Re: [PATCH] i2c: add support for microchip fpga i2c controllers
From: Conor Dooley
Date: Fri Mar 18 2022 - 12:15:38 EST
On 18/03/2022 14:56, Ben Dooks wrote:
On 15/03/2022 15:32, Conor Dooley wrote:
Add Microchip CoreI2C i2c controller support. This driver supports the
"hard" i2c controller on the Microchip PolarFire SoC & the basic feature
set for "soft" i2c controller implemtations in the FPGA fabric.
Co-developed-by: Daire McNamara <daire.mcnamara@xxxxxxxxxxxxx>
Signed-off-by: Daire McNamara <daire.mcnamara@xxxxxxxxxxxxx>
Signed-off-by: Conor Dooley <conor.dooley@xxxxxxxxxxxxx>
---
drivers/i2c/busses/Kconfig | 11 +
drivers/i2c/busses/Makefile | 1 +
drivers/i2c/busses/i2c-microchip-core.c | 487 ++++++++++++++++++++++++
3 files changed, 499 insertions(+)
create mode 100644 drivers/i2c/busses/i2c-microchip-core.c
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index a1bae59208e3..3d4d8e0e9de7 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -781,6 +781,17 @@ config I2C_MESON
If you say yes to this option, support will be included for the
I2C interface on the Amlogic Meson family of SoCs.
snip
+
+static void mchp_corei2c_core_disable(struct mchp_corei2c_dev *idev)
+{
+ u8 ctrl = readl(idev->base + CORE_I2C_CTRL);
+
+ ctrl &= ~CTRL_ENS1;
+ writel(ctrl, idev->base + CORE_I2C_CTRL);
+}
+
+static void mchp_corei2c_core_enable(struct mchp_corei2c_dev *idev)
+{
+ u8 ctrl = readl(idev->base + CORE_I2C_CTRL);
+
+ ctrl |= CTRL_ENS1;
+ writel(ctrl, idev->base + CORE_I2C_CTRL);
+}
Not sure why you would use readl/writel with an u8, surely an
readb/writeb be better?
Sure, can try drop it to b.
+static irqreturn_t mchp_corei2c_handle_isr(struct mchp_corei2c_dev
*idev)
+{
+ u32 status = idev->isr_status;
+ u8 ctrl;
+
+ if (!idev->buf) {
+ dev_warn(idev->dev, "unexpected interrupt\n");
+ return IRQ_HANDLED;
+ }
is IRQ_HANDLED correct here?
Hmm, the dev_warn is probably incorrect too. For the mpfs, the interrupt
line isn't shared, but the generic fabric core could be. Ill change this.
+
+static int mchp_corei2c_probe(struct platform_device *pdev)
+{
+ struct mchp_corei2c_dev *idev = NULL;
+ struct resource *res;
+ int irq, ret;
+ u32 val;
+
+ idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
+ if (!idev)
+ return -ENOMEM;
+
+ idev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
+ if (IS_ERR(idev->base))
+ return PTR_ERR(idev->base);
+
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return dev_err_probe(&pdev->dev, irq,
+ "missing interrupt resource\n");
+
+ idev->i2c_clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(idev->i2c_clk))
+ return dev_err_probe(&pdev->dev, PTR_ERR(idev->i2c_clk),
+ "missing clock\n");
+
+ idev->dev = &pdev->dev;
+ init_completion(&idev->msg_complete);
+ spin_lock_init(&idev->lock);
+
+ val = device_property_read_u32(idev->dev, "clock-frequency",
+ &idev->bus_clk_rate);
+ if (val) {
+ dev_info(&pdev->dev, "default to 100kHz\n");
+ idev->bus_clk_rate = 100000;
+ }
+
+ if (idev->bus_clk_rate > 400000)
+ return dev_err_probe(&pdev->dev, -EINVAL,
+ "clock-frequency too high: %d\n",
+ idev->bus_clk_rate);
+
+ ret = devm_request_irq(&pdev->dev, irq, mchp_corei2c_isr,
IRQF_SHARED,
+ pdev->name, idev);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to claim irq %d\n", irq);
+
+ ret = clk_prepare_enable(idev->i2c_clk);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to enable clock\n");
+
+ ret = mchp_corei2c_init(idev);
+ if (ret)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to program clock divider\n");
going to leak a prepared clock from here on?
Aye, good spot. Thanks.
+ i2c_set_adapdata(&idev->adapter, idev);
+ snprintf(idev->adapter.name, sizeof(idev->adapter.name),
+ "Microchip I2C hw bus");
+ idev->adapter.owner = THIS_MODULE;
+ idev->adapter.algo = &mchp_corei2c_algo;
+ idev->adapter.dev.parent = &pdev->dev;
+ idev->adapter.dev.of_node = pdev->dev.of_node;
+
+ platform_set_drvdata(pdev, idev);
+
+ ret = i2c_add_adapter(&idev->adapter);
+ if (ret) {
+ clk_disable_unprepare(idev->i2c_clk);
+ return ret;
+ }
+
+ dev_info(&pdev->dev, "Microchip I2C Probe Complete\n");
not sure if necessary, doesn't the i2c core also announce?
The only thing I see on boot is this, but I'll take a look and see if I
can do this via the core.
+ return 0;
+}
+
+static int mchp_corei2c_remove(struct platform_device *pdev)
+{
+ struct mchp_corei2c_dev *idev = platform_get_drvdata(pdev);
+
+ clk_disable_unprepare(idev->i2c_clk);
+ i2c_del_adapter(&idev->adapter);
+
+ return 0;
+}
+
+static const struct of_device_id mchp_corei2c_of_match[] = {
+ { .compatible = "microchip,mpfs-i2c" },
+ { .compatible = "microchip,corei2c-rtl-v7" },
+ {},
+};
+MODULE_DEVICE_TABLE(of, mchp_corei2c_of_match);
+
+static struct platform_driver mchp_corei2c_driver = {
+ .probe = mchp_corei2c_probe,
+ .remove = mchp_corei2c_remove,
+ .driver = {
+ .name = "microchip-corei2c",
+ .of_match_table = mchp_corei2c_of_match,
+ },
+};
+
+module_platform_driver(mchp_corei2c_driver);
+
+MODULE_DESCRIPTION("Microchip CoreI2C bus driver");
+MODULE_AUTHOR("Daire McNamara <daire.mcnamara@xxxxxxxxxxxxx>");
+MODULE_AUTHOR("Conor Dooley <conor.dooley@xxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL v2");