mmc: tmio: ioremap memory resource in tmio_mmc_host_alloc()

The register region is ioremap'ed in the tmio_mmc_host_probe(), i.e.
drivers cannot get access to the hardware before mmc_add_host().

Actually, renesas_sdhi_core.c reads out the CTL_VERSION register to
complete the platform-specific settings.  However, at this point,
the MMC host is already running.

Move the register ioremap to tmio_mmc_host_alloc() so that drivers
can perform platform-specific settings between tmio_mmc_host_alloc()
and tmio_mmc_host_probe().

I changed tmio_mmc_host_alloc() to return an error pointer to
propagate the return code from devm_ioremap_resource().

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/tmio_mmc.c

@@ -93,8 +93,10 @@ static int tmio_mmc_probe(struct platform_device *pdev)
 	pdata->flags |= TMIO_MMC_HAVE_HIGH_REG;
 
 	host = tmio_mmc_host_alloc(pdev);
-	if (!host)
+	if (IS_ERR(host)) {
+		ret = PTR_ERR(host);
 		goto cell_disable;
+	}
 
 	/* SD control register space size is 0x200, 0x400 for bus_shift=1 */
 	host->bus_shift = resource_size(res) >> 10;