On 19/10/15 18:47, Mark Brown wrote:
> On Mon, Oct 12, 2015 at 01:40:29PM +0100, Damien Horsley wrote:
>
>> +static inline u32 img_i2s_in_ch_disable(struct img_i2s_in *i2s, u32 chan)
>> +{
>> + u32 reg;
>> +
>> + reg = img_i2s_in_ch_readl(i2s, chan, IMG_I2S_IN_CH_CTL);
>> + reg &= ~IMG_I2S_IN_CH_CTL_ME_MASK;
>> + img_i2s_in_ch_writel(i2s, chan, reg, IMG_I2S_IN_CH_CTL);
>> +
>> + return reg;
>> +}
>> +
>> +static inline void img_i2s_in_ch_enable(struct img_i2s_in *i2s, u32 chan,
>> + u32 reg)
>> +{
>> + reg |= IMG_I2S_IN_CH_CTL_ME_MASK;
>> + img_i2s_in_ch_writel(i2s, chan, reg, IMG_I2S_IN_CH_CTL);
>> +}
>
> The APIs here all seem a bit odd - for example the enable API taking a
> register value as an argument (normally reg is a register address BTW)
> and returning a value but the disable API doing a read/modify/write
> cycle.
>
Sure. It reduces the number of register accesses this way, but the
difference in execution time is not significant. Would you prefer these
to both do read-modify-writes?
>> +static inline void img_i2s_in_flush(struct img_i2s_in *i2s)
>> +{
>> + int i;
>> + u32 reg;
>> +
>> + for (i = 0; i < i2s->active_channels; i++) {
>> + reg = img_i2s_in_ch_disable(i2s, i);
>> + reg |= IMG_I2S_IN_CH_CTL_FIFO_FLUSH_MASK;
>> + img_i2s_in_ch_writel(i2s, i, reg, IMG_I2S_IN_CH_CTL);
>> + reg &= ~IMG_I2S_IN_CH_CTL_FIFO_FLUSH_MASK;
>> + img_i2s_in_ch_writel(i2s, i, reg, IMG_I2S_IN_CH_CTL);
>> + img_i2s_in_ch_enable(i2s, i, reg);
>> + }
>> +}
>
> This all seems to be connected to this, which is itself slightly funky
> especially in the context of the only user...
>
They are also used during hw_params and set_format.
>> + case SNDRV_PCM_TRIGGER_STOP:
>> + case SNDRV_PCM_TRIGGER_SUSPEND:
>> + case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
>> + reg = img_i2s_in_readl(i2s, IMG_I2S_IN_CTL);
>> + reg &= ~IMG_I2S_IN_CTL_ME_MASK;
>> + img_i2s_in_writel(i2s, reg, IMG_I2S_IN_CTL);
>> + img_i2s_in_flush(i2s);
>> + break;
>
> ...which looks like it'll enable everything, then disable and reenable.
> Plus needing to do a flush on trigger seems weird.
>
If the FIFOs are not flushed, some samples from the previous stream will
be transferred to the user application when the block is started again
>> + if ((channels < 2) ||
>> + (channels > (i2s->max_i2s_chan * 2)) ||
>> + (channels % 2))
>> + return -EINVAL;
>
> This indentation is very weird.
>
Ok. What is the correct indentation for this?
>> + control_mask = (u32)(~IMG_I2S_IN_CTL_16PACK_MASK &
>> + ~IMG_I2S_IN_CTL_ACTIVE_CHAN_MASK);
>
>> + chan_control_mask = (u32)(~IMG_I2S_IN_CH_CTL_16PACK_MASK &
>> + ~IMG_I2S_IN_CH_CTL_FEN_MASK &
>> + ~IMG_I2S_IN_CH_CTL_FMODE_MASK &
>> + ~IMG_I2S_IN_CH_CTL_SW_MASK &
>> + ~IMG_I2S_IN_CH_CTL_FW_MASK &
>> + ~IMG_I2S_IN_CH_CTL_PACKH_MASK);
>
> This also looks very odd. Normally we'd write masks as being the valid
> bits and or them together.
>
Ok
>> + i2s->clk_sys = devm_clk_get(dev, "sys");
>> + if (IS_ERR(i2s->clk_sys))
>> + return PTR_ERR(i2s->clk_sys);
>
> Please print an error message so people can tell why things failed.
>
Ok
>> + rst = devm_reset_control_get(dev, "rst");
>> + if (IS_ERR(rst)) {
>> + dev_dbg(dev, "No top level reset found\n");
>
> You should check for -EPROBE_DEFER here and just return the error here
> if you get it (on the basis that the reset framework ought to be using a
> different error if there's nothing bound in DT).
>
Ok
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