From: "Andrii.Tseglytskyi" <andrii.tseglyts...@ti.com>
This patch introduces the Adaptive Body-Bias LDO driver,
which handles LDOs voltage during OPP change routine.
It follows general principles of ABB implementation
in kernel 3.4.
Some new features are added:
1) ABB driver uses clock notifier framework to scale LDO.
To make this working it handles it's own OPP table.
OPP table has the following format in device tree:
operating-points = <
/* kHz ABB (0 - Bypass, 1 - FBB, 2 - RBB) */
499200 0
1099800 1
1500000 1
1699200 1
>;
Generic API is used for OPP table parsing - of_init_opp_table()
2) ABB driver doesn't have any public interfaces. It follows
Voltage/Frequency changes, using only notification mechanism.
3) ABB driver uses PRM_IRQSTATUS register to check tranxdone status.
This register is shared with VP.
Cc: Mike Turquette <mturque...@linaro.org>
Cc: Tero Kristo <t-kri...@ti.com>
Cc: Nishanth Menon <n...@ti.com>
Cc: "Benoît Cousson" <b-cous...@ti.com>
Cc: linux-omap@vger.kernel.org
Signed-off-by: Andrii.Tseglytskyi <andrii.tseglyts...@ti.com>
Signed-off-by: Mike Turquette <mturque...@linaro.org>
---
drivers/power/avs/Makefile | 2 +-
drivers/power/avs/abb.c | 570 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 571 insertions(+), 1 deletion(-)
create mode 100644 drivers/power/avs/abb.c
diff --git a/drivers/power/avs/Makefile b/drivers/power/avs/Makefile
index 0843386..d5fc9c4 100644
--- a/drivers/power/avs/Makefile
+++ b/drivers/power/avs/Makefile
@@ -1 +1 @@
-obj-$(CONFIG_POWER_AVS_OMAP) += smartreflex.o
+obj-$(CONFIG_POWER_AVS_OMAP) += smartreflex.o abb.o
diff --git a/drivers/power/avs/abb.c b/drivers/power/avs/abb.c
new file mode 100644
index 0000000..f5bbb8d
--- /dev/null
+++ b/drivers/power/avs/abb.c
@@ -0,0 +1,570 @@
+/*
+ * OMAP Adaptive Body-Bias core
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * Mike Turquette <mturque...@ti.com>
+ *
+ * Copyright (C) 2013 Texas Instruments, Inc.
+ * Andrii Tseglytskyi <andrii.tseglyts...@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.
+ */
+
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/of_device.h>
+#include <linux/clk-provider.h>
+#include <linux/io.h>
+#include <linux/opp.h>
+
+/* NOMINAL_OPP bypasses the ABB ldo, FAST_OPP sets it to Forward Body-Bias */
+#define OMAP_ABB_NOMINAL_OPP 0
+#define OMAP_ABB_FAST_OPP 1
+#define OMAP_ABB_SLOW_OPP 3
+#define OMAP_ABB_NO_LDO (~0)
+
+/* Time for the ABB ldo to settle after transition (in micro-seconds) */
+#define ABB_TRANXDONE_TIMEOUT 50
+
+/*
+ * struct omap_abb_data - common data for each instance of ABB ldo
+ *
+ * @opp_sel_mask: selects Fast/Nominal/Slow OPP for ABB
+ * @opp_change_mask: selects OPP_CHANGE bit value
+ * @sr2_wtcnt_value_mask: LDO settling time for active-mode OPP change
+ * @sr2en_mask: enables/disables ABB
+ * @fbb_sel_mask: selects FBB mode
+ * @rbb_sel_mask: selects RBB mode
+ * @settling_time: IRQ handle used to resolve IRQSTATUS offset & masks
+ * @clock_cycles: value needed for LDO setting time calculation
+ * @setup_offs: PRM_LDO_ABB_XXX_SETUP register offset
+ * @control_offs: PRM_LDO_ABB_IVA_CTRL register offset
+ */
+struct omap_abb_data {
+ u32 opp_sel_mask;
+ u32 opp_change_mask;
+ u32 sr2_wtcnt_value_mask;
+ u32 sr2en_mask;
+ u32 fbb_sel_mask;
+ u32 rbb_sel_mask;
+ unsigned long settling_time;
+ unsigned long clock_cycles;
+ u8 setup_offs;
+ u8 control_offs;
+};
+
+/*
+ * struct omap_abb - ABB ldo instance
+ *
+ * @control: memory mapped ABB registers
+ * @txdone: memory mapped IRQSTATUS register
+ * @dev: device, for which ABB is created
+ * @txdone_mask: ABB mode change done bit
+ * @opp_sel: current ABB status - Fast/Nominal/Slow
+ * @notify_clk: clock, which rate changes are handled by ABB
+ * @data: common data
+ * @abb_clk_nb: clock rate change notifier block
+ */
+struct omap_abb {
+ void __iomem *control;
+ void __iomem *txdone;
+ struct device *dev;
+ u32 txdone_mask;
+ u32 opp_sel;
+ struct clk *notify_clk;
+ struct omap_abb_data data;
+ struct notifier_block abb_clk_nb;
+};
+
+static const struct omap_abb_data __initdata omap36xx_abb_data = {
+ .opp_sel_mask = (3 << 0), /* OMAP3630_OPP_SEL_MASK */
+ .opp_change_mask = (1 << 2), /* OMAP3630_OPP_CHANGE_MASK */
+ .sr2en_mask = (1 << 0), /* OMAP3630_SR2EN_MASK */
+ .fbb_sel_mask = (1 << 2), /* OMAP3630_ACTIVE_FBB_SEL_MASK */
+ .sr2_wtcnt_value_mask = (0xff << 8), /* OMAP3630_SR2_WTCNT_VALUE_MASK */
+ .setup_offs = 0,
+ .control_offs = 0x4,
+ .settling_time = 30,
+ .clock_cycles = 8,
+};
+
+static const struct omap_abb_data __initdata omap4_abb_data = {
+ .opp_sel_mask = (0x3 << 0), /* OMAP4430_OPP_SEL_MASK */
+ .opp_change_mask = (1 << 2), /* OMAP4430_OPP_CHANGE_MASK */
+ .sr2en_mask = (1 << 0), /* OMAP4430_SR2EN_MASK */
+ .fbb_sel_mask = (1 << 2), /* OMAP4430_ACTIVE_FBB_SEL_MASK */
+ .rbb_sel_mask = (1 << 1), /* OMAP4430_ACTIVE_RBB_SEL_MASK */
+ .sr2_wtcnt_value_mask = (0xff << 8), /* OMAP4430_SR2_WTCNT_VALUE_MASK */
+ .setup_offs = 0,
+ .control_offs = 0x4,
+ .settling_time = 50,
+ .clock_cycles = 16,
+};
+
+static const struct omap_abb_data __initdata omap5_abb_data = {
+ .opp_sel_mask = (0x3 << 0), /* OMAP54XX_OPP_SEL_MASK */
+ .opp_change_mask = (1 << 2), /* OMAP54XX_OPP_CHANGE_MASK */
+ .sr2en_mask = (1 << 0), /* OMAP54XX_SR2EN_MASK */
+ .fbb_sel_mask = (1 << 2), /* OMAP54XX_ACTIVE_FBB_SEL_MASK */
+ .rbb_sel_mask = (1 << 1), /* OMAP54XX_ACTIVE_RBB_SEL_MASK */
+ .sr2_wtcnt_value_mask = (0xff << 8), /* OMAP54XX_SR2_WTCNT_VALUE_MASK */
+ .setup_offs = 0,
+ .control_offs = 0x4,
+ .settling_time = 50,
+ .clock_cycles = 16,
+};
+
+/**
+ * omap_abb_readl() - reads ABB control memory
+ * @abb: pointer to the abb instance
+ * @offs: offset to read
+ *
+ * Returns @offs value
+ */
+static u32 omap_abb_readl(struct omap_abb *abb, u32 offs)
+{
+ return __raw_readl(abb->control + offs);
+}
+
+/**
+ * omap_abb_rmw() - modifies ABB control memory
+ * @abb: pointer to the abb instance
+ * @mask: mask to modify
+ * @bits: bits to store
+ * @offs: offset to modify
+ */
+static void omap_abb_rmw(struct omap_abb *abb, u32 mask, u32 bits, u32 offs)
+{
+ u32 val;
+
+ val = __raw_readl(abb->control + offs);
+ val &= ~mask;
+ val |= bits;
+ __raw_writel(val, abb->control + offs);
+}
+
+/**
+ * omap_abb_check_txdone() - checks ABB tranxdone status
+ * @abb: pointer to the abb instance
+ *
+ * Returns true or false
+ */
+static bool omap_abb_check_txdone(struct omap_abb *abb)
+{
+ return !!(__raw_readl(abb->txdone) & abb->txdone_mask);
+}
+
+/**
+ * omap_abb_clear_txdone() - clears ABB tranxdone status
+ * @abb: pointer to the abb instance
+ */
+static void omap_abb_clear_txdone(struct omap_abb *abb)
+{
+ __raw_writel(abb->txdone_mask, abb->txdone);
+};
+
+/**
+ * omap_abb_wait_tranx() - waits for ABB tranxdone event
+ * @abb: pointer to the abb instance
+ *
+ * Returns -ETIMEDOUT if the event is not set on time.
+ */
+static int omap_abb_wait_tranx(struct omap_abb *abb)
+{
+ int timeout;
+ bool status;
+
+ timeout = 0;
+ while (timeout++ < ABB_TRANXDONE_TIMEOUT) {
+ status = omap_abb_check_txdone(abb);
+ if (status)
+ break;
+
+ udelay(1);
+ }
+
+ if (timeout >= ABB_TRANXDONE_TIMEOUT) {
+ dev_warn(abb->dev, "%s: ABB TRANXDONE timeout=(%d)\n",
+ __func__, timeout);
+ return -ETIMEDOUT;
+ }
+ return 0;
+}
+
+/**
+ * omap_abb_clear_tranx() - clears ABB tranxdone event
+ * @abb: pointer to the abb instance
+ *
+ * Returns -ETIMEDOUT if the event is not cleared on time.
+ */
+static int omap_abb_clear_tranx(struct omap_abb *abb)
+{
+ int timeout;
+ bool status;
+
+ /* clear interrupt status */
+ timeout = 0;
+ while (timeout++ < ABB_TRANXDONE_TIMEOUT) {
+ omap_abb_clear_txdone(abb);
+
+ status = omap_abb_check_txdone(abb);
+ if (!status)
+ break;
+
+ udelay(1);
+ }
+
+ if (timeout >= ABB_TRANXDONE_TIMEOUT) {
+ dev_warn(abb->dev, "%s: ABB TRANXDONE timeout=(%d)\n",
+ __func__, timeout);
+ return -ETIMEDOUT;
+ }
+ return 0;
+}
+
+/**
+ * omap_abb_set_opp() - program ABB ldo based on new voltage
+ * @abb: pointer to the abb instance
+ * @opp_sel: target ABB ldo operating mode
+ *
+ * Program the ABB ldo to the new state (if necessary), clearing the
+ * PRM_IRQSTATUS bit before and after the transition. Returns 0 on
+ * success, -ETIMEDOUT otherwise.
+ */
+static int omap_abb_set_opp(struct omap_abb *abb, u8 opp_sel)
+{
+ int ret = 0;
+ const struct omap_abb_data *data = &abb->data;
+
+ /* bail early if no transition is necessary */
+ if (opp_sel == abb->opp_sel)
+ return ret;
+
+ /* clear interrupt status */
+ ret = omap_abb_clear_tranx(abb);
+ if (ret)
+ goto out;
+
+ /* program the setup register */
+ switch (opp_sel) {
+ case OMAP_ABB_NOMINAL_OPP:
+ omap_abb_rmw(abb,
+ data->fbb_sel_mask | data->rbb_sel_mask,
+ 0x0,
+ data->setup_offs);
+ break;
+ case OMAP_ABB_SLOW_OPP:
+ omap_abb_rmw(abb,
+ data->fbb_sel_mask | data->rbb_sel_mask,
+ data->rbb_sel_mask,
+ data->setup_offs);
+ break;
+ case OMAP_ABB_FAST_OPP:
+ omap_abb_rmw(abb,
+ data->fbb_sel_mask | data->rbb_sel_mask,
+ data->fbb_sel_mask,
+ data->setup_offs);
+ break;
+ default:
+ /* Should have never been here! */
+ WARN_ONCE(1, "%s: opp_sel %d!!!\n",
+ __func__, opp_sel);
+ return -EINVAL;
+ }
+
+ /* program next state of ABB ldo */
+ omap_abb_rmw(abb, data->opp_sel_mask,
+ opp_sel << __ffs(data->opp_sel_mask),
+ data->control_offs);
+
+ /* initiate ABB ldo change */
+ omap_abb_rmw(abb, data->opp_change_mask,
+ data->opp_change_mask,
+ data->control_offs);
+
+ /* Wait for conversion completion */
+ ret = omap_abb_wait_tranx(abb);
+ WARN_ONCE(ret, "%s: ABB TRANXDONE was not set on time:%d\n",
+ __func__, ret);
+
+ /* clear interrupt status */
+ ret |= omap_abb_clear_tranx(abb);
+
+out:
+ if (ret) {
+ dev_warn(abb->dev, "%s: failed to scale: opp_sel=%d (%d)\n",
+ __func__, opp_sel, ret);
+ } else {
+ /* track internal state */
+ abb->opp_sel = opp_sel;
+ dev_dbg(abb->dev, "%s: scaled - opp_sel=%d\n",
+ __func__, opp_sel);
+ }
+ return ret;
+}
+
+/**
+ * omap_abb_pre_scale() - ABB transition pre-frequency scale callback
+ * @abb: pointer to the ABB instance
+ * @old_rate: old notifier clock rate
+ * @new_rate: new notifier clock rate
+ *
+ * Changes the ABB ldo mode prior to scaling the frequency.
+ * Returns 0 on success, otherwise an error code.
+ */
+static int omap_abb_pre_scale(struct omap_abb *abb,
+ unsigned long old_rate,
+ unsigned long new_rate)
+{
+ struct opp *opp;
+
+ /* bail if the sequence is wrong */
+ if (new_rate >= old_rate)
+ return 0;
+
+ rcu_read_lock();
+ opp = opp_find_freq_exact(abb->dev, new_rate, true);
+ rcu_read_unlock();
+
+ if (IS_ERR(opp)) {
+ dev_err(abb->dev, "%s: can't find OPP for Freq (%lu)",
+ __func__, new_rate);
+ return -EINVAL;
+ }
+
+ return omap_abb_set_opp(abb, opp_get_voltage(opp));
+}
+
+/**
+ * omap_abb_post_scale() - ABB transition post-frequency scale callback
+ * @abb: pointer to the ABB instance
+ * @old_rate: old notifier clock rate
+ * @new_rate: new notifier clock rate
+ *
+ * Changes the ABB ldo mode prior to scaling the frequency.
+ * Returns 0 on success, otherwise an error code.
+ */
+static int omap_abb_post_scale(struct omap_abb *abb,
+ unsigned long old_rate,
+ unsigned long new_rate)
+{
+ struct opp *opp;
+
+ /* bail if the sequence is wrong */
+ if (new_rate <= old_rate)
+ return 0;
+
+ rcu_read_lock();
+ opp = opp_find_freq_exact(abb->dev, new_rate, true);
+ rcu_read_unlock();
+
+ if (IS_ERR(opp)) {
+ dev_err(abb->dev, "%s: can't find OPP for Freq (%lu)",
+ __func__, new_rate);
+ return -EINVAL;
+ }
+
+ return omap_abb_set_opp(abb, opp_get_voltage(opp));
+}
+
+/**
+ * omap_abb_clock_rate_change() - ABB clock notifier callback
+ * @nb: notifier block
+ * @flags: notifier event type
+ * @data: notifier data, contains clock rates
+ *
+ * Returns NOTIFY_OK
+ */
+static int omap_abb_clock_rate_change(struct notifier_block *nb,
+ unsigned long flags, void *data)
+{
+ struct clk_notifier_data *cnd = data;
+ struct omap_abb *abb = container_of(nb, struct omap_abb, abb_clk_nb);
+
+ switch (flags) {
+ case PRE_RATE_CHANGE:
+ omap_abb_pre_scale(abb, cnd->old_rate, cnd->new_rate);
+ break;
+ case POST_RATE_CHANGE:
+ omap_abb_post_scale(abb, cnd->old_rate, cnd->new_rate);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block abb_clk_nb = {
+ .notifier_call = omap_abb_clock_rate_change,
+};
+
+#if defined(CONFIG_OF)
+static const struct of_device_id __initdata omap_abb_of_match[] = {
+ { .compatible = "ti,omap36xx-abb", .data = &omap36xx_abb_data},
+ { .compatible = "ti,omap4-abb", .data = &omap4_abb_data},
+ { .compatible = "ti,omap5-abb", .data = &omap5_abb_data},
+ {},
+};
+MODULE_DEVICE_TABLE(of, omap_abb_of_match);
+#endif
+
+/*
+ * omap_abb_probe() - Initialize an ABB ldo instance
+ * @pdev: ABB platform device
+ *
+ * Initializes an individual ABB ldo for Forward Body-Bias. FBB is used to
+ * insure stability at higher voltages. Note that some older OMAP chips have a
+ * Reverse Body-Bias mode meant to save power at low voltage, but that mode is
+ * unsupported and phased out on newer chips.
+ */
+static int __init omap_abb_probe(struct platform_device *pdev)
+{
+ const struct of_device_id *match = NULL;
+ struct omap_abb *abb = NULL;
+ struct resource *mem = NULL;
+ struct clk *sys_clk = NULL;
+ u32 sys_clk_rate, sr2_wt_cnt_val, clock_cycles, abb_sel;
+ int ret = 0;
+
+ match = of_match_device(omap_abb_of_match, &pdev->dev);
+ if (!match) {
+ ret = -ENODEV;
+ goto err;
+ }
+
+ abb = devm_kzalloc(&pdev->dev,
+ sizeof(struct omap_abb),
+ GFP_KERNEL);
+ if (!abb) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ abb->data = *((struct omap_abb_data *)match->data);
+ abb->dev = &pdev->dev;
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!mem) {
+ ret = -ENODEV;
+ goto err;
+ }
+
+ abb->control = devm_request_and_ioremap(&pdev->dev, mem);
+ if (!abb->control) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ if (!mem) {
+ ret = -ENODEV;
+ goto err;
+ }
+
+ abb->txdone = devm_ioremap_nocache(&pdev->dev, mem->start,
+ resource_size(mem));
+ if (!abb->txdone) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ /*
+ * 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.
+ */
+ ret = of_property_read_u32(pdev->dev.of_node,
+ "ti,tranxdone_status_mask",
+ &abb->txdone_mask);
+ if (ret)
+ goto err;
+
+ ret = of_init_opp_table(&pdev->dev);
+ if (ret)
+ goto err;
+
+ abb->notify_clk = clk_get(&pdev->dev, "abb_notify_ck");
+ if (IS_ERR_OR_NULL(abb->notify_clk)) {
+ ret = -ENODEV;
+ goto err;
+ }
+
+ sys_clk = clk_get(&pdev->dev, "abb_sys_ck");
+ if (IS_ERR_OR_NULL(sys_clk)) {
+ ret = -ENODEV;
+ goto err_sys_ck;
+ }
+
+ /* convert SYS_CLK rate to MHz & prevent divide by zero */
+ sys_clk_rate = DIV_ROUND_CLOSEST(clk_get_rate(sys_clk), 1000000);
+
+ /* calculate cycle rate */
+ clock_cycles = DIV_ROUND_CLOSEST((abb->data.clock_cycles * 10),
+ sys_clk_rate);
+
+ /* calulate SR2_WTCNT_VALUE */
+ sr2_wt_cnt_val = DIV_ROUND_CLOSEST((abb->data.settling_time * 10),
+ clock_cycles);
+
+ omap_abb_rmw(abb, abb->data.sr2_wtcnt_value_mask,
+ (sr2_wt_cnt_val << __ffs(abb->data.sr2_wtcnt_value_mask)),
+ abb->data.setup_offs);
+
+ abb->abb_clk_nb = abb_clk_nb;
+ clk_notifier_register(abb->notify_clk, &abb->abb_clk_nb);
+
+ /* did bootloader set OPP_SEL? */
+ abb_sel = omap_abb_readl(abb, abb->data.control_offs);
+ abb_sel &= abb->data.opp_sel_mask;
+ abb->opp_sel = abb_sel >> __ffs(abb->data.opp_sel_mask);
+
+ /* enable the ldo if not done by bootloader */
+ abb_sel = omap_abb_readl(abb, abb->data.setup_offs);
+ abb_sel &= abb->data.sr2en_mask;
+ if (!abb_sel)
+ omap_abb_rmw(abb, abb->data.sr2en_mask,
+ abb->data.sr2en_mask, abb->data.setup_offs);
+
+ clk_put(sys_clk);
+ return 0;
+
+err_sys_ck:
+ clk_put(abb->notify_clk);
+err:
+ dev_err(&pdev->dev, "%s: error on init (%d)\n",
+ __func__, ret);
+
+ return ret;
+}
+
+static struct platform_driver omap_abb_driver = {
+ .driver = {
+ .name = "omap_abb",
+ .of_match_table = of_match_ptr(omap_abb_of_match),
+ },
+};
+
+static int __init omap_abb_driver_init(void)
+{
+ return platform_driver_probe(&omap_abb_driver, omap_abb_probe);
+}
+subsys_initcall(omap_abb_driver_init);
--
1.7.9.5
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