Re: [PATCH v14 8/8] soc: amd: Add support for AMD Pensando SoC Controller
From: Andy Shevchenko
Date: Mon May 15 2023 - 17:06:48 EST
On Mon, May 15, 2023 at 9:18 PM Brad Larson <blarson@xxxxxxx> wrote:
>
> The Pensando SoC controller is a SPI connected companion device
> that is present in all Pensando SoC board designs. The essential
> board management registers are accessed on chip select 0 with
> board mgmt IO support accessed using additional chip selects.
...
> +#include <linux/cdev.h>
> +#include <linux/device.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
Unneeded inclusion.
> +#include <linux/reset-controller.h>
> +#include <linux/spi/spi.h>
...
> + u8 tx_buf[PENCTRL_MAX_MSG_LEN];
> + u8 rx_buf[PENCTRL_MAX_MSG_LEN];
Does it need to be DMA-capable?
...
> + spi->chip_select = current_cs;
> + spi->cs_gpiod = spi->controller->cs_gpiods[current_cs];
Nowadays these require API calls instead of direct assignments.
...
> +static int penctrl_release(struct inode *inode, struct file *filp)
> +{
> + filp->private_data = NULL;
> + return 0;
> +}
Is it possible to unload the module without releasing the device node?
...
> + u8 txbuf[3];
> + u8 rxbuf[1];
Same question about DMA.
...
> + ret = spi_sync(spi, &m);
> + if (ret == 0)
> + *val = rxbuf[0];
> +
> + return ret;
Can also be written in more usual way:
if (ret)
return ret;
...
return 0;
...
> + u8 txbuf[4];
DMA?
...
> + spi->chip_select = 0;
> + spi->cs_gpiod = spi->controller->cs_gpiods[0];
Setter APIs.
...
> + spi->chip_select = 0;
> + spi->cs_gpiod = spi->controller->cs_gpiods[0];
Ditto.
> + ret = device_property_read_u32(spi->dev.parent, "num-cs", &num_cs);
> + if (ret)
> + return dev_err_probe(&spi->dev, ret,
> + "number of chip-selects not defined\n");
Hmm... Shouldn't SPI core take care of this in a generic way? Yes, I
understand that you need the number for the allocation, but I would
expect something like spi_fw_get_num_cs() to exist (seems not?).
...
> + penctrl->rcdev.of_node = spi->dev.of_node;
Use device_set_node(). It helps to modify the data types beneath.
--
With Best Regards,
Andy Shevchenko