pinctrl: intel: Allow to request locked pads

Some firmwares would like to protect pads from being modified by OS
and at the same time provide them to OS as a resource. So, the driver
in such circumstances may request pad and may not change its state.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/drivers/pinctrl/intel/pinctrl-intel.c b/drivers/pinctrl/intel/pinctrl-intel.c
index c949df0..104dfaa 100644 (file)
--- a/drivers/pinctrl/intel/pinctrl-intel.c
+++ b/drivers/pinctrl/intel/pinctrl-intel.c
@@ -220,47 +220,71 @@ static bool intel_pad_acpi_mode(struct intel_pinctrl *pctrl, unsigned int pin)
        return !(readl(hostown) & BIT(gpp_offset));
 }
 
-static bool intel_pad_locked(struct intel_pinctrl *pctrl, unsigned int pin)
+/**
+ * enum - Locking variants of the pad configuration
+ *
+ * @PAD_UNLOCKED:      pad is fully controlled by the configuration registers
+ * @PAD_LOCKED:                pad configuration registers, except TX state, are locked
+ * @PAD_LOCKED_TX:     pad configuration TX state is locked
+ * @PAD_LOCKED_FULL:   pad configuration registers are locked completely
+ *
+ * Locking is considered as read-only mode for corresponding registers and
+ * their respective fields. That said, TX state bit is locked separately from
+ * the main locking scheme.
+ */
+enum {
+       PAD_UNLOCKED    = 0,
+       PAD_LOCKED      = 1,
+       PAD_LOCKED_TX   = 2,
+       PAD_LOCKED_FULL = PAD_LOCKED | PAD_LOCKED_TX,
+};
+
+static int intel_pad_locked(struct intel_pinctrl *pctrl, unsigned int pin)
 {
        struct intel_community *community;
        const struct intel_padgroup *padgrp;
        unsigned int offset, gpp_offset;
        u32 value;
+       int ret = PAD_UNLOCKED;
 
        community = intel_get_community(pctrl, pin);
        if (!community)
-               return true;
+               return PAD_LOCKED_FULL;
        if (!community->padcfglock_offset)
-               return false;
+               return PAD_UNLOCKED;
 
        padgrp = intel_community_get_padgroup(community, pin);
        if (!padgrp)
-               return true;
+               return PAD_LOCKED_FULL;
 
        gpp_offset = padgroup_offset(padgrp, pin);
 
        /*
         * If PADCFGLOCK and PADCFGLOCKTX bits are both clear for this pad,
         * the pad is considered unlocked. Any other case means that it is
-        * either fully or partially locked and we don't touch it.
+        * either fully or partially locked.
         */
-       offset = community->padcfglock_offset + padgrp->reg_num * 8;
+       offset = community->padcfglock_offset + 0 + padgrp->reg_num * 8;
        value = readl(community->regs + offset);
        if (value & BIT(gpp_offset))
-               return true;
+               ret |= PAD_LOCKED;
 
        offset = community->padcfglock_offset + 4 + padgrp->reg_num * 8;
        value = readl(community->regs + offset);
        if (value & BIT(gpp_offset))
-               return true;
+               ret |= PAD_LOCKED_TX;
 
-       return false;
+       return ret;
+}
+
+static bool intel_pad_is_unlocked(struct intel_pinctrl *pctrl, unsigned int pin)
+{
+       return (intel_pad_locked(pctrl, pin) & PAD_LOCKED) == PAD_UNLOCKED;
 }
 
 static bool intel_pad_usable(struct intel_pinctrl *pctrl, unsigned int pin)
 {
-       return intel_pad_owned_by_host(pctrl, pin) &&
-               !intel_pad_locked(pctrl, pin);
+       return intel_pad_owned_by_host(pctrl, pin) && intel_pad_is_unlocked(pctrl, pin);
 }
 
 static int intel_get_groups_count(struct pinctrl_dev *pctldev)
@@ -294,7 +318,8 @@ static void intel_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
        struct intel_pinctrl *pctrl = pinctrl_dev_get_drvdata(pctldev);
        void __iomem *padcfg;
        u32 cfg0, cfg1, mode;
-       bool locked, acpi;
+       int locked;
+       bool acpi;
 
        if (!intel_pad_owned_by_host(pctrl, pin)) {
                seq_puts(s, "not available");
@@ -322,11 +347,16 @@ static void intel_pin_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
 
        if (locked || acpi) {
                seq_puts(s, " [");
-               if (locked) {
+               if (locked)
                        seq_puts(s, "LOCKED");
-                       if (acpi)
-                               seq_puts(s, ", ");
-               }
+               if ((locked & PAD_LOCKED_FULL) == PAD_LOCKED_TX)
+                       seq_puts(s, " tx");
+               else if ((locked & PAD_LOCKED_FULL) == PAD_LOCKED_FULL)
+                       seq_puts(s, " full");
+
+               if (locked && acpi)
+                       seq_puts(s, ", ");
+
                if (acpi)
                        seq_puts(s, "ACPI");
                seq_puts(s, "]");
@@ -448,11 +478,16 @@ static int intel_gpio_request_enable(struct pinctrl_dev *pctldev,
 
        raw_spin_lock_irqsave(&pctrl->lock, flags);
 
-       if (!intel_pad_usable(pctrl, pin)) {
+       if (!intel_pad_owned_by_host(pctrl, pin)) {
                raw_spin_unlock_irqrestore(&pctrl->lock, flags);
                return -EBUSY;
        }
 
+       if (!intel_pad_is_unlocked(pctrl, pin)) {
+               raw_spin_unlock_irqrestore(&pctrl->lock, flags);
+               return 0;
+       }
+
        padcfg0 = intel_get_padcfg(pctrl, pin, PADCFG0);
        intel_gpio_set_gpio_mode(padcfg0);
        /* Disable TX buffer and enable RX (this will be input) */