[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 2/7] spi: spi-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 ep93xx-spi.0
CPU: 0 PID: 1 Comm: swapper Tainted: G        W         5.13.0-rc5-... #1
Hardware name: Cirrus Logic EDB9302 Evaluation Board
[<c000d5b0>] (unwind_backtrace) from [<c000c590>] (show_stack+0x10/0x18)
[<c000c590>] (show_stack) from [<c03a5f38>] (dump_stack+0x20/0x2c)
[<c03a5f38>] (dump_stack) from [<c03a2098>] (__warn+0x98/0xc0)
[<c03a2098>] (__warn) from [<c03a2150>] (warn_slowpath_fmt+0x90/0xc0)
[<c03a2150>] (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 [<c023eeb4>] (ep93xx_spi_prepare_hardware+0x10/0x30)
[<c023eeb4>] (ep93xx_spi_prepare_hardware) from [<c023c0f8>] (__spi_pump_messages+0x124/0x620)
[<c023c0f8>] (__spi_pump_messages) from [<c023e5b8>] (__spi_sync+0x280/0x2c0)
[<c023e5b8>] (__spi_sync) from [<c023e61c>] (spi_sync+0x24/0x40)
[<c023e61c>] (spi_sync) from [<c021f8a4>] (spi_sync_transfer.constprop.0+0x64/0x8c)
[<c021f8a4>] (spi_sync_transfer.constprop.0) from [<c021f914>] (regmap_spi_write+0x48/0x70)
[<c021f914>] (regmap_spi_write) from [<c021c320>] (_regmap_raw_write_impl+0x640/0x740)
[<c021c320>] (_regmap_raw_write_impl) from [<c021c49c>] (_regmap_bus_raw_write+0x7c/0xac)
[<c021c49c>] (_regmap_bus_raw_write) from [<c021bbd4>] (_regmap_update_bits+0xec/0xf8)
[<c021bbd4>] (_regmap_update_bits) from [<c021dac4>] (regmap_update_bits_base+0x50/0x7c)
[<c021dac4>] (regmap_update_bits_base) from [<c0290ea8>] (cs4271_component_probe+0x74/0x148)
[<c0290ea8>] (cs4271_component_probe) from [<c02889b4>] (snd_soc_component_probe+0x24/0x74)
[<c02889b4>] (snd_soc_component_probe) from [<c027e9d0>] (soc_probe_component+0x11c/0x29c)
[<c027e9d0>] (soc_probe_component) from [<c027ef14>] (snd_soc_bind_card+0x3c4/0x8a8)
[<c027ef14>] (snd_soc_bind_card) from [<c0291798>] (edb93xx_probe+0x34/0x5c)
[<c0291798>] (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 [<c03a64d0>] (kernel_init+0x8/0xf8)
[<c03a64d0>] (kernel_init) from [<c00082d8>] (ret_from_fork+0x14/0x3c)
...
spi_master spi0: failed to prepare transfer hardware: -108

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@gmail.com>
---
 drivers/spi/spi-ep93xx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-ep93xx.c b/drivers/spi/spi-ep93xx.c
index aa676559d273..5896a7b2fade 100644
--- a/drivers/spi/spi-ep93xx.c
+++ b/drivers/spi/spi-ep93xx.c
@@ -550,7 +550,7 @@ static int ep93xx_spi_prepare_hardware(struct spi_master *master)
 	u32 val;
 	int ret;
 
-	ret = clk_enable(espi->clk);
+	ret = clk_prepare_enable(espi->clk);
 	if (ret)
 		return ret;
 
@@ -570,7 +570,7 @@ static int ep93xx_spi_unprepare_hardware(struct spi_master *master)
 	val &= ~SSPCR1_SSE;
 	writel(val, espi->mmio + SSPCR1);
 
-	clk_disable(espi->clk);
+	clk_disable_unprepare(espi->clk);
 
 	return 0;
 }
-- 
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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Re: [PATCH 2/7] spi: spi-ep93xx: Prepare clock before using it

[Mark Brown]

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On Mon, Jun 14, 2021 at 01:30:36AM +0200, Alexander Sverdlin wrote:
> 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 ep93xx-spi.0
> CPU: 0 PID: 1 Comm: swapper Tainted: G        W         5.13.0-rc5-... #1
> Hardware name: Cirrus Logic EDB9302 Evaluation Board
> [<c000d5b0>] (unwind_backtrace) from [<c000c590>] (show_stack+0x10/0x18)
> [<c000c590>] (show_stack) from [<c03a5f38>] (dump_stack+0x20/0x2c)
> [<c03a5f38>] (dump_stack) from [<c03a2098>] (__warn+0x98/0xc0)
> [<c03a2098>] (__warn) from [<c03a2150>] (warn_slowpath_fmt+0x90/0xc0)
> [<c03a2150>] (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 [<c023eeb4>] (ep93xx_spi_prepare_hardware+0x10/0x30)

Please think hard before including complete backtraces in upstream
reports, they are very large and contain almost no useful information
relative to their size so often obscure the relevant content in your
message. If part of the backtrace is usefully illustrative (it often is
for search engines if nothing else) then it's usually better to pull out
the relevant sections.

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