Re: [PATCH 2/2] i2c: xgene-slimpro: Add ACPI support by using PCC mailbox

From: Wolfram Sang
Date: Thu Apr 20 2017 - 04:06:03 EST


Hi,

have you tested these patches also without PCC? So, we can be sure there
is no regression?

> diff --git a/drivers/i2c/busses/i2c-xgene-slimpro.c b/drivers/i2c/busses/i2c-xgene-slimpro.c
> index 96545aa..a5771c1 100644
> --- a/drivers/i2c/busses/i2c-xgene-slimpro.c
> +++ b/drivers/i2c/busses/i2c-xgene-slimpro.c
> @@ -32,6 +32,8 @@
> #include <linux/platform_device.h>
> #include <linux/version.h>
>
> +#include <acpi/pcc.h>
> +

Please keep it sorted alphabetically.

> +#define PCC_CMD_GENERATE_DB_INT BIT(15)
> +#define PCC_STS_CMD_COMPLETE BIT(0)
> +#define PCC_STS_SCI_DOORBELL BIT(1)
> +#define PCC_STS_ERR BIT(2)
> +#define PCC_STS_PLAT_NOTIFY BIT(3)

Please keep it sorted by number.

> + if (!acpi_disabled) {
> + mutex_lock(&ctx->tx_mutex);
> + init_completion(&ctx->rd_complete);

reinit_completion?

> + slimpro_i2c_pcc_tx_prepare(ctx, msg);
> + }
> +
> + mutex_init(&ctx->tx_mutex);

Why this mutex, by the way? The i2c-core serializes access to the
adapter. Maybe I am missing something?

> + cppc_ss = ctx->mbox_chan->con_priv;
> + if (!cppc_ss) {
> + dev_err(&pdev->dev, "PPC subspace not found\n");
> + rc = -ENODEV;
> + goto mbox_err;
> + }
> +
> + if (!ctx->mbox_chan->mbox->txdone_irq) {
> + dev_err(&pdev->dev, "PCC IRQ not supported\n");
> + rc = -ENODEV;
> + goto mbox_err;
> + }
>
> + /*
> + * This is the shared communication region
> + * for the OS and Platform to communicate over.
> + */
> + ctx->comm_base_addr = cppc_ss->base_address;
> + if (ctx->comm_base_addr) {
> + ctx->pcc_comm_addr = memremap(ctx->comm_base_addr,
> + cppc_ss->length,
> + MEMREMAP_WB);
> + } else {
> + dev_err(&pdev->dev, "Failed to get PCC comm region\n");
> + rc = -ENODEV;
> + goto mbox_err;
> + }

I think it doesn't make sense to print a dev_err and return ENODEV which
is treated by the driver core as a non-error. It means "not present, but
OK". You probably want other error codes here.

Regards,

Wolfram

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