[U-Boot] [PATCH 07/15] iMX28: Add SPI driver

Marek Vasut marek.vasut at gmail.com
Tue Sep 13 00:45:14 CEST 2011


On Monday, September 12, 2011 10:26:11 PM Mike Frysinger wrote:
> On Monday, September 12, 2011 13:42:22 Marek Vasut wrote:
> > On Monday, September 12, 2011 06:35:10 PM Mike Frysinger wrote:
> > > On Monday, September 12, 2011 00:06:41 Marek Vasut wrote:
> > > > +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
> > > > +				  unsigned int max_hz, unsigned int 
mode)
> > > > +{
> > > > +
> > > > +	mx28_reset_block(&ssp_regs->hw_ssp_ctrl0_reg);
> > > > +
> > > > +	writel(SSP_CTRL0_BUS_WIDTH_ONE_BIT, &ssp_regs->hw_ssp_ctrl0);
> > > > +
> > > > +	reg = SSP_CTRL1_SSP_MODE_SPI | SSP_CTRL1_WORD_LENGTH_EIGHT_BITS;
> > > > +	reg |= (mode & SPI_CPOL) ? SSP_CTRL1_POLARITY : 0;
> > > > +	reg |= (mode & SPI_CPHA) ? SSP_CTRL1_PHASE : 0;
> > > > +	writel(reg, &ssp_regs->hw_ssp_ctrl1);
> > > > +
> > > > +	writel(0, &ssp_regs->hw_ssp_cmd0);
> > > > +
> > > > +	mx28_set_ssp_busclock(bus, max_hz / 1000);
> > > 
> > > these steps should be done in the claim_bus func
> > 
> > I don't think so ... I need to access max_hz and mode. This seems more
> > fitting to me.
> 
> that's not how the API works.  you create clients, then you acquire the bus
> for a specific client, do a transfer, and then release it.  your bus breaks
> with the trivial case:
> 	- setup slave A
> 	- setup slave B
> 	- claim bus for slave A
> 	- transfer with slave A	<- uses settings from slave B
> -mike

Thanks for clearing this, fixed in V3


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