[2/2] pinctrl: Introduce TI IOdelay configuration driver

Message ID 20170105185414.27247-3-tony@atomide.com
State New
Headers show

Commit Message

Tony Lindgren Jan. 5, 2017, 6:54 p.m.
From: Nishanth Menon <nm@ti.com>


SoC family such as DRA7 family of processors have, in addition
to the regular muxing of pins (as done by pinctrl-single), a separate
hardware module called IODelay which is also expected to be configured.
The "IODelay" module has it's own register space that is independent
of the control module and the padconf register area.

With recent changes to the pinctrl framework, we can now support
this hardware with a reasonably minimal driver by using #pinctrl-cells,
GENERIC_PINCTRL_GROUPS and GENERIC_PINMUX_FUNCTIONS.

It is advocated strongly in TI's official documentation considering
the existing design of the DRA7 family of processors during mux or
IODelay reconfiguration, there is a potential for a significant glitch
which may cause functional impairment to certain hardware. It is
hence recommended to do as little of muxing as absolutely necessary
without I/O isolation (which can only be done in initial stages of
bootloader).

NOTE: with the system wide I/O isolation scheme present in DRA7 SoC
family, it is not reasonable to do stop all I/O operations for every
such pad configuration scheme. So, we will let it glitch when used in
this mode.

Even with the above limitation, certain functionality such as MMC has
mandatory need for IODelay reconfiguration requirements, depending on
speed of transfer. In these cases, with careful examination of usecase
involved, the expected glitch can be controlled such that it does not
impact functionality.

In short, IODelay module support as a padconf driver being introduced
here is not expected to do SoC wide I/O Isolation and is meant for
a limited subset of IODelay configuration requirements that need to
be dynamic and whose glitchy behavior will not cause functionality
failure for that interface.

IMPORTANT NOTE: we take the approach of keeping LOCK_BITs cleared
to 0x0 at all times, even when configuring Manual IO Timing Modes.
This is done by eliminating the LOCK_BIT=1 setting from Step
of the Manual IO timing Mode configuration procedure. This option
leaves the CFG_* registers unprotected from unintended writes to the
CTRL_CORE_PAD_* registers while Manual IO Timing Modes are configured.

This approach is taken to allow for a generic driver to exist in kernel
world that has to be used carefully in required usecases.

Signed-off-by: Nishanth Menon <nm@ti.com>

Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>

[tony@atomide.com: updated to use generic pinctrl functions, added
 binding documentation, updated comments]
Acked-by: Rob Herring <robh@kernel.org>

Signed-off-by: Tony Lindgren <tony@atomide.com>

---
 .../devicetree/bindings/pinctrl/ti,iodelay.txt     |  47 +
 drivers/pinctrl/Kconfig                            |   1 +
 drivers/pinctrl/Makefile                           |   1 +
 drivers/pinctrl/ti/Kconfig                         |  10 +
 drivers/pinctrl/ti/Makefile                        |   1 +
 drivers/pinctrl/ti/pinctrl-ti-iodelay.c            | 944 +++++++++++++++++++++
 6 files changed, 1004 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pinctrl/ti,iodelay.txt
 create mode 100644 drivers/pinctrl/ti/Kconfig
 create mode 100644 drivers/pinctrl/ti/Makefile
 create mode 100644 drivers/pinctrl/ti/pinctrl-ti-iodelay.c

-- 
2.11.0
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diff --git a/Documentation/devicetree/bindings/pinctrl/ti,iodelay.txt b/Documentation/devicetree/bindings/pinctrl/ti,iodelay.txt
new file mode 100644
--- /dev/null
+++ b/Documentation/devicetree/bindings/pinctrl/ti,iodelay.txt
@@ -0,0 +1,47 @@ 
+* Pin configuration for TI IODELAY controller
+
+TI dra7 based SoCs such as am57xx have a controller for setting the IO delay
+for each pin. For most part the IO delay values are programmed by the bootloader,
+but some pins need to be configured dynamically by the kernel such as the
+MMC pins.
+
+Required Properties:
+
+  - compatible: Must be "ti,dra7-iodelay"
+  - reg: Base address and length of the memory resource used
+  - #address-cells: Number of address cells
+  - #size-cells: Size of cells
+  - #pinctrl-cells: Number of pinctrl cells, must be 2. See also
+    Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+
+Example
+-------
+
+In the SoC specific dtsi file:
+
+	dra7_iodelay_core: padconf@4844a000 {
+		compatible = "ti,dra7-iodelay";
+		reg = <0x4844a000 0x0d1c>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		#pinctrl-cells = <2>;
+	};
+
+In board-specific file:
+
+&dra7_iodelay_core {
+	mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
+		pinctrl-pin-array = <
+		0x18c A_DELAY_PS(0) G_DELAY_PS(120)	/* CFG_GPMC_A19_IN */
+		0x1a4 A_DELAY_PS(265) G_DELAY_PS(360)	/* CFG_GPMC_A20_IN */
+		0x1b0 A_DELAY_PS(0) G_DELAY_PS(120)	/* CFG_GPMC_A21_IN */
+		0x1bc A_DELAY_PS(0) G_DELAY_PS(120)	/* CFG_GPMC_A22_IN */
+		0x1c8 A_DELAY_PS(287) G_DELAY_PS(420)	/* CFG_GPMC_A23_IN */
+		0x1d4 A_DELAY_PS(144) G_DELAY_PS(240)	/* CFG_GPMC_A24_IN */
+		0x1e0 A_DELAY_PS(0) G_DELAY_PS(0)	/* CFG_GPMC_A25_IN */
+		0x1ec A_DELAY_PS(120) G_DELAY_PS(0)	/* CFG_GPMC_A26_IN */
+		0x1f8 A_DELAY_PS(120) G_DELAY_PS(180)	/* CFG_GPMC_A27_IN */
+		0x360 A_DELAY_PS(0) G_DELAY_PS(0)	/* CFG_GPMC_CS1_IN */
+		>;
+	};
+};
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -300,6 +300,7 @@  source "drivers/pinctrl/spear/Kconfig"
 source "drivers/pinctrl/stm32/Kconfig"
 source "drivers/pinctrl/sunxi/Kconfig"
 source "drivers/pinctrl/tegra/Kconfig"
+source "drivers/pinctrl/ti/Kconfig"
 source "drivers/pinctrl/uniphier/Kconfig"
 source "drivers/pinctrl/vt8500/Kconfig"
 source "drivers/pinctrl/mediatek/Kconfig"
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -53,6 +53,7 @@  obj-$(CONFIG_PINCTRL_SH_PFC)	+= sh-pfc/
 obj-$(CONFIG_PINCTRL_SPEAR)	+= spear/
 obj-$(CONFIG_PINCTRL_STM32)	+= stm32/
 obj-$(CONFIG_PINCTRL_SUNXI)	+= sunxi/
+obj-y				+= ti/
 obj-$(CONFIG_PINCTRL_UNIPHIER)	+= uniphier/
 obj-$(CONFIG_ARCH_VT8500)	+= vt8500/
 obj-$(CONFIG_PINCTRL_MTK)	+= mediatek/
diff --git a/drivers/pinctrl/ti/Kconfig b/drivers/pinctrl/ti/Kconfig
new file mode 100644
--- /dev/null
+++ b/drivers/pinctrl/ti/Kconfig
@@ -0,0 +1,10 @@ 
+config PINCTRL_TI_IODELAY
+	tristate "TI IODelay Module pinconf driver"
+	depends on OF
+	select GENERIC_PINCTRL_GROUPS
+	select GENERIC_PINMUX_FUNCTIONS
+	select GENERIC_PINCONF
+	select REGMAP_MMIO
+	help
+	  Say Y here to support Texas Instruments' IO delay pinconf driver.
+	  IO delay module is used for the DRA7 SoC family.
diff --git a/drivers/pinctrl/ti/Makefile b/drivers/pinctrl/ti/Makefile
new file mode 100644
--- /dev/null
+++ b/drivers/pinctrl/ti/Makefile
@@ -0,0 +1 @@ 
+obj-$(CONFIG_PINCTRL_TI_IODELAY)	+= pinctrl-ti-iodelay.o
diff --git a/drivers/pinctrl/ti/pinctrl-ti-iodelay.c b/drivers/pinctrl/ti/pinctrl-ti-iodelay.c
new file mode 100644
--- /dev/null
+++ b/drivers/pinctrl/ti/pinctrl-ti-iodelay.c
@@ -0,0 +1,944 @@ 
+/*
+ * Support for configuration of IO Delay module found on Texas Instruments SoCs
+ * such as DRA7
+ *
+ * Copyright (C) 2015-2017 Texas Instruments Incorporated - http://www.ti.com/
+ *
+ * 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/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#include "../core.h"
+#include "../devicetree.h"
+
+#define DRIVER_NAME	"ti-iodelay"
+
+/**
+ * struct ti_iodelay_reg_data - Describes the registers for the iodelay instance
+ * @signature_mask: CONFIG_REG mask for the signature bits (see TRM)
+ * @signature_value: CONFIG_REG signature value to be written (see TRM)
+ * @lock_mask: CONFIG_REG mask for the lock bits (see TRM)
+ * @lock_val: CONFIG_REG lock value for the lock bits (see TRM)
+ * @unlock_val:CONFIG_REG unlock value for the lock bits (see TRM)
+ * @binary_data_coarse_mask: CONFIG_REG coarse mask (see TRM)
+ * @binary_data_fine_mask: CONFIG_REG fine mask (see TRM)
+ * @reg_refclk_offset: Refclk register offset
+ * @refclk_period_mask: Refclk mask
+ * @reg_coarse_offset: Coarse register configuration offset
+ * @coarse_delay_count_mask: Coarse delay count mask
+ * @coarse_ref_count_mask: Coarse ref count mask
+ * @reg_fine_offset: Fine register configuration offset
+ * @fine_delay_count_mask: Fine delay count mask
+ * @fine_ref_count_mask: Fine ref count mask
+ * @reg_global_lock_offset: Global iodelay module lock register offset
+ * @global_lock_mask: Lock mask
+ * @global_unlock_val: Unlock value
+ * @global_lock_val: Lock value
+ * @reg_start_offset: Offset to iodelay registers after the CONFIG_REG_0 to 8
+ * @reg_nr_per_pin: Number of iodelay registers for each pin
+ * @regmap_config: Regmap configuration for the IODelay region
+ */
+struct ti_iodelay_reg_data {
+	u32 signature_mask;
+	u32 signature_value;
+	u32 lock_mask;
+	u32 lock_val;
+	u32 unlock_val;
+	u32 binary_data_coarse_mask;
+	u32 binary_data_fine_mask;
+
+	u32 reg_refclk_offset;
+	u32 refclk_period_mask;
+
+	u32 reg_coarse_offset;
+	u32 coarse_delay_count_mask;
+	u32 coarse_ref_count_mask;
+
+	u32 reg_fine_offset;
+	u32 fine_delay_count_mask;
+	u32 fine_ref_count_mask;
+
+	u32 reg_global_lock_offset;
+	u32 global_lock_mask;
+	u32 global_unlock_val;
+	u32 global_lock_val;
+
+	u32 reg_start_offset;
+	u32 reg_nr_per_pin;
+
+	struct regmap_config *regmap_config;
+};
+
+/**
+ * struct ti_iodelay_reg_values - Computed io_reg configuration values (see TRM)
+ * @coarse_ref_count: Coarse reference count
+ * @coarse_delay_count: Coarse delay count
+ * @fine_ref_count: Fine reference count
+ * @fine_delay_count: Fine Delay count
+ * @ref_clk_period: Reference Clock period
+ * @cdpe: Coarse delay parameter
+ * @fdpe: Fine delay parameter
+ */
+struct ti_iodelay_reg_values {
+	u16 coarse_ref_count;
+	u16 coarse_delay_count;
+
+	u16 fine_ref_count;
+	u16 fine_delay_count;
+
+	u16 ref_clk_period;
+
+	u32 cdpe;
+	u32 fdpe;
+};
+
+/**
+ * struct ti_iodelay_cfg - Description of each configuration parameters
+ * @offset: Configuration register offset
+ * @a_delay: Agnostic Delay (in ps)
+ * @g_delay: Gnostic Delay (in ps)
+ */
+struct ti_iodelay_cfg {
+	u16 offset;
+	u16 a_delay;
+	u16 g_delay;
+};
+
+/**
+ * struct ti_iodelay_pingroup - Structure that describes one group
+ * @cfg: configuration array for the pin (from dt)
+ * @ncfg: number of configuration values allocated
+ * @config: pinconf "Config" - currently a dummy value
+ */
+struct ti_iodelay_pingroup {
+	struct ti_iodelay_cfg *cfg;
+	int ncfg;
+	unsigned long config;
+};
+
+/**
+ * struct ti_iodelay_device - Represents information for a iodelay instance
+ * @dev: Device pointer
+ * @phys_base: Physical address base of the iodelay device
+ * @reg_base: Virtual address base of the iodelay device
+ * @regmap: Regmap for this iodelay instance
+ * @pctl: Pinctrl device
+ * @desc: pinctrl descriptor for pctl
+ * @pa: pinctrl pin wise description
+ * @reg_data: Register definition data for the IODelay instance
+ * @reg_init_conf_values: Initial configuration values.
+ */
+struct ti_iodelay_device {
+	struct device *dev;
+	unsigned long phys_base;
+	void __iomem *reg_base;
+	struct regmap *regmap;
+
+	struct pinctrl_dev *pctl;
+	struct pinctrl_desc desc;
+	struct pinctrl_pin_desc *pa;
+
+	const struct ti_iodelay_reg_data *reg_data;
+	struct ti_iodelay_reg_values reg_init_conf_values;
+};
+
+/**
+ * ti_iodelay_extract() - extract bits for a field
+ * @val: Register value
+ * @mask: Mask
+ *
+ * Return: extracted value which is appropriately shifted
+ */
+static inline u32 ti_iodelay_extract(u32 val, u32 mask)
+{
+	return (val & mask) >> __ffs(mask);
+}
+
+/**
+ * ti_iodelay_compute_dpe() - Compute equation for delay parameter
+ * @period: Period to use
+ * @ref: Reference Count
+ * @delay: Delay count
+ * @delay_m: Delay multiplier
+ *
+ * Return: Computed delay parameter
+ */
+static inline u32 ti_iodelay_compute_dpe(u16 period, u16 ref, u16 delay,
+					 u16 delay_m)
+{
+	u64 m, d;
+
+	/* Handle overflow conditions */
+	m = 10 * (u64)period * (u64)ref;
+	d = 2 * (u64)delay * (u64)delay_m;
+
+	/* Truncate result back to 32 bits */
+	return div64_u64(m, d);
+}
+
+/**
+ * ti_iodelay_pinconf_set() - Configure the pin configuration
+ * @iod: iodelay device
+ * @cfg: Configuration
+ *
+ * Update the configuration register as per TRM and lockup once done.
+ * *IMPORTANT NOTE* SoC TRM does recommend doing iodelay programmation only
+ * while in Isolation. But, then, isolation also implies that every pin
+ * on the SoC (including DDR) will be isolated out. The only benefit being
+ * a glitchless configuration, However, the intent of this driver is purely
+ * to support a "glitchy" configuration where applicable.
+ *
+ * Return: 0 in case of success, else appropriate error value
+ */
+static int ti_iodelay_pinconf_set(struct ti_iodelay_device *iod,
+				  struct ti_iodelay_cfg *cfg)
+{
+	const struct ti_iodelay_reg_data *reg = iod->reg_data;
+	struct ti_iodelay_reg_values *ival = &iod->reg_init_conf_values;
+	struct device *dev = iod->dev;
+	u32 g_delay_coarse, g_delay_fine;
+	u32 a_delay_coarse, a_delay_fine;
+	u32 c_elements, f_elements;
+	u32 total_delay;
+	u32 reg_mask, reg_val, tmp_val;
+	int r;
+
+	/* NOTE: Truncation is expected in all division below */
+	g_delay_coarse = cfg->g_delay / 920;
+	g_delay_fine = ((cfg->g_delay % 920) * 10) / 60;
+
+	a_delay_coarse = cfg->a_delay / ival->cdpe;
+	a_delay_fine = ((cfg->a_delay % ival->cdpe) * 10) / ival->fdpe;
+
+	c_elements = g_delay_coarse + a_delay_coarse;
+	f_elements = (g_delay_fine + a_delay_fine) / 10;
+
+	if (f_elements > 22) {
+		total_delay = c_elements * ival->cdpe + f_elements * ival->fdpe;
+		c_elements = total_delay / ival->cdpe;
+		f_elements = (total_delay % ival->cdpe) / ival->fdpe;
+	}
+
+	reg_mask = reg->signature_mask;
+	reg_val = reg->signature_value << __ffs(reg->signature_mask);
+
+	reg_mask |= reg->binary_data_coarse_mask;
+	tmp_val = c_elements << __ffs(reg->binary_data_coarse_mask);
+	if (tmp_val & ~reg->binary_data_coarse_mask) {
+		dev_err(dev, "Masking overflow of coarse elements %08x\n",
+			tmp_val);
+		tmp_val &= reg->binary_data_coarse_mask;
+	}
+	reg_val |= tmp_val;
+
+	reg_mask |= reg->binary_data_fine_mask;
+	tmp_val = f_elements << __ffs(reg->binary_data_fine_mask);
+	if (tmp_val & ~reg->binary_data_fine_mask) {
+		dev_err(dev, "Masking overflow of fine elements %08x\n",
+			tmp_val);
+		tmp_val &= reg->binary_data_fine_mask;
+	}
+	reg_val |= tmp_val;
+
+	/*
+	 * NOTE: we leave the iodelay values unlocked - this is to work around
+	 * situations such as those found with mmc mode change.
+	 * However, this leaves open any unwarranted changes to padconf register
+	 * impacting iodelay configuration. Use with care!
+	 */
+	reg_mask |= reg->lock_mask;
+	reg_val |= reg->unlock_val << __ffs(reg->lock_mask);
+	r = regmap_update_bits(iod->regmap, cfg->offset, reg_mask, reg_val);
+
+	dev_info(dev, "Set reg 0x%x Delay(a: %d g: %d), Elements(C=%d F=%d)0x%x\n",
+		 cfg->offset, cfg->a_delay, cfg->g_delay, c_elements,
+		 f_elements, reg_val);
+
+	return r;
+}
+
+/**
+ * ti_iodelay_pinconf_init_dev() - Initialize IODelay device
+ * @iod: iodelay device
+ *
+ * Unlocks the iodelay region, computes the common parameters
+ *
+ * Return: 0 in case of success, else appropriate error value
+ */
+static int ti_iodelay_pinconf_init_dev(struct ti_iodelay_device *iod)
+{
+	const struct ti_iodelay_reg_data *reg = iod->reg_data;
+	struct device *dev = iod->dev;
+	struct ti_iodelay_reg_values *ival = &iod->reg_init_conf_values;
+	u32 val;
+	int r;
+
+	/* unlock the iodelay region */
+	r = regmap_update_bits(iod->regmap, reg->reg_global_lock_offset,
+			       reg->global_lock_mask, reg->global_unlock_val);
+	if (r)
+		return r;
+
+	/* Read up Recalibration sequence done by bootloader */
+	r = regmap_read(iod->regmap, reg->reg_refclk_offset, &val);
+	if (r)
+		return r;
+	ival->ref_clk_period = ti_iodelay_extract(val, reg->refclk_period_mask);
+	dev_dbg(dev, "refclk_period=0x%04x\n", ival->ref_clk_period);
+
+	r = regmap_read(iod->regmap, reg->reg_coarse_offset, &val);
+	if (r)
+		return r;
+	ival->coarse_ref_count =
+	    ti_iodelay_extract(val, reg->coarse_ref_count_mask);
+	ival->coarse_delay_count =
+	    ti_iodelay_extract(val, reg->coarse_delay_count_mask);
+	if (!ival->coarse_delay_count) {
+		dev_err(dev, "Invalid Coarse delay count (0) (reg=0x%08x)\n",
+			val);
+		return -EINVAL;
+	}
+	ival->cdpe = ti_iodelay_compute_dpe(ival->ref_clk_period,
+					    ival->coarse_ref_count,
+					    ival->coarse_delay_count, 88);
+	if (!ival->cdpe) {
+		dev_err(dev, "Invalid cdpe computed params = %d %d %d\n",
+			ival->ref_clk_period, ival->coarse_ref_count,
+			ival->coarse_delay_count);
+		return -EINVAL;
+	}
+	dev_dbg(iod->dev, "coarse: ref=0x%04x delay=0x%04x cdpe=0x%08x\n",
+		ival->coarse_ref_count, ival->coarse_delay_count, ival->cdpe);
+
+	r = regmap_read(iod->regmap, reg->reg_fine_offset, &val);
+	if (r)
+		return r;
+	ival->fine_ref_count =
+	    ti_iodelay_extract(val, reg->fine_ref_count_mask);
+	ival->fine_delay_count =
+	    ti_iodelay_extract(val, reg->fine_delay_count_mask);
+	if (!ival->fine_delay_count) {
+		dev_err(dev, "Invalid Fine delay count (0) (reg=0x%08x)\n",
+			val);
+		return -EINVAL;
+	}
+	ival->fdpe = ti_iodelay_compute_dpe(ival->ref_clk_period,
+					    ival->fine_ref_count,
+					    ival->fine_delay_count, 264);
+	if (!ival->fdpe) {
+		dev_err(dev, "Invalid fdpe(0) computed params = %d %d %d\n",
+			ival->ref_clk_period, ival->fine_ref_count,
+			ival->fine_delay_count);
+		return -EINVAL;
+	}
+	dev_dbg(iod->dev, "fine: ref=0x%04x delay=0x%04x fdpe=0x%08x\n",
+		ival->fine_ref_count, ival->fine_delay_count, ival->fdpe);
+
+	return 0;
+}
+
+/**
+ * ti_iodelay_pinconf_deinit_dev() - deinit the iodelay device
+ * @iod:	IODelay device
+ *
+ * Deinitialize the IODelay device (basically just lock the region back up.
+ */
+static void ti_iodelay_pinconf_deinit_dev(struct ti_iodelay_device *iod)
+{
+	const struct ti_iodelay_reg_data *reg = iod->reg_data;
+
+	/* lock the iodelay region back again */
+	regmap_update_bits(iod->regmap, reg->reg_global_lock_offset,
+			   reg->global_lock_mask, reg->global_lock_val);
+}
+
+/**
+ * ti_iodelay_get_pingroup() - Find the group mapped by a group selector
+ * @iod: iodelay device
+ * @selector: Group Selector
+ *
+ * Return: Corresponding group representing group selector
+ */
+static struct ti_iodelay_pingroup *
+ti_iodelay_get_pingroup(struct ti_iodelay_device *iod, unsigned int selector)
+{
+	struct group_desc *g;
+
+	g = pinctrl_generic_get_group(iod->pctl, selector);
+	if (!g) {
+		dev_err(iod->dev, "%s could not find pingroup %i\n", __func__,
+			selector);
+
+		return NULL;
+	}
+
+	return g->data;
+}
+
+/**
+ * ti_iodelay_offset_to_pin() - get a pin index based on the register offset
+ * @iod: iodelay driver instance
+ * @offset: register offset from the base
+ */
+static int ti_iodelay_offset_to_pin(struct ti_iodelay_device *iod,
+				    unsigned int offset)
+{
+	const struct ti_iodelay_reg_data *r = iod->reg_data;
+	unsigned int index;
+
+	if (offset > r->regmap_config->max_register) {
+		dev_err(iod->dev, "mux offset out of range: 0x%x (0x%x)\n",
+			offset, r->regmap_config->max_register);
+		return -EINVAL;
+	}
+
+	index = (offset - r->reg_start_offset) / r->regmap_config->reg_stride;
+	index /= r->reg_nr_per_pin;
+
+	return index;
+}
+
+/**
+ * ti_iodelay_node_iterator() - Iterate iodelay node
+ * @pctldev: Pin controller driver
+ * @np: Device node
+ * @pinctrl_spec: Parsed arguments from device tree
+ * @pins: Array of pins in the pin group
+ * @pin_index: Pin index in the pin array
+ * @data: Pin controller driver specific data
+ *
+ */
+static int ti_iodelay_node_iterator(struct pinctrl_dev *pctldev,
+				    struct device_node *np,
+				    const struct of_phandle_args *pinctrl_spec,
+				    int *pins, int pin_index, void *data)
+{
+	struct ti_iodelay_device *iod;
+	struct ti_iodelay_cfg *cfg = data;
+	const struct ti_iodelay_reg_data *r;
+	struct pinctrl_pin_desc *pd;
+	int pin;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	if (!iod)
+		return -EINVAL;
+
+	r = iod->reg_data;
+
+	if (pinctrl_spec->args_count < r->reg_nr_per_pin) {
+		dev_err(iod->dev, "invalid args_count for spec: %i\n",
+			pinctrl_spec->args_count);
+
+		return -EINVAL;
+	}
+
+	/* Index plus two value cells */
+	cfg[pin_index].offset = pinctrl_spec->args[0];
+	cfg[pin_index].a_delay = pinctrl_spec->args[1] & 0xffff;
+	cfg[pin_index].g_delay = pinctrl_spec->args[2] & 0xffff;
+
+	pin = ti_iodelay_offset_to_pin(iod, cfg[pin_index].offset);
+	if (pin < 0) {
+		dev_err(iod->dev, "could not add functions for %s %ux\n",
+			np->name, cfg[pin_index].offset);
+		return -ENODEV;
+	}
+	pins[pin_index] = pin;
+
+	pd = &iod->pa[pin];
+	pd->drv_data = &cfg[pin_index];
+
+	dev_dbg(iod->dev, "%s offset=%x a_delay = %d g_delay = %d\n",
+		np->name, cfg[pin_index].offset, cfg[pin_index].a_delay,
+		cfg[pin_index].g_delay);
+
+	return 0;
+}
+
+/**
+ * ti_iodelay_dt_node_to_map() - Map a device tree node to appropriate group
+ * @pctldev: pinctrl device representing IODelay device
+ * @np: Node Pointer (device tree)
+ * @map: Pinctrl Map returned back to pinctrl framework
+ * @num_maps: Number of maps (1)
+ *
+ * Maps the device tree description into a group of configuration parameters
+ * for iodelay block entry.
+ *
+ * Return: 0 in case of success, else appropriate error value
+ */
+static int ti_iodelay_dt_node_to_map(struct pinctrl_dev *pctldev,
+				     struct device_node *np,
+				     struct pinctrl_map **map,
+				     unsigned int *num_maps)
+{
+	struct ti_iodelay_device *iod;
+	struct ti_iodelay_cfg *cfg;
+	struct ti_iodelay_pingroup *g;
+	const char *name = "pinctrl-pin-array";
+	int rows, *pins, error = -EINVAL, i;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	if (!iod)
+		return -EINVAL;
+
+	rows = pinctrl_count_index_with_args(np, name);
+	if (rows == -EINVAL)
+		return rows;
+
+	*map = devm_kzalloc(iod->dev, sizeof(**map), GFP_KERNEL);
+	if (!*map)
+		return -ENOMEM;
+	*num_maps = 0;
+
+	g = devm_kzalloc(iod->dev, sizeof(*g), GFP_KERNEL);
+	if (!g) {
+		error = -ENOMEM;
+		goto free_map;
+	}
+
+	pins = devm_kzalloc(iod->dev, sizeof(*pins) * rows, GFP_KERNEL);
+	if (!pins)
+		goto free_group;
+
+	cfg = devm_kzalloc(iod->dev, sizeof(*cfg) * rows, GFP_KERNEL);
+	if (!cfg) {
+		error = -ENOMEM;
+		goto free_pins;
+	}
+
+	for (i = 0; i < rows; i++) {
+		struct of_phandle_args pinctrl_spec;
+
+		error = pinctrl_parse_index_with_args(np, name, i,
+						      &pinctrl_spec);
+		if (error)
+			goto free_data;
+
+		error = ti_iodelay_node_iterator(pctldev, np, &pinctrl_spec,
+						 pins, i, cfg);
+		if (error)
+			goto free_data;
+	}
+
+	g->cfg = cfg;
+	g->ncfg = i;
+	g->config = PIN_CONFIG_END;
+
+	error = pinctrl_generic_add_group(iod->pctl, np->name, pins, i, g);
+	if (error < 0)
+		goto free_data;
+
+	(*map)->type = PIN_MAP_TYPE_CONFIGS_GROUP;
+	(*map)->data.configs.group_or_pin = np->name;
+	(*map)->data.configs.configs = &g->config;
+	(*map)->data.configs.num_configs = 1;
+	*num_maps = 1;
+
+	return 0;
+
+free_data:
+	devm_kfree(iod->dev, cfg);
+free_pins:
+	devm_kfree(iod->dev, pins);
+free_group:
+	devm_kfree(iod->dev, g);
+free_map:
+	devm_kfree(iod->dev, *map);
+
+	return error;
+}
+
+/**
+ * ti_iodelay_pinconf_group_get() - Get the group configuration
+ * @pctldev: pinctrl device representing IODelay device
+ * @selector: Group selector
+ * @config: Configuration returned
+ *
+ * Return: The configuration if the group is valid, else returns -EINVAL
+ */
+static int ti_iodelay_pinconf_group_get(struct pinctrl_dev *pctldev,
+					unsigned int selector,
+					unsigned long *config)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	struct ti_iodelay_pingroup *group;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	dev = iod->dev;
+	group = ti_iodelay_get_pingroup(iod, selector);
+
+	if (!group)
+		return -EINVAL;
+
+	*config = group->config;
+	return 0;
+}
+
+/**
+ * ti_iodelay_pinconf_group_set() - Configure the groups of pins
+ * @pctldev: pinctrl device representing IODelay device
+ * @selector: Group selector
+ * @configs: Configurations
+ * @num_configs: Number of configurations
+ *
+ * Return: 0 if all went fine, else appropriate error value.
+ */
+static int ti_iodelay_pinconf_group_set(struct pinctrl_dev *pctldev,
+					unsigned int selector,
+					unsigned long *configs,
+					unsigned int num_configs)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	struct ti_iodelay_pingroup *group;
+	int i;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	dev = iod->dev;
+	group = ti_iodelay_get_pingroup(iod, selector);
+
+	if (num_configs != 1) {
+		dev_err(dev, "Unsupported number of configurations %d\n",
+			num_configs);
+		return -EINVAL;
+	}
+
+	if (*configs != PIN_CONFIG_END) {
+		dev_err(dev, "Unsupported configuration\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < group->ncfg; i++) {
+		if (ti_iodelay_pinconf_set(iod, &group->cfg[i]))
+			return -ENOTSUPP;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+/**
+ * ti_iodelay_pin_to_offset() - get pin register offset based on the pin index
+ * @iod: iodelay driver instance
+ * @selector: Pin index
+ */
+static unsigned int ti_iodelay_pin_to_offset(struct ti_iodelay_device *iod,
+					     unsigned int selector)
+{
+	const struct ti_iodelay_reg_data *r = iod->reg_data;
+	unsigned int offset;
+
+	offset = selector * r->regmap_config->reg_stride;
+	offset *= r->reg_nr_per_pin;
+	offset += r->reg_start_offset;
+
+	return offset;
+}
+
+static void ti_iodelay_pin_dbg_show(struct pinctrl_dev *pctldev,
+				    struct seq_file *s,
+				    unsigned int pin)
+{
+	struct ti_iodelay_device *iod;
+	struct pinctrl_pin_desc *pd;
+	struct ti_iodelay_cfg *cfg;
+	const struct ti_iodelay_reg_data *r;
+	unsigned long offset;
+	u32 in, oen, out;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	r = iod->reg_data;
+
+	offset = ti_iodelay_pin_to_offset(iod, pin);
+	if (pin < 0) {
+		dev_err(iod->dev, "invalid pin offset for pin%i\n", pin);
+
+		return;
+	}
+
+	pd = &iod->pa[pin];
+	cfg = pd->drv_data;
+
+	regmap_read(iod->regmap, offset, &in);
+	regmap_read(iod->regmap, offset + r->regmap_config->reg_stride, &oen);
+	regmap_read(iod->regmap, offset + r->regmap_config->reg_stride * 2,
+		    &out);
+
+	seq_printf(s, "%lx a: %i g: %i (%08x %08x %08x) %s ",
+		   iod->phys_base + offset,
+		   cfg ? cfg->a_delay : -1,
+		   cfg ? cfg->g_delay : -1,
+		   in, oen, out, DRIVER_NAME);
+}
+
+/**
+ * ti_iodelay_pinconf_group_dbg_show() - show the group information
+ * @pctldev: Show the group information
+ * @s: Sequence file
+ * @selector: Group selector
+ *
+ * Provide the configuration information of the selected group
+ */
+static void ti_iodelay_pinconf_group_dbg_show(struct pinctrl_dev *pctldev,
+					      struct seq_file *s,
+					      unsigned int selector)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	struct ti_iodelay_pingroup *group;
+	int i;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	dev = iod->dev;
+	group = ti_iodelay_get_pingroup(iod, selector);
+	if (!group)
+		return;
+
+	for (i = 0; i < group->ncfg; i++) {
+		struct ti_iodelay_cfg *cfg;
+		u32 reg = 0;
+
+		cfg = &group->cfg[i];
+		regmap_read(iod->regmap, cfg->offset, &reg),
+			seq_printf(s, "\n\t0x%08x = 0x%08x (%3d, %3d)",
+				   cfg->offset, reg, cfg->a_delay,
+				   cfg->g_delay);
+	}
+}
+#endif
+
+static struct pinctrl_ops ti_iodelay_pinctrl_ops = {
+	.get_groups_count = pinctrl_generic_get_group_count,
+	.get_group_name = pinctrl_generic_get_group_name,
+	.get_group_pins = pinctrl_generic_get_group_pins,
+#ifdef CONFIG_DEBUG_FS
+	.pin_dbg_show = ti_iodelay_pin_dbg_show,
+#endif
+	.dt_node_to_map = ti_iodelay_dt_node_to_map,
+};
+
+static struct pinconf_ops ti_iodelay_pinctrl_pinconf_ops = {
+	.pin_config_group_get = ti_iodelay_pinconf_group_get,
+	.pin_config_group_set = ti_iodelay_pinconf_group_set,
+#ifdef CONFIG_DEBUG_FS
+	.pin_config_group_dbg_show = ti_iodelay_pinconf_group_dbg_show,
+#endif
+};
+
+/**
+ * ti_iodelay_alloc_pins() - Allocate structures needed for pins for iodelay
+ * @dev: Device pointer
+ * @iod: iodelay device
+ * @base_phy: Base Physical Address
+ *
+ * Return: 0 if all went fine, else appropriate error value.
+ */
+static int ti_iodelay_alloc_pins(struct device *dev,
+				 struct ti_iodelay_device *iod, u32 base_phy)
+{
+	const struct ti_iodelay_reg_data *r = iod->reg_data;
+	struct pinctrl_pin_desc *pin;
+	u32 phy_reg;
+	int nr_pins, i;
+
+	nr_pins = ti_iodelay_offset_to_pin(iod, r->regmap_config->max_register);
+	dev_dbg(dev, "Allocating %i pins\n", nr_pins);
+
+	iod->pa = devm_kzalloc(dev, sizeof(*iod->pa) * nr_pins, GFP_KERNEL);
+	if (!iod->pa)
+		return -ENOMEM;
+
+	iod->desc.pins = iod->pa;
+	iod->desc.npins = nr_pins;
+
+	phy_reg = r->reg_start_offset + base_phy;
+
+	for (i = 0; i < nr_pins; i++, phy_reg += 4) {
+		pin = &iod->pa[i];
+		pin->number = i;
+	}
+
+	return 0;
+}
+
+static struct regmap_config dra7_iodelay_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.max_register = 0xd1c,
+};
+
+static struct ti_iodelay_reg_data dra7_iodelay_data = {
+	.signature_mask = 0x0003f000,
+	.signature_value = 0x29,
+	.lock_mask = 0x00000400,
+	.lock_val = 1,
+	.unlock_val = 0,
+	.binary_data_coarse_mask = 0x000003e0,
+	.binary_data_fine_mask = 0x0000001f,
+
+	.reg_refclk_offset = 0x14,
+	.refclk_period_mask = 0xffff,
+
+	.reg_coarse_offset = 0x18,
+	.coarse_delay_count_mask = 0xffff0000,
+	.coarse_ref_count_mask = 0x0000ffff,
+
+	.reg_fine_offset = 0x1C,
+	.fine_delay_count_mask = 0xffff0000,
+	.fine_ref_count_mask = 0x0000ffff,
+
+	.reg_global_lock_offset = 0x2c,
+	.global_lock_mask = 0x0000ffff,
+	.global_unlock_val = 0x0000aaaa,
+	.global_lock_val = 0x0000aaab,
+
+	.reg_start_offset = 0x30,
+	.reg_nr_per_pin = 3,
+	.regmap_config = &dra7_iodelay_regmap_config,
+};
+
+static const struct of_device_id ti_iodelay_of_match[] = {
+	{.compatible = "ti,dra7-iodelay", .data = &dra7_iodelay_data},
+	{ /* Hopefully no more.. */ },
+};
+MODULE_DEVICE_TABLE(of, ti_iodelay_of_match);
+
+/**
+ * ti_iodelay_probe() - Standard probe
+ * @pdev: platform device
+ *
+ * Return: 0 if all went fine, else appropriate error value.
+ */
+static int ti_iodelay_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = of_node_get(dev->of_node);
+	const struct of_device_id *match;
+	struct resource *res;
+	struct ti_iodelay_device *iod;
+	int ret = 0;
+
+	if (!np) {
+		ret = -EINVAL;
+		dev_err(dev, "No OF node\n");
+		goto exit_out;
+	}
+
+	match = of_match_device(ti_iodelay_of_match, dev);
+	if (!match) {
+		ret = -EINVAL;
+		dev_err(dev, "No DATA match\n");
+		goto exit_out;
+	}
+
+	iod = devm_kzalloc(dev, sizeof(*iod), GFP_KERNEL);
+	if (!iod) {
+		ret = -ENOMEM;
+		goto exit_out;
+	}
+	iod->dev = dev;
+	iod->reg_data = match->data;
+
+	/* So far We can assume there is only 1 bank of registers */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "Missing MEM resource\n");
+		ret = -ENODEV;
+		goto exit_out;
+	}
+
+	iod->phys_base = res->start;
+	iod->reg_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(iod->reg_base)) {
+		ret = PTR_ERR(iod->reg_base);
+		goto exit_out;
+	}
+
+	iod->regmap = devm_regmap_init_mmio(dev, iod->reg_base,
+					    iod->reg_data->regmap_config);
+	if (IS_ERR(iod->regmap)) {
+		dev_err(dev, "Regmap MMIO init failed.\n");
+		ret = PTR_ERR(iod->regmap);
+		goto exit_out;
+	}
+
+	if (ti_iodelay_pinconf_init_dev(iod))
+		goto exit_out;
+
+	ret = ti_iodelay_alloc_pins(dev, iod, res->start);
+	if (ret)
+		goto exit_out;
+
+	iod->desc.pctlops = &ti_iodelay_pinctrl_ops;
+	/* no pinmux ops - we are pinconf */
+	iod->desc.confops = &ti_iodelay_pinctrl_pinconf_ops;
+	iod->desc.name = dev_name(dev);
+	iod->desc.owner = THIS_MODULE;
+
+	iod->pctl = pinctrl_register(&iod->desc, dev, iod);
+	if (!iod->pctl) {
+		dev_err(dev, "Failed to register pinctrl\n");
+		ret = -ENODEV;
+		goto exit_out;
+	}
+
+	platform_set_drvdata(pdev, iod);
+
+exit_out:
+	of_node_put(np);
+	return ret;
+}
+
+/**
+ * ti_iodelay_remove() - standard remove
+ * @pdev: platform device
+ *
+ * Return: 0 if all went fine, else appropriate error value.
+ */
+static int ti_iodelay_remove(struct platform_device *pdev)
+{
+	struct ti_iodelay_device *iod = platform_get_drvdata(pdev);
+
+	if (!iod)
+		return 0;
+
+	if (iod->pctl)
+		pinctrl_unregister(iod->pctl);
+
+	ti_iodelay_pinconf_deinit_dev(iod);
+
+	/* Expect other allocations to be freed by devm */
+
+	return 0;
+}
+
+static struct platform_driver ti_iodelay_driver = {
+	.probe = ti_iodelay_probe,
+	.remove = ti_iodelay_remove,
+	.driver = {
+		   .owner = THIS_MODULE,
+		   .name = DRIVER_NAME,
+		   .of_match_table = ti_iodelay_of_match,
+	},
+};
+module_platform_driver(ti_iodelay_driver);
+
+MODULE_AUTHOR("Texas Instruments, Inc.");
+MODULE_DESCRIPTION("Pinconf driver for TI's IO Delay module");
+MODULE_LICENSE("GPL v2");