mmc: Move regulator handling closer to core

After discovering a problem in regulator reference counting I took Mark
Brown's advice to move the reference count into the MMC core by making the
regulator status a member of struct mmc_host.

I took this opportunity to also implement NULL versions of
the regulator functions so as to rid the driver code from
some ugly #ifdef CONFIG_REGULATOR clauses.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Liam Girdwood <lrg@slimlogic.co.uk>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Adrian Hunter <adrian.hunter@nokia.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Sundar Iyer <sundar.iyer@stericsson.com>
Cc: Daniel Mack <daniel@caiaq.de>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: Matt Fleming <matt@console-pimps.org>
Cc: David Brownell <dbrownell@users.sourceforge.net>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Eric Miao <eric.y.miao@gmail.com>
Cc: Cliff Brake <cbrake@bec-systems.com>
Cc: Jarkko Lavinen <jarkko.lavinen@nokia.com>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/host/pxamci.c

@@ -99,14 +99,25 @@ static inline void pxamci_init_ocr(struct pxamci_host *host)
 	}
 }
 
-static inline void pxamci_set_power(struct pxamci_host *host, unsigned int vdd)
+static inline int pxamci_set_power(struct pxamci_host *host,
+				    unsigned char power_mode,
+				    unsigned int vdd)
 {
 	int on;
 
-#ifdef CONFIG_REGULATOR
-	if (host->vcc)
-		mmc_regulator_set_ocr(host->vcc, vdd);
-#endif
+	if (host->vcc) {
+		int ret;
+
+		if (power_mode == MMC_POWER_UP) {
+			ret = mmc_regulator_set_ocr(host->mmc, host->vcc, vdd);
+			if (ret)
+				return ret;
+		} else if (power_mode == MMC_POWER_OFF) {
+			ret = mmc_regulator_set_ocr(host->mmc, host->vcc, 0);
+			if (ret)
+				return ret;
+		}
+	}
 	if (!host->vcc && host->pdata &&
 	    gpio_is_valid(host->pdata->gpio_power)) {
 		on = ((1 << vdd) & host->pdata->ocr_mask);
@@ -115,6 +126,8 @@ static inline void pxamci_set_power(struct pxamci_host *host, unsigned int vdd)
 	}
 	if (!host->vcc && host->pdata && host->pdata->setpower)
 		host->pdata->setpower(mmc_dev(host->mmc), vdd);
+
+	return 0;
 }
 
 static void pxamci_stop_clock(struct pxamci_host *host)
@@ -490,9 +503,21 @@ static void pxamci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 	}
 
 	if (host->power_mode != ios->power_mode) {
+		int ret;
+
 		host->power_mode = ios->power_mode;
 
-		pxamci_set_power(host, ios->vdd);
+		ret = pxamci_set_power(host, ios->power_mode, ios->vdd);
+		if (ret) {
+			dev_err(mmc_dev(mmc), "unable to set power\n");
+			/*
+			 * The .set_ios() function in the mmc_host_ops
+			 * struct return void, and failing to set the
+			 * power should be rare so we print an error and
+			 * return here.
+			 */
+			return;
+		}
 
 		if (ios->power_mode == MMC_POWER_ON)
 			host->cmdat |= CMDAT_INIT;
@@ -503,8 +528,8 @@ static void pxamci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 	else
 		host->cmdat &= ~CMDAT_SD_4DAT;
 
-	pr_debug("PXAMCI: clkrt = %x cmdat = %x\n",
-		 host->clkrt, host->cmdat);
+	dev_dbg(mmc_dev(mmc), "PXAMCI: clkrt = %x cmdat = %x\n",
+		host->clkrt, host->cmdat);
 }
 
 static void pxamci_enable_sdio_irq(struct mmc_host *host, int enable)