linux-kernel - [PATCH v2 1/2] MMC: P2020 SDHC: Add support for 8-bit bus width and non-removable card

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Date:	Sun, 16 Jun 2013 10:07:20 +0300
From:	Oded Gabbay <ogabbay@...aoptical.com>
To:	<cjb@...top.org>, <ogabbay@...aoptical.com>,
	<shawn.guo@...aro.org>, <Chang-Ming.Huang@...escale.com>,
	<wfp5p@...ginia.edu>, <gregkh@...uxfoundation.org>,
	<cbouatmailru@...il.com>
CC:	<linux-mmc@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 1/2] MMC: P2020 SDHC: Add support for 8-bit bus width and non-removable card

This patch adds support of connecting an MMC media using an 8-bit
bus width connection to Freescale's P2020 H/W SDHC controller. During
the probe function, the generic function mmc_of_parse is called to detect
whether the controller is configured with 8-bit bus width. Also, the generic
function detecs if the non-removable property is set in the device tree.
The function esdhc_pltfm_bus_width was added because the bus width configuration
is platform specific.

Signed-off-by: Oded Gabbay <ogabbay@...aoptical.com>
Reviewed-by: Anton Vorontsov <anton@...msg.org>
---
 drivers/mmc/host/sdhci-esdhc.h    |  7 +++++++
 drivers/mmc/host/sdhci-of-esdhc.c | 44 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-esdhc.h b/drivers/mmc/host/sdhci-esdhc.h
index d25f9ab..6f9a018 100644
--- a/drivers/mmc/host/sdhci-esdhc.h
+++ b/drivers/mmc/host/sdhci-esdhc.h
@@ -36,6 +36,13 @@
 /* pltfm-specific */
 #define ESDHC_HOST_CONTROL_LE	0x20
 
+/*
+ * P2020 interpretation of the SDHCI_HOST_CONTROL register
+ */
+#define ESDHC_CTRL_4BITBUS          (0x1 << 1)
+#define ESDHC_CTRL_8BITBUS          (0x2 << 1)
+#define ESDHC_CTRL_BUSWIDTH_MASK    (0x3 << 1)
+
 /* OF-specific */
 #define ESDHC_DMA_SYSCTL	0x40c
 #define ESDHC_DMA_SNOOP		0x00000040
diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
index 5e68adc..fd149a0 100644
--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c
@@ -13,6 +13,7 @@
  * your option) any later version.
  */
 
+#include <linux/err.h>
 #include <linux/io.h>
 #include <linux/of.h>
 #include <linux/delay.h>
@@ -230,6 +231,30 @@ static void esdhc_of_platform_init(struct sdhci_host *host)
 		host->quirks &= ~SDHCI_QUIRK_NO_BUSY_IRQ;
 }
 
+static int esdhc_pltfm_bus_width(struct sdhci_host *host, int width)
+{
+	u32 ctrl;
+
+	switch (width) {
+	case MMC_BUS_WIDTH_8:
+		ctrl = ESDHC_CTRL_8BITBUS;
+		break;
+
+	case MMC_BUS_WIDTH_4:
+		ctrl = ESDHC_CTRL_4BITBUS;
+		break;
+
+	default:
+		ctrl = 0;
+		break;
+	}
+
+	clrsetbits_be32(host->ioaddr + SDHCI_HOST_CONTROL,
+			ESDHC_CTRL_BUSWIDTH_MASK, ctrl);
+
+	return 0;
+}
+
 static const struct sdhci_ops sdhci_esdhc_ops = {
 	.read_l = esdhc_readl,
 	.read_w = esdhc_readw,
@@ -247,6 +272,7 @@ static const struct sdhci_ops sdhci_esdhc_ops = {
 	.platform_resume = esdhc_of_resume,
 #endif
 	.adma_workaround = esdhci_of_adma_workaround,
+	.platform_bus_width = esdhc_pltfm_bus_width,
 };
 
 static const struct sdhci_pltfm_data sdhci_esdhc_pdata = {
@@ -262,7 +288,23 @@ static const struct sdhci_pltfm_data sdhci_esdhc_pdata = {
 
 static int sdhci_esdhc_probe(struct platform_device *pdev)
 {
-	return sdhci_pltfm_register(pdev, &sdhci_esdhc_pdata);
+	struct sdhci_host *host;
+	int ret;
+
+	host = sdhci_pltfm_init(pdev, &sdhci_esdhc_pdata);
+	if (IS_ERR(host))
+		return PTR_ERR(host);
+
+	sdhci_get_of_property(pdev);
+
+	/* call to generic mmc_of_parse to support additional capabilities */
+	mmc_of_parse(host->mmc);
+
+	ret = sdhci_add_host(host);
+	if (ret)
+		sdhci_pltfm_free(pdev);
+
+	return ret;
 }
 
 static int sdhci_esdhc_remove(struct platform_device *pdev)
-- 
1.8.3.1

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