arasan_resume_phy(struct phy *phy)
+{
+ int ret = 0;
+
+ ret = phy_power_on(phy);
+ if (ret)
Similar comment as above.
Ditto.
+ phy_power_off(phy);
+
+ return ret;
+}
+
+/**
* sdhci_arasan_suspend - Suspend method for the driver
* @dev: Address of the device structure
* Returns 0 on success and error value on error
@@ -88,6 +126,15 @@ static int sdhci_arasan_suspend(struct device *dev)
if (ret)
return ret;
+ if (!IS_ERR(sdhci_arasan->phy)) {
+ ret = sdhci_arasan_suspend_phy(sdhci_arasan->phy);
+ if (ret) {
+ dev_err(dev, "Cannot suspend phy.\n");
+ sdhci_resume_host(host);
This is an odd error handling, why do sdhci_resume_host()?
right, no need there, sorry for the bit.
+ return ret;
+ }
+ }
+
clk_disable(pltfm_host->clk);
clk_disable(sdhci_arasan->clk_ahb);
@@ -122,6 +169,16 @@ static int sdhci_arasan_resume(struct device *dev)
return ret;
}
+ if (!IS_ERR(sdhci_arasan->phy)) {
+ ret = sdhci_arasan_resume_phy(sdhci_arasan->phy);
+ if (ret) {
+ dev_err(dev, "Cannot resume phy.\n");
+ clk_disable(sdhci_arasan->clk_ahb);
+ clk_disable(pltfm_host->clk);
+ return ret;
The error handling is starting to be a bit complex in
sdhci_arasan_resume(), perhaps it's time to add some labels to make
the code more readable?
Agreed.
+ }
+ }
+
return sdhci_resume_host(host);
}
#endif /* ! CONFIG_PM_SLEEP */
@@ -166,6 +223,33 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
goto clk_dis_ahb;
}
+ sdhci_arasan->phy = NULL;
NULL isn't an error. You probably want something like:
sdhci_arasan->phy = ERR_PTR(-ENODEV);
Although, I just realize that the phy API works a bit differently than
other APIs. More precisely, instead of returning an error while you
provide a NULL pointer to the APIs, it will treat it as a NOOP and
return a non-error code (at least according to the documentation). I
don't know why the phy API is different, but to me I prefer to use the
regular kernel style and thus, please adopt to my suggestion above.
Got it.
+ if (of_device_is_compatible(pdev->dev.of_node,
+ "arasan,sdhci-5.1")) {
+ sdhci_arasan->phy = devm_phy_get(&pdev->dev,
+ "phy_arasan");
+ if (IS_ERR(sdhci_arasan->phy)) {
+ ret = -ENODEV;
You should give "ret" the error code from devm_phy_get(), via
PTR_ERR(sdhci_arasan->phy).
Ah, yes.
+ dev_err(&pdev->dev, "No phy for arasan,sdhci-5.1.\n");
+ goto clk_dis_ahb;
+ }
+
+ ret = phy_init(sdhci_arasan->phy);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "phy_init err.\n");
+ phy_exit(sdhci_arasan->phy);
phy_exit(), that seems like and odd error handling as the phy_init() failed.
As above, I am going to remove it.
+ goto clk_dis_ahb;
+ }
+
+ ret = phy_power_on(sdhci_arasan->phy);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "phy_power_on err.\n");
+ phy_power_off(sdhci_arasan->phy);
Similar comment as above.
+ phy_exit(sdhci_arasan->phy);
+ goto clk_dis_ahb;
+ }
+ }
+
I believe you need at least phy_exit() if a failure occurs after this
point!? Perhaps some new error labels will deal with this nicely!?
right, I will do it.
host = sdhci_pltfm_init(pdev, &sdhci_arasan_pdata, 0);
if (IS_ERR(host)) {
ret = PTR_ERR(host);
@@ -210,6 +294,9 @@ static int sdhci_arasan_remove(struct platform_device *pdev)
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct sdhci_arasan_data *sdhci_arasan = pltfm_host->priv;
+ if (!IS_ERR(sdhci_arasan->phy))
+ phy_exit(sdhci_arasan->phy);
+
clk_disable_unprepare(sdhci_arasan->clk_ahb);
return sdhci_pltfm_unregister(pdev);
--
2.3.7
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Best Regards
Shawn Lin
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