// SPDX-License-Identifier: GPL-2.0-only
/*
* RTC Driver for X-Powers AC100
*
* Copyright (c) 2016 Chen-Yu Tsai
*
* Chen-Yu Tsai <wens@csie.org>
*/
#include <linux/bcd.h>
#include <linux/clk-provider.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/mfd/ac100.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/rtc.h>
#include <linux/types.h>
/* Control register */
#define AC100_RTC_CTRL_24HOUR BIT(0)
/* Clock output register bits */
#define AC100_CLKOUT_PRE_DIV_SHIFT 5
#define AC100_CLKOUT_PRE_DIV_WIDTH 3
#define AC100_CLKOUT_MUX_SHIFT 4
#define AC100_CLKOUT_MUX_WIDTH 1
#define AC100_CLKOUT_DIV_SHIFT 1
#define AC100_CLKOUT_DIV_WIDTH 3
#define AC100_CLKOUT_EN BIT(0)
/* RTC */
#define AC100_RTC_SEC_MASK GENMASK(6, 0)
#define AC100_RTC_MIN_MASK GENMASK(6, 0)
#define AC100_RTC_HOU_MASK GENMASK(5, 0)
#define AC100_RTC_WEE_MASK GENMASK(2, 0)
#define AC100_RTC_DAY_MASK GENMASK(5, 0)
#define AC100_RTC_MON_MASK GENMASK(4, 0)
#define AC100_RTC_YEA_MASK GENMASK(7, 0)
#define AC100_RTC_YEA_LEAP BIT(15)
#define AC100_RTC_UPD_TRIGGER BIT(15)
/* Alarm (wall clock) */
#define AC100_ALM_INT_ENABLE BIT(0)
#define AC100_ALM_SEC_MASK GENMASK(6, 0)
#define AC100_ALM_MIN_MASK GENMASK(6, 0)
#define AC100_ALM_HOU_MASK GENMASK(5, 0)
#define AC100_ALM_WEE_MASK GENMASK(2, 0)
#define AC100_ALM_DAY_MASK GENMASK(5, 0)
#define AC100_ALM_MON_MASK GENMASK(4, 0)
#define AC100_ALM_YEA_MASK GENMASK(7, 0)
#define AC100_ALM_ENABLE_FLAG BIT(15)
#define AC100_ALM_UPD_TRIGGER BIT(15)
/*
* The year parameter passed to the driver is usually an offset relative to
* the year 1900. This macro is used to convert this offset to another one
* relative to the minimum year allowed by the hardware.
*
* The year range is 1970 - 2069. This range is selected to match Allwinner's
* driver.
*/
#define AC100_YEAR_MIN 1970
#define AC100_YEAR_MAX 2069
#define AC100_YEAR_OFF (AC100_YEAR_MIN - 1900)
struct ac100_clkout {
struct clk_hw hw;
struct regmap *regmap;
u8 offset;
};
#define to_ac100_clkout(_hw) container_of(_hw, struct ac100_clkout, hw)
#define AC100_RTC_32K_NAME "ac100-rtc-32k"
#define AC100_RTC_32K_RATE 32768
#define AC100_CLKOUT_NUM 3
static const char * const ac100_clkout_names[AC100_CLKOUT_NUM] = {
"ac100-cko1-rtc",
"ac100-cko2-rtc",
"ac100-cko3-rtc",
};
struct ac100_rtc_dev {
struct rtc_device *rtc;
struct device *dev;
struct regmap *regmap;
int irq;
unsigned long alarm;
struct clk_hw *rtc_32k_clk;
struct ac100_clkout clks[AC100_CLKOUT_NUM];
struct clk_hw_onecell_data *clk_data;
};
/**
* Clock controls for 3 clock output pins
*/
static const struct clk_div_table ac100_clkout_prediv[] = {
{ .val = 0, .div = 1 },
{ .val = 1, .div = 2 },
{ .val = 2, .div = 4 },
{ .val = 3, .div = 8 },
{ .val = 4, .div = 16 },
{ .val = 5, .div = 32 },
{ .val = 6, .div = 64 },
{ .val = 7, .div = 122 },
{ },
};
/* Abuse the fact that one parent is 32768 Hz, and the other is 4 MHz */
static unsigned long ac100_clkout_recalc_rate(struct clk_hw *hw,
unsigned long prate)
{
struct ac100_clkout *clk = to_ac100_clkout(hw);
unsigned int reg, div;
regmap_read(clk->regmap, clk->offset, ®);
/* Handle pre-divider first */
if (prate != AC100_RTC_32K_RATE) {
div = (reg >> AC100_CLKOUT_PRE_DIV_SHIFT) &
((1 << AC100_CLKOUT_PRE_DIV_WIDTH) - 1);
prate = divider_recalc_rate(hw, prate, div,
ac100_clkout_prediv, 0,
AC100_CLKOUT_PRE_DIV_WIDTH);
}
div = (reg >> AC100_CLKOUT_DIV_SHIFT) &
(BIT(AC100_CLKOUT_DIV_WIDTH) - 1);
return divider_recalc_rate(hw, prate, div, NULL,
CLK_DIVIDER_POWER_OF_TWO,
AC100_CLKOUT_DIV_WIDTH);
}
static long ac100_clkout_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long prate)
{
unsigned long best_rate = 0, tmp_rate, tmp_prate;
int i;
if (prate == AC100_RTC_32K_RATE)
return divider_round_rate(hw, rate, &prate, NULL,
AC100_CLKOUT_DIV_WIDTH,
CLK_DIVIDER_POWER_OF_TWO);
for (i = 0; ac100_clkout_prediv[i].div; i++) {
tmp_prate = DIV_ROUND_UP(prate, ac100_clkout_prediv[i].val);
tmp_rate = divider_round_rate(hw, rate, &tmp_prate, NULL,
AC100_CLKOUT_DIV_WIDTH,
CLK_DIVIDER_POWER_OF_TWO);
if (tmp_rate > rate)
continue;
if (rate - tmp_rate < best_rate - tmp_rate)
best_rate = tmp_rate;
}
return best_rate;
}
static int ac100_clkout_determine_rate(struct clk_hw *hw,
struct clk_rate_request *req)
{
struct clk_hw *best_parent;
unsigned long best = 0;
int i, num_parents = clk_hw_get_num_parents(hw);
for (i = 0; i < num_parents; i++) {
struct clk_hw *parent = clk_hw_get_parent_by_index(hw, i);
unsigned long tmp, prate;
/*
* The clock has two parents, one is a fixed clock which is
* internally registered by the ac100 driver. The other parent
* is a clock from the codec side of the chip, which we
* properly declare and reference in the devicetree and is
* not implemented in any driver right now.
* If the clock core looks for the parent of that second
* missing clock, it can't find one that is registered and
* returns NULL.
* So we end up in a situation where clk_hw_get_num_parents
* returns the amount of clocks we can be parented to, but
* clk_hw_get_parent_by_index will not return the orphan
* clocks.
* Thus we need to check if the parent exists before
* we get the parent rate, so we could use the RTC
* without waiting for the codec to be supported.
*/
if (!parent)
continue;
prate = clk_hw_get_rate(parent);
tmp = ac100_clkout_round_rate(hw, req->rate, prate);
if (tmp > req->rate)
continue;
if (req->rate - tmp < req->rate - best) {
best = tmp;
best_parent = parent;
}
}
if (!best)
return -EINVAL;
req->best_parent_hw = best_parent;
req->best_parent_rate = best;
req->rate = best;
return 0;
}
static int ac100_clkout_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long prate)
{
struct ac100_clkout *clk = to_ac100_clkout(hw);
int div = 0, pre_div = 0;
do {
div = divider_get_val(rate * ac100_clkout_prediv[pre_div].div,
prate, NULL, AC100_CLKOUT_DIV_WIDTH,
CLK_DIVIDER_POWER_OF_TWO);
if (div >= 0)
break;
} while (prate != AC100_RTC_32K_RATE &&
ac100_clkout_prediv[++pre_div].div);
if (div < 0)
return div;
pre_div = ac100_clkout_prediv[pre_div].val;
regmap_update_bits(clk->regmap, clk->offset,
((1 << AC100_CLKOUT_DIV_WIDTH) - 1) << AC100_CLKOUT_DIV_SHIFT |
((1 << AC100_CLKOUT_PRE_DIV_WIDTH) - 1) << AC100_CLKOUT_PRE_DIV_SHIFT,
(div - 1) << AC100_CLKOUT_DIV_SHIFT |
(pre_div - 1) << AC100_CLKOUT_PRE_DIV_SHIFT);
return 0;
}
static int ac100_clkout_prepare(struct clk_hw *hw)
{
struct ac100_clkout *clk = to_ac100_clkout(hw);
return regmap_update_bits(clk->regmap, clk->offset, AC100_CLKOUT_EN,
AC100_CLKOUT_EN);
}
static void ac100_clkout_unprepare(struct clk_hw *hw)
{
struct ac100_clkout *clk = to_ac100_clkout(hw);
regmap_update_bits(clk->regmap, clk->offset, AC100_CLKOUT_EN, 0);
}
static int ac100_clkout_is_prepared(struct clk_hw *hw)
{
struct ac100_clkout *clk = to_ac100_clkout(hw);
unsigned int reg;
regmap_read(clk->regmap, clk->offset, ®);
return reg & AC100_CLKOUT_EN;
}
static u8 ac100_clkout_get_parent(struct clk_hw *hw)
{
struct ac100_clkout *clk = to_ac100_clkout(hw);
unsigned int reg;
regmap_read(clk->regmap, clk->offset, ®);
return (reg >> AC100_CLKOUT_MUX_SHIFT) & 0x1;
}
static int ac100_clkout_set_parent(struct clk_hw *hw, u8 index)
{
struct ac100_clkout *clk = to_ac100_clkout(hw);
return regmap_update_bits(clk->regmap, clk->offset,
BIT(AC100_CLKOUT_MUX_SHIFT),
index ? BIT(AC100_CLKOUT_MUX_SHIFT) : 0);
}
static const struct clk_ops ac100_clkout_ops = {
.prepare = ac100_clkout_prepare,
.unprepare = ac100_clkout_unprepare,
.is_prepared = ac100_clkout_is_prepared,
.recalc_rate = ac100_clkout_recalc_rate,
.determine_rate = ac100_clkout_determine_rate,
.get_parent = ac100_clkout_get_parent,
.set_parent = ac100_clkout_set_parent,
.set_rate = ac100_clkout_set_rate,
};
static int ac100_rtc_register_clks(struct ac100_rtc_dev *chip)
{
struct device_node *np = chip->dev->of_node;
const char *parents[2] = {AC100_RTC_32K_NAME};
int i, ret;
chip->clk_data = devm_kzalloc(chip->dev,
struct_size(chip->clk_data, hws,
AC100_CLKOUT_NUM),
GFP_KERNEL);
if (!chip->clk_data)
return -ENOMEM;
chip->rtc_32k_clk = clk_hw_register_fixed_rate(chip->dev,
AC100_RTC_32K_NAME,
NULL, 0,
AC100_RTC_32K_RATE);
if (IS_ERR(chip->rtc_32k_clk)) {
ret = PTR_ERR(chip->rtc_32k_clk);
dev_err(chip->dev, "Failed to register RTC-32k clock: %d\n",
ret);
return ret;
}
parents[1] = of_clk_get_parent_name(np, 0);
if (!parents[1]) {
dev_err(chip->dev, "Failed to get ADDA 4M clock\n");
return -EINVAL;
}
for (i = 0; i < AC100_CLKOUT_NUM; i++) {
struct ac100_clkout *clk = &chip->clks[i];
struct clk_init_data init = {
.name = ac100_clkout_names[i],
.ops = &ac100_clkout_ops,
.parent_names = parents,
.num_parents = ARRAY_SIZE(parents),
.flags = 0,
};
of_property_read_string_index(np, "clock-output-names",
i, &init.name);
clk->regmap = chip->regmap;
clk->offset = AC100_CLKOUT_CTRL1 + i;
clk->hw.init = &init;
ret = devm_clk_hw_register(chip->dev, &clk->hw);
if (ret) {
dev_err(chip->dev, "Failed to register clk '%s': %d\n",
init.name, ret);
goto err_unregister_rtc_32k;
}
chip->clk_data->hws[i] = &clk->hw;
}
chip->clk_data->num = i;
ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, chip->clk_data);
if (ret)
goto err_unregister_rtc_32k;
return 0;
err_unregister_rtc_32k:
clk_unregister_fixed_rate(chip->rtc_32k_clk->clk);
return ret;
}
static void ac100_rtc_unregister_clks(struct ac100_rtc_dev *chip)
{
of_clk_del_provider(chip->dev->of_node);
clk_unregister_fixed_rate(chip->rtc_32k_clk->clk);
}
/**
* RTC related bits
*/
static int ac100_rtc_get_time(struct device *dev, struct rtc_time *rtc_tm)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
u16 reg[7];
int ret;
ret = regmap_bulk_read(regmap, AC100_RTC_SEC, reg, 7);
if (ret)
return ret;
rtc_tm->tm_sec = bcd2bin(reg[0] & AC100_RTC_SEC_MASK);
rtc_tm->tm_min = bcd2bin(reg[1] & AC100_RTC_MIN_MASK);
rtc_tm->tm_hour = bcd2bin(reg[2] & AC100_RTC_HOU_MASK);
rtc_tm->tm_wday = bcd2bin(reg[3] & AC100_RTC_WEE_MASK);
rtc_tm->tm_mday = bcd2bin(reg[4] & AC100_RTC_DAY_MASK);
rtc_tm->tm_mon = bcd2bin(reg[5] & AC100_RTC_MON_MASK) - 1;
rtc_tm->tm_year = bcd2bin(reg[6] & AC100_RTC_YEA_MASK) +
AC100_YEAR_OFF;
return 0;
}
static int ac100_rtc_set_time(struct device *dev, struct rtc_time *rtc_tm)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
int year;
u16 reg[8];
/* our RTC has a limited year range... */
year = rtc_tm->tm_year - AC100_YEAR_OFF;
if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {
dev_err(dev, "rtc only supports year in range %d - %d\n",
AC100_YEAR_MIN, AC100_YEAR_MAX);
return -EINVAL;
}
/* convert to BCD */
reg[0] = bin2bcd(rtc_tm->tm_sec) & AC100_RTC_SEC_MASK;
reg[1] = bin2bcd(rtc_tm->tm_min) & AC100_RTC_MIN_MASK;
reg[2] = bin2bcd(rtc_tm->tm_hour) & AC100_RTC_HOU_MASK;
reg[3] = bin2bcd(rtc_tm->tm_wday) & AC100_RTC_WEE_MASK;
reg[4] = bin2bcd(rtc_tm->tm_mday) & AC100_RTC_DAY_MASK;
reg[5] = bin2bcd(rtc_tm->tm_mon + 1) & AC100_RTC_MON_MASK;
reg[6] = bin2bcd(year) & AC100_RTC_YEA_MASK;
/* trigger write */
reg[7] = AC100_RTC_UPD_TRIGGER;
/* Is it a leap year? */
if (is_leap_year(year + AC100_YEAR_OFF + 1900))
reg[6] |= AC100_RTC_YEA_LEAP;
return regmap_bulk_write(regmap, AC100_RTC_SEC, reg, 8);
}
static int ac100_rtc_alarm_irq_enable(struct device *dev, unsigned int en)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
unsigned int val;
val = en ? AC100_ALM_INT_ENABLE : 0;
return regmap_write(regmap, AC100_ALM_INT_ENA, val);
}
static int ac100_rtc_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
struct rtc_time *alrm_tm = &alrm->time;
u16 reg[7];
unsigned int val;
int ret;
ret = regmap_read(regmap, AC100_ALM_INT_ENA, &val);
if (ret)
return ret;
alrm->enabled = !!(val & AC100_ALM_INT_ENABLE);
ret = regmap_bulk_read(regmap, AC100_ALM_SEC, reg, 7);
if (ret)
return ret;
alrm_tm->tm_sec = bcd2bin(reg[0] & AC100_ALM_SEC_MASK);
alrm_tm->tm_min = bcd2bin(reg[1] & AC100_ALM_MIN_MASK);
alrm_tm->tm_hour = bcd2bin(reg[2] & AC100_ALM_HOU_MASK);
alrm_tm->tm_wday = bcd2bin(reg[3] & AC100_ALM_WEE_MASK);
alrm_tm->tm_mday = bcd2bin(reg[4] & AC100_ALM_DAY_MASK);
alrm_tm->tm_mon = bcd2bin(reg[5] & AC100_ALM_MON_MASK) - 1;
alrm_tm->tm_year = bcd2bin(reg[6] & AC100_ALM_YEA_MASK) +
AC100_YEAR_OFF;
return 0;
}
static int ac100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
{
struct ac100_rtc_dev *chip = dev_get_drvdata(dev);
struct regmap *regmap = chip->regmap;
struct rtc_time *alrm_tm = &alrm->time;
u16 reg[8];
int year;
int ret;
/* our alarm has a limited year range... */
year = alrm_tm->tm_year - AC100_YEAR_OFF;
if (year < 0 || year > (AC100_YEAR_MAX - 1900)) {
dev_err(dev, "alarm only supports year in range %d - %d\n",
AC100_YEAR_MIN, AC100_YEAR_MAX);
return -EINVAL;
}
/* convert to BCD */
reg[0] = (bin2bcd(alrm_tm->tm_sec) & AC100_ALM_SEC_MASK) |
AC100_ALM_ENABLE_FLAG;
reg[1] = (bin2bcd(alrm_tm->tm_min) & AC100_ALM_MIN_MASK) |
AC100_ALM_ENABLE_FLAG;
reg[2] = (bin2bcd(alrm_tm->tm_hour) & AC100_ALM_HOU_MASK) |
AC100_ALM_ENABLE_FLAG;
/* Do not enable weekday alarm */
reg[3] = bin2bcd(alrm_tm->tm_wday) & AC100_ALM_WEE_MASK;
reg[4] = (bin2bcd(alrm_tm->tm_mday) & AC100_ALM_DAY_MASK) |
AC100_ALM_ENABLE_FLAG;
reg[5] = (bin2bcd(alrm_tm->tm_mon + 1) & AC100_ALM_MON_MASK) |
AC100_ALM_ENABLE_FLAG;
reg[6] = (bin2bcd(year) & AC100_ALM_YEA_MASK) |
AC100_ALM_ENABLE_FLAG;
/* trigger write */
reg[7] = AC100_ALM_UPD_TRIGGER;
ret = regmap_bulk_write(regmap, AC100_ALM_SEC, reg, 8);
if (ret)
return ret;
return ac100_rtc_alarm_irq_enable(dev, alrm->enabled);
}
static irqreturn_t ac100_rtc_irq(int irq, void *data)
{
struct ac100_rtc_dev *chip = data;
struct regmap *regmap = chip->regmap;
unsigned int val = 0;
int ret;
mutex_lock(&chip->rtc->ops_lock);
/* read status */
ret = regmap_read(regmap, AC100_ALM_INT_STA, &val);
if (ret)
goto out;
if (val & AC100_ALM_INT_ENABLE) {
/* signal rtc framework */
rtc_update_irq(chip->rtc, 1, RTC_AF | RTC_IRQF);
/* clear status */
ret = regmap_write(regmap, AC100_ALM_INT_STA, val);
if (ret)
goto out;
/* disable interrupt */
ret = ac100_rtc_alarm_irq_enable(chip->dev, 0);
if (ret)
goto out;
}
out:
mutex_unlock(&chip->rtc->ops_lock);
return IRQ_HANDLED;
}
static const struct rtc_class_ops ac100_rtc_ops = {
.read_time = ac100_rtc_get_time,
.set_time = ac100_rtc_set_time,
.read_alarm = ac100_rtc_get_alarm,
.set_alarm = ac100_rtc_set_alarm,
.alarm_irq_enable = ac100_rtc_alarm_irq_enable,
};
static int ac100_rtc_probe(struct platform_device *pdev)
{
struct ac100_dev *ac100 = dev_get_drvdata(pdev->dev.parent);
struct ac100_rtc_dev *chip;
int ret;
chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
if (!chip)
return -ENOMEM;
platform_set_drvdata(pdev, chip);
chip->dev = &pdev->dev;
chip->regmap = ac100->regmap;
chip->irq = platform_get_irq(pdev, 0);
if (chip->irq < 0) {
dev_err(&pdev->dev, "No IRQ resource\n");
return chip->irq;
}
chip->rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(chip->rtc))
return PTR_ERR(chip->rtc);
chip->rtc->ops = &ac100_rtc_ops;
ret = devm_request_threaded_irq(&pdev->dev, chip->irq, NULL,
ac100_rtc_irq,
IRQF_SHARED | IRQF_ONESHOT,
dev_name(&pdev->dev), chip);
if (ret) {
dev_err(&pdev->dev, "Could not request IRQ\n");
return ret;
}
/* always use 24 hour mode */
regmap_write_bits(chip->regmap, AC100_RTC_CTRL, AC100_RTC_CTRL_24HOUR,
AC100_RTC_CTRL_24HOUR);
/* disable counter alarm interrupt */
regmap_write(chip->regmap, AC100_ALM_INT_ENA, 0);
/* clear counter alarm pending interrupts */
regmap_write(chip->regmap, AC100_ALM_INT_STA, AC100_ALM_INT_ENABLE);
ret = ac100_rtc_register_clks(chip);
if (ret)
return ret;
ret = rtc_register_device(chip->rtc);
if (ret) {
dev_err(&pdev->dev, "unable to register device\n");
return ret;
}
dev_info(&pdev->dev, "RTC enabled\n");
return 0;
}
static int ac100_rtc_remove(struct platform_device *pdev)
{
struct ac100_rtc_dev *chip = platform_get_drvdata(pdev);
ac100_rtc_unregister_clks(chip);
return 0;
}
static const struct of_device_id ac100_rtc_match[] = {
{ .compatible = "x-powers,ac100-rtc" },
{ },
};
MODULE_DEVICE_TABLE(of, ac100_rtc_match);
static struct platform_driver ac100_rtc_driver = {
.probe = ac100_rtc_probe,
.remove = ac100_rtc_remove,
.driver = {
.name = "ac100-rtc",
.of_match_table = of_match_ptr(ac100_rtc_match),
},
};
module_platform_driver(ac100_rtc_driver);
MODULE_DESCRIPTION("X-Powers AC100 RTC driver");
MODULE_AUTHOR("Chen-Yu Tsai <wens@csie.org>");
MODULE_LICENSE("GPL v2");
