Date:   Fri, 14 Jul 2023 10:51:18 +0530
From:   Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>
To:     Praveen Talari <quic_ptalari@...cinc.com>, <agross@...nel.org>,
        <andersson@...nel.org>, <konrad.dybcio@...aro.org>,
        <broonie@...nel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-spi@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC:     <quic_msavaliy@...cinc.com>, <quic_vtanuku@...cinc.com>,
        <quic_arandive@...cinc.com>
Subject: Re: [PATCH v7 2/2] spi: spi-geni-qcom: Add SPI Device mode support
 for GENI based QuPv3

Hi,

With no knowledge of spi slave setup, I should say this looks good to me.

A few nits below which can be added in if there is going to be a v8, 
otherwise can be done later...



On 7/14/2023 9:52 AM, Praveen Talari wrote:
> Currently spi geni driver supports only master mode operation.
>
> Add spi device mode support to GENI based QuPv3.
>
> Signed-off-by: Praveen Talari <quic_ptalari@...cinc.com>
> ---
> v6 -> v7:
> - corrected author mail
>
> v4 -> v5:
> - added code comments
> - dropped get_spi_master api.
>
> v3 -> v4:
> - Used existing property spi-slave.
>
> v2 -> v3:
> - modified commit message to use device mode instead of slave mode
>
> v1 -> v2
> - modified the commit message
> - added the code changes for code comments
> ---
>   drivers/spi/spi-geni-qcom.c | 53 ++++++++++++++++++++++++++++++++-----
>   1 file changed, 47 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/spi/spi-geni-qcom.c b/drivers/spi/spi-geni-qcom.c
> index 206cc04bb1ed..06b114f3f21a 100644
> --- a/drivers/spi/spi-geni-qcom.c
> +++ b/drivers/spi/spi-geni-qcom.c
> @@ -12,6 +12,7 @@
>   #include <linux/platform_device.h>
>   #include <linux/pm_opp.h>
>   #include <linux/pm_runtime.h>
> +#include <linux/property.h>
>   #include <linux/soc/qcom/geni-se.h>
>   #include <linux/spi/spi.h>
>   #include <linux/spinlock.h>
> @@ -52,6 +53,9 @@
>   #define SPI_CS_CLK_DELAY_MSK		GENMASK(19, 10)
>   #define SPI_CS_CLK_DELAY_SHFT		10
>   
> +#define SE_SPI_SLAVE_EN				(0x2BC)
> +#define SPI_SLAVE_EN				BIT(0)
> +

perhaps correct indentation here?

please check in an editor which uses correct number of spaces for a tab

>   /* M_CMD OP codes for SPI */
>   #define SPI_TX_ONLY		1
>   #define SPI_RX_ONLY		2
> @@ -99,6 +103,16 @@ struct spi_geni_master {
>   	int cur_xfer_mode;
>   };
>   
> +static void spi_slv_setup(struct spi_geni_master *mas)
> +{
> +	struct geni_se *se = &mas->se;
> +
> +	writel(SPI_SLAVE_EN, se->base + SE_SPI_SLAVE_EN);
> +	writel(GENI_IO_MUX_0_EN, se->base + GENI_OUTPUT_CTRL);
> +	writel(START_TRIGGER, se->base + SE_GENI_CFG_SEQ_START);
> +	dev_dbg(mas->dev, "spi slave setup done\n");
> +}
> +
>   static int get_spi_clk_cfg(unsigned int speed_hz,
>   			struct spi_geni_master *mas,
>   			unsigned int *clk_idx,
> @@ -140,12 +154,22 @@ static void handle_se_timeout(struct spi_master *spi,
>   	const struct spi_transfer *xfer;
>   
>   	spin_lock_irq(&mas->lock);
> -	reinit_completion(&mas->cancel_done);

good to see reinit moved to after newly added goto

>   	if (mas->cur_xfer_mode == GENI_SE_FIFO)
>   		writel(0, se->base + SE_GENI_TX_WATERMARK_REG);
>   
>   	xfer = mas->cur_xfer;
>   	mas->cur_xfer = NULL;
> +
> +	if (spi->slave) {
> +		/*
> +		 * skip CMD Cancel sequnece since spi slave
> +		 * doesn`t support CMD Cancel sequnece

typo for sequence in 2 lines.

Or better, a more concise comment...

/* spi slave doesnt support CMD_CANCEL sequence */

> +		 */
> +		spin_unlock_irq(&mas->lock);
> +		goto unmap_if_dma;
> +	}
> +
> +	reinit_completion(&mas->cancel_done);
>   	geni_se_cancel_m_cmd(se);
>   	spin_unlock_irq(&mas->lock);
>   
> @@ -542,6 +566,10 @@ static bool geni_can_dma(struct spi_controller *ctlr,
>   	if (mas->cur_xfer_mode == GENI_GPI_DMA)
>   		return true;
>   
> +	/* Set SE DMA mode for SPI slave. */
> +	if (ctlr->slave)
> +		return true;
> +
>   	len = get_xfer_len_in_words(xfer, mas);
>   	fifo_size = mas->tx_fifo_depth * mas->fifo_width_bits / mas->cur_bits_per_word;
>   
> @@ -619,6 +647,7 @@ static void spi_geni_release_dma_chan(struct spi_geni_master *mas)
>   
>   static int spi_geni_init(struct spi_geni_master *mas)
>   {
> +	struct spi_master *spi = dev_get_drvdata(mas->dev);
>   	struct geni_se *se = &mas->se;
>   	unsigned int proto, major, minor, ver;
>   	u32 spi_tx_cfg, fifo_disable;
> @@ -627,7 +656,14 @@ static int spi_geni_init(struct spi_geni_master *mas)
>   	pm_runtime_get_sync(mas->dev);
>   
>   	proto = geni_se_read_proto(se);
> -	if (proto != GENI_SE_SPI) {
> +
> +	if (spi->slave) {
> +		if (proto != GENI_SE_SPI_SLAVE) {
> +			dev_err(mas->dev, "Invalid proto %d\n", proto);
> +			goto out_pm;
> +		}
> +		spi_slv_setup(mas);
> +	} else if (proto != GENI_SE_SPI) {
>   		dev_err(mas->dev, "Invalid proto %d\n", proto);
>   		goto out_pm;
>   	}
> @@ -677,9 +713,11 @@ static int spi_geni_init(struct spi_geni_master *mas)
>   	}
>   
>   	/* We always control CS manually */
> -	spi_tx_cfg = readl(se->base + SE_SPI_TRANS_CFG);
> -	spi_tx_cfg &= ~CS_TOGGLE;
> -	writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);
> +	if (!spi->slave) {
> +		spi_tx_cfg = readl(se->base + SE_SPI_TRANS_CFG);
> +		spi_tx_cfg &= ~CS_TOGGLE;
> +		writel(spi_tx_cfg, se->base + SE_SPI_TRANS_CFG);
> +	}
>   
>   out_pm:
>   	pm_runtime_put(mas->dev);
> @@ -1072,6 +1110,9 @@ static int spi_geni_probe(struct platform_device *pdev)
>   	pm_runtime_set_autosuspend_delay(&pdev->dev, 250);
>   	pm_runtime_enable(dev);
>   
> +	if (device_property_read_bool(&pdev->dev, "spi-slave"))
> +		spi->slave = true;
> +
>   	ret = geni_icc_get(&mas->se, NULL);
>   	if (ret)
>   		goto spi_geni_probe_runtime_disable;
> @@ -1092,7 +1133,7 @@ static int spi_geni_probe(struct platform_device *pdev)
>   	 * for dma (gsi) mode, the gsi will set cs based on params passed in
>   	 * TRE
>   	 */
> -	if (mas->cur_xfer_mode == GENI_SE_FIFO)
> +	if (!spi->slave && mas->cur_xfer_mode == GENI_SE_FIFO)
>   		spi->set_cs = spi_geni_set_cs;
>   
>   	ret = request_irq(mas->irq, geni_spi_isr, 0, dev_name(dev), spi);

Thank you...

-Vijay/

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