On Tue, Aug 07, 2018 at 06:43:38PM +0800, Baolin Wang wrote: > From: Lanqing Liu <lanqing....@spreadtrum.com> > > This patch adds the SPI controller driver for Spreadtrum SC9860 platform.
This all looks pretty clean, a few comments below but nothing too major:
> +static void sprd_spi_chipselect(struct spi_device *sdev, bool cs)
> +{
> + struct spi_controller *sctlr = sdev->controller;
> + struct sprd_spi *ss = spi_controller_get_devdata(sctlr);
> + u32 val;
> + int ret;
> +
> + ret = pm_runtime_get_sync(ss->dev);
> + if (ret < 0) {
> + dev_err(ss->dev, "failed to resume SPI controller\n");
> + return;
> + }
Something else further up the stack should probably have runtime PM
enabled already - we should only be changing chip select as part of a
bigger operation. If you use the core auto_runtime_pm feature this will
definitely happen.
> + bits_per_word = bits_per_word > 16 ? round_up(bits_per_word, 16) :
> + round_up(bits_per_word, 8);
Please
> + switch (bits_per_word) {
> + case 8:
> + case 16:
> + case 32:
It'd be nice to have a default case, the core should check for you but
it's nice to have defensive programming here.
> +static int sprd_spi_transfer_one(struct spi_controller *sctlr,
> + struct spi_device *sdev,
> + struct spi_transfer *t)
> +{
> + struct sprd_spi *ss = spi_controller_get_devdata(sctlr);
> + int ret;
> +
> + ret = pm_runtime_get_sync(ss->dev);
> + if (ret < 0) {
> + dev_err(ss->dev, "failed to resume SPI controller\n");
> + goto rpm_err;
> + }
Same thing with runtime PM here - the core can do this for you.
> +static int sprd_spi_setup(struct spi_device *spi_dev)
> +{
> + struct spi_controller *sctlr = spi_dev->controller;
> + struct sprd_spi *ss = spi_controller_get_devdata(sctlr);
> + int ret;
> +
> + ret = pm_runtime_get_sync(ss->dev);
> + if (ret < 0) {
> + dev_err(ss->dev, "failed to resume SPI controller\n");
> + return ret;
> + }
> +
> + ss->hw_mode = spi_dev->mode;
> + sprd_spi_init_hw(ss);
This can be called for one chip select while another is in progress so
it's not good to actually configure the hardware here unless the
configuration is in a chip select specific set of registers. Instead
you should defer to when the transfer is being set up.
> +static int sprd_spi_clk_init(struct platform_device *pdev, struct sprd_spi
> *ss)
> +{
> + struct clk *clk_spi, *clk_parent;
> +
> + clk_spi = devm_clk_get(&pdev->dev, "spi");
> + if (IS_ERR(clk_spi)) {
> + dev_warn(&pdev->dev, "can't get the spi clock\n");
> + clk_spi = NULL;
> + }
I suspect some of these clocks are essential and you should probably
return an error if you can't get them (especially if probe deferral
becomes a factor).
> + if (!clk_set_parent(clk_spi, clk_parent))
> + ss->src_clk = clk_get_rate(clk_spi);
> + else
> + ss->src_clk = SPRD_SPI_DEFAULT_SOURCE;
Are upstream DTs going to be missing the clock setup needed here?
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