[PATCH 0/7] Prepare EP93xx drivers for Common Clock Framework

[PATCH 0/7] Prepare EP93xx drivers for Common Clock Framework

[Alexander Sverdlin]

Nikita posted a patch converting EP93xx to use Common Clock Framework. It
turns out some cleanup is necessary in the EP93xx drivers to avoid
"Enabling unprepared" clock warnings.

Patches with stack traces in the commit messages are tested on EP9302.

Link: https://lore.kernel.org/patchwork/patch/1435884/

Alexander Sverdlin (7):
  iio: ep93xx: Prepare clock before using it
  spi: spi-ep93xx: Prepare clock before using it
  Input: ep93xx_keypad: Prepare clock before using it
  video: ep93xx: Prepare clock before using it
  dmaengine: ep93xx: Prepare clock before using it
  ASoC: cirrus: i2s: Prepare clock before using it
  pwm: ep93xx: Prepare clock before using it

 drivers/dma/ep93xx_dma.c               |  6 +++---
 drivers/iio/adc/ep93xx_adc.c           |  6 +++---
 drivers/input/keyboard/ep93xx_keypad.c |  4 ++--
 drivers/pwm/pwm-ep93xx.c               | 12 ++++++------
 drivers/spi/spi-ep93xx.c               |  4 ++--
 drivers/video/fbdev/ep93xx-fb.c        |  4 ++--
 sound/soc/cirrus/ep93xx-i2s.c          | 12 ++++++------
 7 files changed, 24 insertions(+), 24 deletions(-)

-- 
2.32.0

[PATCH 5/7] dmaengine: ep93xx: Prepare clock before using it

[Alexander Sverdlin]

Use clk_prepare_enable()/clk_disable_unprepare() in preparation for switch
to Common Clock Framework, otherwise the following is visible:

WARNING: CPU: 0 PID: 1 at drivers/clk/clk.c:1011 clk_core_enable+0x9c/0xbc
Enabling unprepared m2p0
CPU: 0 PID: 1 Comm: swapper Not tainted 5.13.0-rc5-tekon #1
Hardware name: Cirrus Logic EDB9302 Evaluation Board
[<c000d5b0>] (unwind_backtrace) from [<c000c590>] (show_stack+0x10/0x18)
[<c000c590>] (show_stack) from [<c03a5fb8>] (dump_stack+0x20/0x2c)
[<c03a5fb8>] (dump_stack) from [<c03a2118>] (__warn+0x98/0xc0)
[<c03a2118>] (__warn) from [<c03a21d0>] (warn_slowpath_fmt+0x90/0xc0)
[<c03a21d0>] (warn_slowpath_fmt) from [<c01d8358>] (clk_core_enable+0x9c/0xbc)
[<c01d8358>] (clk_core_enable) from [<c01d8698>] (clk_core_enable_lock+0x18/0x30)
[<c01d8698>] (clk_core_enable_lock) from [<c01e1844>] (ep93xx_dma_alloc_chan_resources+0x94/0x244)
[<c01e1844>] (ep93xx_dma_alloc_chan_resources) from [<c01df7d4>] (dma_chan_get+0x90/0x124)
[<c01df7d4>] (dma_chan_get) from [<c01df92c>] (find_candidate+0xc4/0x188)
[<c01df92c>] (find_candidate) from [<c01dff30>] (__dma_request_channel+0x68/0xb0)
[<c01dff30>] (__dma_request_channel) from [<c027d2e4>] (snd_dmaengine_pcm_request_channel+0x68/0x90)
[<c027d2e4>] (snd_dmaengine_pcm_request_channel) from [<c0290618>] (dmaengine_pcm_new+0x254/0x29c)
[<c0290618>] (dmaengine_pcm_new) from [<c0289b84>] (snd_soc_pcm_component_new+0x40/0xa0)
[<c0289b84>] (snd_soc_pcm_component_new) from [<c028c7f8>] (soc_new_pcm+0x47c/0x5fc)
[<c028c7f8>] (soc_new_pcm) from [<c027f300>] (snd_soc_bind_card+0x73c/0x8a8)
[<c027f300>] (snd_soc_bind_card) from [<c029180c>] (edb93xx_probe+0x34/0x5c)
[<c029180c>] (edb93xx_probe) from [<c02126e0>] (platform_probe+0x34/0x80)
[<c02126e0>] (platform_probe) from [<c0210bf8>] (really_probe+0xe8/0x394)
[<c0210bf8>] (really_probe) from [<c0211464>] (device_driver_attach+0x5c/0x64)
[<c0211464>] (device_driver_attach) from [<c02114e8>] (__driver_attach+0x7c/0xec)
[<c02114e8>] (__driver_attach) from [<c020f1b4>] (bus_for_each_dev+0x78/0xc4)
[<c020f1b4>] (bus_for_each_dev) from [<c0211570>] (driver_attach+0x18/0x24)
[<c0211570>] (driver_attach) from [<c020fab4>] (bus_add_driver+0x140/0x1cc)
[<c020fab4>] (bus_add_driver) from [<c0211c44>] (driver_register+0x74/0x114)
[<c0211c44>] (driver_register) from [<c02134f8>] (__platform_driver_register+0x18/0x24)
[<c02134f8>] (__platform_driver_register) from [<c047084c>] (edb93xx_driver_init+0x10/0x1c)
[<c047084c>] (edb93xx_driver_init) from [<c045ce88>] (do_one_initcall+0x7c/0x1a4)
[<c045ce88>] (do_one_initcall) from [<c045d184>] (kernel_init_freeable+0x17c/0x1fc)
[<c045d184>] (kernel_init_freeable) from [<c03a6550>] (kernel_init+0x8/0xf8)
[<c03a6550>] (kernel_init) from [<c00082d8>] (ret_from_fork+0x14/0x3c)
...
ep93xx-i2s ep93xx-i2s: Missing dma channel for stream: 0
ep93xx-i2s ep93xx-i2s: ASoC: error at snd_soc_pcm_component_new on ep93xx-i2s: -22
edb93xx-audio edb93xx-audio: ASoC: can't create pcm CS4271 HiFi :-22
edb93xx-audio edb93xx-audio: snd_soc_register_card() failed: -22
edb93xx-audio: probe of edb93xx-audio failed with error -22

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
---
 drivers/dma/ep93xx_dma.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/ep93xx_dma.c b/drivers/dma/ep93xx_dma.c
index 01027779beb8..98f9ee70362e 100644
--- a/drivers/dma/ep93xx_dma.c
+++ b/drivers/dma/ep93xx_dma.c
@@ -897,7 +897,7 @@ static int ep93xx_dma_alloc_chan_resources(struct dma_chan *chan)
 	if (data && data->name)
 		name = data->name;
 
-	ret = clk_enable(edmac->clk);
+	ret = clk_prepare_enable(edmac->clk);
 	if (ret)
 		return ret;
 
@@ -936,7 +936,7 @@ static int ep93xx_dma_alloc_chan_resources(struct dma_chan *chan)
 fail_free_irq:
 	free_irq(edmac->irq, edmac);
 fail_clk_disable:
-	clk_disable(edmac->clk);
+	clk_disable_unprepare(edmac->clk);
 
 	return ret;
 }
@@ -969,7 +969,7 @@ static void ep93xx_dma_free_chan_resources(struct dma_chan *chan)
 	list_for_each_entry_safe(desc, d, &list, node)
 		kfree(desc);
 
-	clk_disable(edmac->clk);
+	clk_disable_unprepare(edmac->clk);
 	free_irq(edmac->irq, edmac);
 }
 
-- 
2.32.0

Re: [PATCH 0/7] Prepare EP93xx drivers for Common Clock Framework

[Uwe Kleine-König]

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On Mon, Jun 14, 2021 at 01:30:34AM +0200, Alexander Sverdlin wrote:
> Nikita posted a patch converting EP93xx to use Common Clock Framework. It
> turns out some cleanup is necessary in the EP93xx drivers to avoid
> "Enabling unprepared" clock warnings.
> 
> Patches with stack traces in the commit messages are tested on EP9302.

One thing to note is: ep93xx currently doesn't provide a clk_prepare
function, this isn't a problem though because include/linux/clk.h
provides a dummy if CONFIG_HAVE_CLK_PREPARE isn't defined. So as ep93xx
doesn't define this symbol the changes here effectively only add a
might_sleep.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

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