ARM: 5666/1: Revamped U300 padmux API

This abstracts the hackish padmux API on the U300 platform into
something more manageable. It provides a way for drivers to
activate/deactivate a certain padmux setting. It will also switch
the users of the old API over to using the new style, pushing
muxing into the apropriate setup files.
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-u300/gpio.c

@@ -25,11 +25,6 @@
 #include <linux/platform_device.h>
 #include <linux/gpio.h>
 
-/* Need access to SYSCON registers for PADmuxing */
-#include <mach/syscon.h>
-
-#include "padmux.h"
-
 /* Reference to GPIO block clock */
 static struct clk *clk;
 
@@ -606,14 +601,6 @@ static int __init gpio_probe(struct platform_device *pdev)
 	writel(U300_GPIO_CR_BLOCK_CLKRQ_ENABLE, virtbase + U300_GPIO_CR);
 #endif
 
-	/* Set up some padmuxing here */
-#ifdef CONFIG_MMC
-	pmx_set_mission_mode_mmc();
-#endif
-#ifdef CONFIG_SPI_PL022
-	pmx_set_mission_mode_spi();
-#endif
-
 	gpio_set_initial_values();
 
 	for (num_irqs = 0 ; num_irqs < U300_GPIO_NUM_PORTS; num_irqs++) {

arch/arm/mach-u300/mmc.c

@@ -22,6 +22,7 @@
 
 #include <asm/mach/mmc.h>
 #include "mmc.h"
+#include "padmux.h"
 
 struct mmci_card_event {
 	struct input_dev *mmc_input;
@@ -146,6 +147,7 @@ int __devinit mmc_init(struct amba_device *adev)
 {
 	struct mmci_card_event *mmci_card;
 	struct device *mmcsd_device = &adev->dev;
+	struct pmx *pmx;
 	int ret = 0;
 
 	mmci_card = kzalloc(sizeof(struct mmci_card_event), GFP_KERNEL);
@@ -205,6 +207,20 @@ int __devinit mmc_init(struct amba_device *adev)
 
 	input_set_drvdata(mmci_card->mmc_input, mmci_card);
 
+	/*
+	 * Setup padmuxing for MMC. Since this must always be
+	 * compiled into the kernel, pmx is never released.
+	 */
+	pmx = pmx_get(mmcsd_device, U300_APP_PMX_MMC_SETTING);
+
+	if (IS_ERR(pmx))
+		pr_warning("Could not get padmux handle\n");
+	else {
+		ret = pmx_activate(mmcsd_device, pmx);
+		if (IS_ERR_VALUE(ret))
+			pr_warning("Could not activate padmuxing\n");
+	}
+
 	ret = gpio_register_callback(U300_GPIO_PIN_MMC_CD, mmci_callback,
 				     mmci_card);
 

arch/arm/mach-u300/padmux.c

@@ -6,53 +6,362 @@
  * Copyright (C) 2009 ST-Ericsson AB
  * License terms: GNU General Public License (GPL) version 2
  * U300 PADMUX functions
- * Author: Linus Walleij <linus.walleij@stericsson.com>
- *
+ * Author: Martin Persson <martin.persson@stericsson.com>
  */
-#include <linux/io.h>
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/device.h>
 #include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#include <linux/bug.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
 #include <mach/u300-regs.h>
 #include <mach/syscon.h>
-
 #include "padmux.h"
 
-/* Set the PAD MUX to route the MMC reader correctly to GPIO0. */
-void pmx_set_mission_mode_mmc(void)
+static DEFINE_MUTEX(pmx_mutex);
+
+const u32 pmx_registers[] = {
+	(U300_SYSCON_VBASE + U300_SYSCON_PMC1LR),
+	(U300_SYSCON_VBASE + U300_SYSCON_PMC1HR),
+	(U300_SYSCON_VBASE + U300_SYSCON_PMC2R),
+	(U300_SYSCON_VBASE + U300_SYSCON_PMC3R),
+	(U300_SYSCON_VBASE + U300_SYSCON_PMC4R)
+};
+
+/* High level functionality */
+
+/* Lazy dog:
+ * onmask = {
+ *   {"PMC1LR" mask, "PMC1LR" value},
+ *   {"PMC1HR" mask, "PMC1HR" value},
+ *   {"PMC2R"  mask, "PMC2R"  value},
+ *   {"PMC3R"  mask, "PMC3R"  value},
+ *   {"PMC4R"  mask, "PMC4R"  value}
+ * }
+ */
+static struct pmx mmc_setting = {
+	.setting = U300_APP_PMX_MMC_SETTING,
+	.default_on = false,
+	.activated = false,
+	.name = "MMC",
+	.onmask = {
+		   {U300_SYSCON_PMC1LR_MMCSD_MASK,
+		    U300_SYSCON_PMC1LR_MMCSD_MMCSD},
+		   {0, 0},
+		   {0, 0},
+		   {0, 0},
+		   {U300_SYSCON_PMC4R_APP_MISC_12_MASK,
+		    U300_SYSCON_PMC4R_APP_MISC_12_APP_GPIO}
+		   },
+};
+
+static struct pmx spi_setting = {
+	.setting = U300_APP_PMX_SPI_SETTING,
+	.default_on = false,
+	.activated = false,
+	.name = "SPI",
+	.onmask = {{0, 0},
+		   {U300_SYSCON_PMC1HR_APP_SPI_2_MASK |
+		    U300_SYSCON_PMC1HR_APP_SPI_CS_1_MASK |
+		    U300_SYSCON_PMC1HR_APP_SPI_CS_2_MASK,
+		    U300_SYSCON_PMC1HR_APP_SPI_2_SPI |
+		    U300_SYSCON_PMC1HR_APP_SPI_CS_1_SPI |
+		    U300_SYSCON_PMC1HR_APP_SPI_CS_2_SPI},
+		   {0, 0},
+		   {0, 0},
+		   {0, 0}
+		   },
+};
+
+/* Available padmux settings */
+static struct pmx *pmx_settings[] = {
+	&mmc_setting,
+	&spi_setting,
+};
+
+static void update_registers(struct pmx *pmx, bool activate)
 {
-	u16 val;
+	u16 regval, val, mask;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pmx_registers); i++) {
+		if (activate)
+			val = pmx->onmask[i].val;
+		else
+			val = 0;
 
-	val = readw(U300_SYSCON_VBASE + U300_SYSCON_PMC1LR);
-	val &= ~U300_SYSCON_PMC1LR_MMCSD_MASK;
-	writew(val, U300_SYSCON_VBASE + U300_SYSCON_PMC1LR);
-	val = readw(U300_SYSCON_VBASE + U300_SYSCON_PMC1HR);
-	val &= ~U300_SYSCON_PMC1HR_APP_GPIO_1_MASK;
-	val |= U300_SYSCON_PMC1HR_APP_GPIO_1_MMC;
-	writew(val, U300_SYSCON_VBASE + U300_SYSCON_PMC1HR);
+		mask = pmx->onmask[i].mask;
+		if (mask != 0) {
+			regval = readw(pmx_registers[i]);
+			regval &= ~mask;
+			regval |= val;
+			writew(regval, pmx_registers[i]);
+		}
+	}
 }
 
-void pmx_set_mission_mode_spi(void)
+struct pmx *pmx_get(struct device *dev, enum pmx_settings setting)
 {
-	u16 val;
+	int i;
+	struct pmx *pmx = ERR_PTR(-ENOENT);
 
-	/* Set up padmuxing so the SPI port and its chipselects are active */
-	val = readw(U300_SYSCON_VBASE + U300_SYSCON_PMC1HR);
-	/*
-	 * Activate the SPI port (disable the use of these pins for generic
-	 * GPIO, DSP, AAIF
-	 */
-	val &= ~U300_SYSCON_PMC1HR_APP_SPI_2_MASK;
-	val |= U300_SYSCON_PMC1HR_APP_SPI_2_SPI;
-	/*
-	 * Use GPIO pin SPI CS1 for CS1 actually (it can be used for other
-	 * things also)
+	if (dev == NULL)
+		return ERR_PTR(-EINVAL);
+
+	mutex_lock(&pmx_mutex);
+	for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
+
+		if (setting == pmx_settings[i]->setting) {
+
+			if (pmx_settings[i]->dev != NULL) {
+				WARN(1, "padmux: required setting "
+				     "in use by another consumer\n");
+			} else {
+				pmx = pmx_settings[i];
+				pmx->dev = dev;
+				dev_dbg(dev, "padmux: setting nr %d is now "
+					"bound to %s and ready to use\n",
+					setting, dev_name(dev));
+				break;
+			}
+		}
+	}
+	mutex_unlock(&pmx_mutex);
+
+	return pmx;
+}
+EXPORT_SYMBOL(pmx_get);
+
+int pmx_put(struct device *dev, struct pmx *pmx)
+{
+	int i;
+	int ret = -ENOENT;
+
+	if (pmx == NULL || dev == NULL)
+		return -EINVAL;
+
+	mutex_lock(&pmx_mutex);
+	for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
+
+		if (pmx->setting == pmx_settings[i]->setting) {
+
+			if (dev != pmx->dev) {
+				WARN(1, "padmux: cannot release handle as "
+					"it is bound to another consumer\n");
+				ret = -EINVAL;
+				break;
+			} else {
+				pmx_settings[i]->dev = NULL;
+				ret = 0;
+				break;
+			}
+		}
+	}
+	mutex_unlock(&pmx_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL(pmx_put);
+
+int pmx_activate(struct device *dev, struct pmx *pmx)
+{
+	int i, j, ret;
+	ret = 0;
+
+	if (pmx == NULL || dev == NULL)
+		return -EINVAL;
+
+	mutex_lock(&pmx_mutex);
+
+	/* Make sure the required bits are not used */
+	for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
+
+		if (pmx_settings[i]->dev == NULL || pmx_settings[i] == pmx)
+			continue;
+
+		for (j = 0; j < ARRAY_SIZE(pmx_registers); j++) {
+
+			if (pmx_settings[i]->onmask[j].mask & pmx->
+				onmask[j].mask) {
+				/* More than one entry on the same bits */
+				WARN(1, "padmux: cannot activate "
+					"setting. Bit conflict with "
+					"an active setting\n");
+
+				ret = -EUSERS;
+				goto exit;
+			}
+		}
+	}
+	update_registers(pmx, true);
+	pmx->activated = true;
+	dev_dbg(dev, "padmux: setting nr %d is activated\n",
+		pmx->setting);
+
+exit:
+	mutex_unlock(&pmx_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(pmx_activate);
+
+int pmx_deactivate(struct device *dev, struct pmx *pmx)
+{
+	int i;
+	int ret = -ENOENT;
+
+	if (pmx == NULL || dev == NULL)
+		return -EINVAL;
+
+	mutex_lock(&pmx_mutex);
+	for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
+
+		if (pmx_settings[i]->dev == NULL)
+			continue;
+
+		if (pmx->setting == pmx_settings[i]->setting) {
+
+			if (dev != pmx->dev) {
+				WARN(1, "padmux: cannot deactivate "
+				     "pmx setting as it was activated "
+				     "by another consumer\n");
+
+				ret = -EBUSY;
+				continue;
+			} else {
+				update_registers(pmx, false);
+				pmx_settings[i]->dev = NULL;
+				pmx->activated = false;
+				ret = 0;
+				dev_dbg(dev, "padmux: setting nr %d is deactivated",
+					pmx->setting);
+				break;
+			}
+		}
+	}
+	mutex_unlock(&pmx_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL(pmx_deactivate);
+
+/*
+ * For internal use only. If it is to be exported,
+ * it should be reentrant. Notice that pmx_activate
+ * (i.e. runtime settings) always override default settings.
  */
-	val &= ~U300_SYSCON_PMC1HR_APP_SPI_CS_1_MASK;
-	val |= U300_SYSCON_PMC1HR_APP_SPI_CS_1_SPI;
-	/*
-	 * Use GPIO pin SPI CS2 for CS2 actually (it can be used for other
-	 * things also)
+static int pmx_set_default(void)
+{
+	/* Used to identify several entries on the same bits */
+	u16 modbits[ARRAY_SIZE(pmx_registers)];
+
+	int i, j;
+
+	memset(modbits, 0, ARRAY_SIZE(pmx_registers) * sizeof(u16));
+
+	for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
+
+		if (!pmx_settings[i]->default_on)
+			continue;
+
+		for (j = 0; j < ARRAY_SIZE(pmx_registers); j++) {
+
+			/* Make sure there is only one entry on the same bits */
+			if (modbits[j] & pmx_settings[i]->onmask[j].mask) {
+				BUG();
+				return -EUSERS;
+			}
+			modbits[j] |= pmx_settings[i]->onmask[j].mask;
+		}
+		update_registers(pmx_settings[i], true);
+	}
+	return 0;
+}
+
+#if (defined(CONFIG_DEBUG_FS) && defined(CONFIG_U300_DEBUG))
+static int pmx_show(struct seq_file *s, void *data)
+{
+	int i;
+	seq_printf(s, "-------------------------------------------------\n");
+	seq_printf(s, "SETTING     BOUND TO DEVICE               STATE\n");
+	seq_printf(s, "-------------------------------------------------\n");
+	mutex_lock(&pmx_mutex);
+	for (i = 0; i < ARRAY_SIZE(pmx_settings); i++) {
+		/* Format pmx and device name nicely */
+		char cdp[33];
+		int chars;
+
+		chars = snprintf(&cdp[0], 17, "%s", pmx_settings[i]->name);
+		while (chars < 16) {
+			cdp[chars] = ' ';
+			chars++;
+		}
+		chars = snprintf(&cdp[16], 17, "%s", pmx_settings[i]->dev ?
+				dev_name(pmx_settings[i]->dev) : "N/A");
+		while (chars < 16) {
+			cdp[chars+16] = ' ';
+			chars++;
+		}
+		cdp[32] = '\0';
+
+		seq_printf(s,
+			"%s\t%s\n",
+			&cdp[0],
+			pmx_settings[i]->activated ?
+			"ACTIVATED" : "DEACTIVATED"
+			);
+
+	}
+	mutex_unlock(&pmx_mutex);
+	return 0;
+}
+
+static int pmx_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pmx_show, NULL);
+}
+
+static const struct file_operations pmx_operations = {
+	.owner		= THIS_MODULE,
+	.open		= pmx_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init init_pmx_read_debugfs(void)
+{
+	/* Expose a simple debugfs interface to view pmx settings */
+	(void) debugfs_create_file("padmux", S_IFREG | S_IRUGO,
+				   NULL, NULL,
+				   &pmx_operations);
+	return 0;
+}
+
+/*
+ * This needs to come in after the core_initcall(),
+ * because debugfs is not available until
+ * the subsystems come up.
  */
-	val &= ~U300_SYSCON_PMC1HR_APP_SPI_CS_2_MASK;
-	val |= U300_SYSCON_PMC1HR_APP_SPI_CS_2_SPI;
-	writew(val, U300_SYSCON_VBASE + U300_SYSCON_PMC1HR);
+module_init(init_pmx_read_debugfs);
+#endif
+
+static int __init pmx_init(void)
+{
+	int ret;
+
+	ret = pmx_set_default();
+
+	if (IS_ERR_VALUE(ret))
+		pr_crit("padmux: default settings could not be set\n");
+
+	return 0;
 }
+
+/* Should be initialized before consumers */
+core_initcall(pmx_init);

arch/arm/mach-u300/padmux.h

@@ -6,14 +6,34 @@
  * Copyright (C) 2009 ST-Ericsson AB
  * License terms: GNU General Public License (GPL) version 2
  * U300 PADMUX API
- * Author: Linus Walleij <linus.walleij@stericsson.com>
- *
+ * Author: Martin Persson <martin.persson@stericsson.com>
  */
 
 #ifndef __MACH_U300_PADMUX_H
 #define __MACH_U300_PADMUX_H
 
-void pmx_set_mission_mode_mmc(void);
-void pmx_set_mission_mode_spi(void);
+enum pmx_settings {
+	U300_APP_PMX_MMC_SETTING,
+	U300_APP_PMX_SPI_SETTING
+};
+
+struct pmx_onmask {
+	u16 mask;		/* Mask bits */
+	u16 val;		/* Value when active */
+};
+
+struct pmx {
+	struct device *dev;
+	enum pmx_settings setting;
+	char *name;
+	bool activated;
+	bool default_on;
+	struct pmx_onmask onmask[];
+};
+
+struct pmx *pmx_get(struct device *dev, enum pmx_settings setting);
+int pmx_put(struct device *dev, struct pmx *pmx);
+int pmx_activate(struct device *dev, struct pmx *pmx);
+int pmx_deactivate(struct device *dev, struct pmx *pmx);
 
 #endif