]> Pileus Git - ~andy/linux/commitdiff
Merge remote-tracking branch 'regulator/topic/abb' into regulator-next
authorMark Brown <broonie@linaro.org>
Mon, 1 Jul 2013 10:17:06 +0000 (11:17 +0100)
committerMark Brown <broonie@linaro.org>
Mon, 1 Jul 2013 10:17:06 +0000 (11:17 +0100)
Documentation/devicetree/bindings/regulator/ti-abb-regulator.txt [new file with mode: 0644]
drivers/regulator/Kconfig
drivers/regulator/Makefile
drivers/regulator/ti-abb-regulator.c [new file with mode: 0644]

diff --git a/Documentation/devicetree/bindings/regulator/ti-abb-regulator.txt b/Documentation/devicetree/bindings/regulator/ti-abb-regulator.txt
new file mode 100644 (file)
index 0000000..2e57a33
--- /dev/null
@@ -0,0 +1,128 @@
+Adaptive Body Bias(ABB) SoC internal LDO regulator for Texas Instruments SoCs
+
+Required Properties:
+- compatible: Should be one of:
+  - "ti,abb-v1" for older SoCs like OMAP3
+  - "ti,abb-v2" for newer SoCs like OMAP4, OMAP5
+- reg: Address and length of the register set for the device. It contains
+  the information of registers in the same order as described by reg-names
+- reg-names: Should contain the reg names
+  - "base-address"     - contains base address of ABB module
+  - "int-address"      - contains address of interrupt register for ABB module
+  (also see Optional properties)
+- #address-cell: should be 0
+- #size-cell: should be 0
+- clocks: should point to the clock node used by ABB module
+- ti,settling-time: Settling time in uSecs from SoC documentation for ABB module
+       to settle down(target time for SR2_WTCNT_VALUE).
+- ti,clock-cycles: SoC specific data about count of system ti,clock-cycles used for
+       computing settling time from SoC Documentation for ABB module(clock
+       cycles for SR2_WTCNT_VALUE).
+- ti,tranxdone-status-mask: Mask to the int-register to write-to-clear mask
+       indicating LDO tranxdone (operation complete).
+- ti,abb_info: An array of 6-tuples u32 items providing information about ABB
+       configuration needed per operational voltage of the device.
+       Each item consists of the following in the same order:
+       volt: voltage in uV - Only used to index ABB information.
+       ABB mode: one of the following:
+               0-bypass
+               1-Forward Body Bias(FBB)
+               3-Reverse Body Bias(RBB)
+       efuse:  (see Optional properties)
+       RBB enable efuse Mask:  (See Optional properties)
+       FBB enable efuse Mask:  (See Optional properties)
+       Vset value efuse Mask:  (See Optional properties)
+
+       NOTE: If more than 1 entry is present, then regulator is setup to change
+             voltage, allowing for various modes to be selected indexed off
+             the regulator. Further, ABB LDOs are considered always-on by
+             default.
+
+Optional Properties:
+- reg-names: In addition to the required properties, the following are optional
+  - "efuse-address"    - Contains efuse base address used to pick up ABB info.
+  - "ldo-address"      - Contains address of ABB LDO overide register address.
+       "efuse-address" is required for this.
+- ti,ldovbb-vset-mask  - Required if ldo-address is set, mask for LDO override
+       register to provide override vset value.
+- ti,ldovbb-override-mask - Required if ldo-address is set, mask for LDO
+       override register to enable override vset value.
+- ti,abb_opp_sel: Addendum to the description in required properties
+       efuse: Mandatory if 'efuse-address' register is defined. Provides offset
+              from efuse-address to pick up ABB characteristics. Set to 0 if
+              'efuse-address' is not defined.
+       RBB enable efuse Mask:  Optional if 'efuse-address' register is defined.
+               'ABB mode' is force set to RBB mode if value at "efuse-address"
+               + efuse maps to RBB mask. Set to 0 to ignore this.
+       FBB enable efuse Mask:  Optional if 'efuse-address' register is defined.
+               'ABB mode' is force set to FBB mode if value at "efuse-address"
+               + efuse maps to FBB mask (valid only if RBB mask does not match)
+               Set to 0 to ignore this.
+       Vset value efuse Mask:  Mandatory if ldo-address is set. Picks up from
+               efuse the value to set in 'ti,ldovbb-vset-mask' at ldo-address.
+
+Example #1: Simplest configuration (no efuse data, hard coded ABB table):
+abb_x: regulator-abb-x {
+       compatible = "ti,abb-v1";
+       regulator-name = "abb_x";
+       #address-cell = <0>;
+       #size-cells = <0>;
+       reg = <0x483072f0 0x8>, <0x48306818 0x4>;
+       reg-names = "base-address", "int-address";
+       ti,tranxdone-status-mask = <0x4000000>;
+       clocks = <&sysclk>;
+       ti,settling-time = <30>;
+       ti,clock-cycles = <8>;
+       ti,abb_info = <
+       /* uV           ABB     efuse   rbb_m   fbb_m   vset_m */
+       1012500         0       0       0       0       0 /* Bypass */
+       1200000         3       0       0       0       0 /* RBB mandatory */
+       1320000         1       0       0       0       0 /* FBB mandatory */
+       >;
+};
+
+Example #2: Efuse bits contain ABB mode setting (no LDO override capability)
+abb_y: regulator-abb-y {
+       compatible = "ti,abb-v2";
+       regulator-name = "abb_y";
+       #address-cell = <0>;
+       #size-cells = <0>;
+       reg = <0x4a307bd0 0x8>, <0x4a306014 0x4>, <0x4A002268 0x8>;
+       reg-names = "base-address", "int-address", "efuse-address";
+       ti,tranxdone-status-mask = <0x4000000>;
+       clocks = <&sysclk>;
+       ti,settling-time = <50>;
+       ti,clock-cycles = <16>;
+       ti,abb_info = <
+       /* uV           ABB     efuse   rbb_m   fbb_m   vset_m */
+       975000          0       0       0       0       0 /* Bypass */
+       1012500         0       0       0x40000 0       0 /* RBB optional */
+       1200000         0       0x4     0       0x40000 0 /* FBB optional */
+       1320000         1       0       0       0       0 /* FBB mandatory */
+       >;
+};
+
+Example #3: Efuse bits contain ABB mode setting and LDO override capability
+abb_z: regulator-abb-z {
+       compatible = "ti,abb-v2";
+       regulator-name = "abb_z";
+       #address-cell = <0>;
+       #size-cells = <0>;
+       reg = <0x4ae07ce4 0x8>, <0x4ae06010 0x4>,
+             <0x4a002194 0x8>, <0x4ae0C314 0x4>;
+       reg-names = "base-address", "int-address",
+                   "efuse-address", "ldo-address";
+       ti,tranxdone-status-mask = <0x8000000>;
+       /* LDOVBBMM_MUX_CTRL */
+       ti,ldovbb-override-mask = <0x400>;
+       /* LDOVBBMM_VSET_OUT */
+       ti,ldovbb-vset-mask = <0x1F>;
+       clocks = <&sysclk>;
+       ti,settling-time = <50>;
+       ti,clock-cycles = <16>;
+       ti,abb_info = <
+       /* uV   ABB     efuse   rbb_m   fbb_m   vset_m */
+       975000  0       0       0       0       0       /* Bypass */
+       1200000 0       0x4     0       0x40000 0x1f00  /* FBB optional, vset */
+       >;
+};
index 9744437afe32424e5a86eff4b0810f61c35dff9e..f1e6ad98eebaa2c784a748e700785af479b80e96 100644 (file)
@@ -481,6 +481,16 @@ config REGULATOR_TWL4030
          This driver supports the voltage regulators provided by
          this family of companion chips.
 
+config REGULATOR_TI_ABB
+       bool "TI Adaptive Body Bias on-chip LDO"
+       depends on ARCH_OMAP
+       help
+         Select this option to support Texas Instruments' on-chip Adaptive Body
+         Bias (ABB) LDO regulators. It is recommended that this option be
+         enabled on required TI SoC. Certain Operating Performance Points
+         on TI SoCs may be unstable without enabling this as it provides
+         device specific optimized bias to allow/optimize functionality.
+
 config REGULATOR_VEXPRESS
        tristate "Versatile Express regulators"
        depends on VEXPRESS_CONFIG
index c4b50fc7f44fd9e04290e62676e0a1aa24c09a0f..ba4a3cf3afec57eef79179abf72ae1f51d5b3073 100644 (file)
@@ -64,6 +64,7 @@ obj-$(CONFIG_REGULATOR_TPS65910) += tps65910-regulator.o
 obj-$(CONFIG_REGULATOR_TPS65912) += tps65912-regulator.o
 obj-$(CONFIG_REGULATOR_TPS80031) += tps80031-regulator.o
 obj-$(CONFIG_REGULATOR_TWL4030) += twl-regulator.o
+obj-$(CONFIG_REGULATOR_TI_ABB) += ti-abb-regulator.o
 obj-$(CONFIG_REGULATOR_VEXPRESS) += vexpress.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-dcdc.o
 obj-$(CONFIG_REGULATOR_WM831X) += wm831x-isink.o
diff --git a/drivers/regulator/ti-abb-regulator.c b/drivers/regulator/ti-abb-regulator.c
new file mode 100644 (file)
index 0000000..3753ed0
--- /dev/null
@@ -0,0 +1,910 @@
+/*
+ * Texas Instruments SoC Adaptive Body Bias(ABB) Regulator
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Mike Turquette <mturquette@ti.com>
+ *
+ * Copyright (C) 2012-2013 Texas Instruments, Inc.
+ * Andrii Tseglytskyi <andrii.tseglytskyi@ti.com>
+ * Nishanth Menon <nm@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+
+/*
+ * ABB LDO operating states:
+ * NOMINAL_OPP:        bypasses the ABB LDO
+ * FAST_OPP:   sets ABB LDO to Forward Body-Bias
+ * SLOW_OPP:   sets ABB LDO to Reverse Body-Bias
+ */
+#define TI_ABB_NOMINAL_OPP     0
+#define TI_ABB_FAST_OPP                1
+#define TI_ABB_SLOW_OPP                3
+
+/**
+ * struct ti_abb_info - ABB information per voltage setting
+ * @opp_sel:   one of TI_ABB macro
+ * @vset:      (optional) vset value that LDOVBB needs to be overriden with.
+ *
+ * Array of per voltage entries organized in the same order as regulator_desc's
+ * volt_table list. (selector is used to index from this array)
+ */
+struct ti_abb_info {
+       u32 opp_sel;
+       u32 vset;
+};
+
+/**
+ * struct ti_abb_reg - Register description for ABB block
+ * @setup_reg:                 setup register offset from base
+ * @control_reg:               control register offset from base
+ * @sr2_wtcnt_value_mask:      setup register- sr2_wtcnt_value mask
+ * @fbb_sel_mask:              setup register- FBB sel mask
+ * @rbb_sel_mask:              setup register- RBB sel mask
+ * @sr2_en_mask:               setup register- enable mask
+ * @opp_change_mask:           control register - mask to trigger LDOVBB change
+ * @opp_sel_mask:              control register - mask for mode to operate
+ */
+struct ti_abb_reg {
+       u32 setup_reg;
+       u32 control_reg;
+
+       /* Setup register fields */
+       u32 sr2_wtcnt_value_mask;
+       u32 fbb_sel_mask;
+       u32 rbb_sel_mask;
+       u32 sr2_en_mask;
+
+       /* Control register fields */
+       u32 opp_change_mask;
+       u32 opp_sel_mask;
+};
+
+/**
+ * struct ti_abb - ABB instance data
+ * @rdesc:                     regulator descriptor
+ * @clk:                       clock(usually sysclk) supplying ABB block
+ * @base:                      base address of ABB block
+ * @int_base:                  interrupt register base address
+ * @efuse_base:                        (optional) efuse base address for ABB modes
+ * @ldo_base:                  (optional) LDOVBB vset override base address
+ * @regs:                      pointer to struct ti_abb_reg for ABB block
+ * @txdone_mask:               mask on int_base for tranxdone interrupt
+ * @ldovbb_override_mask:      mask to ldo_base for overriding default LDO VBB
+ *                             vset with value from efuse
+ * @ldovbb_vset_mask:          mask to ldo_base for providing the VSET override
+ * @info:                      array to per voltage ABB configuration
+ * @current_info_idx:          current index to info
+ * @settling_time:             SoC specific settling time for LDO VBB
+ */
+struct ti_abb {
+       struct regulator_desc rdesc;
+       struct clk *clk;
+       void __iomem *base;
+       void __iomem *int_base;
+       void __iomem *efuse_base;
+       void __iomem *ldo_base;
+
+       const struct ti_abb_reg *regs;
+       u32 txdone_mask;
+       u32 ldovbb_override_mask;
+       u32 ldovbb_vset_mask;
+
+       struct ti_abb_info *info;
+       int current_info_idx;
+
+       u32 settling_time;
+};
+
+/**
+ * ti_abb_rmw() - handy wrapper to set specific register bits
+ * @mask:      mask for register field
+ * @value:     value shifted to mask location and written
+ * @offset:    offset of register
+ * @base:      base address
+ *
+ * Return: final register value (may be unused)
+ */
+static inline u32 ti_abb_rmw(u32 mask, u32 value, u32 offset,
+                            void __iomem *base)
+{
+       u32 val;
+
+       val = readl(base + offset);
+       val &= ~mask;
+       val |= (value << __ffs(mask)) & mask;
+       writel(val, base + offset);
+
+       return val;
+}
+
+/**
+ * ti_abb_check_txdone() - handy wrapper to check ABB tranxdone status
+ * @abb:       pointer to the abb instance
+ *
+ * Return: true or false
+ */
+static inline bool ti_abb_check_txdone(const struct ti_abb *abb)
+{
+       return !!(readl(abb->int_base) & abb->txdone_mask);
+}
+
+/**
+ * ti_abb_clear_txdone() - handy wrapper to clear ABB tranxdone status
+ * @abb:       pointer to the abb instance
+ */
+static inline void ti_abb_clear_txdone(const struct ti_abb *abb)
+{
+       writel(abb->txdone_mask, abb->int_base);
+};
+
+/**
+ * ti_abb_wait_tranx() - waits for ABB tranxdone event
+ * @dev:       device
+ * @abb:       pointer to the abb instance
+ *
+ * Return: 0 on success or -ETIMEDOUT if the event is not cleared on time.
+ */
+static int ti_abb_wait_txdone(struct device *dev, struct ti_abb *abb)
+{
+       int timeout = 0;
+       bool status;
+
+       while (timeout++ <= abb->settling_time) {
+               status = ti_abb_check_txdone(abb);
+               if (status)
+                       break;
+
+               udelay(1);
+       }
+
+       if (timeout > abb->settling_time) {
+               dev_warn_ratelimited(dev,
+                                    "%s:TRANXDONE timeout(%duS) int=0x%08x\n",
+                                    __func__, timeout, readl(abb->int_base));
+               return -ETIMEDOUT;
+       }
+
+       return 0;
+}
+
+/**
+ * ti_abb_clear_all_txdone() - clears ABB tranxdone event
+ * @dev:       device
+ * @abb:       pointer to the abb instance
+ *
+ * Return: 0 on success or -ETIMEDOUT if the event is not cleared on time.
+ */
+static int ti_abb_clear_all_txdone(struct device *dev, const struct ti_abb *abb)
+{
+       int timeout = 0;
+       bool status;
+
+       while (timeout++ <= abb->settling_time) {
+               ti_abb_clear_txdone(abb);
+
+               status = ti_abb_check_txdone(abb);
+               if (!status)
+                       break;
+
+               udelay(1);
+       }
+
+       if (timeout > abb->settling_time) {
+               dev_warn_ratelimited(dev,
+                                    "%s:TRANXDONE timeout(%duS) int=0x%08x\n",
+                                    __func__, timeout, readl(abb->int_base));
+               return -ETIMEDOUT;
+       }
+
+       return 0;
+}
+
+/**
+ * ti_abb_program_ldovbb() - program LDOVBB register for override value
+ * @dev:       device
+ * @abb:       pointer to the abb instance
+ * @info:      ABB info to program
+ */
+static void ti_abb_program_ldovbb(struct device *dev, const struct ti_abb *abb,
+                                 struct ti_abb_info *info)
+{
+       u32 val;
+
+       val = readl(abb->ldo_base);
+       /* clear up previous values */
+       val &= ~(abb->ldovbb_override_mask | abb->ldovbb_vset_mask);
+
+       switch (info->opp_sel) {
+       case TI_ABB_SLOW_OPP:
+       case TI_ABB_FAST_OPP:
+               val |= abb->ldovbb_override_mask;
+               val |= info->vset << __ffs(abb->ldovbb_vset_mask);
+               break;
+       }
+
+       writel(val, abb->ldo_base);
+}
+
+/**
+ * ti_abb_set_opp() - Setup ABB and LDO VBB for required bias
+ * @rdev:      regulator device
+ * @abb:       pointer to the abb instance
+ * @info:      ABB info to program
+ *
+ * Return: 0 on success or appropriate error value when fails
+ */
+static int ti_abb_set_opp(struct regulator_dev *rdev, struct ti_abb *abb,
+                         struct ti_abb_info *info)
+{
+       const struct ti_abb_reg *regs = abb->regs;
+       struct device *dev = &rdev->dev;
+       int ret;
+
+       ret = ti_abb_clear_all_txdone(dev, abb);
+       if (ret)
+               goto out;
+
+       ti_abb_rmw(regs->fbb_sel_mask | regs->rbb_sel_mask, 0, regs->setup_reg,
+                  abb->base);
+
+       switch (info->opp_sel) {
+       case TI_ABB_SLOW_OPP:
+               ti_abb_rmw(regs->rbb_sel_mask, 1, regs->setup_reg, abb->base);
+               break;
+       case TI_ABB_FAST_OPP:
+               ti_abb_rmw(regs->fbb_sel_mask, 1, regs->setup_reg, abb->base);
+               break;
+       }
+
+       /* program next state of ABB ldo */
+       ti_abb_rmw(regs->opp_sel_mask, info->opp_sel, regs->control_reg,
+                  abb->base);
+
+       /* program LDO VBB vset override if needed */
+       if (abb->ldo_base)
+               ti_abb_program_ldovbb(dev, abb, info);
+
+       /* Initiate ABB ldo change */
+       ti_abb_rmw(regs->opp_change_mask, 1, regs->control_reg, abb->base);
+
+       /* Wait for ABB LDO to complete transition to new Bias setting */
+       ret = ti_abb_wait_txdone(dev, abb);
+       if (ret)
+               goto out;
+
+       ret = ti_abb_clear_all_txdone(dev, abb);
+       if (ret)
+               goto out;
+
+out:
+       return ret;
+}
+
+/**
+ * ti_abb_set_voltage_sel() - regulator accessor function to set ABB LDO
+ * @rdev:      regulator device
+ * @sel:       selector to index into required ABB LDO settings (maps to
+ *             regulator descriptor's volt_table)
+ *
+ * Return: 0 on success or appropriate error value when fails
+ */
+static int ti_abb_set_voltage_sel(struct regulator_dev *rdev, unsigned sel)
+{
+       const struct regulator_desc *desc = rdev->desc;
+       struct ti_abb *abb = rdev_get_drvdata(rdev);
+       struct device *dev = &rdev->dev;
+       struct ti_abb_info *info, *oinfo;
+       int ret = 0;
+
+       if (!abb) {
+               dev_err_ratelimited(dev, "%s: No regulator drvdata\n",
+                                   __func__);
+               return -ENODEV;
+       }
+
+       if (!desc->n_voltages || !abb->info) {
+               dev_err_ratelimited(dev,
+                                   "%s: No valid voltage table entries?\n",
+                                   __func__);
+               return -EINVAL;
+       }
+
+       if (sel >= desc->n_voltages) {
+               dev_err(dev, "%s: sel idx(%d) >= n_voltages(%d)\n", __func__,
+                       sel, desc->n_voltages);
+               return -EINVAL;
+       }
+
+       /* If we are in the same index as we were, nothing to do here! */
+       if (sel == abb->current_info_idx) {
+               dev_dbg(dev, "%s: Already at sel=%d\n", __func__, sel);
+               return ret;
+       }
+
+       /* If data is exactly the same, then just update index, no change */
+       info = &abb->info[sel];
+       oinfo = &abb->info[abb->current_info_idx];
+       if (!memcmp(info, oinfo, sizeof(*info))) {
+               dev_dbg(dev, "%s: Same data new idx=%d, old idx=%d\n", __func__,
+                       sel, abb->current_info_idx);
+               goto out;
+       }
+
+       ret = ti_abb_set_opp(rdev, abb, info);
+
+out:
+       if (!ret)
+               abb->current_info_idx = sel;
+       else
+               dev_err_ratelimited(dev,
+                                   "%s: Volt[%d] idx[%d] mode[%d] Fail(%d)\n",
+                                   __func__, desc->volt_table[sel], sel,
+                                   info->opp_sel, ret);
+       return ret;
+}
+
+/**
+ * ti_abb_get_voltage_sel() - Regulator accessor to get current ABB LDO setting
+ * @rdev:      regulator device
+ *
+ * Return: 0 on success or appropriate error value when fails
+ */
+static int ti_abb_get_voltage_sel(struct regulator_dev *rdev)
+{
+       const struct regulator_desc *desc = rdev->desc;
+       struct ti_abb *abb = rdev_get_drvdata(rdev);
+       struct device *dev = &rdev->dev;
+
+       if (!abb) {
+               dev_err_ratelimited(dev, "%s: No regulator drvdata\n",
+                                   __func__);
+               return -ENODEV;
+       }
+
+       if (!desc->n_voltages || !abb->info) {
+               dev_err_ratelimited(dev,
+                                   "%s: No valid voltage table entries?\n",
+                                   __func__);
+               return -EINVAL;
+       }
+
+       if (abb->current_info_idx >= (int)desc->n_voltages) {
+               dev_err(dev, "%s: Corrupted data? idx(%d) >= n_voltages(%d)\n",
+                       __func__, abb->current_info_idx, desc->n_voltages);
+               return -EINVAL;
+       }
+
+       return abb->current_info_idx;
+}
+
+/**
+ * ti_abb_init_timings() - setup ABB clock timing for the current platform
+ * @dev:       device
+ * @abb:       pointer to the abb instance
+ *
+ * Return: 0 if timing is updated, else returns error result.
+ */
+static int ti_abb_init_timings(struct device *dev, struct ti_abb *abb)
+{
+       u32 clock_cycles;
+       u32 clk_rate, sr2_wt_cnt_val, cycle_rate;
+       const struct ti_abb_reg *regs = abb->regs;
+       int ret;
+       char *pname = "ti,settling-time";
+
+       /* read device tree properties */
+       ret = of_property_read_u32(dev->of_node, pname, &abb->settling_time);
+       if (ret) {
+               dev_err(dev, "Unable to get property '%s'(%d)\n", pname, ret);
+               return ret;
+       }
+
+       /* ABB LDO cannot be settle in 0 time */
+       if (!abb->settling_time) {
+               dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
+               return -EINVAL;
+       }
+
+       pname = "ti,clock-cycles";
+       ret = of_property_read_u32(dev->of_node, pname, &clock_cycles);
+       if (ret) {
+               dev_err(dev, "Unable to get property '%s'(%d)\n", pname, ret);
+               return ret;
+       }
+       /* ABB LDO cannot be settle in 0 clock cycles */
+       if (!clock_cycles) {
+               dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
+               return -EINVAL;
+       }
+
+       abb->clk = devm_clk_get(dev, NULL);
+       if (IS_ERR(abb->clk)) {
+               ret = PTR_ERR(abb->clk);
+               dev_err(dev, "%s: Unable to get clk(%d)\n", __func__, ret);
+               return ret;
+       }
+
+       /*
+        * SR2_WTCNT_VALUE is the settling time for the ABB ldo after a
+        * transition and must be programmed with the correct time at boot.
+        * The value programmed into the register is the number of SYS_CLK
+        * clock cycles that match a given wall time profiled for the ldo.
+        * This value depends on:
+        * settling time of ldo in micro-seconds (varies per OMAP family)
+        * # of clock cycles per SYS_CLK period (varies per OMAP family)
+        * the SYS_CLK frequency in MHz (varies per board)
+        * The formula is:
+        *
+        *                      ldo settling time (in micro-seconds)
+        * SR2_WTCNT_VALUE = ------------------------------------------
+        *                   (# system clock cycles) * (sys_clk period)
+        *
+        * Put another way:
+        *
+        * SR2_WTCNT_VALUE = settling time / (# SYS_CLK cycles / SYS_CLK rate))
+        *
+        * To avoid dividing by zero multiply both "# clock cycles" and
+        * "settling time" by 10 such that the final result is the one we want.
+        */
+
+       /* Convert SYS_CLK rate to MHz & prevent divide by zero */
+       clk_rate = DIV_ROUND_CLOSEST(clk_get_rate(abb->clk), 1000000);
+
+       /* Calculate cycle rate */
+       cycle_rate = DIV_ROUND_CLOSEST(clock_cycles * 10, clk_rate);
+
+       /* Calulate SR2_WTCNT_VALUE */
+       sr2_wt_cnt_val = DIV_ROUND_CLOSEST(abb->settling_time * 10, cycle_rate);
+
+       dev_dbg(dev, "%s: Clk_rate=%ld, sr2_cnt=0x%08x\n", __func__,
+               clk_get_rate(abb->clk), sr2_wt_cnt_val);
+
+       ti_abb_rmw(regs->sr2_wtcnt_value_mask, sr2_wt_cnt_val, regs->setup_reg,
+                  abb->base);
+
+       return 0;
+}
+
+/**
+ * ti_abb_init_table() - Initialize ABB table from device tree
+ * @dev:       device
+ * @abb:       pointer to the abb instance
+ * @rinit_data:        regulator initdata
+ *
+ * Return: 0 on success or appropriate error value when fails
+ */
+static int ti_abb_init_table(struct device *dev, struct ti_abb *abb,
+                            struct regulator_init_data *rinit_data)
+{
+       struct ti_abb_info *info;
+       const struct property *prop;
+       const __be32 *abb_info;
+       const u32 num_values = 6;
+       char *pname = "ti,abb_info";
+       u32 num_entries, i;
+       unsigned int *volt_table;
+       int min_uV = INT_MAX, max_uV = 0;
+       struct regulation_constraints *c = &rinit_data->constraints;
+
+       prop = of_find_property(dev->of_node, pname, NULL);
+       if (!prop) {
+               dev_err(dev, "No '%s' property?\n", pname);
+               return -ENODEV;
+       }
+
+       if (!prop->value) {
+               dev_err(dev, "Empty '%s' property?\n", pname);
+               return -ENODATA;
+       }
+
+       /*
+        * Each abb_info is a set of n-tuple, where n is num_values, consisting
+        * of voltage and a set of detection logic for ABB information for that
+        * voltage to apply.
+        */
+       num_entries = prop->length / sizeof(u32);
+       if (!num_entries || (num_entries % num_values)) {
+               dev_err(dev, "All '%s' list entries need %d vals\n", pname,
+                       num_values);
+               return -EINVAL;
+       }
+       num_entries /= num_values;
+
+       info = devm_kzalloc(dev, sizeof(*info) * num_entries, GFP_KERNEL);
+       if (!info) {
+               dev_err(dev, "Can't allocate info table for '%s' property\n",
+                       pname);
+               return -ENOMEM;
+       }
+       abb->info = info;
+
+       volt_table = devm_kzalloc(dev, sizeof(unsigned int) * num_entries,
+                                 GFP_KERNEL);
+       if (!volt_table) {
+               dev_err(dev, "Can't allocate voltage table for '%s' property\n",
+                       pname);
+               return -ENOMEM;
+       }
+
+       abb->rdesc.n_voltages = num_entries;
+       abb->rdesc.volt_table = volt_table;
+       /* We do not know where the OPP voltage is at the moment */
+       abb->current_info_idx = -EINVAL;
+
+       abb_info = prop->value;
+       for (i = 0; i < num_entries; i++, info++, volt_table++) {
+               u32 efuse_offset, rbb_mask, fbb_mask, vset_mask;
+               u32 efuse_val;
+
+               /* NOTE: num_values should equal to entries picked up here */
+               *volt_table = be32_to_cpup(abb_info++);
+               info->opp_sel = be32_to_cpup(abb_info++);
+               efuse_offset = be32_to_cpup(abb_info++);
+               rbb_mask = be32_to_cpup(abb_info++);
+               fbb_mask = be32_to_cpup(abb_info++);
+               vset_mask = be32_to_cpup(abb_info++);
+
+               dev_dbg(dev,
+                       "[%d]v=%d ABB=%d ef=0x%x rbb=0x%x fbb=0x%x vset=0x%x\n",
+                       i, *volt_table, info->opp_sel, efuse_offset, rbb_mask,
+                       fbb_mask, vset_mask);
+
+               /* Find min/max for voltage set */
+               if (min_uV > *volt_table)
+                       min_uV = *volt_table;
+               if (max_uV < *volt_table)
+                       max_uV = *volt_table;
+
+               if (!abb->efuse_base) {
+                       /* Ignore invalid data, but warn to help cleanup */
+                       if (efuse_offset || rbb_mask || fbb_mask || vset_mask)
+                               dev_err(dev, "prop '%s': v=%d,bad efuse/mask\n",
+                                       pname, *volt_table);
+                       goto check_abb;
+               }
+
+               efuse_val = readl(abb->efuse_base + efuse_offset);
+
+               /* Use ABB recommendation from Efuse */
+               if (efuse_val & rbb_mask)
+                       info->opp_sel = TI_ABB_SLOW_OPP;
+               else if (efuse_val & fbb_mask)
+                       info->opp_sel = TI_ABB_FAST_OPP;
+               else if (rbb_mask || fbb_mask)
+                       info->opp_sel = TI_ABB_NOMINAL_OPP;
+
+               dev_dbg(dev,
+                       "[%d]v=%d efusev=0x%x final ABB=%d\n",
+                       i, *volt_table, efuse_val, info->opp_sel);
+
+               /* Use recommended Vset bits from Efuse */
+               if (!abb->ldo_base) {
+                       if (vset_mask)
+                               dev_err(dev, "prop'%s':v=%d vst=%x LDO base?\n",
+                                       pname, *volt_table, vset_mask);
+                       continue;
+               }
+               info->vset = efuse_val & vset_mask >> __ffs(vset_mask);
+               dev_dbg(dev, "[%d]v=%d vset=%x\n", i, *volt_table, info->vset);
+check_abb:
+               switch (info->opp_sel) {
+               case TI_ABB_NOMINAL_OPP:
+               case TI_ABB_FAST_OPP:
+               case TI_ABB_SLOW_OPP:
+                       /* Valid values */
+                       break;
+               default:
+                       dev_err(dev, "%s:[%d]v=%d, ABB=%d is invalid! Abort!\n",
+                               __func__, i, *volt_table, info->opp_sel);
+                       return -EINVAL;
+               }
+       }
+
+       /* Setup the min/max voltage constraints from the supported list */
+       c->min_uV = min_uV;
+       c->max_uV = max_uV;
+
+       return 0;
+}
+
+static struct regulator_ops ti_abb_reg_ops = {
+       .list_voltage = regulator_list_voltage_table,
+
+       .set_voltage_sel = ti_abb_set_voltage_sel,
+       .get_voltage_sel = ti_abb_get_voltage_sel,
+};
+
+/* Default ABB block offsets, IF this changes in future, create new one */
+static const struct ti_abb_reg abb_regs_v1 = {
+       /* WARNING: registers are wrongly documented in TRM */
+       .setup_reg              = 0x04,
+       .control_reg            = 0x00,
+
+       .sr2_wtcnt_value_mask   = (0xff << 8),
+       .fbb_sel_mask           = (0x01 << 2),
+       .rbb_sel_mask           = (0x01 << 1),
+       .sr2_en_mask            = (0x01 << 0),
+
+       .opp_change_mask        = (0x01 << 2),
+       .opp_sel_mask           = (0x03 << 0),
+};
+
+static const struct ti_abb_reg abb_regs_v2 = {
+       .setup_reg              = 0x00,
+       .control_reg            = 0x04,
+
+       .sr2_wtcnt_value_mask   = (0xff << 8),
+       .fbb_sel_mask           = (0x01 << 2),
+       .rbb_sel_mask           = (0x01 << 1),
+       .sr2_en_mask            = (0x01 << 0),
+
+       .opp_change_mask        = (0x01 << 2),
+       .opp_sel_mask           = (0x03 << 0),
+};
+
+static const struct of_device_id ti_abb_of_match[] = {
+       {.compatible = "ti,abb-v1", .data = &abb_regs_v1},
+       {.compatible = "ti,abb-v2", .data = &abb_regs_v2},
+       { },
+};
+
+MODULE_DEVICE_TABLE(of, ti_abb_of_match);
+
+/**
+ * ti_abb_probe() - Initialize an ABB ldo instance
+ * @pdev: ABB platform device
+ *
+ * Initializes an individual ABB LDO for required Body-Bias. ABB is used to
+ * addional bias supply to SoC modules for power savings or mandatory stability
+ * configuration at certain Operating Performance Points(OPPs).
+ *
+ * Return: 0 on success or appropriate error value when fails
+ */
+static int ti_abb_probe(struct platform_device *pdev)
+{
+       struct device *dev = &pdev->dev;
+       const struct of_device_id *match;
+       struct resource *res;
+       struct ti_abb *abb;
+       struct regulator_init_data *initdata = NULL;
+       struct regulator_dev *rdev = NULL;
+       struct regulator_desc *desc;
+       struct regulation_constraints *c;
+       struct regulator_config config = { };
+       char *pname;
+       int ret = 0;
+
+       match = of_match_device(ti_abb_of_match, dev);
+       if (!match) {
+               /* We do not expect this to happen */
+               ret = -ENODEV;
+               dev_err(dev, "%s: Unable to match device\n", __func__);
+               goto err;
+       }
+       if (!match->data) {
+               ret = -EINVAL;
+               dev_err(dev, "%s: Bad data in match\n", __func__);
+               goto err;
+       }
+
+       abb = devm_kzalloc(dev, sizeof(struct ti_abb), GFP_KERNEL);
+       if (!abb) {
+               dev_err(dev, "%s: Unable to allocate ABB struct\n", __func__);
+               ret = -ENOMEM;
+               goto err;
+       }
+       abb->regs = match->data;
+
+       /* Map ABB resources */
+       pname = "base-address";
+       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
+       if (!res) {
+               dev_err(dev, "Missing '%s' IO resource\n", pname);
+               ret = -ENODEV;
+               goto err;
+       }
+       abb->base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(abb->base)) {
+               ret = PTR_ERR(abb->base);
+               goto err;
+       }
+
+       pname = "int-address";
+       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
+       if (!res) {
+               dev_err(dev, "Missing '%s' IO resource\n", pname);
+               ret = -ENODEV;
+               goto err;
+       }
+       /*
+        * We may have shared interrupt register offsets which are
+        * write-1-to-clear between domains ensuring exclusivity.
+        */
+       abb->int_base = devm_ioremap_nocache(dev, res->start,
+                                            resource_size(res));
+       if (!abb->int_base) {
+               dev_err(dev, "Unable to map '%s'\n", pname);
+               ret = -ENOMEM;
+               goto err;
+       }
+
+       /* Map Optional resources */
+       pname = "efuse-address";
+       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
+       if (!res) {
+               dev_dbg(dev, "Missing '%s' IO resource\n", pname);
+               ret = -ENODEV;
+               goto skip_opt;
+       }
+
+       /*
+        * We may have shared efuse register offsets which are read-only
+        * between domains
+        */
+       abb->efuse_base = devm_ioremap_nocache(dev, res->start,
+                                              resource_size(res));
+       if (!abb->efuse_base) {
+               dev_err(dev, "Unable to map '%s'\n", pname);
+               ret = -ENOMEM;
+               goto err;
+       }
+
+       pname = "ldo-address";
+       res = platform_get_resource_byname(pdev, IORESOURCE_MEM, pname);
+       if (!res) {
+               dev_dbg(dev, "Missing '%s' IO resource\n", pname);
+               ret = -ENODEV;
+               goto skip_opt;
+       }
+       abb->ldo_base = devm_ioremap_resource(dev, res);
+       if (IS_ERR(abb->ldo_base)) {
+               ret = PTR_ERR(abb->ldo_base);
+               goto err;
+       }
+
+       /* IF ldo_base is set, the following are mandatory */
+       pname = "ti,ldovbb-override-mask";
+       ret =
+           of_property_read_u32(pdev->dev.of_node, pname,
+                                &abb->ldovbb_override_mask);
+       if (ret) {
+               dev_err(dev, "Missing '%s' (%d)\n", pname, ret);
+               goto err;
+       }
+       if (!abb->ldovbb_override_mask) {
+               dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
+               ret = -EINVAL;
+               goto err;
+       }
+
+       pname = "ti,ldovbb-vset-mask";
+       ret =
+           of_property_read_u32(pdev->dev.of_node, pname,
+                                &abb->ldovbb_vset_mask);
+       if (ret) {
+               dev_err(dev, "Missing '%s' (%d)\n", pname, ret);
+               goto err;
+       }
+       if (!abb->ldovbb_vset_mask) {
+               dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
+               ret = -EINVAL;
+               goto err;
+       }
+
+skip_opt:
+       pname = "ti,tranxdone-status-mask";
+       ret =
+           of_property_read_u32(pdev->dev.of_node, pname,
+                                &abb->txdone_mask);
+       if (ret) {
+               dev_err(dev, "Missing '%s' (%d)\n", pname, ret);
+               goto err;
+       }
+       if (!abb->txdone_mask) {
+               dev_err(dev, "Invalid property:'%s' set as 0!\n", pname);
+               ret = -EINVAL;
+               goto err;
+       }
+
+       initdata = of_get_regulator_init_data(dev, pdev->dev.of_node);
+       if (!initdata) {
+               ret = -ENOMEM;
+               dev_err(dev, "%s: Unable to alloc regulator init data\n",
+                       __func__);
+               goto err;
+       }
+
+       /* init ABB opp_sel table */
+       ret = ti_abb_init_table(dev, abb, initdata);
+       if (ret)
+               goto err;
+
+       /* init ABB timing */
+       ret = ti_abb_init_timings(dev, abb);
+       if (ret)
+               goto err;
+
+       desc = &abb->rdesc;
+       desc->name = dev_name(dev);
+       desc->owner = THIS_MODULE;
+       desc->type = REGULATOR_VOLTAGE;
+       desc->ops = &ti_abb_reg_ops;
+
+       c = &initdata->constraints;
+       if (desc->n_voltages > 1)
+               c->valid_ops_mask |= REGULATOR_CHANGE_VOLTAGE;
+       c->always_on = true;
+
+       config.dev = dev;
+       config.init_data = initdata;
+       config.driver_data = abb;
+       config.of_node = pdev->dev.of_node;
+
+       rdev = regulator_register(desc, &config);
+       if (IS_ERR(rdev)) {
+               ret = PTR_ERR(rdev);
+               dev_err(dev, "%s: failed to register regulator(%d)\n",
+                       __func__, ret);
+               goto err;
+       }
+       platform_set_drvdata(pdev, rdev);
+
+       /* Enable the ldo if not already done by bootloader */
+       ti_abb_rmw(abb->regs->sr2_en_mask, 1, abb->regs->setup_reg, abb->base);
+
+       return 0;
+
+err:
+       dev_err(dev, "%s: Failed to initialize(%d)\n", __func__, ret);
+       return ret;
+}
+
+/**
+ * ti_abb_remove() - cleanups
+ * @pdev: ABB platform device
+ *
+ * Return: 0
+ */
+static int ti_abb_remove(struct platform_device *pdev)
+{
+       struct regulator_dev *rdev = platform_get_drvdata(pdev);
+
+       regulator_unregister(rdev);
+       return 0;
+}
+
+MODULE_ALIAS("platform:ti_abb");
+
+static struct platform_driver ti_abb_driver = {
+       .probe = ti_abb_probe,
+       .remove = ti_abb_remove,
+       .driver = {
+                  .name = "ti_abb",
+                  .owner = THIS_MODULE,
+                  .of_match_table = of_match_ptr(ti_abb_of_match),
+                  },
+};
+module_platform_driver(ti_abb_driver);
+
+MODULE_DESCRIPTION("Texas Instruments ABB LDO regulator driver");
+MODULE_AUTHOR("Texas Instruments Inc.");
+MODULE_LICENSE("GPL v2");