[PATCH 4/4] mci_spi: add clock frequency change support

[Jean-Christophe PLAGNIOL-VILLARD]

setup the spi master correctly

provide f_min and f_max

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj at jcrosoft.com>
---
 drivers/mci/mci_spi.c |   29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/mci/mci_spi.c b/drivers/mci/mci_spi.c
index 08939be..679a0e1 100644
--- a/drivers/mci/mci_spi.c
+++ b/drivers/mci/mci_spi.c
@@ -318,7 +318,15 @@ static void mmc_spi_set_ios(struct mci_host *mci, struct mci_ios *ios)
 {
 	struct mmc_spi_host	*host = to_spi_host(mci);
 
-	spi_setup(host->spi);
+	if (host->spi->max_speed_hz != ios->clock && ios->clock != 0) {
+		int		status;
+
+		host->spi->max_speed_hz = ios->clock;
+		status = spi_setup(host->spi);
+		dev_dbg(&host->spi->dev,
+			"mmc_spi:  clock to %d Hz, %d\n",
+			host->spi->max_speed_hz, status);
+	}
 }
 
 static int mmc_spi_init(struct mci_host *mci, struct device_d *mci_dev)
@@ -384,6 +392,25 @@ static int spi_mci_probe(struct device_d *dev)
 		spi->mode = SPI_MODE_0;
 	spi->bits_per_word = 8;
 
+	status = spi_setup(spi);
+	if (status < 0) {
+		dev_dbg(&spi->dev, "needs SPI mode %02x, %d KHz; %d\n",
+				spi->mode, spi->max_speed_hz / 1000,
+				status);
+		return status;
+	}
+
+	/* SPI doesn't need the lowspeed device identification thing for
+	 * MMC or SD cards, since it never comes up in open drain mode.
+	 * That's good; some SPI masters can't handle very low speeds!
+	 *
+	 * However, low speed SDIO cards need not handle over 400 KHz;
+	 * that's the only reason not to use a few MHz for f_min (until
+	 * the upper layer reads the target frequency from the CSD).
+	 */
+	host->mci.f_min = 400000;
+	host->mci.f_max = spi->max_speed_hz;
+
 	host->dev = dev;
 	host->spi = spi;
 	dev->priv = host;
-- 
1.7.10.4