WIP: spi: rockchip: Support atomic transfers

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>

drivers/spi/spi-rockchip.c

@@ -379,6 +379,26 @@ static irqreturn_t rockchip_spi_isr(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static void rockchip_spi_poll_completion(struct rockchip_spi *rs,
+					 struct spi_controller *ctlr,
+					 unsigned int timeout_ms)
+{
+	ktime_t ktime = ktime_get();
+	ktime_t ktimeout = ktime_add_ms(ktime, timeout_ms);
+
+	do {
+		rockchip_spi_isr(0, ctlr);
+
+		if (completion_done(&ctlr->xfer_completion))
+			return;
+
+		ktime = ktime_get();
+
+	} while (ktime_before(ktime, ktimeout));
+
+	dev_err(rs->dev, "atomic transfer timeout\n");
+}
+
 static int rockchip_spi_prepare_irq(struct rockchip_spi *rs,
 				    struct spi_controller *ctlr,
 				    struct spi_transfer *xfer)
@@ -400,6 +420,11 @@ static int rockchip_spi_prepare_irq(struct rockchip_spi *rs,
 	else
 		writel_relaxed(INT_RF_FULL, rs->regs + ROCKCHIP_SPI_IMR);
 
+	if (ctlr->atomic_xfer) {
+		rockchip_spi_poll_completion(rs, ctlr, 1000);
+		return 0;
+	}
+
 	/* 1 means the transfer is in progress */
 	return 1;
 }
@@ -677,7 +702,7 @@ static int rockchip_spi_transfer_one(
 {
 	struct rockchip_spi *rs = spi_controller_get_devdata(ctlr);
 	int ret;
-	bool use_dma;
+	bool use_dma = false;
 
 	/* Zero length transfers won't trigger an interrupt on completion */
 	if (!xfer->len) {
@@ -700,6 +725,8 @@ static int rockchip_spi_transfer_one(
 
 	rs->n_bytes = xfer->bits_per_word <= 8 ? 1 : 2;
 	rs->xfer = xfer;
+
+	if (!ctlr->atomic_xfer)
 		use_dma = ctlr->can_dma ? ctlr->can_dma(ctlr, spi, xfer) : false;
 
 	ret = rockchip_spi_config(rs, spi, xfer, use_dma, ctlr->target);
@@ -1015,6 +1042,11 @@ static int rockchip_spi_runtime_resume(struct device *dev)
 }
 #endif /* CONFIG_PM */
 
+static void rockchip_spi_shutdown(struct platform_device *pdev)
+{
+	pm_runtime_get_sync(&pdev->dev);
+}
+
 static const struct dev_pm_ops rockchip_spi_pm = {
 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(rockchip_spi_suspend, rockchip_spi_resume)
 	SET_RUNTIME_PM_OPS(rockchip_spi_runtime_suspend,
@@ -1046,6 +1078,7 @@ static struct platform_driver rockchip_spi_driver = {
 	},
 	.probe = rockchip_spi_probe,
 	.remove = rockchip_spi_remove,
+	.shutdown = rockchip_spi_shutdown,
 };
 
 module_platform_driver(rockchip_spi_driver);

[Sebastian Reichel]

I suppose this is a hack to ensure that the SPI controller is runtime PM enabled when the PMIC wants to do the shutdown? In that case maybe the poweroff prepare handler should be used instead to avoid doing this on rockchip boards not using SPI PMIC for shutdown (i.e. anything that is not RK3588)?