Re: [PATCH 1/3] phy: ti-pipe3: fix suspend

From: Kishon Vijay Abraham I
Date: Wed May 20 2015 - 09:05:03 EST

Hi Roger,

On Tuesday 12 May 2015 09:37 PM, Roger Quadros wrote:
Relying on PM-ops for shutting down PHY clocks was a
bad idea since the users (e.g. PCIe/SATA) might not
have been suspended by then.

The main culprit for not shutting down the clocks was
the stray pm_runtime_get() call in probe.

Fix the whole thing in the right way by getting rid
of that pm_runtime_get() call from probe and
removing all PM-ops. It is the sole responsibility
of the PHY user to properly turn OFF and de-initialize
the PHY as part of its suspend routine.

As PHY core serializes init/exit we don't need
to use a spinlock in this driver. So get rid of it.

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
Signed-off-by: Sekhar Nori <nsekhar@xxxxxx>
---
drivers/phy/phy-ti-pipe3.c | 112 ++++++++-------------------------------------
1 file changed, 18 insertions(+), 94 deletions(-)

diff --git a/drivers/phy/phy-ti-pipe3.c b/drivers/phy/phy-ti-pipe3.c
index 53f295c..e13a306 100644
--- a/drivers/phy/phy-ti-pipe3.c
+++ b/drivers/phy/phy-ti-pipe3.c
@@ -28,7 +28,6 @@
#include <linux/delay.h>
#include <linux/phy/omap_control_phy.h>
#include <linux/of_platform.h>
-#include <linux/spinlock.h>

#define PLL_STATUS 0x00000004
#define PLL_GO 0x00000008
@@ -83,10 +82,6 @@ struct ti_pipe3 {
struct clk *refclk;
struct clk *div_clk;
struct pipe3_dpll_map *dpll_map;
- bool enabled;
- spinlock_t lock; /* serialize clock enable/disable */
- /* the below flag is needed specifically for SATA */
- bool refclk_enabled;
};

static struct pipe3_dpll_map dpll_map_usb[] = {
@@ -137,6 +132,9 @@ static struct pipe3_dpll_params *ti_pipe3_get_dpll_params(struct ti_pipe3 *phy)
return NULL;
}

+static int ti_pipe3_enable_clocks(struct ti_pipe3 *phy);
+static void ti_pipe3_disable_clocks(struct ti_pipe3 *phy);
+
static int ti_pipe3_power_off(struct phy *x)
{
struct ti_pipe3 *phy = phy_get_drvdata(x);
@@ -217,6 +215,7 @@ static int ti_pipe3_init(struct phy *x)
u32 val;
int ret = 0;

+ ti_pipe3_enable_clocks(phy);
/*
* Set pcie_pcs register to 0x96 for proper functioning of phy
* as recommended in AM572x TRM SPRUHZ6, section 18.5.2.2, table
@@ -277,6 +276,8 @@ static int ti_pipe3_exit(struct phy *x)
return -EBUSY;
}

+ ti_pipe3_disable_clocks(phy);
+
return 0;
}
static struct phy_ops ops = {
@@ -305,8 +306,7 @@ static int ti_pipe3_probe(struct platform_device *pdev)
if (!phy)
return -ENOMEM;

- phy->dev = &pdev->dev;
- spin_lock_init(&phy->lock);
+ phy->dev = &pdev->dev;

this looks more of a cleanup.

if (!of_device_is_compatible(node, "ti,phy-pipe3-pcie")) {
match = of_match_device(ti_pipe3_id_table, &pdev->dev);
@@ -402,6 +402,9 @@ static int ti_pipe3_probe(struct platform_device *pdev)

platform_set_drvdata(pdev, phy);
pm_runtime_enable(phy->dev);
+ /* Prevent auto-disable of refclk for SATA PHY due to Errata i783 */
+ if (of_device_is_compatible(node, "ti,phy-pipe3-sata"))
+ clk_prepare_enable(phy->refclk);

generic_phy = devm_phy_create(phy->dev, NULL, &ops);
if (IS_ERR(generic_phy))
@@ -413,24 +416,19 @@ static int ti_pipe3_probe(struct platform_device *pdev)
if (IS_ERR(phy_provider))
return PTR_ERR(phy_provider);

- pm_runtime_get(&pdev->dev);
-
return 0;
}

static int ti_pipe3_remove(struct platform_device *pdev)
{
- if (!pm_runtime_suspended(&pdev->dev))
- pm_runtime_put(&pdev->dev);
pm_runtime_disable(&pdev->dev);

return 0;
}

-#ifdef CONFIG_PM
static int ti_pipe3_enable_refclk(struct ti_pipe3 *phy)
{
- if (!IS_ERR(phy->refclk) && !phy->refclk_enabled) {
+ if (!IS_ERR(phy->refclk)) {
int ret;

ret = clk_prepare_enable(phy->refclk);
@@ -438,7 +436,6 @@ static int ti_pipe3_enable_refclk(struct ti_pipe3 *phy)
dev_err(phy->dev, "Failed to enable refclk %d\n", ret);
return ret;
}
- phy->refclk_enabled = true;
}

return 0;
@@ -448,28 +445,21 @@ static void ti_pipe3_disable_refclk(struct ti_pipe3 *phy)
{
if (!IS_ERR(phy->refclk))
clk_disable_unprepare(phy->refclk);
-
- phy->refclk_enabled = false;
}

static int ti_pipe3_enable_clocks(struct ti_pipe3 *phy)
{
int ret = 0;
- unsigned long flags;
-
- spin_lock_irqsave(&phy->lock, flags);
- if (phy->enabled)
- goto err1;

ret = ti_pipe3_enable_refclk(phy);

we can enable refclk here itself instead of having a separate function it?
if (ret)
- goto err1;
+ return ret;

if (!IS_ERR(phy->wkupclk)) {
ret = clk_prepare_enable(phy->wkupclk);
if (ret) {
dev_err(phy->dev, "Failed to enable wkupclk %d\n", ret);
- goto err2;
+ goto disable_refclk;
}
}

@@ -477,96 +467,31 @@ static int ti_pipe3_enable_clocks(struct ti_pipe3 *phy)
ret = clk_prepare_enable(phy->div_clk);
if (ret) {
dev_err(phy->dev, "Failed to enable div_clk %d\n", ret);
- goto err3;
+ goto disable_wkupclk;
}
}

- phy->enabled = true;
- spin_unlock_irqrestore(&phy->lock, flags);
return 0;

-err3:
+disable_wkupclk:
if (!IS_ERR(phy->wkupclk))
clk_disable_unprepare(phy->wkupclk);

-err2:
- if (!IS_ERR(phy->refclk))
- clk_disable_unprepare(phy->refclk);
-
+disable_refclk:
ti_pipe3_disable_refclk(phy);
-err1:
- spin_unlock_irqrestore(&phy->lock, flags);
+
return ret;
}

static void ti_pipe3_disable_clocks(struct ti_pipe3 *phy)
{
- unsigned long flags;
-
- spin_lock_irqsave(&phy->lock, flags);
- if (!phy->enabled) {
- spin_unlock_irqrestore(&phy->lock, flags);
- return;
- }
-
if (!IS_ERR(phy->wkupclk))
clk_disable_unprepare(phy->wkupclk);
- /* Don't disable refclk for SATA PHY due to Errata i783 */
- if (!of_device_is_compatible(phy->dev->of_node, "ti,phy-pipe3-sata"))
- ti_pipe3_disable_refclk(phy);
+ ti_pipe3_disable_refclk(phy);

here too. we can get rid of ti_pipe3_disable_refclk and ti_pipe3_enable_refclk.

Thanks
Kishon
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