linux-kernel - Re: [PATCH v3 1/3] spi: spi-mem: add automatic poll status functions

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Date:   Tue, 18 May 2021 13:40:37 +0200
From:   Boris Brezillon <boris.brezillon@...labora.com>
To:     <patrice.chotard@...s.st.com>
Cc:     Mark Brown <broonie@...nel.org>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        <linux-spi@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <christophe.kerello@...s.st.com>
Subject: Re: [PATCH v3 1/3] spi: spi-mem: add automatic poll status
 functions

On Tue, 18 May 2021 11:39:49 +0200
<patrice.chotard@...s.st.com> wrote:

> +/**
> + * spi_mem_poll_status() - Poll memory device status
> + * @mem: SPI memory device
> + * @op: the memory operation to execute
> + * @mask: status bitmask to ckeck
> + * @match: (status & mask) expected value
> + * @initial_delay_us: delay in us before starting to poll
> + * @polling_delay_us: time to sleep between reads in us
> + * @timeout_ms: timeout in milliseconds
> + *
> + * This function send a polling status request to the controller driver
> + *
> + * Return: 0 in case of success, -ETIMEDOUT in case of error,
> + *         -EOPNOTSUPP if not supported.
> + */
> +int spi_mem_poll_status(struct spi_mem *mem,
> +			const struct spi_mem_op *op,
> +			u16 mask, u16 match,
> +			unsigned long initial_delay_us,
> +			unsigned long polling_delay_us,
> +			u16 timeout_ms)
> +{
> +	struct spi_controller *ctlr = mem->spi->controller;
> +	int ret = -EOPNOTSUPP;
> +	int read_status_ret;
> +	u16 status;
> +
> +	if (op->data.nbytes < 1 || op->data.nbytes > 2)
> +		return -EINVAL;

We should also make sure this is a read operation.

> +
> +	if (ctlr->mem_ops && ctlr->mem_ops->poll_status) {
> +		ret = spi_mem_access_start(mem);
> +		if (ret)
> +			return ret;
> +
> +		ret = ctlr->mem_ops->poll_status(mem, op, mask, match,
> +						 initial_delay_us, polling_delay_us,
> +						 timeout_ms);
> +
> +		spi_mem_access_end(mem);
> +	}
> +
> +	if (ret == -EOPNOTSUPP) {
> +		if (!spi_mem_supports_op(mem, op))
> +			return ret;
> +
> +		if (initial_delay_us < 10)
> +			udelay(initial_delay_us);
> +		else
> +			usleep_range((initial_delay_us >> 2) + 1,
> +				     initial_delay_us);
> +
> +		ret = read_poll_timeout(spi_mem_read_status, read_status_ret,
> +					(read_status_ret || ((status) & mask) == match),
> +					polling_delay_us, timeout_ms * 1000, false, mem,
> +					op, &status);
> +		if (read_status_ret)
> +			return read_status_ret;
> +	}
> +
> +	return ret;
> +}