Hi,

On Fri, Mar 7, 2025, at 21:09, Sasha Finkelstein via B4 Relay wrote:

I'd either add a comment that these are in us or add a _US suffix

+
+struct apple_spmi {
+	void __iomem *regs;
+};
+
+#define poll_reg(spmi, reg, val, cond) \
+	readl_poll_timeout((spmi)->regs + (reg), (val), (cond), \
+			   REG_POLL_INTERVAL, REG_POLL_TIMEOUT)
+
+static inline u32 read_reg(struct apple_spmi *spmi, int offset)
+{
+	return readl(spmi->regs + offset);
+}
+
+static inline void write_reg(u32 value, struct apple_spmi *spmi, int 
offset)
+{
+	writel(value, spmi->regs + offset);
+}
+
+static inline u32 apple_spmi_pack_cmd(u8 opc, u8 sid, u16 saddr, 
size_t len)
+{
+	return opc | sid << 8 | saddr << 16 | (len - 1) | (1 << 15);
+}
+
+/* Wait for Rx FIFO to have something */
+static int apple_spmi_wait_rx_not_empty(struct spmi_controller *ctrl)
+{
+	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
+	int ret;
+	u32 status;
+
+	ret = poll_reg(spmi, SPMI_STATUS_REG, status, !(status & 
SPMI_RX_FIFO_EMPTY));
+	if (ret) {
+		dev_err(&ctrl->dev,
+			"%s: Failed to wait for RX FIFO not empty\n", __func__);

__func__ is always the same here now. I'd just drop that prefix.

With that and Alyssa's remark addressed: 

Reviewed-by: Sven Peter <redacted>

+		return ret;
+	}
+
+	return 0;
+}
+
+static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
+			 u16 saddr, u8 *buf, size_t len)
+{
+	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
+	u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
+	u32 rsp;
+	size_t len_read = 0;
+	u8 i;
+	int ret;
+
+	write_reg(spmi_cmd, spmi, SPMI_CMD_REG);
+
+	ret = apple_spmi_wait_rx_not_empty(ctrl);
+	if (ret)
+		return ret;
+
+	/* Discard SPMI reply status */
+	read_reg(spmi, SPMI_RSP_REG);
+
+	/* Read SPMI data reply */
+	while (len_read < len) {
+		rsp = read_reg(spmi, SPMI_RSP_REG);
+		i = 0;
+		while ((len_read < len) && (i < 4)) {
+			buf[len_read++] = ((0xff << (8 * i)) & rsp) >> (8 * i);
+			i += 1;
+		}
+	}
+
+	return 0;
+}
+
+static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
+			  u16 saddr, const u8 *buf, size_t len)
+{
+	struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
+	u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
+	size_t i = 0, j;
+	int ret;
+
+	write_reg(spmi_cmd, spmi, SPMI_CMD_REG);
+
+	while (i < len) {
+		j = 0;
+		spmi_cmd = 0;
+		while ((j < 4) & (i < len))
+			spmi_cmd |= buf[i++] << (j++ * 8);
+
+		write_reg(spmi_cmd, spmi, SPMI_CMD_REG);
+	}
+
+	ret = apple_spmi_wait_rx_not_empty(ctrl);
+	if (ret)
+		return ret;
+
+	/* Discard */
+	read_reg(spmi, SPMI_RSP_REG);
+
+	return 0;
+}
+
+static int apple_spmi_probe(struct platform_device *pdev)
+{
+	struct apple_spmi *spmi;
+	struct spmi_controller *ctrl;
+	int ret;
+
+	ctrl = devm_spmi_controller_alloc(&pdev->dev, sizeof(*spmi));
+	if (IS_ERR(ctrl))
+		return -ENOMEM;
+
+	spmi = spmi_controller_get_drvdata(ctrl);
+
+	spmi->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(spmi->regs))
+		return PTR_ERR(spmi->regs);
+
+	ctrl->dev.of_node = pdev->dev.of_node;
+
+	ctrl->read_cmd = spmi_read_cmd;
+	ctrl->write_cmd = spmi_write_cmd;
+
+	ret = devm_spmi_controller_add(&pdev->dev, ctrl);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "spmi_controller_add failed\n");
+
+	return 0;
+}
+
+static const struct of_device_id apple_spmi_match_table[] = {
+	{ .compatible = "apple,spmi", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, apple_spmi_match_table);
+
+static struct platform_driver apple_spmi_driver = {
+	.probe		= apple_spmi_probe,
+	.driver		= {
+		.name	= "apple-spmi",
+		.of_match_table = apple_spmi_match_table,
+	},
+};
+module_platform_driver(apple_spmi_driver);
+
+MODULE_AUTHOR("Jean-Francois Bortolotti [off-list ref]");
+MODULE_DESCRIPTION("Apple SoC SPMI driver");
+MODULE_LICENSE("GPL");

-- 
2.48.1

Sven