On 3/16/25 2:43 AM, Troy Mitchell wrote:
This patch introduces basic I2C support for the SpacemiT K1 SoC,
utilizing interrupts for transfers.
The driver has been tested using i2c-tools on a Bananapi-F3 board,
and basic I2C read/write operations have been confirmed to work.
Reviewed-by: Alex Elder <elder@xxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20250128-k1-maintainer-1-v1-1-e5dec4f379eb@xxxxxxxxxx [1]
Signed-off-by: Troy Mitchell <troymitchell988@xxxxxxxxx>
I know I said it was fine, but I'm going to reiterate two comments in
the probe function.
---
drivers/i2c/busses/Kconfig | 17 ++
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-k1.c | 605 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 623 insertions(+)
. . .
diff --git a/drivers/i2c/busses/i2c-k1.c b/drivers/i2c/busses/i2c-k1.c
new file mode 100644
index 0000000000000000000000000000000000000000..ae43dcd31e8aa480766b44be91656657c7aaaf4a
--- /dev/null
+++ b/drivers/i2c/busses/i2c-k1.c
@@ -0,0 +1,605 @@
. . .
+static int spacemit_i2c_probe(struct platform_device *pdev)
+{
+ struct clk *clk;
+ struct device *dev = &pdev->dev;
+ struct device_node *of_node = pdev->dev.of_node;
+ struct spacemit_i2c_dev *i2c;
+ int ret;
+
+ i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL);
+ if (!i2c)
+ return -ENOMEM;
+
+ ret = of_property_read_u32(of_node, "clock-frequency", &i2c->clock_freq);
+ if (ret)
+ dev_warn(dev, "failed to read clock-frequency property\n");
If the property doesn't exist, I don't think this warrants a warning,
because it's optional. Perhaps if a different error (something other
than -EINVAL) is returned it would warrant a warning.
+
+ /* For now, this driver doesn't support high-speed. */
+ if (!i2c->clock_freq || i2c->clock_freq < 1 ||
For an unsigned value, !i2c->clock_freq is *the same as*
i2c->clock_freq < 1. Get rid of the latter.
I'll leave it up to the maintainer to decide whether these
comments can just be ignored--my Reviewed-by is fine, even
if you don't change these.
-Alex
+ i2c->clock_freq > SPACEMIT_I2C_MAX_FAST_MODE_FREQ) {
+ dev_warn(dev, "unsupported clock frequency %u; using %u\n",
+ i2c->clock_freq, SPACEMIT_I2C_MAX_FAST_MODE_FREQ);
+ i2c->clock_freq = SPACEMIT_I2C_MAX_FAST_MODE_FREQ;
+ } else if (i2c->clock_freq < SPACEMIT_I2C_MAX_STANDARD_MODE_FREQ) {
+ dev_warn(dev, "unsupported clock frequency %u; using %u\n",
+ i2c->clock_freq, SPACEMIT_I2C_MAX_STANDARD_MODE_FREQ);
+ i2c->clock_freq = SPACEMIT_I2C_MAX_STANDARD_MODE_FREQ;
+ }
+
+ i2c->dev = &pdev->dev;
+
+ i2c->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(i2c->base))
+ return dev_err_probe(dev, PTR_ERR(i2c->base), "failed to do ioremap");
+
+ i2c->irq = platform_get_irq(pdev, 0);
+ if (i2c->irq < 0)
+ return dev_err_probe(dev, i2c->irq, "failed to get irq resource");
+
+ ret = devm_request_irq(i2c->dev, i2c->irq, spacemit_i2c_irq_handler,
+ IRQF_NO_SUSPEND | IRQF_ONESHOT, dev_name(i2c->dev), i2c);
+ if (ret)
+ return dev_err_probe(dev, ret, "failed to request irq");
+
+ clk = devm_clk_get_enabled(dev, "func");
+ if (IS_ERR(clk))
+ return dev_err_probe(dev, PTR_ERR(clk), "failed to enable func clock");
+
+ clk = devm_clk_get_enabled(dev, "bus");
+ if (IS_ERR(clk))
+ return dev_err_probe(dev, PTR_ERR(clk), "failed to enable bus clock");
+
+ spacemit_i2c_reset(i2c);
+
+ i2c_set_adapdata(&i2c->adapt, i2c);
+ i2c->adapt.owner = THIS_MODULE;
+ i2c->adapt.algo = &spacemit_i2c_algo;
+ i2c->adapt.dev.parent = i2c->dev;
+ i2c->adapt.nr = pdev->id;
+
+ i2c->adapt.dev.of_node = of_node;
+
+ strscpy(i2c->adapt.name, "spacemit-i2c-adapter", sizeof(i2c->adapt.name));
+
+ init_completion(&i2c->complete);
+
+ platform_set_drvdata(pdev, i2c);
+
+ ret = i2c_add_numbered_adapter(&i2c->adapt);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret, "failed to add i2c adapter");
+
+ return 0;
+}
+
+static void spacemit_i2c_remove(struct platform_device *pdev)
+{
+ struct spacemit_i2c_dev *i2c = platform_get_drvdata(pdev);
+
+ i2c_del_adapter(&i2c->adapt);
+}
+
+static const struct of_device_id spacemit_i2c_of_match[] = {
+ { .compatible = "spacemit,k1-i2c", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, spacemit_i2c_of_match);
+
+static struct platform_driver spacemit_i2c_driver = {
+ .probe = spacemit_i2c_probe,
+ .remove = spacemit_i2c_remove,
+ .driver = {
+ .name = "i2c-k1",
+ .of_match_table = spacemit_i2c_of_match,
+ },
+};
+module_platform_driver(spacemit_i2c_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("I2C bus driver for SpacemiT K1 SoC");
