[PATCH v2 1/2] can: mcp251xfd: Try to get crystal clock rate from property

[PATCH v2 1/2] can: mcp251xfd: Try to get crystal clock rate from property

[Andy Shevchenko]

In some configurations, mainly ACPI-based, the clock frequency of the device
is supplied by very well established 'clock-frequency' property. Hence, try
to get it from the property at last if no other providers are available.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: new patch
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index e0ae00e34c7b..e42f87c3f2ec 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -2856,7 +2856,7 @@ static int mcp251xfd_probe(struct spi_device *spi)
 	struct gpio_desc *rx_int;
 	struct regulator *reg_vdd, *reg_xceiver;
 	struct clk *clk;
-	u32 freq;
+	u32 freq, rate;
 	int err;
 
 	if (!spi->irq)
@@ -2883,11 +2883,16 @@ static int mcp251xfd_probe(struct spi_device *spi)
 		return dev_err_probe(&spi->dev, PTR_ERR(reg_xceiver),
 				     "Failed to get Transceiver regulator!\n");
 
-	clk = devm_clk_get(&spi->dev, NULL);
+	/* Always ask for fixed clock rate from a property. */
+	device_property_read_u32(&spi->dev, "clock-frequency", &rate);
+
+	clk = devm_clk_get_optional(&spi->dev, NULL);
 	if (IS_ERR(clk))
 		return dev_err_probe(&spi->dev, PTR_ERR(clk),
 				     "Failed to get Oscillator (clock)!\n");
 	freq = clk_get_rate(clk);
+	if (freq == 0)
+		freq = rate;
 
 	/* Sanity check */
 	if (freq < MCP251XFD_SYSCLOCK_HZ_MIN ||
-- 
2.30.2

[PATCH v2 2/2] can: mcp251xfd: Fix header block to clarify independence from OF

[Andy Shevchenko]

The driver is neither dependent on OF, nor it requires any OF headers.
Fix header block to clarify independence from OF.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
v2: included property.h
 drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
index e42f87c3f2ec..e919f7e4d566 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
@@ -15,10 +15,10 @@
 #include <linux/bitfield.h>
 #include <linux/clk.h>
 #include <linux/device.h>
+#include <linux/mod_devicetable.h>
 #include <linux/module.h>
-#include <linux/of.h>
-#include <linux/of_device.h>
 #include <linux/pm_runtime.h>
+#include <linux/property.h>
 
 #include <asm/unaligned.h>
 
-- 
2.30.2

Re: [PATCH v2 1/2] can: mcp251xfd: Try to get crystal clock rate from property

[Marc Kleine-Budde]

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On 26.05.2021 22:33:26, Andy Shevchenko wrote:
> In some configurations, mainly ACPI-based, the clock frequency of the device
> is supplied by very well established 'clock-frequency' property. Hence, try
> to get it from the property at last if no other providers are available.
> 
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> v2: new patch
>  drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
> index e0ae00e34c7b..e42f87c3f2ec 100644
> --- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
> +++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-core.c
> @@ -2856,7 +2856,7 @@ static int mcp251xfd_probe(struct spi_device *spi)
>  	struct gpio_desc *rx_int;
>  	struct regulator *reg_vdd, *reg_xceiver;
>  	struct clk *clk;
> -	u32 freq;
> +	u32 freq, rate;
>  	int err;
>  
>  	if (!spi->irq)
> @@ -2883,11 +2883,16 @@ static int mcp251xfd_probe(struct spi_device *spi)
>  		return dev_err_probe(&spi->dev, PTR_ERR(reg_xceiver),
>  				     "Failed to get Transceiver regulator!\n");
>  
> -	clk = devm_clk_get(&spi->dev, NULL);
> +	/* Always ask for fixed clock rate from a property. */
> +	device_property_read_u32(&spi->dev, "clock-frequency", &rate);

what about error handling....?

> +
> +	clk = devm_clk_get_optional(&spi->dev, NULL);
>  	if (IS_ERR(clk))
>  		return dev_err_probe(&spi->dev, PTR_ERR(clk),
>  				     "Failed to get Oscillator (clock)!\n");
>  	freq = clk_get_rate(clk);
> +	if (freq == 0)
> +		freq = rate;

... this means we don't fail if there is neither a clk nor a
clock-frequency property. I've send a v3 to fix this.

>  
>  	/* Sanity check */
>  	if (freq < MCP251XFD_SYSCLOCK_HZ_MIN ||
> -- 
> 2.30.2
> 
>

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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Re: [PATCH v2 1/2] can: mcp251xfd: Try to get crystal clock rate from property

[Andy Shevchenko]

On Mon, May 31, 2021 at 10:47:20AM +0200, Marc Kleine-Budde wrote:
> On 26.05.2021 22:33:26, Andy Shevchenko wrote:
> > In some configurations, mainly ACPI-based, the clock frequency of the device
> > is supplied by very well established 'clock-frequency' property. Hence, try
> > to get it from the property at last if no other providers are available.

> >  		return dev_err_probe(&spi->dev, PTR_ERR(reg_xceiver),
> >  				     "Failed to get Transceiver regulator!\n");
> >  
> > -	clk = devm_clk_get(&spi->dev, NULL);
> > +	/* Always ask for fixed clock rate from a property. */
> > +	device_property_read_u32(&spi->dev, "clock-frequency", &rate);
> 
> what about error handling....?

Not needed, but rate should be assigned to 0, which is missed.

> > +	clk = devm_clk_get_optional(&spi->dev, NULL);
> >  	if (IS_ERR(clk))
> >  		return dev_err_probe(&spi->dev, PTR_ERR(clk),
> >  				     "Failed to get Oscillator (clock)!\n");
> >  	freq = clk_get_rate(clk);
> > +	if (freq == 0)
> > +		freq = rate;
> 
> ... this means we don't fail if there is neither a clk nor a
> clock-frequency property.

The following will check for it (which is already in the code)

  if (freq <= MCP251XFD_SYSCLOCK_HZ_MAX / MCP251XFD_OSC_PLL_MULTIPLIER) {

> I've send a v3 to fix this.

You mean I have to send v3?
Sure!


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 1/2] can: mcp251xfd: Try to get crystal clock rate from property

[Andy Shevchenko]

On Mon, May 31, 2021 at 12:58:29PM +0300, Andy Shevchenko wrote:
> On Mon, May 31, 2021 at 10:47:20AM +0200, Marc Kleine-Budde wrote:
> > On 26.05.2021 22:33:26, Andy Shevchenko wrote:
> > > In some configurations, mainly ACPI-based, the clock frequency of the device
> > > is supplied by very well established 'clock-frequency' property. Hence, try
> > > to get it from the property at last if no other providers are available.
> 
> > >  		return dev_err_probe(&spi->dev, PTR_ERR(reg_xceiver),
> > >  				     "Failed to get Transceiver regulator!\n");
> > >  
> > > -	clk = devm_clk_get(&spi->dev, NULL);
> > > +	/* Always ask for fixed clock rate from a property. */
> > > +	device_property_read_u32(&spi->dev, "clock-frequency", &rate);
> > 
> > what about error handling....?
> 
> Not needed, but rate should be assigned to 0, which is missed.
> 
> > > +	clk = devm_clk_get_optional(&spi->dev, NULL);
> > >  	if (IS_ERR(clk))
> > >  		return dev_err_probe(&spi->dev, PTR_ERR(clk),
> > >  				     "Failed to get Oscillator (clock)!\n");
> > >  	freq = clk_get_rate(clk);
> > > +	if (freq == 0)
> > > +		freq = rate;
> > 
> > ... this means we don't fail if there is neither a clk nor a
> > clock-frequency property.
> 
> The following will check for it (which is already in the code)
> 
>   if (freq <= MCP251XFD_SYSCLOCK_HZ_MAX / MCP251XFD_OSC_PLL_MULTIPLIER) {

Even before, actually,

             /* Sanity check */
             if (freq < MCP251XFD_SYSCLOCK_HZ_MIN ||
		 freq > MCP251XFD_SYSCLOCK_HZ_MAX) {


> > I've send a v3 to fix this.
> 
> You mean I have to send v3?
> Sure!

So, I am going to send a v3 with amended commit message and assigning rate
to 0.

-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v2 1/2] can: mcp251xfd: Try to get crystal clock rate from property

[Marc Kleine-Budde]

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On 31.05.2021 12:58:29, Andy Shevchenko wrote:
> On Mon, May 31, 2021 at 10:47:20AM +0200, Marc Kleine-Budde wrote:
> > On 26.05.2021 22:33:26, Andy Shevchenko wrote:
> > > In some configurations, mainly ACPI-based, the clock frequency of the device
> > > is supplied by very well established 'clock-frequency' property. Hence, try
> > > to get it from the property at last if no other providers are available.
> 
> > >  		return dev_err_probe(&spi->dev, PTR_ERR(reg_xceiver),
> > >  				     "Failed to get Transceiver regulator!\n");
> > >  
> > > -	clk = devm_clk_get(&spi->dev, NULL);
> > > +	/* Always ask for fixed clock rate from a property. */
> > > +	device_property_read_u32(&spi->dev, "clock-frequency", &rate);
> > 
> > what about error handling....?
> 
> Not needed, but rate should be assigned to 0, which is missed.
> 
> > > +	clk = devm_clk_get_optional(&spi->dev, NULL);
> > >  	if (IS_ERR(clk))
> > >  		return dev_err_probe(&spi->dev, PTR_ERR(clk),
> > >  				     "Failed to get Oscillator (clock)!\n");
> > >  	freq = clk_get_rate(clk);
> > > +	if (freq == 0)
> > > +		freq = rate;
> > 
> > ... this means we don't fail if there is neither a clk nor a
> > clock-frequency property.
> 
> The following will check for it (which is already in the code)
> 
>   if (freq <= MCP251XFD_SYSCLOCK_HZ_MAX / MCP251XFD_OSC_PLL_MULTIPLIER) {

Good point.

> > I've send a v3 to fix this.
> 
> You mean I have to send v3?
> Sure!

I have send a v3, see:

https://lore.kernel.org/r/20210531084444.1785397-1-mkl@pengutronix.de

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |

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