Re: [PATCH v2 2/2] spi: loongson: add bus driver for the loongson spi controller

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在 2023/3/18 上午12:26, Mark Brown 写道:
On Fri, Mar 17, 2023 at 04:29:50PM +0800, Yinbo Zhu wrote:

+static int loongson_spi_update_state(struct loongson_spi *loongson_spi,
+				     struct spi_device *spi, struct spi_transfer *t)

+		loongson_spi->hz = hz;
+		loongson_spi->spcr = div_tmp & 3;
+		loongson_spi->sper = (div_tmp >> 2) & 3;
+		val = loongson_spi_read_reg(loongson_spi, LOONGSON_SPI_SPCR_REG);
This is writing to general chip registers, apparently not per chip
select ones.

The loongson_spi_update_state was only be called in setup or transfer_one, and I will also
add a spin lock in tranfser_one.

+static int loongson_spi_setup(struct spi_device *spi)
+	struct loongson_spi *loongson_spi;
+	spin_lock(&loongson_spi->lock);
+	loongson_spi_update_state(loongson_spi, spi, NULL);
As IIRC I mentioned last time setup() might be called while other
transfers are happening and therefore shouldn't affect parallel
operations on other devices.
I think add spin_lock in  transfer_one interface that should be to fix this issue, Do you think so?
loongson_spi_transfer_one(struct spi_controller *ctrl, struct spi_dev
        struct loongson_spi *loongson_spi = spi_master_get_devdata(spi->master);

+       spin_lock(&loongson_spi->lock);
        loongson_spi_update_state(loongson_spi, spi, xfer);
+       spin_unlock(&loongson_spi->lock);

+static const struct of_device_id loongson_spi_id_table[] = {
+	{ .compatible = "loongson,ls2k-spi", },
+	{ }
+MODULE_DEVICE_TABLE(of, loongson_spi_id_table);
+static struct platform_driver loongson_spi_driver = {
+	.probe = loongson_spi_platform_probe,
+	.driver	= {
+		.name	= "loongson-spi",
+		.owner	= THIS_MODULE,
+		.bus = &platform_bus_type,
+		.pm = &loongson_spi_dev_pm_ops,
+		.of_match_table = loongson_spi_id_table,
+	},
+#ifdef CONFIG_PCI
+static int loongson_spi_pci_register(struct pci_dev *pdev,
+			const struct pci_device_id *ent)
Again as I said last time the two buses should probably be separate

Otherwise this looks fine.
okay, I will do it.

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