[PATCH v4 0/2] mmc: Add support for the ASPEED SD controller

[PATCH v4 0/2] mmc: Add support for the ASPEED SD controller

[Andrew Jeffery]

Hello,

v4 of the ASPEED SDHCI driver addresses Rob's comments on the binding, making
it utilise the new mmc-controller schema and describing the sdhci,auto-cmd12
property.

v3 can be found here:

http://patchwork.ozlabs.org/cover/1138793/

Please review!

Andrew

Andrew Jeffery (2):
  dt-bindings: mmc: Document Aspeed SD controller
  mmc: Add support for the ASPEED SD controller

 .../devicetree/bindings/mmc/aspeed,sdhci.yaml | 105 ++++++
 drivers/mmc/host/Kconfig                      |  12 +
 drivers/mmc/host/Makefile                     |   1 +
 drivers/mmc/host/sdhci-of-aspeed.c            | 328 ++++++++++++++++++
 4 files changed, 446 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
 create mode 100644 drivers/mmc/host/sdhci-of-aspeed.c

-- 
2.20.1

[PATCH v4 1/2] dt-bindings: mmc: Document Aspeed SD controller

[Andrew Jeffery]

The ASPEED SD/SDIO/MMC controller exposes two slots implementing the
SDIO Host Specification v2.00, with 1 or 4 bit data buses, or an 8 bit
data bus if only a single slot is enabled.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>

---
v3:
* Make use of mmc-controller.yaml
* Document sdhci,auto-cmd12

v2:
* Fix compatible enums
* Add AST2600 compatibles
* Describe #address-cells / #size-cells
---
 .../devicetree/bindings/mmc/aspeed,sdhci.yaml | 105 ++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml

diff --git a/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml b/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
new file mode 100644
index 000000000000..ca8684f47962
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
@@ -0,0 +1,105 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mmc/aspeed,sdhci.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ASPEED SD/SDIO/eMMC Controller
+
+maintainers:
+  - Andrew Jeffery <andrew@aj.id.au>
+  - Ryan Chen <ryanchen.aspeed@gmail.com>
+
+description: |+
+  The ASPEED SD/SDIO/eMMC controller exposes two slots implementing the SDIO
+  Host Specification v2.00, with 1 or 4 bit data buses, or an 8 bit data bus if
+  only a single slot is enabled.
+
+  The two slots are supported by a common configuration area. As the SDHCIs for
+  the slots are dependent on the common configuration area, they are described
+  as child nodes.
+
+properties:
+  compatible:
+    enum:
+      - aspeed,ast2400-sd-controller
+      - aspeed,ast2500-sd-controller
+      - aspeed,ast2600-sd-controller
+  reg:
+    maxItems: 1
+    description: Common configuration registers
+  "#address-cells":
+    const: 1
+  "#size-cells":
+    const: 1
+  ranges: true
+  clocks:
+    maxItems: 1
+    description: The SD/SDIO controller clock gate
+
+patternProperties:
+  "^sdhci@[0-9a-f]+$":
+    type: object
+    allOf:
+        - $ref: mmc-controller.yaml
+    properties:
+      compatible:
+        enum:
+          - aspeed,ast2400-sdhci
+          - aspeed,ast2500-sdhci
+          - aspeed,ast2600-sdhci
+      reg:
+        maxItems: 1
+        description: The SDHCI registers
+      clocks:
+        maxItems: 1
+        description: The SD bus clock
+      interrupts:
+        maxItems: 1
+        description: The SD interrupt shared between both slots
+      sdhci,auto-cmd12:
+        type: boolean
+        description: Specifies that controller should use auto CMD12
+    required:
+      - compatible
+      - reg
+      - clocks
+      - interrupts
+
+additionalProperties: false
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+  - ranges
+  - clocks
+
+examples:
+  - |
+    #include <dt-bindings/clock/aspeed-clock.h>
+    sdc@1e740000 {
+            compatible = "aspeed,ast2500-sd-controller";
+            reg = <0x1e740000 0x100>;
+            #address-cells = <1>;
+            #size-cells = <1>;
+            ranges = <0 0x1e740000 0x10000>;
+            clocks = <&syscon ASPEED_CLK_GATE_SDCLK>;
+
+            sdhci0: sdhci@100 {
+                    compatible = "aspeed,ast2500-sdhci";
+                    reg = <0x100 0x100>;
+                    interrupts = <26>;
+                    sdhci,auto-cmd12;
+                    clocks = <&syscon ASPEED_CLK_SDIO>;
+            };
+
+            sdhci1: sdhci@200 {
+                    compatible = "aspeed,ast2500-sdhci";
+                    reg = <0x200 0x100>;
+                    interrupts = <26>;
+                    sdhci,auto-cmd12;
+                    clocks = <&syscon ASPEED_CLK_SDIO>;
+            };
+    };
-- 
2.20.1

[PATCH v4 2/2] mmc: Add support for the ASPEED SD controller

[Andrew Jeffery]

Add a minimal driver for ASPEED's SD controller, which exposes two
SDHCIs.

The ASPEED design implements a common register set for the SDHCIs, and
moves some of the standard configuration elements out to this common
area (e.g. 8-bit mode, and card detect configuration which is not
currently supported).

The SD controller has a dedicated hardware interrupt that is shared
between the slots. The common register set exposes information on which
slot triggered the interrupt; early revisions of the patch introduced an
irqchip for the register, but reality is it doesn't behave as an
irqchip, and the result fits awkwardly into the irqchip APIs. Instead
I've taken the simple approach of using the IRQ as a shared IRQ with
some minor performance impact for the second slot.

Ryan was the original author of the patch - I've taken his work and
massaged it to drop the irqchip support and rework the devicetree
integration. The driver has been smoke tested under qemu against a
minimal SD controller model and lightly tested on an ast2500-evb.

Signed-off-by: Ryan Chen <ryanchen.aspeed@gmail.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>

---
v3: No change
v2:
* Add AST2600 compatible
* Drop SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN
* Ensure slot number is valid
* Fix build with CONFIG_MODULES
* Fix module license string
* Non-PCI devices won't die
* Rename aspeed_sdc_configure_8bit_mode()
* Rename aspeed_sdhci_pdata
* Switch to sdhci_enable_clk()
* Use PTR_ERR() on the right `struct platform_device *`
---
 drivers/mmc/host/Kconfig           |  12 ++
 drivers/mmc/host/Makefile          |   1 +
 drivers/mmc/host/sdhci-of-aspeed.c | 328 +++++++++++++++++++++++++++++
 3 files changed, 341 insertions(+)
 create mode 100644 drivers/mmc/host/sdhci-of-aspeed.c

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 14d89a108edd..0f8a230de2f3 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -154,6 +154,18 @@ config MMC_SDHCI_OF_ARASAN
 
 	  If unsure, say N.
 
+config MMC_SDHCI_OF_ASPEED
+	tristate "SDHCI OF support for the ASPEED SDHCI controller"
+	depends on MMC_SDHCI_PLTFM
+	depends on OF
+	help
+	  This selects the ASPEED Secure Digital Host Controller Interface.
+
+	  If you have a controller with this interface, say Y or M here. You
+	  also need to enable an appropriate bus interface.
+
+	  If unsure, say N.
+
 config MMC_SDHCI_OF_AT91
 	tristate "SDHCI OF support for the Atmel SDMMC controller"
 	depends on MMC_SDHCI_PLTFM
diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
index 73578718f119..390ee162fe71 100644
--- a/drivers/mmc/host/Makefile
+++ b/drivers/mmc/host/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_MMC_SDHCI_ESDHC_IMX)	+= sdhci-esdhc-imx.o
 obj-$(CONFIG_MMC_SDHCI_DOVE)		+= sdhci-dove.o
 obj-$(CONFIG_MMC_SDHCI_TEGRA)		+= sdhci-tegra.o
 obj-$(CONFIG_MMC_SDHCI_OF_ARASAN)	+= sdhci-of-arasan.o
+obj-$(CONFIG_MMC_SDHCI_OF_ASPEED)	+= sdhci-of-aspeed.o
 obj-$(CONFIG_MMC_SDHCI_OF_AT91)		+= sdhci-of-at91.o
 obj-$(CONFIG_MMC_SDHCI_OF_ESDHC)	+= sdhci-of-esdhc.o
 obj-$(CONFIG_MMC_SDHCI_OF_HLWD)		+= sdhci-of-hlwd.o
diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
new file mode 100644
index 000000000000..d31785ec90d7
--- /dev/null
+++ b/drivers/mmc/host/sdhci-of-aspeed.c
@@ -0,0 +1,328 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Copyright (C) 2019 ASPEED Technology Inc. */
+/* Copyright (C) 2019 IBM Corp. */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/io.h>
+#include <linux/mmc/host.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+
+#include "sdhci-pltfm.h"
+
+#define ASPEED_SDC_INFO		0x00
+#define   ASPEED_SDC_S1MMC8	BIT(25)
+#define   ASPEED_SDC_S0MMC8	BIT(24)
+
+struct aspeed_sdc {
+	struct clk *clk;
+	struct resource *res;
+
+	spinlock_t lock;
+	void __iomem *regs;
+};
+
+struct aspeed_sdhci {
+	struct aspeed_sdc *parent;
+	u32 width_mask;
+};
+
+static void aspeed_sdc_configure_8bit_mode(struct aspeed_sdc *sdc,
+					   struct aspeed_sdhci *sdhci,
+					   bool bus8)
+{
+	u32 info;
+
+	/* Set/clear 8 bit mode */
+	spin_lock(&sdc->lock);
+	info = readl(sdc->regs + ASPEED_SDC_INFO);
+	if (bus8)
+		info |= sdhci->width_mask;
+	else
+		info &= ~sdhci->width_mask;
+	writel(info, sdc->regs + ASPEED_SDC_INFO);
+	spin_unlock(&sdc->lock);
+}
+
+static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
+{
+	int div;
+	u16 clk;
+
+	if (clock == host->clock)
+		return;
+
+	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
+
+	if (clock == 0)
+		goto out;
+
+	for (div = 1; div < 256; div *= 2) {
+		if ((host->max_clk / div) <= clock)
+			break;
+	}
+	div >>= 1;
+
+	clk = div << SDHCI_DIVIDER_SHIFT;
+
+	sdhci_enable_clk(host, clk);
+
+out:
+	host->clock = clock;
+}
+
+static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)
+{
+	struct sdhci_pltfm_host *pltfm_priv;
+	struct aspeed_sdhci *aspeed_sdhci;
+	struct aspeed_sdc *aspeed_sdc;
+	u8 ctrl;
+
+	pltfm_priv = sdhci_priv(host);
+	aspeed_sdhci = sdhci_pltfm_priv(pltfm_priv);
+	aspeed_sdc = aspeed_sdhci->parent;
+
+	/* Set/clear 8-bit mode */
+	aspeed_sdc_configure_8bit_mode(aspeed_sdc, aspeed_sdhci,
+				       width == MMC_BUS_WIDTH_8);
+
+	/* Set/clear 1 or 4 bit mode */
+	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
+	if (width == MMC_BUS_WIDTH_4)
+		ctrl |= SDHCI_CTRL_4BITBUS;
+	else
+		ctrl &= ~SDHCI_CTRL_4BITBUS;
+	sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
+}
+
+static const struct sdhci_ops aspeed_sdhci_ops = {
+	.set_clock = aspeed_sdhci_set_clock,
+	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
+	.set_bus_width = aspeed_sdhci_set_bus_width,
+	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
+	.reset = sdhci_reset,
+	.set_uhs_signaling = sdhci_set_uhs_signaling,
+};
+
+static const struct sdhci_pltfm_data aspeed_sdhci_pdata = {
+	.ops = &aspeed_sdhci_ops,
+	.quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
+};
+
+static inline int aspeed_sdhci_calculate_slot(struct aspeed_sdhci *dev,
+					      struct resource *res)
+{
+	resource_size_t delta;
+
+	if (!res || resource_type(res) != IORESOURCE_MEM)
+		return -EINVAL;
+
+	if (res->start < dev->parent->res->start)
+		return -EINVAL;
+
+	delta = res->start - dev->parent->res->start;
+	if (delta & (0x100 - 1))
+		return -EINVAL;
+
+	return (delta / 0x100) - 1;
+}
+
+static int aspeed_sdhci_probe(struct platform_device *pdev)
+{
+	struct sdhci_pltfm_host *pltfm_host;
+	struct aspeed_sdhci *dev;
+	struct sdhci_host *host;
+	struct resource *res;
+	int slot;
+	int ret;
+
+	host = sdhci_pltfm_init(pdev, &aspeed_sdhci_pdata, sizeof(*dev));
+	if (IS_ERR(host))
+		return PTR_ERR(host);
+
+	pltfm_host = sdhci_priv(host);
+	dev = sdhci_pltfm_priv(pltfm_host);
+	dev->parent = dev_get_drvdata(pdev->dev.parent);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	slot = aspeed_sdhci_calculate_slot(dev, res);
+
+	if (slot < 0)
+		return slot;
+	else if (slot >= 2)
+		return -EINVAL;
+
+	dev_info(&pdev->dev, "Configuring for slot %d\n", slot);
+	dev->width_mask = !slot ? ASPEED_SDC_S0MMC8 : ASPEED_SDC_S1MMC8;
+
+	sdhci_get_of_property(pdev);
+
+	pltfm_host->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(pltfm_host->clk))
+		return PTR_ERR(pltfm_host->clk);
+
+	ret = clk_prepare_enable(pltfm_host->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to enable SDIO clock\n");
+		goto err_pltfm_free;
+	}
+
+	ret = mmc_of_parse(host->mmc);
+	if (ret)
+		goto err_sdhci_add;
+
+	ret = sdhci_add_host(host);
+	if (ret)
+		goto err_sdhci_add;
+
+	return 0;
+
+err_sdhci_add:
+	clk_disable_unprepare(pltfm_host->clk);
+err_pltfm_free:
+	sdhci_pltfm_free(pdev);
+	return ret;
+}
+
+static int aspeed_sdhci_remove(struct platform_device *pdev)
+{
+	struct sdhci_pltfm_host *pltfm_host;
+	struct sdhci_host *host;
+	int dead = 0;
+
+	host = platform_get_drvdata(pdev);
+	pltfm_host = sdhci_priv(host);
+
+	sdhci_remove_host(host, dead);
+
+	clk_disable_unprepare(pltfm_host->clk);
+
+	sdhci_pltfm_free(pdev);
+
+	return 0;
+}
+
+static const struct of_device_id aspeed_sdhci_of_match[] = {
+	{ .compatible = "aspeed,ast2400-sdhci", },
+	{ .compatible = "aspeed,ast2500-sdhci", },
+	{ .compatible = "aspeed,ast2600-sdhci", },
+	{ }
+};
+
+static struct platform_driver aspeed_sdhci_driver = {
+	.driver		= {
+		.name	= "sdhci-aspeed",
+		.of_match_table = aspeed_sdhci_of_match,
+	},
+	.probe		= aspeed_sdhci_probe,
+	.remove		= aspeed_sdhci_remove,
+};
+
+static int aspeed_sdc_probe(struct platform_device *pdev)
+
+{
+	struct device_node *parent, *child;
+	struct aspeed_sdc *sdc;
+	int ret;
+
+	sdc = devm_kzalloc(&pdev->dev, sizeof(*sdc), GFP_KERNEL);
+	if (!sdc)
+		return -ENOMEM;
+
+	spin_lock_init(&sdc->lock);
+
+	sdc->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(sdc->clk))
+		return PTR_ERR(sdc->clk);
+
+	ret = clk_prepare_enable(sdc->clk);
+	if (ret) {
+		dev_err(&pdev->dev, "Unable to enable SDCLK\n");
+		return ret;
+	}
+
+	sdc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	sdc->regs = devm_ioremap_resource(&pdev->dev, sdc->res);
+	if (IS_ERR(sdc->regs)) {
+		ret = PTR_ERR(sdc->regs);
+		goto err_clk;
+	}
+
+	dev_set_drvdata(&pdev->dev, sdc);
+
+	parent = pdev->dev.of_node;
+	for_each_available_child_of_node(parent, child) {
+		struct platform_device *cpdev;
+
+		cpdev = of_platform_device_create(child, NULL, &pdev->dev);
+		if (IS_ERR(cpdev)) {
+			of_node_put(child);
+			ret = PTR_ERR(cpdev);
+			goto err_clk;
+		}
+	}
+
+	return 0;
+
+err_clk:
+	clk_disable_unprepare(sdc->clk);
+	return ret;
+}
+
+static int aspeed_sdc_remove(struct platform_device *pdev)
+{
+	struct aspeed_sdc *sdc = dev_get_drvdata(&pdev->dev);
+
+	clk_disable_unprepare(sdc->clk);
+
+	return 0;
+}
+
+static const struct of_device_id aspeed_sdc_of_match[] = {
+	{ .compatible = "aspeed,ast2400-sd-controller", },
+	{ .compatible = "aspeed,ast2500-sd-controller", },
+	{ .compatible = "aspeed,ast2600-sd-controller", },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, aspeed_sdc_of_match);
+
+static struct platform_driver aspeed_sdc_driver = {
+	.driver		= {
+		.name	= "sd-controller-aspeed",
+		.pm	= &sdhci_pltfm_pmops,
+		.of_match_table = aspeed_sdc_of_match,
+	},
+	.probe		= aspeed_sdc_probe,
+	.remove		= aspeed_sdc_remove,
+};
+
+static int __init aspeed_sdc_init(void)
+{
+	int rc;
+
+	rc = platform_driver_register(&aspeed_sdhci_driver);
+	if (rc < 0)
+		return rc;
+
+	return platform_driver_register(&aspeed_sdc_driver);
+}
+module_init(aspeed_sdc_init);
+
+static void __exit aspeed_sdc_exit(void)
+{
+	platform_driver_unregister(&aspeed_sdc_driver);
+	platform_driver_unregister(&aspeed_sdhci_driver);
+}
+module_exit(aspeed_sdc_exit);
+
+MODULE_DESCRIPTION("Driver for the ASPEED SD/SDIO/SDHCI Controllers");
+MODULE_AUTHOR("Ryan Chen <ryan_chen@aspeedtech.com>");
+MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
+MODULE_LICENSE("GPL");
-- 
2.20.1

Re: [PATCH v4 2/2] mmc: Add support for the ASPEED SD controller

[Adrian Hunter]

On 5/08/19 5:51 AM, Andrew Jeffery wrote:
> Add a minimal driver for ASPEED's SD controller, which exposes two
> SDHCIs.
> 
> The ASPEED design implements a common register set for the SDHCIs, and
> moves some of the standard configuration elements out to this common
> area (e.g. 8-bit mode, and card detect configuration which is not
> currently supported).
> 
> The SD controller has a dedicated hardware interrupt that is shared
> between the slots. The common register set exposes information on which
> slot triggered the interrupt; early revisions of the patch introduced an
> irqchip for the register, but reality is it doesn't behave as an
> irqchip, and the result fits awkwardly into the irqchip APIs. Instead
> I've taken the simple approach of using the IRQ as a shared IRQ with
> some minor performance impact for the second slot.
> 
> Ryan was the original author of the patch - I've taken his work and
> massaged it to drop the irqchip support and rework the devicetree
> integration. The driver has been smoke tested under qemu against a
> minimal SD controller model and lightly tested on an ast2500-evb.
> 
> Signed-off-by: Ryan Chen <ryanchen.aspeed@gmail.com>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>

One minor comment otherwise:

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> 
> ---
> v3: No change
> v2:
> * Add AST2600 compatible
> * Drop SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN
> * Ensure slot number is valid
> * Fix build with CONFIG_MODULES
> * Fix module license string
> * Non-PCI devices won't die
> * Rename aspeed_sdc_configure_8bit_mode()
> * Rename aspeed_sdhci_pdata
> * Switch to sdhci_enable_clk()
> * Use PTR_ERR() on the right `struct platform_device *`
> ---
>  drivers/mmc/host/Kconfig           |  12 ++
>  drivers/mmc/host/Makefile          |   1 +
>  drivers/mmc/host/sdhci-of-aspeed.c | 328 +++++++++++++++++++++++++++++
>  3 files changed, 341 insertions(+)
>  create mode 100644 drivers/mmc/host/sdhci-of-aspeed.c
> 
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 14d89a108edd..0f8a230de2f3 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -154,6 +154,18 @@ config MMC_SDHCI_OF_ARASAN
>  
>  	  If unsure, say N.
>  
> +config MMC_SDHCI_OF_ASPEED
> +	tristate "SDHCI OF support for the ASPEED SDHCI controller"
> +	depends on MMC_SDHCI_PLTFM
> +	depends on OF
> +	help
> +	  This selects the ASPEED Secure Digital Host Controller Interface.
> +
> +	  If you have a controller with this interface, say Y or M here. You
> +	  also need to enable an appropriate bus interface.
> +
> +	  If unsure, say N.
> +
>  config MMC_SDHCI_OF_AT91
>  	tristate "SDHCI OF support for the Atmel SDMMC controller"
>  	depends on MMC_SDHCI_PLTFM
> diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> index 73578718f119..390ee162fe71 100644
> --- a/drivers/mmc/host/Makefile
> +++ b/drivers/mmc/host/Makefile
> @@ -84,6 +84,7 @@ obj-$(CONFIG_MMC_SDHCI_ESDHC_IMX)	+= sdhci-esdhc-imx.o
>  obj-$(CONFIG_MMC_SDHCI_DOVE)		+= sdhci-dove.o
>  obj-$(CONFIG_MMC_SDHCI_TEGRA)		+= sdhci-tegra.o
>  obj-$(CONFIG_MMC_SDHCI_OF_ARASAN)	+= sdhci-of-arasan.o
> +obj-$(CONFIG_MMC_SDHCI_OF_ASPEED)	+= sdhci-of-aspeed.o
>  obj-$(CONFIG_MMC_SDHCI_OF_AT91)		+= sdhci-of-at91.o
>  obj-$(CONFIG_MMC_SDHCI_OF_ESDHC)	+= sdhci-of-esdhc.o
>  obj-$(CONFIG_MMC_SDHCI_OF_HLWD)		+= sdhci-of-hlwd.o
> diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
> new file mode 100644
> index 000000000000..d31785ec90d7
> --- /dev/null
> +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> @@ -0,0 +1,328 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/* Copyright (C) 2019 ASPEED Technology Inc. */
> +/* Copyright (C) 2019 IBM Corp. */
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/io.h>
> +#include <linux/mmc/host.h>
> +#include <linux/module.h>
> +#include <linux/of_address.h>
> +#include <linux/of.h>
> +#include <linux/of_platform.h>
> +#include <linux/platform_device.h>
> +#include <linux/spinlock.h>
> +
> +#include "sdhci-pltfm.h"
> +
> +#define ASPEED_SDC_INFO		0x00
> +#define   ASPEED_SDC_S1MMC8	BIT(25)
> +#define   ASPEED_SDC_S0MMC8	BIT(24)
> +
> +struct aspeed_sdc {
> +	struct clk *clk;
> +	struct resource *res;
> +
> +	spinlock_t lock;
> +	void __iomem *regs;
> +};
> +
> +struct aspeed_sdhci {
> +	struct aspeed_sdc *parent;
> +	u32 width_mask;
> +};
> +
> +static void aspeed_sdc_configure_8bit_mode(struct aspeed_sdc *sdc,
> +					   struct aspeed_sdhci *sdhci,
> +					   bool bus8)
> +{
> +	u32 info;
> +
> +	/* Set/clear 8 bit mode */
> +	spin_lock(&sdc->lock);
> +	info = readl(sdc->regs + ASPEED_SDC_INFO);
> +	if (bus8)
> +		info |= sdhci->width_mask;
> +	else
> +		info &= ~sdhci->width_mask;
> +	writel(info, sdc->regs + ASPEED_SDC_INFO);
> +	spin_unlock(&sdc->lock);
> +}
> +
> +static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> +{
> +	int div;
> +	u16 clk;
> +
> +	if (clock == host->clock)
> +		return;
> +
> +	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> +
> +	if (clock == 0)
> +		goto out;
> +
> +	for (div = 1; div < 256; div *= 2) {
> +		if ((host->max_clk / div) <= clock)
> +			break;
> +	}
> +	div >>= 1;
> +
> +	clk = div << SDHCI_DIVIDER_SHIFT;
> +
> +	sdhci_enable_clk(host, clk);
> +
> +out:
> +	host->clock = clock;
> +}
> +
> +static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)
> +{
> +	struct sdhci_pltfm_host *pltfm_priv;
> +	struct aspeed_sdhci *aspeed_sdhci;
> +	struct aspeed_sdc *aspeed_sdc;
> +	u8 ctrl;
> +
> +	pltfm_priv = sdhci_priv(host);
> +	aspeed_sdhci = sdhci_pltfm_priv(pltfm_priv);
> +	aspeed_sdc = aspeed_sdhci->parent;
> +
> +	/* Set/clear 8-bit mode */
> +	aspeed_sdc_configure_8bit_mode(aspeed_sdc, aspeed_sdhci,
> +				       width == MMC_BUS_WIDTH_8);
> +
> +	/* Set/clear 1 or 4 bit mode */
> +	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
> +	if (width == MMC_BUS_WIDTH_4)
> +		ctrl |= SDHCI_CTRL_4BITBUS;
> +	else
> +		ctrl &= ~SDHCI_CTRL_4BITBUS;
> +	sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> +}
> +
> +static const struct sdhci_ops aspeed_sdhci_ops = {
> +	.set_clock = aspeed_sdhci_set_clock,
> +	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
> +	.set_bus_width = aspeed_sdhci_set_bus_width,
> +	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
> +	.reset = sdhci_reset,
> +	.set_uhs_signaling = sdhci_set_uhs_signaling,
> +};
> +
> +static const struct sdhci_pltfm_data aspeed_sdhci_pdata = {
> +	.ops = &aspeed_sdhci_ops,
> +	.quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
> +};
> +
> +static inline int aspeed_sdhci_calculate_slot(struct aspeed_sdhci *dev,
> +					      struct resource *res)
> +{
> +	resource_size_t delta;
> +
> +	if (!res || resource_type(res) != IORESOURCE_MEM)
> +		return -EINVAL;
> +
> +	if (res->start < dev->parent->res->start)
> +		return -EINVAL;
> +
> +	delta = res->start - dev->parent->res->start;
> +	if (delta & (0x100 - 1))
> +		return -EINVAL;
> +
> +	return (delta / 0x100) - 1;
> +}
> +
> +static int aspeed_sdhci_probe(struct platform_device *pdev)
> +{
> +	struct sdhci_pltfm_host *pltfm_host;
> +	struct aspeed_sdhci *dev;
> +	struct sdhci_host *host;
> +	struct resource *res;
> +	int slot;
> +	int ret;
> +
> +	host = sdhci_pltfm_init(pdev, &aspeed_sdhci_pdata, sizeof(*dev));
> +	if (IS_ERR(host))
> +		return PTR_ERR(host);
> +
> +	pltfm_host = sdhci_priv(host);
> +	dev = sdhci_pltfm_priv(pltfm_host);
> +	dev->parent = dev_get_drvdata(pdev->dev.parent);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	slot = aspeed_sdhci_calculate_slot(dev, res);
> +
> +	if (slot < 0)
> +		return slot;
> +	else if (slot >= 2)
> +		return -EINVAL;
> +
> +	dev_info(&pdev->dev, "Configuring for slot %d\n", slot);
> +	dev->width_mask = !slot ? ASPEED_SDC_S0MMC8 : ASPEED_SDC_S1MMC8;
> +
> +	sdhci_get_of_property(pdev);
> +
> +	pltfm_host->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(pltfm_host->clk))
> +		return PTR_ERR(pltfm_host->clk);
> +
> +	ret = clk_prepare_enable(pltfm_host->clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Unable to enable SDIO clock\n");
> +		goto err_pltfm_free;
> +	}
> +
> +	ret = mmc_of_parse(host->mmc);
> +	if (ret)
> +		goto err_sdhci_add;
> +
> +	ret = sdhci_add_host(host);
> +	if (ret)
> +		goto err_sdhci_add;
> +
> +	return 0;
> +
> +err_sdhci_add:
> +	clk_disable_unprepare(pltfm_host->clk);
> +err_pltfm_free:
> +	sdhci_pltfm_free(pdev);
> +	return ret;
> +}
> +
> +static int aspeed_sdhci_remove(struct platform_device *pdev)
> +{
> +	struct sdhci_pltfm_host *pltfm_host;
> +	struct sdhci_host *host;
> +	int dead = 0;
> +
> +	host = platform_get_drvdata(pdev);
> +	pltfm_host = sdhci_priv(host);
> +
> +	sdhci_remove_host(host, dead);
> +
> +	clk_disable_unprepare(pltfm_host->clk);
> +
> +	sdhci_pltfm_free(pdev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id aspeed_sdhci_of_match[] = {
> +	{ .compatible = "aspeed,ast2400-sdhci", },
> +	{ .compatible = "aspeed,ast2500-sdhci", },
> +	{ .compatible = "aspeed,ast2600-sdhci", },
> +	{ }
> +};
> +
> +static struct platform_driver aspeed_sdhci_driver = {
> +	.driver		= {
> +		.name	= "sdhci-aspeed",
> +		.of_match_table = aspeed_sdhci_of_match,
> +	},
> +	.probe		= aspeed_sdhci_probe,
> +	.remove		= aspeed_sdhci_remove,
> +};
> +
> +static int aspeed_sdc_probe(struct platform_device *pdev)
> +
> +{
> +	struct device_node *parent, *child;
> +	struct aspeed_sdc *sdc;
> +	int ret;
> +
> +	sdc = devm_kzalloc(&pdev->dev, sizeof(*sdc), GFP_KERNEL);
> +	if (!sdc)
> +		return -ENOMEM;
> +
> +	spin_lock_init(&sdc->lock);
> +
> +	sdc->clk = devm_clk_get(&pdev->dev, NULL);
> +	if (IS_ERR(sdc->clk))
> +		return PTR_ERR(sdc->clk);
> +
> +	ret = clk_prepare_enable(sdc->clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Unable to enable SDCLK\n");
> +		return ret;
> +	}
> +
> +	sdc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	sdc->regs = devm_ioremap_resource(&pdev->dev, sdc->res);
> +	if (IS_ERR(sdc->regs)) {
> +		ret = PTR_ERR(sdc->regs);
> +		goto err_clk;
> +	}
> +
> +	dev_set_drvdata(&pdev->dev, sdc);
> +
> +	parent = pdev->dev.of_node;
> +	for_each_available_child_of_node(parent, child) {
> +		struct platform_device *cpdev;
> +
> +		cpdev = of_platform_device_create(child, NULL, &pdev->dev);
> +		if (IS_ERR(cpdev)) {
> +			of_node_put(child);
> +			ret = PTR_ERR(cpdev);
> +			goto err_clk;
> +		}
> +	}
> +
> +	return 0;
> +
> +err_clk:
> +	clk_disable_unprepare(sdc->clk);
> +	return ret;
> +}
> +
> +static int aspeed_sdc_remove(struct platform_device *pdev)
> +{
> +	struct aspeed_sdc *sdc = dev_get_drvdata(&pdev->dev);
> +
> +	clk_disable_unprepare(sdc->clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id aspeed_sdc_of_match[] = {
> +	{ .compatible = "aspeed,ast2400-sd-controller", },
> +	{ .compatible = "aspeed,ast2500-sd-controller", },
> +	{ .compatible = "aspeed,ast2600-sd-controller", },
> +	{ }
> +};
> +
> +MODULE_DEVICE_TABLE(of, aspeed_sdc_of_match);
> +
> +static struct platform_driver aspeed_sdc_driver = {
> +	.driver		= {
> +		.name	= "sd-controller-aspeed",
> +		.pm	= &sdhci_pltfm_pmops,
> +		.of_match_table = aspeed_sdc_of_match,
> +	},
> +	.probe		= aspeed_sdc_probe,
> +	.remove		= aspeed_sdc_remove,
> +};
> +
> +static int __init aspeed_sdc_init(void)
> +{
> +	int rc;
> +
> +	rc = platform_driver_register(&aspeed_sdhci_driver);
> +	if (rc < 0)
> +		return rc;
> +
> +	return platform_driver_register(&aspeed_sdc_driver);

Shouldn't aspeed_sdhci_driver be unregistered here if there was an error.

> +}
> +module_init(aspeed_sdc_init);
> +
> +static void __exit aspeed_sdc_exit(void)
> +{
> +	platform_driver_unregister(&aspeed_sdc_driver);
> +	platform_driver_unregister(&aspeed_sdhci_driver);
> +}
> +module_exit(aspeed_sdc_exit);
> +
> +MODULE_DESCRIPTION("Driver for the ASPEED SD/SDIO/SDHCI Controllers");
> +MODULE_AUTHOR("Ryan Chen <ryan_chen@aspeedtech.com>");
> +MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
> +MODULE_LICENSE("GPL");
> 

Re: [PATCH v4 2/2] mmc: Add support for the ASPEED SD controller

[Andrew Jeffery]

On Mon, 5 Aug 2019, at 23:08, Adrian Hunter wrote:
> On 5/08/19 5:51 AM, Andrew Jeffery wrote:
> > Add a minimal driver for ASPEED's SD controller, which exposes two
> > SDHCIs.
> > 
> > The ASPEED design implements a common register set for the SDHCIs, and
> > moves some of the standard configuration elements out to this common
> > area (e.g. 8-bit mode, and card detect configuration which is not
> > currently supported).
> > 
> > The SD controller has a dedicated hardware interrupt that is shared
> > between the slots. The common register set exposes information on which
> > slot triggered the interrupt; early revisions of the patch introduced an
> > irqchip for the register, but reality is it doesn't behave as an
> > irqchip, and the result fits awkwardly into the irqchip APIs. Instead
> > I've taken the simple approach of using the IRQ as a shared IRQ with
> > some minor performance impact for the second slot.
> > 
> > Ryan was the original author of the patch - I've taken his work and
> > massaged it to drop the irqchip support and rework the devicetree
> > integration. The driver has been smoke tested under qemu against a
> > minimal SD controller model and lightly tested on an ast2500-evb.
> > 
> > Signed-off-by: Ryan Chen <ryanchen.aspeed@gmail.com>
> > Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> 
> One minor comment otherwise:
> 
> Acked-by: Adrian Hunter <adrian.hunter@intel.com>
> 
> > 
> > ---
> > v3: No change
> > v2:
> > * Add AST2600 compatible
> > * Drop SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN
> > * Ensure slot number is valid
> > * Fix build with CONFIG_MODULES
> > * Fix module license string
> > * Non-PCI devices won't die
> > * Rename aspeed_sdc_configure_8bit_mode()
> > * Rename aspeed_sdhci_pdata
> > * Switch to sdhci_enable_clk()
> > * Use PTR_ERR() on the right `struct platform_device *`
> > ---
> >  drivers/mmc/host/Kconfig           |  12 ++
> >  drivers/mmc/host/Makefile          |   1 +
> >  drivers/mmc/host/sdhci-of-aspeed.c | 328 +++++++++++++++++++++++++++++
> >  3 files changed, 341 insertions(+)
> >  create mode 100644 drivers/mmc/host/sdhci-of-aspeed.c
> > 
> > diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> > index 14d89a108edd..0f8a230de2f3 100644
> > --- a/drivers/mmc/host/Kconfig
> > +++ b/drivers/mmc/host/Kconfig
> > @@ -154,6 +154,18 @@ config MMC_SDHCI_OF_ARASAN
> >  
> >  	  If unsure, say N.
> >  
> > +config MMC_SDHCI_OF_ASPEED
> > +	tristate "SDHCI OF support for the ASPEED SDHCI controller"
> > +	depends on MMC_SDHCI_PLTFM
> > +	depends on OF
> > +	help
> > +	  This selects the ASPEED Secure Digital Host Controller Interface.
> > +
> > +	  If you have a controller with this interface, say Y or M here. You
> > +	  also need to enable an appropriate bus interface.
> > +
> > +	  If unsure, say N.
> > +
> >  config MMC_SDHCI_OF_AT91
> >  	tristate "SDHCI OF support for the Atmel SDMMC controller"
> >  	depends on MMC_SDHCI_PLTFM
> > diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile
> > index 73578718f119..390ee162fe71 100644
> > --- a/drivers/mmc/host/Makefile
> > +++ b/drivers/mmc/host/Makefile
> > @@ -84,6 +84,7 @@ obj-$(CONFIG_MMC_SDHCI_ESDHC_IMX)	+= sdhci-esdhc-imx.o
> >  obj-$(CONFIG_MMC_SDHCI_DOVE)		+= sdhci-dove.o
> >  obj-$(CONFIG_MMC_SDHCI_TEGRA)		+= sdhci-tegra.o
> >  obj-$(CONFIG_MMC_SDHCI_OF_ARASAN)	+= sdhci-of-arasan.o
> > +obj-$(CONFIG_MMC_SDHCI_OF_ASPEED)	+= sdhci-of-aspeed.o
> >  obj-$(CONFIG_MMC_SDHCI_OF_AT91)		+= sdhci-of-at91.o
> >  obj-$(CONFIG_MMC_SDHCI_OF_ESDHC)	+= sdhci-of-esdhc.o
> >  obj-$(CONFIG_MMC_SDHCI_OF_HLWD)		+= sdhci-of-hlwd.o
> > diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
> > new file mode 100644
> > index 000000000000..d31785ec90d7
> > --- /dev/null
> > +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> > @@ -0,0 +1,328 @@
> > +// SPDX-License-Identifier: GPL-2.0-or-later
> > +/* Copyright (C) 2019 ASPEED Technology Inc. */
> > +/* Copyright (C) 2019 IBM Corp. */
> > +
> > +#include <linux/clk.h>
> > +#include <linux/delay.h>
> > +#include <linux/device.h>
> > +#include <linux/io.h>
> > +#include <linux/mmc/host.h>
> > +#include <linux/module.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/spinlock.h>
> > +
> > +#include "sdhci-pltfm.h"
> > +
> > +#define ASPEED_SDC_INFO		0x00
> > +#define   ASPEED_SDC_S1MMC8	BIT(25)
> > +#define   ASPEED_SDC_S0MMC8	BIT(24)
> > +
> > +struct aspeed_sdc {
> > +	struct clk *clk;
> > +	struct resource *res;
> > +
> > +	spinlock_t lock;
> > +	void __iomem *regs;
> > +};
> > +
> > +struct aspeed_sdhci {
> > +	struct aspeed_sdc *parent;
> > +	u32 width_mask;
> > +};
> > +
> > +static void aspeed_sdc_configure_8bit_mode(struct aspeed_sdc *sdc,
> > +					   struct aspeed_sdhci *sdhci,
> > +					   bool bus8)
> > +{
> > +	u32 info;
> > +
> > +	/* Set/clear 8 bit mode */
> > +	spin_lock(&sdc->lock);
> > +	info = readl(sdc->regs + ASPEED_SDC_INFO);
> > +	if (bus8)
> > +		info |= sdhci->width_mask;
> > +	else
> > +		info &= ~sdhci->width_mask;
> > +	writel(info, sdc->regs + ASPEED_SDC_INFO);
> > +	spin_unlock(&sdc->lock);
> > +}
> > +
> > +static void aspeed_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> > +{
> > +	int div;
> > +	u16 clk;
> > +
> > +	if (clock == host->clock)
> > +		return;
> > +
> > +	sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
> > +
> > +	if (clock == 0)
> > +		goto out;
> > +
> > +	for (div = 1; div < 256; div *= 2) {
> > +		if ((host->max_clk / div) <= clock)
> > +			break;
> > +	}
> > +	div >>= 1;
> > +
> > +	clk = div << SDHCI_DIVIDER_SHIFT;
> > +
> > +	sdhci_enable_clk(host, clk);
> > +
> > +out:
> > +	host->clock = clock;
> > +}
> > +
> > +static void aspeed_sdhci_set_bus_width(struct sdhci_host *host, int width)
> > +{
> > +	struct sdhci_pltfm_host *pltfm_priv;
> > +	struct aspeed_sdhci *aspeed_sdhci;
> > +	struct aspeed_sdc *aspeed_sdc;
> > +	u8 ctrl;
> > +
> > +	pltfm_priv = sdhci_priv(host);
> > +	aspeed_sdhci = sdhci_pltfm_priv(pltfm_priv);
> > +	aspeed_sdc = aspeed_sdhci->parent;
> > +
> > +	/* Set/clear 8-bit mode */
> > +	aspeed_sdc_configure_8bit_mode(aspeed_sdc, aspeed_sdhci,
> > +				       width == MMC_BUS_WIDTH_8);
> > +
> > +	/* Set/clear 1 or 4 bit mode */
> > +	ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
> > +	if (width == MMC_BUS_WIDTH_4)
> > +		ctrl |= SDHCI_CTRL_4BITBUS;
> > +	else
> > +		ctrl &= ~SDHCI_CTRL_4BITBUS;
> > +	sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
> > +}
> > +
> > +static const struct sdhci_ops aspeed_sdhci_ops = {
> > +	.set_clock = aspeed_sdhci_set_clock,
> > +	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
> > +	.set_bus_width = aspeed_sdhci_set_bus_width,
> > +	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
> > +	.reset = sdhci_reset,
> > +	.set_uhs_signaling = sdhci_set_uhs_signaling,
> > +};
> > +
> > +static const struct sdhci_pltfm_data aspeed_sdhci_pdata = {
> > +	.ops = &aspeed_sdhci_ops,
> > +	.quirks = SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
> > +};
> > +
> > +static inline int aspeed_sdhci_calculate_slot(struct aspeed_sdhci *dev,
> > +					      struct resource *res)
> > +{
> > +	resource_size_t delta;
> > +
> > +	if (!res || resource_type(res) != IORESOURCE_MEM)
> > +		return -EINVAL;
> > +
> > +	if (res->start < dev->parent->res->start)
> > +		return -EINVAL;
> > +
> > +	delta = res->start - dev->parent->res->start;
> > +	if (delta & (0x100 - 1))
> > +		return -EINVAL;
> > +
> > +	return (delta / 0x100) - 1;
> > +}
> > +
> > +static int aspeed_sdhci_probe(struct platform_device *pdev)
> > +{
> > +	struct sdhci_pltfm_host *pltfm_host;
> > +	struct aspeed_sdhci *dev;
> > +	struct sdhci_host *host;
> > +	struct resource *res;
> > +	int slot;
> > +	int ret;
> > +
> > +	host = sdhci_pltfm_init(pdev, &aspeed_sdhci_pdata, sizeof(*dev));
> > +	if (IS_ERR(host))
> > +		return PTR_ERR(host);
> > +
> > +	pltfm_host = sdhci_priv(host);
> > +	dev = sdhci_pltfm_priv(pltfm_host);
> > +	dev->parent = dev_get_drvdata(pdev->dev.parent);
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	slot = aspeed_sdhci_calculate_slot(dev, res);
> > +
> > +	if (slot < 0)
> > +		return slot;
> > +	else if (slot >= 2)
> > +		return -EINVAL;
> > +
> > +	dev_info(&pdev->dev, "Configuring for slot %d\n", slot);
> > +	dev->width_mask = !slot ? ASPEED_SDC_S0MMC8 : ASPEED_SDC_S1MMC8;
> > +
> > +	sdhci_get_of_property(pdev);
> > +
> > +	pltfm_host->clk = devm_clk_get(&pdev->dev, NULL);
> > +	if (IS_ERR(pltfm_host->clk))
> > +		return PTR_ERR(pltfm_host->clk);
> > +
> > +	ret = clk_prepare_enable(pltfm_host->clk);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "Unable to enable SDIO clock\n");
> > +		goto err_pltfm_free;
> > +	}
> > +
> > +	ret = mmc_of_parse(host->mmc);
> > +	if (ret)
> > +		goto err_sdhci_add;
> > +
> > +	ret = sdhci_add_host(host);
> > +	if (ret)
> > +		goto err_sdhci_add;
> > +
> > +	return 0;
> > +
> > +err_sdhci_add:
> > +	clk_disable_unprepare(pltfm_host->clk);
> > +err_pltfm_free:
> > +	sdhci_pltfm_free(pdev);
> > +	return ret;
> > +}
> > +
> > +static int aspeed_sdhci_remove(struct platform_device *pdev)
> > +{
> > +	struct sdhci_pltfm_host *pltfm_host;
> > +	struct sdhci_host *host;
> > +	int dead = 0;
> > +
> > +	host = platform_get_drvdata(pdev);
> > +	pltfm_host = sdhci_priv(host);
> > +
> > +	sdhci_remove_host(host, dead);
> > +
> > +	clk_disable_unprepare(pltfm_host->clk);
> > +
> > +	sdhci_pltfm_free(pdev);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id aspeed_sdhci_of_match[] = {
> > +	{ .compatible = "aspeed,ast2400-sdhci", },
> > +	{ .compatible = "aspeed,ast2500-sdhci", },
> > +	{ .compatible = "aspeed,ast2600-sdhci", },
> > +	{ }
> > +};
> > +
> > +static struct platform_driver aspeed_sdhci_driver = {
> > +	.driver		= {
> > +		.name	= "sdhci-aspeed",
> > +		.of_match_table = aspeed_sdhci_of_match,
> > +	},
> > +	.probe		= aspeed_sdhci_probe,
> > +	.remove		= aspeed_sdhci_remove,
> > +};
> > +
> > +static int aspeed_sdc_probe(struct platform_device *pdev)
> > +
> > +{
> > +	struct device_node *parent, *child;
> > +	struct aspeed_sdc *sdc;
> > +	int ret;
> > +
> > +	sdc = devm_kzalloc(&pdev->dev, sizeof(*sdc), GFP_KERNEL);
> > +	if (!sdc)
> > +		return -ENOMEM;
> > +
> > +	spin_lock_init(&sdc->lock);
> > +
> > +	sdc->clk = devm_clk_get(&pdev->dev, NULL);
> > +	if (IS_ERR(sdc->clk))
> > +		return PTR_ERR(sdc->clk);
> > +
> > +	ret = clk_prepare_enable(sdc->clk);
> > +	if (ret) {
> > +		dev_err(&pdev->dev, "Unable to enable SDCLK\n");
> > +		return ret;
> > +	}
> > +
> > +	sdc->res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	sdc->regs = devm_ioremap_resource(&pdev->dev, sdc->res);
> > +	if (IS_ERR(sdc->regs)) {
> > +		ret = PTR_ERR(sdc->regs);
> > +		goto err_clk;
> > +	}
> > +
> > +	dev_set_drvdata(&pdev->dev, sdc);
> > +
> > +	parent = pdev->dev.of_node;
> > +	for_each_available_child_of_node(parent, child) {
> > +		struct platform_device *cpdev;
> > +
> > +		cpdev = of_platform_device_create(child, NULL, &pdev->dev);
> > +		if (IS_ERR(cpdev)) {
> > +			of_node_put(child);
> > +			ret = PTR_ERR(cpdev);
> > +			goto err_clk;
> > +		}
> > +	}
> > +
> > +	return 0;
> > +
> > +err_clk:
> > +	clk_disable_unprepare(sdc->clk);
> > +	return ret;
> > +}
> > +
> > +static int aspeed_sdc_remove(struct platform_device *pdev)
> > +{
> > +	struct aspeed_sdc *sdc = dev_get_drvdata(&pdev->dev);
> > +
> > +	clk_disable_unprepare(sdc->clk);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id aspeed_sdc_of_match[] = {
> > +	{ .compatible = "aspeed,ast2400-sd-controller", },
> > +	{ .compatible = "aspeed,ast2500-sd-controller", },
> > +	{ .compatible = "aspeed,ast2600-sd-controller", },
> > +	{ }
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, aspeed_sdc_of_match);
> > +
> > +static struct platform_driver aspeed_sdc_driver = {
> > +	.driver		= {
> > +		.name	= "sd-controller-aspeed",
> > +		.pm	= &sdhci_pltfm_pmops,
> > +		.of_match_table = aspeed_sdc_of_match,
> > +	},
> > +	.probe		= aspeed_sdc_probe,
> > +	.remove		= aspeed_sdc_remove,
> > +};
> > +
> > +static int __init aspeed_sdc_init(void)
> > +{
> > +	int rc;
> > +
> > +	rc = platform_driver_register(&aspeed_sdhci_driver);
> > +	if (rc < 0)
> > +		return rc;
> > +
> > +	return platform_driver_register(&aspeed_sdc_driver);
> 
> Shouldn't aspeed_sdhci_driver be unregistered here if there was an error.

Yeah, fair point. I'll send a v5 to fix that.

Thanks for the feedback.

Andrew