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Message-ID: <20080516165057.GC24196@polina.dev.rtsoft.ru>
Date: Fri, 16 May 2008 20:50:57 +0400
From: Anton Vorontsov <avorontsov@...mvista.com>
To: Kumar Gala <galak@...nel.crashing.org>,
David Brownell <dbrownell@...rs.sourceforge.net>,
Pierre Ossman <drzeus-mmc@...eus.cx>
Cc: Jochen Friedrich <jochen@...am.de>,
Timur Tabi <timur@...escale.com>, linuxppc-dev@...abs.org,
linux-kernel@...r.kernel.org,
spi-devel-general@...ts.sourceforge.net
Subject: [PATCH 3/4] [MMC] mmc_spi: add polling support for the card detect
line
Some boards do not use interrupts on the CD line, so we want to poll
the CD and see if there was a change. 1 second poll interval seems
resonable.
Signed-off-by: Anton Vorontsov <avorontsov@...mvista.com>
---
drivers/mmc/host/mmc_spi.c | 51 +++++++++++++++++++++++++++++++++++++++++-
include/linux/spi/mmc_spi.h | 10 ++++++++
2 files changed, 59 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 3550858..a3b46b1 100644
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -31,6 +31,7 @@
#include <linux/crc7.h>
#include <linux/crc-itu-t.h>
#include <linux/scatterlist.h>
+#include <linux/workqueue.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h> /* for R1_SPI_* bit values */
@@ -122,6 +123,11 @@ struct mmc_spi_host {
struct mmc_spi_platform_data *pdata;
+ /* stores last Card-Detect status (when polling) */
+ int cd_status;
+ struct workqueue_struct *cd_poll_wqueue;
+ struct delayed_work cd_poll_work;
+
/* for bulk data transfers */
struct spi_transfer token, t, crc, early_status;
struct spi_message m;
@@ -1155,6 +1161,26 @@ mmc_spi_detect_irq(int irq, void *mmc)
return IRQ_HANDLED;
}
+static void mmc_spi_cd_poll_work(struct work_struct *work)
+{
+ struct mmc_spi_host *host = container_of(work, struct mmc_spi_host,
+ cd_poll_work.work);
+ struct mmc_host *mmc = host->mmc;
+ int old_cd;
+
+ dev_dbg(&host->spi->dev, "polling for card detect...\n");
+
+ old_cd = host->cd_status;
+ host->cd_status = host->pdata->get_cd(mmc->parent);
+ if (old_cd != host->cd_status) {
+ /* ugh... this is ugly, but better than code duplication */
+ mmc_spi_detect_irq(NO_IRQ, mmc);
+ }
+
+ queue_delayed_work(host->cd_poll_wqueue, &host->cd_poll_work,
+ MMC_SPI_POLL_INT);
+}
+
struct count_children {
unsigned n;
struct bus_type *bus;
@@ -1323,13 +1349,28 @@ static int mmc_spi_probe(struct spi_device *spi)
if (status != 0)
goto fail_add_host;
- dev_info(&spi->dev, "SD/MMC host %s%s%s%s\n",
+ if (host->pdata && host->pdata->get_cd) {
+ host->cd_status = host->pdata->get_cd(mmc->parent);
+ INIT_DELAYED_WORK(&host->cd_poll_work, mmc_spi_cd_poll_work);
+ host->cd_poll_wqueue = create_singlethread_workqueue(
+ mmc->class_dev.bus_id);
+ if (!host->cd_poll_wqueue) {
+ status = -ENOMEM;
+ goto fail_add_host;
+ }
+ queue_delayed_work(host->cd_poll_wqueue, &host->cd_poll_work,
+ MMC_SPI_POLL_INT);
+ }
+
+ dev_info(&spi->dev, "SD/MMC host %s%s%s%s%s\n",
mmc->class_dev.bus_id,
host->dma_dev ? "" : ", no DMA",
(host->pdata && host->pdata->get_ro)
? "" : ", no WP",
(host->pdata && host->pdata->setpower)
- ? "" : ", no poweroff");
+ ? "" : ", no poweroff",
+ (host->pdata && host->pdata->get_cd)
+ ? ", cd polling" : "");
return 0;
fail_add_host:
@@ -1362,6 +1403,12 @@ static int __devexit mmc_spi_remove(struct spi_device *spi)
if (host->pdata && host->pdata->exit)
host->pdata->exit(&spi->dev, mmc);
+ if (host->pdata && host->pdata->get_cd) {
+ cancel_rearming_delayed_workqueue(
+ host->cd_poll_wqueue, &host->cd_poll_work);
+ destroy_workqueue(host->cd_poll_wqueue);
+ }
+
mmc_remove_host(mmc);
if (host->dma_dev) {
diff --git a/include/linux/spi/mmc_spi.h b/include/linux/spi/mmc_spi.h
index e9bbe3e..6ed6ee9 100644
--- a/include/linux/spi/mmc_spi.h
+++ b/include/linux/spi/mmc_spi.h
@@ -1,6 +1,10 @@
#ifndef __LINUX_SPI_MMC_SPI_H
#define __LINUX_SPI_MMC_SPI_H
+#include <asm/param.h> /* for HZ */
+
+#define MMC_SPI_POLL_INT HZ
+
struct device;
struct mmc_host;
@@ -21,6 +25,12 @@ struct mmc_spi_platform_data {
/* sense switch on sd cards */
int (*get_ro)(struct device *);
+ /*
+ * if board does not use CD interrupts, driver can poll the CD
+ * line using this function.
+ */
+ int (*get_cd)(struct device *);
+
/* how long to debounce card detect, in msecs */
u16 detect_delay;
--
1.5.5.1
--
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