2013-06-12 13:53:52

by Oded Gabbay

Subject: [PATCH 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 <[email protected]>
---
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 = 0;
+
+ 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

2013-06-13 18:44:43

by Anton Vorontsov

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

On Wed, Jun 12, 2013 at 04:53:25PM +0300, Oded Gabbay wrote:
> @@ -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 = 0;

No need for the 0 initializer.

Otherwise it looks OK, thanks!

Reviewed-by: Anton Vorontsov <[email protected]>