rtc: ac100: Add clk output support

The AC100's RTC side has 3 clock outputs on external pins, which can
provide a clock signal to the SoC or other modules, such as WiFi or
GSM modules.

Support this with a custom clk driver integrated with the rtc driver.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Chen-Yu Tsai 2016-07-08 22:33:39 +08:00 committed by Lee Jones
parent d00a18a42c
commit 04940631b8
1 changed files with 302 additions and 0 deletions

View File

@ -16,6 +16,7 @@
*/
#include <linux/bcd.h>
#include <linux/clk-provider.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
@ -31,6 +32,15 @@
/* 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)
@ -67,14 +77,292 @@
#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,
};
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);
@ -300,11 +588,24 @@ static int ac100_rtc_probe(struct platform_device *pdev)
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" },
{ },
@ -313,6 +614,7 @@ 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),