[PATCH v2] pwm: atmel-hlcdc: add at91sam9x5 and sama5d3 errata handling

Thierry Reding thierry.reding at gmail.com
Thu Dec 4 05:12:31 PST 2014


On Wed, Nov 19, 2014 at 03:33:09PM +0100, Boris Brezillon wrote:
> at91sam9x5 has an errata forbidding the use of slow clk as a clk source and
> sama5d3 SoCs has another errata forbidding the use of div1 prescaler.
> 
> Take both of these erratas into account.
> 
> Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
> ---
> Hi Thierry,
> 
> I've addressed the "erratas stored in of_device_id data" part, but still
> haven't modified the compatible strings of the HLCDC subdevices.
> 
> Please let me know if you really want to handle erratas through pwm
> compatibles instead of parent device compatibles.
> 
> Regards,
> 
> Boris
> 
> Changes since v1:
> - use data field in of_device_id to attach erratas to an IP revision
> 
>  drivers/pwm/pwm-atmel-hlcdc.c | 50 ++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 45 insertions(+), 5 deletions(-)

I applied this, but this was really much more difficult than I would've
wanted. Since the MFD driver hasn't been merged into Linus' tree yet I
wasn't able to actually build test this driver at all without manually
pulling in the patches that add the MFD support. I went through this
trouble this time because it's what we had agreed upon, but for the
record, next time I'll request a stable branch that I can pull into the
PWM tree to resolve this kind of dependency. Or patches will have to
wait until the next merge window. I don't want to have to jump through
hoops just to make sure the code in my tree actually compiles.

Oh, and it's good that I do compile tests because...

> diff --git a/drivers/pwm/pwm-atmel-hlcdc.c b/drivers/pwm/pwm-atmel-hlcdc.c
[...]
> +const struct atmel_hlcdc_pwm_erratas atmel_hlcdc_pwm_at91sam9x5_erratas = {
> +	.slow_clk_errata = true,
> +};
> +
> +const struct atmel_hlcdc_pwm_erratas atmel_hlcdc_pwm_sama5d3_erratas = {
> +	.div1_clk_errata = true,
> +};

... these actually should be static.

Also I took the liberty of substituting "erratum" for "errata" and
"errata" for "erratas".

Thierry
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