[U-Boot] [PATCH v6 2/2] DW SPI: Get clock value from Device Tree

Marek Vasut
2017-12-11T16:41:21Z

On 12/11/2017 05:37 PM, Eugeniy Paltsev wrote:
> On Mon, 2017-12-11 at 17:21 +0100, Marek Vasut wrote:
>> On 12/11/2017 05:18 PM, Eugeniy Paltsev wrote:
>>> Add option to set spi controller clock frequency via device tree
>>> using standard clock bindings.
>>>
>>> Define dw_spi_get_clk function as 'weak' as some targets
>>> (like SOCFPGA_GEN5 and SOCFPGA_ARRIA10) fon't use standard clock API
>>> and implement dw_spi_get_clk their own way in their clock manager.
>>>
>>> Get rid of clock_manager.h include as we don't use
>>> cm_get_spi_controller_clk_hz function anymore. (we use redefined
>>> dw_spi_get_clk in SOCFPGA clock managers instead)
>>>
>>> Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
>>> ---
>>>  drivers/spi/designware_spi.c | 43 +++++++++++++++++++++++++++++++++++++++++--
>>>  1 file changed, 41 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
>>> index 5aa507b..a037376 100644
>>> --- a/drivers/spi/designware_spi.c
>>> +++ b/drivers/spi/designware_spi.c
>>> @@ -11,6 +11,7 @@
>>>   */
>>>
>>>  #include <common.h>
>>> +#include <clk.h>
>>>  #include <dm.h>
>>>  #include <errno.h>
>>>  #include <malloc.h>
>>> @@ -18,7 +19,6 @@
>>>  #include <fdtdec.h>
>>>  #include <linux/compat.h>
>>>  #include <asm/io.h>
>>> -#include <asm/arch/clock_manager.h>
>>>
>>>  DECLARE_GLOBAL_DATA_PTR;
>>>
>>> @@ -94,6 +94,8 @@ struct dw_spi_priv {
>>>   void __iomem *regs;
>>>   unsigned int freq; /* Default frequency */
>>>   unsigned int mode;
>>> + struct clk clk;
>>> + unsigned long bus_clk_rate;
>>>
>>>   int bits_per_word;
>>>   u8 cs; /* chip select pin */
>>> @@ -176,14 +178,51 @@ static void spi_hw_init(struct dw_spi_priv *priv)
>>>   debug("%s: fifo_len=%d\n", __func__, priv->fifo_len);
>>>  }
>>>
>>> +/*
>>> + * We define dw_spi_get_clk function as 'weak' as some targets
>>> + * (like SOCFPGA_GEN5 and SOCFPGA_ARRIA10) fon't use standard clock API
>>> + * and implement dw_spi_get_clk their own way in their clock manager.
>>> + */
>>> +__weak int dw_spi_get_clk(struct udevice *bus, ulong *rate)
>>> +{
>>> + struct dw_spi_priv *priv = dev_get_priv(bus);
>>> + int ret;
>>> +
>>> + ret = clk_get_by_index(bus, 0, &priv->clk);
>>> + if (ret)
>>> + return -EINVAL;
>>
>> if (ret)
>>  return ret;
> Ok.
>
>>
>>> + ret = clk_enable(&priv->clk);
>>> + if (ret && ret != -ENOSYS && ret != -ENOSYS && ret != -ENOTSUPP)
>>
>> You have ENOSYS twice in there, but you can do just if (ret) return ret
>> again.
>
> The idea is to skip error if error code is -ENOSYS or -ENOTSUPP
> as it is OK situation: some clock drivers don't implement .enable/.disable
> callbacks so clk_enable returns -ENOSYS.
> Also some clock drivers implement .enable/.disable callbacks not for all
> clock IDs and return -ENOSYS or -ENOTSUPP for others.
>
> But definitely I should remove second ENOSYS here.
+CC Simon, that's somewhat iffy ...

--
Best regards,
Marek Vasut