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linux-next/drivers/rtc/rtc-ac100.c
Chen-Yu Tsai 637cac7c13 rtc: ac100: support clock-output-names in device tree binding
The ac100 device tree binding specifies the usage of clock-output-names
to specify the names of its 3 clock outputs. This is needed for orphan
clock resolution, when the ac100 is probed much later than any clocks
that consume any of its outputs. This wasn't supported by the driver.

Add support for this.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-08-31 18:23:50 +02:00

630 lines
17 KiB
C

/*
* RTC Driver for X-Powers AC100
*
* Copyright (c) 2016 Chen-Yu Tsai
*
* Chen-Yu Tsai <wens@csie.org>
*
* 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 in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
#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, &reg);
/* 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);
}
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);
}
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 = 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, &reg);
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, &reg);
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, sizeof(*chip->clk_data) +
sizeof(*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 rtc_valid_tm(rtc_tm);
}
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);
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;
}
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);
chip->rtc = devm_rtc_device_register(&pdev->dev, "rtc-ac100",
&ac100_rtc_ops, THIS_MODULE);
if (IS_ERR(chip->rtc)) {
dev_err(&pdev->dev, "unable to register device\n");
return PTR_ERR(chip->rtc);
}
ret = ac100_rtc_register_clks(chip);
if (ret)
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");