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SubjectRe: [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
> modules.
>
> Otherwise this looks fine.
okay, I will do it.

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