diff options
Diffstat (limited to 'drivers/rtc/rtc-ac100.c')
| -rw-r--r-- | drivers/rtc/rtc-ac100.c | 632 |
1 files changed, 632 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-ac100.c b/drivers/rtc/rtc-ac100.c new file mode 100644 index 000000000000..9e336184491c --- /dev/null +++ b/drivers/rtc/rtc-ac100.c @@ -0,0 +1,632 @@ +/* + * 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, ®); + + /* 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, ®); + + 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, 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); + 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; + } + + 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"); |