Re: [PATCH] i2c: add support for microchip fpga i2c controllers

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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");





[Index of Archives]     [Linux GPIO]     [Linux SPI]     [Linux Hardward Monitoring]     [LM Sensors]     [Linux USB Devel]     [Linux Media]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux