On 10/29/2012 11:18 AM, Laxman Dewangan wrote:
> Tegra20/Tegra30 supports the spi interface through its SLINK
> controller. Add spi driver for SLINK controller.
> diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
> +config SPI_TEGRA20_SLINK
> + tristate "Nvidia Tegra20/Tegra30 SLINK Controller"
> + depends on ARCH_TEGRA && TEGRA20_APB_DMA
I think it depends on DMAENGINE, not the specific driver now, doesn't it?
> +static unsigned tegra_slink_fill_tx_fifo_from_client_txbuf(
> + struct tegra_slink_data *tspi, struct spi_transfer *t)
> + if (tspi->is_packed) {
> + fifo_words_left = tx_empty_count * tspi->words_per_32bit;
> + written_words = min(fifo_words_left, tspi->curr_dma_words);
> + nbytes = written_words * tspi->bytes_per_word;
> + max_n_32bit = DIV_ROUND_UP(nbytes, 4);
> + for (count = 0; count < max_n_32bit; count++) {
> + x = 0;
> + for (i = 0; (i < 4) && nbytes; i++, nbytes--)
> + x |= (*tx_buf++) << (i*8);
> + tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
> + }
> + } else {
> + max_n_32bit = min(tspi->curr_dma_words, tx_empty_count);
> + written_words = max_n_32bit;
> + nbytes = written_words * tspi->bytes_per_word;
> + for (count = 0; count < max_n_32bit; count++) {
> + x = 0;
> + for (i = 0; nbytes && (i < tspi->bytes_per_word);
> + i++, nbytes--)
> + x |= ((*tx_buf++) << i*8);
> + tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
> + }
> + }
The if and the else there are basically identical now. Can't the else
branch simply be replaced by the if branch? At most I think the
difference comes down to max_n_32bit v.s. fifo_words_left calculations
being slight different; everything else is the same.
I suppose this isn't a big deal though; we could clean it up later if
necessary.
> +static int tegra_slink_start_cpu_based_transfer(
> + struct tegra_slink_data *tspi, struct spi_transfer *t)
> + tspi->is_curr_dma_xfer = false;
> + if (tspi->is_packed) {
> + val |= SLINK_PACKED;
> + tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
> + udelay(1);
> + wmb();
Why the udelay() and wmb()?
> +static int tegra_slink_runtime_suspend(struct device *dev)
> +{
> + struct spi_master *master = dev_get_drvdata(dev);
> + struct tegra_slink_data *tspi = spi_master_get_devdata(master);
> +
> + tegra_slink_clk_unprepare(tspi);
> + return 0;
> +}
> +
> +static int tegra_slink_runtime_resume(struct device *dev)
> +{
> + struct spi_master *master = dev_get_drvdata(dev);
> + struct tegra_slink_data *tspi = spi_master_get_devdata(master);
> +
> + return tegra_slink_clk_prepare(tspi);
> +}
Why not move the body of tegra_slink_clk_{un,prepare} inside those
functions, since they're only called from those functions?
> +MODULE_ALIAS("platform:tegra_slink-slink");
I think that's a typo.
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