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>

4 files changed, 392 insertions, 60 deletions

diff --git a/arch/arm/mach-u300/gpio.c b/arch/arm/mach-u300/gpio.c
index 308cdb197a92..63c8f27fb15a 100644
--- a/arch/arm/mach-u300/gpio.c
+++ b/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++) {
diff --git a/arch/arm/mach-u300/mmc.c b/arch/arm/mach-u300/mmc.c
index 3138d3955c9e..e66284d73565 100644
--- a/arch/arm/mach-u300/mmc.c
+++ b/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);
 
diff --git a/arch/arm/mach-u300/padmux.c b/arch/arm/mach-u300/padmux.c
index f3664564f086..4c93c6cefd37 100644
--- a/arch/arm/mach-u300/padmux.c
+++ b/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)
-{
-        u16 val;
-
-        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);
-}
-
-void pmx_set_mission_mode_spi(void)
-{
-        u16 val;
-
-        /* 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)
-         */
-        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)
-         */
-        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);
+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 regval, val, mask;
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(pmx_registers); i++) {
+                if (activate)
+                        val = pmx->onmask[i].val;
+                else
+                        val = 0;
+
+                mask = pmx->onmask[i].mask;
+                if (mask != 0) {
+                        regval = readw(pmx_registers[i]);
+                        regval &= ~mask;
+                        regval |= val;
+                        writew(regval, pmx_registers[i]);
+                }
+        }
+}
+
+struct pmx *pmx_get(struct device *dev, enum pmx_settings setting)
+{
+        int i;
+        struct pmx *pmx = ERR_PTR(-ENOENT);
+
+        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.
+ */
+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.
+ */
+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);
diff --git a/arch/arm/mach-u300/padmux.h b/arch/arm/mach-u300/padmux.h
index 8c2099ac5046..6e8b86064097 100644
--- a/arch/arm/mach-u300/padmux.h
+++ b/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