pinctrl: Add one-register-per-pin type device tree based pinctrl driver
authorTony Lindgren <tony@atomide.com>
Tue, 10 Jul 2012 09:05:46 +0000 (02:05 -0700)
committerLinus Walleij <linus.walleij@linaro.org>
Sat, 14 Jul 2012 20:33:08 +0000 (22:33 +0200)
Add one-register-per-pin type device tree based pinctrl driver.

This driver has been tested on omap2+ series of processors,
where there is either an 8 or 16-bit padconf register for each pin.
Support for other similar pinmux controllers can be added.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Documentation/devicetree/bindings/pinctrl/pinctrl-single.txt [new file with mode: 0644]
drivers/pinctrl/Kconfig
drivers/pinctrl/Makefile
drivers/pinctrl/pinctrl-single.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-single.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-single.txt
new file mode 100644 (file)
index 0000000..5187f0d
--- /dev/null
@@ -0,0 +1,93 @@
+One-register-per-pin type device tree based pinctrl driver
+
+Required properties:
+- compatible : "pinctrl-single"
+
+- reg : offset and length of the register set for the mux registers
+
+- pinctrl-single,register-width : pinmux register access width in bits
+
+- pinctrl-single,function-mask : mask of allowed pinmux function bits
+  in the pinmux register
+
+Optional properties:
+- pinctrl-single,function-off : function off mode for disabled state if
+  available and same for all registers; if not specified, disabling of
+  pin functions is ignored
+
+This driver assumes that there is only one register for each pin,
+and uses the common pinctrl bindings as specified in the pinctrl-bindings.txt
+document in this directory.
+
+The pin configuration nodes for pinctrl-single are specified as pinctrl
+register offset and value pairs using pinctrl-single,pins. Only the bits
+specified in pinctrl-single,function-mask are updated. For example, setting
+a pin for a device could be done with:
+
+       pinctrl-single,pins = <0xdc 0x118>;
+
+Where 0xdc is the offset from the pinctrl register base address for the
+device pinctrl register, and 0x118 contains the desired value of the
+pinctrl register. See the device example and static board pins example
+below for more information.
+
+Example:
+
+/* SoC common file */
+
+/* first controller instance for pins in core domain */
+pmx_core: pinmux@4a100040 {
+       compatible = "pinctrl-single";
+       reg = <0x4a100040 0x0196>;
+       #address-cells = <1>;
+       #size-cells = <0>;
+       pinctrl-single,register-width = <16>;
+       pinctrl-single,function-mask = <0xffff>;
+};
+
+/* second controller instance for pins in wkup domain */
+pmx_wkup: pinmux@4a31e040 {
+       compatible = "pinctrl-single;
+       reg = <0x4a31e040 0x0038>;
+       #address-cells = <1>;
+       #size-cells = <0>;
+       pinctrl-single,register-width = <16>;
+       pinctrl-single,function-mask = <0xffff>;
+};
+
+
+/* board specific .dts file */
+
+&pmx_core {
+
+       /*
+        * map all board specific static pins enabled by the pinctrl driver
+        * itself during the boot (or just set them up in the bootloader)
+        */
+       pinctrl-names = "default";
+       pinctrl-0 = <&board_pins>;
+
+       board_pins: pinmux_board_pins {
+               pinctrl-single,pins = <
+                       0x6c 0xf
+                       0x6e 0xf
+                       0x70 0xf
+                       0x72 0xf
+               >;
+       };
+
+       /* map uart2 pins */
+       uart2_pins: pinmux_uart2_pins {
+               pinctrl-single,pins = <
+                       0xd8 0x118
+                       0xda 0
+                       0xdc 0x118
+                       0xde 0
+               >;
+       };
+};
+
+&uart2 {
+       pinctrl-names = "default";
+       pinctrl-0 = <&uart2_pins>;
+};
index 4c05fe8ced599a944564b8dff352139c8fff0861..54e3588bef62ab73ef75cbc6f8878d84c72e43ec 100644 (file)
@@ -102,6 +102,14 @@ config PINCTRL_PXA910
        select PINCTRL_PXA3xx
        select PINCONF
 
+config PINCTRL_SINGLE
+       tristate "One-register-per-pin type device tree based pinctrl driver"
+       depends on OF
+       select PINMUX
+       select PINCONF
+       help
+         This selects the device tree based generic pinctrl driver.
+
 config PINCTRL_SIRF
        bool "CSR SiRFprimaII pin controller driver"
        depends on ARCH_PRIMA2
index 8c074376cdeac3dfd313f72397771e1cd809199e..f40b1f81ff2ceea2f7421bc8d9761f7bb990bb11 100644 (file)
@@ -22,6 +22,7 @@ obj-$(CONFIG_PINCTRL_NOMADIK) += pinctrl-nomadik.o
 obj-$(CONFIG_PINCTRL_DB8500)   += pinctrl-nomadik-db8500.o
 obj-$(CONFIG_PINCTRL_PXA168)   += pinctrl-pxa168.o
 obj-$(CONFIG_PINCTRL_PXA910)   += pinctrl-pxa910.o
+obj-$(CONFIG_PINCTRL_SINGLE)   += pinctrl-single.o
 obj-$(CONFIG_PINCTRL_SIRF)     += pinctrl-sirf.o
 obj-$(CONFIG_PINCTRL_TEGRA)    += pinctrl-tegra.o
 obj-$(CONFIG_PINCTRL_TEGRA20)  += pinctrl-tegra20.o
diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
new file mode 100644 (file)
index 0000000..76a4260
--- /dev/null
@@ -0,0 +1,987 @@
+/*
+ * Generic device tree based pinctrl driver for one register per pin
+ * type pinmux controllers
+ *
+ * Copyright (C) 2012 Texas Instruments, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/list.h>
+
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.h>
+
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/pinctrl/pinmux.h>
+
+#include "core.h"
+
+#define DRIVER_NAME                    "pinctrl-single"
+#define PCS_MUX_NAME                   "pinctrl-single,pins"
+#define PCS_REG_NAME_LEN               ((sizeof(unsigned long) * 2) + 1)
+#define PCS_OFF_DISABLED               ~0U
+
+/**
+ * struct pcs_pingroup - pingroups for a function
+ * @np:                pingroup device node pointer
+ * @name:      pingroup name
+ * @gpins:     array of the pins in the group
+ * @ngpins:    number of pins in the group
+ * @node:      list node
+ */
+struct pcs_pingroup {
+       struct device_node *np;
+       const char *name;
+       int *gpins;
+       int ngpins;
+       struct list_head node;
+};
+
+/**
+ * struct pcs_func_vals - mux function register offset and value pair
+ * @reg:       register virtual address
+ * @val:       register value
+ */
+struct pcs_func_vals {
+       void __iomem *reg;
+       unsigned val;
+};
+
+/**
+ * struct pcs_function - pinctrl function
+ * @name:      pinctrl function name
+ * @vals:      register and vals array
+ * @nvals:     number of entries in vals array
+ * @pgnames:   array of pingroup names the function uses
+ * @npgnames:  number of pingroup names the function uses
+ * @node:      list node
+ */
+struct pcs_function {
+       const char *name;
+       struct pcs_func_vals *vals;
+       unsigned nvals;
+       const char **pgnames;
+       int npgnames;
+       struct list_head node;
+};
+
+/**
+ * struct pcs_data - wrapper for data needed by pinctrl framework
+ * @pa:                pindesc array
+ * @cur:       index to current element
+ *
+ * REVISIT: We should be able to drop this eventually by adding
+ * support for registering pins individually in the pinctrl
+ * framework for those drivers that don't need a static array.
+ */
+struct pcs_data {
+       struct pinctrl_pin_desc *pa;
+       int cur;
+};
+
+/**
+ * struct pcs_name - register name for a pin
+ * @name:      name of the pinctrl register
+ *
+ * REVISIT: We may want to make names optional in the pinctrl
+ * framework as some drivers may not care about pin names to
+ * avoid kernel bloat. The pin names can be deciphered by user
+ * space tools using debugfs based on the register address and
+ * SoC packaging information.
+ */
+struct pcs_name {
+       char name[PCS_REG_NAME_LEN];
+};
+
+/**
+ * struct pcs_device - pinctrl device instance
+ * @res:       resources
+ * @base:      virtual address of the controller
+ * @size:      size of the ioremapped area
+ * @dev:       device entry
+ * @pctl:      pin controller device
+ * @mutex:     mutex protecting the lists
+ * @width:     bits per mux register
+ * @fmask:     function register mask
+ * @fshift:    function register shift
+ * @foff:      value to turn mux off
+ * @fmax:      max number of functions in fmask
+ * @names:     array of register names for pins
+ * @pins:      physical pins on the SoC
+ * @pgtree:    pingroup index radix tree
+ * @ftree:     function index radix tree
+ * @pingroups: list of pingroups
+ * @functions: list of functions
+ * @ngroups:   number of pingroups
+ * @nfuncs:    number of functions
+ * @desc:      pin controller descriptor
+ * @read:      register read function to use
+ * @write:     register write function to use
+ */
+struct pcs_device {
+       struct resource *res;
+       void __iomem *base;
+       unsigned size;
+       struct device *dev;
+       struct pinctrl_dev *pctl;
+       struct mutex mutex;
+       unsigned width;
+       unsigned fmask;
+       unsigned fshift;
+       unsigned foff;
+       unsigned fmax;
+       struct pcs_name *names;
+       struct pcs_data pins;
+       struct radix_tree_root pgtree;
+       struct radix_tree_root ftree;
+       struct list_head pingroups;
+       struct list_head functions;
+       unsigned ngroups;
+       unsigned nfuncs;
+       struct pinctrl_desc desc;
+       unsigned (*read)(void __iomem *reg);
+       void (*write)(unsigned val, void __iomem *reg);
+};
+
+/*
+ * REVISIT: Reads and writes could eventually use regmap or something
+ * generic. But at least on omaps, some mux registers are performance
+ * critical as they may need to be remuxed every time before and after
+ * idle. Adding tests for register access width for every read and
+ * write like regmap is doing is not desired, and caching the registers
+ * does not help in this case.
+ */
+
+static unsigned __maybe_unused pcs_readb(void __iomem *reg)
+{
+       return readb(reg);
+}
+
+static unsigned __maybe_unused pcs_readw(void __iomem *reg)
+{
+       return readw(reg);
+}
+
+static unsigned __maybe_unused pcs_readl(void __iomem *reg)
+{
+       return readl(reg);
+}
+
+static void __maybe_unused pcs_writeb(unsigned val, void __iomem *reg)
+{
+       writeb(val, reg);
+}
+
+static void __maybe_unused pcs_writew(unsigned val, void __iomem *reg)
+{
+       writew(val, reg);
+}
+
+static void __maybe_unused pcs_writel(unsigned val, void __iomem *reg)
+{
+       writel(val, reg);
+}
+
+static int pcs_get_groups_count(struct pinctrl_dev *pctldev)
+{
+       struct pcs_device *pcs;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+
+       return pcs->ngroups;
+}
+
+static const char *pcs_get_group_name(struct pinctrl_dev *pctldev,
+                                       unsigned gselector)
+{
+       struct pcs_device *pcs;
+       struct pcs_pingroup *group;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+       group = radix_tree_lookup(&pcs->pgtree, gselector);
+       if (!group) {
+               dev_err(pcs->dev, "%s could not find pingroup%i\n",
+                       __func__, gselector);
+               return NULL;
+       }
+
+       return group->name;
+}
+
+static int pcs_get_group_pins(struct pinctrl_dev *pctldev,
+                                       unsigned gselector,
+                                       const unsigned **pins,
+                                       unsigned *npins)
+{
+       struct pcs_device *pcs;
+       struct pcs_pingroup *group;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+       group = radix_tree_lookup(&pcs->pgtree, gselector);
+       if (!group) {
+               dev_err(pcs->dev, "%s could not find pingroup%i\n",
+                       __func__, gselector);
+               return -EINVAL;
+       }
+
+       *pins = group->gpins;
+       *npins = group->ngpins;
+
+       return 0;
+}
+
+static void pcs_pin_dbg_show(struct pinctrl_dev *pctldev,
+                                       struct seq_file *s,
+                                       unsigned offset)
+{
+       seq_printf(s, " " DRIVER_NAME);
+}
+
+static void pcs_dt_free_map(struct pinctrl_dev *pctldev,
+                               struct pinctrl_map *map, unsigned num_maps)
+{
+       struct pcs_device *pcs;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+       devm_kfree(pcs->dev, map);
+}
+
+static int pcs_dt_node_to_map(struct pinctrl_dev *pctldev,
+                               struct device_node *np_config,
+                               struct pinctrl_map **map, unsigned *num_maps);
+
+static struct pinctrl_ops pcs_pinctrl_ops = {
+       .get_groups_count = pcs_get_groups_count,
+       .get_group_name = pcs_get_group_name,
+       .get_group_pins = pcs_get_group_pins,
+       .pin_dbg_show = pcs_pin_dbg_show,
+       .dt_node_to_map = pcs_dt_node_to_map,
+       .dt_free_map = pcs_dt_free_map,
+};
+
+static int pcs_get_functions_count(struct pinctrl_dev *pctldev)
+{
+       struct pcs_device *pcs;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+
+       return pcs->nfuncs;
+}
+
+static const char *pcs_get_function_name(struct pinctrl_dev *pctldev,
+                                               unsigned fselector)
+{
+       struct pcs_device *pcs;
+       struct pcs_function *func;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+       func = radix_tree_lookup(&pcs->ftree, fselector);
+       if (!func) {
+               dev_err(pcs->dev, "%s could not find function%i\n",
+                       __func__, fselector);
+               return NULL;
+       }
+
+       return func->name;
+}
+
+static int pcs_get_function_groups(struct pinctrl_dev *pctldev,
+                                       unsigned fselector,
+                                       const char * const **groups,
+                                       unsigned * const ngroups)
+{
+       struct pcs_device *pcs;
+       struct pcs_function *func;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+       func = radix_tree_lookup(&pcs->ftree, fselector);
+       if (!func) {
+               dev_err(pcs->dev, "%s could not find function%i\n",
+                       __func__, fselector);
+               return -EINVAL;
+       }
+       *groups = func->pgnames;
+       *ngroups = func->npgnames;
+
+       return 0;
+}
+
+static int pcs_enable(struct pinctrl_dev *pctldev, unsigned fselector,
+       unsigned group)
+{
+       struct pcs_device *pcs;
+       struct pcs_function *func;
+       int i;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+       func = radix_tree_lookup(&pcs->ftree, fselector);
+       if (!func)
+               return -EINVAL;
+
+       dev_dbg(pcs->dev, "enabling %s function%i\n",
+               func->name, fselector);
+
+       for (i = 0; i < func->nvals; i++) {
+               struct pcs_func_vals *vals;
+               unsigned val;
+
+               vals = &func->vals[i];
+               val = pcs->read(vals->reg);
+               val &= ~pcs->fmask;
+               val |= vals->val;
+               pcs->write(val, vals->reg);
+       }
+
+       return 0;
+}
+
+static void pcs_disable(struct pinctrl_dev *pctldev, unsigned fselector,
+                                       unsigned group)
+{
+       struct pcs_device *pcs;
+       struct pcs_function *func;
+       int i;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+       func = radix_tree_lookup(&pcs->ftree, fselector);
+       if (!func) {
+               dev_err(pcs->dev, "%s could not find function%i\n",
+                       __func__, fselector);
+               return;
+       }
+
+       /*
+        * Ignore disable if function-off is not specified. Some hardware
+        * does not have clearly defined disable function. For pin specific
+        * off modes, you can use alternate named states as described in
+        * pinctrl-bindings.txt.
+        */
+       if (pcs->foff == PCS_OFF_DISABLED) {
+               dev_dbg(pcs->dev, "ignoring disable for %s function%i\n",
+                       func->name, fselector);
+               return;
+       }
+
+       dev_dbg(pcs->dev, "disabling function%i %s\n",
+               fselector, func->name);
+
+       for (i = 0; i < func->nvals; i++) {
+               struct pcs_func_vals *vals;
+               unsigned val;
+
+               vals = &func->vals[i];
+               val = pcs->read(vals->reg);
+               val &= ~pcs->fmask;
+               val |= pcs->foff << pcs->fshift;
+               pcs->write(val, vals->reg);
+       }
+}
+
+static int pcs_request_gpio(struct pinctrl_dev *pctldev,
+                       struct pinctrl_gpio_range *range, unsigned offset)
+{
+       return -ENOTSUPP;
+}
+
+static struct pinmux_ops pcs_pinmux_ops = {
+       .get_functions_count = pcs_get_functions_count,
+       .get_function_name = pcs_get_function_name,
+       .get_function_groups = pcs_get_function_groups,
+       .enable = pcs_enable,
+       .disable = pcs_disable,
+       .gpio_request_enable = pcs_request_gpio,
+};
+
+static int pcs_pinconf_get(struct pinctrl_dev *pctldev,
+                               unsigned pin, unsigned long *config)
+{
+       return -ENOTSUPP;
+}
+
+static int pcs_pinconf_set(struct pinctrl_dev *pctldev,
+                               unsigned pin, unsigned long config)
+{
+       return -ENOTSUPP;
+}
+
+static int pcs_pinconf_group_get(struct pinctrl_dev *pctldev,
+                               unsigned group, unsigned long *config)
+{
+       return -ENOTSUPP;
+}
+
+static int pcs_pinconf_group_set(struct pinctrl_dev *pctldev,
+                               unsigned group, unsigned long config)
+{
+       return -ENOTSUPP;
+}
+
+static void pcs_pinconf_dbg_show(struct pinctrl_dev *pctldev,
+                               struct seq_file *s, unsigned offset)
+{
+}
+
+static void pcs_pinconf_group_dbg_show(struct pinctrl_dev *pctldev,
+                               struct seq_file *s, unsigned selector)
+{
+}
+
+static struct pinconf_ops pcs_pinconf_ops = {
+       .pin_config_get = pcs_pinconf_get,
+       .pin_config_set = pcs_pinconf_set,
+       .pin_config_group_get = pcs_pinconf_group_get,
+       .pin_config_group_set = pcs_pinconf_group_set,
+       .pin_config_dbg_show = pcs_pinconf_dbg_show,
+       .pin_config_group_dbg_show = pcs_pinconf_group_dbg_show,
+};
+
+/**
+ * pcs_add_pin() - add a pin to the static per controller pin array
+ * @pcs: pcs driver instance
+ * @offset: register offset from base
+ */
+static int __devinit pcs_add_pin(struct pcs_device *pcs, unsigned offset)
+{
+       struct pinctrl_pin_desc *pin;
+       struct pcs_name *pn;
+       int i;
+
+       i = pcs->pins.cur;
+       if (i >= pcs->desc.npins) {
+               dev_err(pcs->dev, "too many pins, max %i\n",
+                       pcs->desc.npins);
+               return -ENOMEM;
+       }
+
+       pin = &pcs->pins.pa[i];
+       pn = &pcs->names[i];
+       sprintf(pn->name, "%lx",
+               (unsigned long)pcs->res->start + offset);
+       pin->name = pn->name;
+       pin->number = i;
+       pcs->pins.cur++;
+
+       return i;
+}
+
+/**
+ * pcs_allocate_pin_table() - adds all the pins for the pinctrl driver
+ * @pcs: pcs driver instance
+ *
+ * In case of errors, resources are freed in pcs_free_resources.
+ *
+ * If your hardware needs holes in the address space, then just set
+ * up multiple driver instances.
+ */
+static int __devinit pcs_allocate_pin_table(struct pcs_device *pcs)
+{
+       int mux_bytes, nr_pins, i;
+
+       mux_bytes = pcs->width / BITS_PER_BYTE;
+       nr_pins = pcs->size / mux_bytes;
+
+       dev_dbg(pcs->dev, "allocating %i pins\n", nr_pins);
+       pcs->pins.pa = devm_kzalloc(pcs->dev,
+                               sizeof(*pcs->pins.pa) * nr_pins,
+                               GFP_KERNEL);
+       if (!pcs->pins.pa)
+               return -ENOMEM;
+
+       pcs->names = devm_kzalloc(pcs->dev,
+                               sizeof(struct pcs_name) * nr_pins,
+                               GFP_KERNEL);
+       if (!pcs->names)
+               return -ENOMEM;
+
+       pcs->desc.pins = pcs->pins.pa;
+       pcs->desc.npins = nr_pins;
+
+       for (i = 0; i < pcs->desc.npins; i++) {
+               unsigned offset;
+               int res;
+
+               offset = i * mux_bytes;
+               res = pcs_add_pin(pcs, offset);
+               if (res < 0) {
+                       dev_err(pcs->dev, "error adding pins: %i\n", res);
+                       return res;
+               }
+       }
+
+       return 0;
+}
+
+/**
+ * pcs_add_function() - adds a new function to the function list
+ * @pcs: pcs driver instance
+ * @np: device node of the mux entry
+ * @name: name of the function
+ * @vals: array of mux register value pairs used by the function
+ * @nvals: number of mux register value pairs
+ * @pgnames: array of pingroup names for the function
+ * @npgnames: number of pingroup names
+ */
+static struct pcs_function *pcs_add_function(struct pcs_device *pcs,
+                                       struct device_node *np,
+                                       const char *name,
+                                       struct pcs_func_vals *vals,
+                                       unsigned nvals,
+                                       const char **pgnames,
+                                       unsigned npgnames)
+{
+       struct pcs_function *function;
+
+       function = devm_kzalloc(pcs->dev, sizeof(*function), GFP_KERNEL);
+       if (!function)
+               return NULL;
+
+       function->name = name;
+       function->vals = vals;
+       function->nvals = nvals;
+       function->pgnames = pgnames;
+       function->npgnames = npgnames;
+
+       mutex_lock(&pcs->mutex);
+       list_add_tail(&function->node, &pcs->functions);
+       radix_tree_insert(&pcs->ftree, pcs->nfuncs, function);
+       pcs->nfuncs++;
+       mutex_unlock(&pcs->mutex);
+
+       return function;
+}
+
+static void pcs_remove_function(struct pcs_device *pcs,
+                               struct pcs_function *function)
+{
+       int i;
+
+       mutex_lock(&pcs->mutex);
+       for (i = 0; i < pcs->nfuncs; i++) {
+               struct pcs_function *found;
+
+               found = radix_tree_lookup(&pcs->ftree, i);
+               if (found == function)
+                       radix_tree_delete(&pcs->ftree, i);
+       }
+       list_del(&function->node);
+       mutex_unlock(&pcs->mutex);
+}
+
+/**
+ * pcs_add_pingroup() - add a pingroup to the pingroup list
+ * @pcs: pcs driver instance
+ * @np: device node of the mux entry
+ * @name: name of the pingroup
+ * @gpins: array of the pins that belong to the group
+ * @ngpins: number of pins in the group
+ */
+static int pcs_add_pingroup(struct pcs_device *pcs,
+                                       struct device_node *np,
+                                       const char *name,
+                                       int *gpins,
+                                       int ngpins)
+{
+       struct pcs_pingroup *pingroup;
+
+       pingroup = devm_kzalloc(pcs->dev, sizeof(*pingroup), GFP_KERNEL);
+       if (!pingroup)
+               return -ENOMEM;
+
+       pingroup->name = name;
+       pingroup->np = np;
+       pingroup->gpins = gpins;
+       pingroup->ngpins = ngpins;
+
+       mutex_lock(&pcs->mutex);
+       list_add_tail(&pingroup->node, &pcs->pingroups);
+       radix_tree_insert(&pcs->pgtree, pcs->ngroups, pingroup);
+       pcs->ngroups++;
+       mutex_unlock(&pcs->mutex);
+
+       return 0;
+}
+
+/**
+ * pcs_get_pin_by_offset() - get a pin index based on the register offset
+ * @pcs: pcs driver instance
+ * @offset: register offset from the base
+ *
+ * Note that this is OK as long as the pins are in a static array.
+ */
+static int pcs_get_pin_by_offset(struct pcs_device *pcs, unsigned offset)
+{
+       unsigned index;
+
+       if (offset >= pcs->size) {
+               dev_err(pcs->dev, "mux offset out of range: 0x%x (0x%x)\n",
+                       offset, pcs->size);
+               return -EINVAL;
+       }
+
+       index = offset / (pcs->width / BITS_PER_BYTE);
+
+       return index;
+}
+
+/**
+ * smux_parse_one_pinctrl_entry() - parses a device tree mux entry
+ * @pcs: pinctrl driver instance
+ * @np: device node of the mux entry
+ * @map: map entry
+ * @pgnames: pingroup names
+ *
+ * Note that this binding currently supports only sets of one register + value.
+ *
+ * Also note that this driver tries to avoid understanding pin and function
+ * names because of the extra bloat they would cause especially in the case of
+ * a large number of pins. This driver just sets what is specified for the board
+ * in the .dts file. Further user space debugging tools can be developed to
+ * decipher the pin and function names using debugfs.
+ *
+ * If you are concerned about the boot time, set up the static pins in
+ * the bootloader, and only set up selected pins as device tree entries.
+ */
+static int pcs_parse_one_pinctrl_entry(struct pcs_device *pcs,
+                                               struct device_node *np,
+                                               struct pinctrl_map **map,
+                                               const char **pgnames)
+{
+       struct pcs_func_vals *vals;
+       const __be32 *mux;
+       int size, rows, *pins, index = 0, found = 0, res = -ENOMEM;
+       struct pcs_function *function;
+
+       mux = of_get_property(np, PCS_MUX_NAME, &size);
+       if ((!mux) || (size < sizeof(*mux) * 2)) {
+               dev_err(pcs->dev, "bad data for mux %s\n",
+                       np->name);
+               return -EINVAL;
+       }
+
+       size /= sizeof(*mux);   /* Number of elements in array */
+       rows = size / 2;        /* Each row is a key value pair */
+
+       vals = devm_kzalloc(pcs->dev, sizeof(*vals) * rows, GFP_KERNEL);
+       if (!vals)
+               return -ENOMEM;
+
+       pins = devm_kzalloc(pcs->dev, sizeof(*pins) * rows, GFP_KERNEL);
+       if (!pins)
+               goto free_vals;
+
+       while (index < size) {
+               unsigned offset, val;
+               int pin;
+
+               offset = be32_to_cpup(mux + index++);
+               val = be32_to_cpup(mux + index++);
+               vals[found].reg = pcs->base + offset;
+               vals[found].val = val;
+
+               pin = pcs_get_pin_by_offset(pcs, offset);
+               if (pin < 0) {
+                       dev_err(pcs->dev,
+                               "could not add functions for %s %ux\n",
+                               np->name, offset);
+                       break;
+               }
+               pins[found++] = pin;
+       }
+
+       pgnames[0] = np->name;
+       function = pcs_add_function(pcs, np, np->name, vals, found, pgnames, 1);
+       if (!function)
+               goto free_pins;
+
+       res = pcs_add_pingroup(pcs, np, np->name, pins, found);
+       if (res < 0)
+               goto free_function;
+
+       (*map)->type = PIN_MAP_TYPE_MUX_GROUP;
+       (*map)->data.mux.group = np->name;
+       (*map)->data.mux.function = np->name;
+
+       return 0;
+
+free_function:
+       pcs_remove_function(pcs, function);
+
+free_pins:
+       devm_kfree(pcs->dev, pins);
+
+free_vals:
+       devm_kfree(pcs->dev, vals);
+
+       return res;
+}
+/**
+ * pcs_dt_node_to_map() - allocates and parses pinctrl maps
+ * @pctldev: pinctrl instance
+ * @np_config: device tree pinmux entry
+ * @map: array of map entries
+ * @num_maps: number of maps
+ */
+static int pcs_dt_node_to_map(struct pinctrl_dev *pctldev,
+                               struct device_node *np_config,
+                               struct pinctrl_map **map, unsigned *num_maps)
+{
+       struct pcs_device *pcs;
+       const char **pgnames;
+       int ret;
+
+       pcs = pinctrl_dev_get_drvdata(pctldev);
+
+       *map = devm_kzalloc(pcs->dev, sizeof(**map), GFP_KERNEL);
+       if (!map)
+               return -ENOMEM;
+
+       *num_maps = 0;
+
+       pgnames = devm_kzalloc(pcs->dev, sizeof(*pgnames), GFP_KERNEL);
+       if (!pgnames) {
+               ret = -ENOMEM;
+               goto free_map;
+       }
+
+       ret = pcs_parse_one_pinctrl_entry(pcs, np_config, map, pgnames);
+       if (ret < 0) {
+               dev_err(pcs->dev, "no pins entries for %s\n",
+                       np_config->name);
+               goto free_pgnames;
+       }
+       *num_maps = 1;
+
+       return 0;
+
+free_pgnames:
+       devm_kfree(pcs->dev, pgnames);
+free_map:
+       devm_kfree(pcs->dev, *map);
+
+       return ret;
+}
+
+/**
+ * pcs_free_funcs() - free memory used by functions
+ * @pcs: pcs driver instance
+ */
+static void pcs_free_funcs(struct pcs_device *pcs)
+{
+       struct list_head *pos, *tmp;
+       int i;
+
+       mutex_lock(&pcs->mutex);
+       for (i = 0; i < pcs->nfuncs; i++) {
+               struct pcs_function *func;
+
+               func = radix_tree_lookup(&pcs->ftree, i);
+               if (!func)
+                       continue;
+               radix_tree_delete(&pcs->ftree, i);
+       }
+       list_for_each_safe(pos, tmp, &pcs->functions) {
+               struct pcs_function *function;
+
+               function = list_entry(pos, struct pcs_function, node);
+               list_del(&function->node);
+       }
+       mutex_unlock(&pcs->mutex);
+}
+
+/**
+ * pcs_free_pingroups() - free memory used by pingroups
+ * @pcs: pcs driver instance
+ */
+static void pcs_free_pingroups(struct pcs_device *pcs)
+{
+       struct list_head *pos, *tmp;
+       int i;
+
+       mutex_lock(&pcs->mutex);
+       for (i = 0; i < pcs->ngroups; i++) {
+               struct pcs_pingroup *pingroup;
+
+               pingroup = radix_tree_lookup(&pcs->pgtree, i);
+               if (!pingroup)
+                       continue;
+               radix_tree_delete(&pcs->pgtree, i);
+       }
+       list_for_each_safe(pos, tmp, &pcs->pingroups) {
+               struct pcs_pingroup *pingroup;
+
+               pingroup = list_entry(pos, struct pcs_pingroup, node);
+               list_del(&pingroup->node);
+       }
+       mutex_unlock(&pcs->mutex);
+}
+
+/**
+ * pcs_free_resources() - free memory used by this driver
+ * @pcs: pcs driver instance
+ */
+static void pcs_free_resources(struct pcs_device *pcs)
+{
+       if (pcs->pctl)
+               pinctrl_unregister(pcs->pctl);
+
+       pcs_free_funcs(pcs);
+       pcs_free_pingroups(pcs);
+}
+
+#define PCS_GET_PROP_U32(name, reg, err)                               \
+       do {                                                            \
+               ret = of_property_read_u32(np, name, reg);              \
+               if (ret) {                                              \
+                       dev_err(pcs->dev, err);                         \
+                       return ret;                                     \
+               }                                                       \
+       } while (0);
+
+static struct of_device_id pcs_of_match[];
+
+static int __devinit pcs_probe(struct platform_device *pdev)
+{
+       struct device_node *np = pdev->dev.of_node;
+       const struct of_device_id *match;
+       struct resource *res;
+       struct pcs_device *pcs;
+       int ret;
+
+       match = of_match_device(pcs_of_match, &pdev->dev);
+       if (!match)
+               return -EINVAL;
+
+       pcs = devm_kzalloc(&pdev->dev, sizeof(*pcs), GFP_KERNEL);
+       if (!pcs) {
+               dev_err(&pdev->dev, "could not allocate\n");
+               return -ENOMEM;
+       }
+       pcs->dev = &pdev->dev;
+       mutex_init(&pcs->mutex);
+       INIT_LIST_HEAD(&pcs->pingroups);
+       INIT_LIST_HEAD(&pcs->functions);
+
+       PCS_GET_PROP_U32("pinctrl-single,register-width", &pcs->width,
+                        "register width not specified\n");
+
+       PCS_GET_PROP_U32("pinctrl-single,function-mask", &pcs->fmask,
+                        "function register mask not specified\n");
+       pcs->fshift = ffs(pcs->fmask) - 1;
+       pcs->fmax = pcs->fmask >> pcs->fshift;
+
+       ret = of_property_read_u32(np, "pinctrl-single,function-off",
+                                       &pcs->foff);
+       if (ret)
+               pcs->foff = PCS_OFF_DISABLED;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!res) {
+               dev_err(pcs->dev, "could not get resource\n");
+               return -ENODEV;
+       }
+
+       pcs->res = devm_request_mem_region(pcs->dev, res->start,
+                       resource_size(res), DRIVER_NAME);
+       if (!pcs->res) {
+               dev_err(pcs->dev, "could not get mem_region\n");
+               return -EBUSY;
+       }
+
+       pcs->size = resource_size(pcs->res);
+       pcs->base = devm_ioremap(pcs->dev, pcs->res->start, pcs->size);
+       if (!pcs->base) {
+               dev_err(pcs->dev, "could not ioremap\n");
+               return -ENODEV;
+       }
+
+       INIT_RADIX_TREE(&pcs->pgtree, GFP_KERNEL);
+       INIT_RADIX_TREE(&pcs->ftree, GFP_KERNEL);
+       platform_set_drvdata(pdev, pcs);
+
+       switch (pcs->width) {
+       case 8:
+               pcs->read = pcs_readb;
+               pcs->write = pcs_writeb;
+               break;
+       case 16:
+               pcs->read = pcs_readw;
+               pcs->write = pcs_writew;
+               break;
+       case 32:
+               pcs->read = pcs_readl;
+               pcs->write = pcs_writel;
+               break;
+       default:
+               break;
+       }
+
+       pcs->desc.name = DRIVER_NAME;
+       pcs->desc.pctlops = &pcs_pinctrl_ops;
+       pcs->desc.pmxops = &pcs_pinmux_ops;
+       pcs->desc.confops = &pcs_pinconf_ops;
+       pcs->desc.owner = THIS_MODULE;
+
+       ret = pcs_allocate_pin_table(pcs);
+       if (ret < 0)
+               goto free;
+
+       pcs->pctl = pinctrl_register(&pcs->desc, pcs->dev, pcs);
+       if (!pcs->pctl) {
+               dev_err(pcs->dev, "could not register single pinctrl driver\n");
+               ret = -EINVAL;
+               goto free;
+       }
+
+       dev_info(pcs->dev, "%i pins at pa %p size %u\n",
+                pcs->desc.npins, pcs->base, pcs->size);
+
+       return 0;
+
+free:
+       pcs_free_resources(pcs);
+
+       return ret;
+}
+
+static int __devexit pcs_remove(struct platform_device *pdev)
+{
+       struct pcs_device *pcs = platform_get_drvdata(pdev);
+
+       if (!pcs)
+               return 0;
+
+       pcs_free_resources(pcs);
+
+       return 0;
+}
+
+static struct of_device_id pcs_of_match[] __devinitdata = {
+       { .compatible = DRIVER_NAME, },
+       { },
+};
+MODULE_DEVICE_TABLE(of, pcs_of_match);
+
+static struct platform_driver pcs_driver = {
+       .probe          = pcs_probe,
+       .remove         = __devexit_p(pcs_remove),
+       .driver = {
+               .owner          = THIS_MODULE,
+               .name           = DRIVER_NAME,
+               .of_match_table = pcs_of_match,
+       },
+};
+
+module_platform_driver(pcs_driver);
+
+MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
+MODULE_DESCRIPTION("One-register-per-pin type device tree based pinctrl driver");
+MODULE_LICENSE("GPL v2");