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SubjectRe: [PATCH v2 2/2] spi: Add ADI driver for Spreadtrum platform
On Fri, Sep 08, 2017 at 04:33:42PM +0800, Baolin Wang wrote:
> This patch adds ADI driver based on SPI framework for
> Spreadtrum SC9860 platform.
>
> Signed-off-by: Baolin Wang <baolin.wang@spreadtrum.com>
> ---

[...]

> +++ b/drivers/spi/spi-sprd-adi.c
> @@ -0,0 +1,419 @@
> +/*
> + * Copyright (C) 2017 Spreadtrum Communications Inc.
> + *
> + * SPDX-License-Identifier: (GPL-2.0+ OR MIT)

Kernel code should generally not be MIT license.

[...]

> +static int sprd_adi_drain_fifo(struct sprd_adi *sadi)
> +{
> + u32 timeout = ADI_FIFO_DRAIN_TIMEOUT;
> + u32 sts;
> +
> + do {
> + sts = readl_relaxed(sadi->base + REG_ADI_ARM_FIFO_STS);
> + if (sts & BIT_FIFO_EMPTY)
> + break;
> +
> + cpu_relax();
> + } while (--timeout);

You can use readl_poll_timeout.

> +
> + if (timeout == 0) {
> + dev_err(sadi->dev, "drain write fifo timeout\n");
> + return -EBUSY;
> + }
> +
> + return 0;
> +}
> +
> +static int sprd_adi_fifo_is_full(struct sprd_adi *sadi)
> +{
> + return readl_relaxed(sadi->base + REG_ADI_ARM_FIFO_STS) & BIT_FIFO_FULL;
> +}
> +
> +static int sprd_adi_read(struct sprd_adi *sadi, u32 reg_paddr, u32 *read_val)
> +{
> + int read_timeout = ADI_READ_TIMEOUT;
> + u32 val, rd_addr;
> +
> + /*
> + * Set the physical register address need to read into RD_CMD register,
> + * then ADI controller will start to transfer automatically.
> + */
> + writel_relaxed(reg_paddr, sadi->base + REG_ADI_RD_CMD);
> +
> + /*
> + * Wait read operation complete, the BIT_RD_CMD_BUSY will be set
> + * simultaneously when writing read command to register, and the
> + * BIT_RD_CMD_BUSY will be cleared after the read operation is
> + * completed.
> + */
> + do {
> + val = readl_relaxed(sadi->base + REG_ADI_RD_DATA);
> + if (!(val & BIT_RD_CMD_BUSY))
> + break;
> +
> + cpu_relax();
> + } while (--read_timeout);

readl_poll_timeout

> +
> + if (read_timeout == 0) {
> + dev_err(sadi->dev, "ADI read timeout\n");
> + return -EBUSY;
> + }

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