[U-Boot] [PATCH 2/2] SPI: mxc_spi: delay initialisation until claim bus

[Jagan Teki]

On 24 September 2014 23:53, Jagan Teki <jagannadh.teki at gmail.com> wrote:
> On 1 September 2014 14:16, Markus Niebel <list-09_u-boot at tqsc.de> wrote:
>> From: Markus Niebel <Markus.Niebel at tq-group.com>
>>
>> it is not correct to init for a specific slave in spi_setup_slave.
>> instead buffer the values and delay init until spi_claim_bus.
>>
>> Signed-off-by: Markus Niebel <Markus.Niebel at tq-group.com>
>> ---
>>  drivers/spi/mxc_spi.c | 37 +++++++++++++++++++++----------------
>>  1 file changed, 21 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/spi/mxc_spi.c b/drivers/spi/mxc_spi.c
>> index 6a05d15..c741738 100644
>> --- a/drivers/spi/mxc_spi.c
>> +++ b/drivers/spi/mxc_spi.c
>> @@ -43,6 +43,8 @@ struct mxc_spi_slave {
>>  #endif
>>         int             gpio;
>>         int             ss_pol;
>> +       unsigned int    max_hz;
>> +       unsigned int    mode;
>>  };
>>
>>  static inline struct mxc_spi_slave *to_mxc_spi_slave(struct spi_slave *slave)
>> @@ -77,12 +79,13 @@ u32 get_cspi_div(u32 div)
>>  }
>>
>>  #ifdef MXC_CSPI
>> -static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs,
>> -               unsigned int max_hz, unsigned int mode)
>> +static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs)
>>  {
>>         unsigned int ctrl_reg;
>>         u32 clk_src;
>>         u32 div;
>> +       unsigned int max_hz = mxcs->max_hz;
>> +       unsigned int mode = mxcs->mode;
>>
>>         clk_src = mxc_get_clock(MXC_CSPI_CLK);
>>
>> @@ -114,19 +117,15 @@ static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs,
>>  #endif
>>
>>  #ifdef MXC_ECSPI
>> -static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs,
>> -               unsigned int max_hz, unsigned int mode)
>> +static s32 spi_cfg_mxc(struct mxc_spi_slave *mxcs, unsigned int cs)
>>  {
>>         u32 clk_src = mxc_get_clock(MXC_CSPI_CLK);
>>         s32 reg_ctrl, reg_config;
>>         u32 ss_pol = 0, sclkpol = 0, sclkpha = 0, sclkctl = 0;
>>         u32 pre_div = 0, post_div = 0;
>>         struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;
>> -
>> -       if (max_hz == 0) {
>> -               printf("Error: desired clock is 0\n");
>> -               return -1;
>> -       }
>> +       unsigned int max_hz = mxcs->max_hz;
>> +       unsigned int mode = mxcs->mode;
>>
>>         /*
>>          * Reset SPI and set all CSs to master mode, if toggling
>> @@ -404,6 +403,11 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
>>         if (bus >= ARRAY_SIZE(spi_bases))
>>                 return NULL;
>>
>> +       if (max_hz == 0) {
>> +               printf("Error: desired clock is 0\n");
>> +               return NULL;
>> +       }
>> +
>>         mxcs = spi_alloc_slave(struct mxc_spi_slave, bus, cs);
>>         if (!mxcs) {
>>                 puts("mxc_spi: SPI Slave not allocated !\n");
>> @@ -421,13 +425,9 @@ struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
>>         cs = ret;
>>
>>         mxcs->base = spi_bases[bus];
>> +       mxcs->max_hz = max_hz;
>> +       mxcs->mode = mode;
>>
>> -       ret = spi_cfg_mxc(mxcs, cs, max_hz, mode);
>> -       if (ret) {
>> -               printf("mxc_spi: cannot setup SPI controller\n");
>> -               free(mxcs);
>> -               return NULL;
>> -       }
>>         return &mxcs->slave;
>>  }
>>
>> @@ -440,12 +440,17 @@ void spi_free_slave(struct spi_slave *slave)
>>
>>  int spi_claim_bus(struct spi_slave *slave)
>>  {
>> +       int ret;
>>         struct mxc_spi_slave *mxcs = to_mxc_spi_slave(slave);
>>         struct cspi_regs *regs = (struct cspi_regs *)mxcs->base;
>>
>>         reg_write(&regs->rxdata, 1);
>>         udelay(1);
>> -       reg_write(&regs->ctrl, mxcs->ctrl_reg);
>> +       ret = spi_cfg_mxc(mxcs, slave->cs);
>> +       if (ret) {
>> +               printf("mxc_spi: cannot setup SPI controller\n");
>> +               return ret;
>> +       }
>>         reg_write(&regs->period, MXC_CSPIPERIOD_32KHZ);
>>         reg_write(&regs->intr, 0);
>>
>> --
>> 2.1.0
>>
>
> In fact this driver is using spi_cfg_mxc() for configuring SPI
> clock,polarities and frequency
> in spi_setup_slave() time, but usually spi_setup_slave() will require
> only basic controller reg
> initialization. So while in spi_claim_bus() clock, polarities and
> frequencies will handle.
>
> Please think on that direction and will be good if you fix those and
> send the patches for next time.

I think you did the same, what I mentioned above, could you rebase this
patch on master, I have seen patch failed error while applying.

thanks!
-- 
Jagan.