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clk: stm32f4: Add RTC clock 

This patch introduces the support of the RTC clock.
RTC clock can have 3 sources: lsi, lse and hse_rtc.

Signed-off-by: Gabriel Fernandez <gabriel.fernandez@st.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
hifive-unleashed-5.1
Gabriel Fernandez 2016-10-21 11:23:29 +02:00 committed by Stephen Boyd
parent 861adc44d2
commit 4261a881cf
1 changed files with 136 additions and 1 deletions
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137
drivers/clk/clk-stm32f4.c
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@ -126,7 +126,7 @@ static const struct stm32f4_gate_data stm32f4_gates[] __initconst = {
{ STM32F4_RCC_APB2ENR, 26, "ltdc", "apb2_div" },
};
enum { SYSTICK, FCLK, CLK_LSI, CLK_LSE, END_PRIMARY_CLK };
enum { SYSTICK, FCLK, CLK_LSI, CLK_LSE, CLK_HSE_RTC, CLK_RTC, END_PRIMARY_CLK };
/*
* MAX_CLKS is the maximum value in the enumeration below plus the combined
* hweight of stm32f42xx_gate_map (plus one).
@ -313,6 +313,15 @@ static inline void enable_power_domain_write_protection(void)
regmap_update_bits(pdrm, 0x00, (1 << 8), (0 << 8));
}
static inline void sofware_reset_backup_domain(void)
{
unsigned long val;
val = readl(base + STM32F4_RCC_BDCR);
writel(val | BIT(16), base + STM32F4_RCC_BDCR);
writel(val & ~BIT(16), base + STM32F4_RCC_BDCR);
}
struct stm32_rgate {
struct clk_gate gate;
u8 bit_rdy_idx;
@ -391,6 +400,111 @@ static struct clk_hw *clk_register_rgate(struct device *dev, const char *name,
return hw;
}
static int cclk_gate_enable(struct clk_hw *hw)
{
int ret;
disable_power_domain_write_protection();
ret = clk_gate_ops.enable(hw);
enable_power_domain_write_protection();
return ret;
}
static void cclk_gate_disable(struct clk_hw *hw)
{
disable_power_domain_write_protection();
clk_gate_ops.disable(hw);
enable_power_domain_write_protection();
}
static int cclk_gate_is_enabled(struct clk_hw *hw)
{
return clk_gate_ops.is_enabled(hw);
}
static const struct clk_ops cclk_gate_ops = {
.enable = cclk_gate_enable,
.disable = cclk_gate_disable,
.is_enabled = cclk_gate_is_enabled,
};
static u8 cclk_mux_get_parent(struct clk_hw *hw)
{
return clk_mux_ops.get_parent(hw);
}
static int cclk_mux_set_parent(struct clk_hw *hw, u8 index)
{
int ret;
disable_power_domain_write_protection();
sofware_reset_backup_domain();
ret = clk_mux_ops.set_parent(hw, index);
enable_power_domain_write_protection();
return ret;
}
static const struct clk_ops cclk_mux_ops = {
.get_parent = cclk_mux_get_parent,
.set_parent = cclk_mux_set_parent,
};
static struct clk_hw *stm32_register_cclk(struct device *dev, const char *name,
const char * const *parent_names, int num_parents,
void __iomem *reg, u8 bit_idx, u8 shift, unsigned long flags,
spinlock_t *lock)
{
struct clk_hw *hw;
struct clk_gate *gate;
struct clk_mux *mux;
gate = kzalloc(sizeof(*gate), GFP_KERNEL);
if (!gate) {
hw = ERR_PTR(-EINVAL);
goto fail;
}
mux = kzalloc(sizeof(*mux), GFP_KERNEL);
if (!mux) {
kfree(gate);
hw = ERR_PTR(-EINVAL);
goto fail;
}
gate->reg = reg;
gate->bit_idx = bit_idx;
gate->flags = 0;
gate->lock = lock;
mux->reg = reg;
mux->shift = shift;
mux->mask = 3;
mux->flags = 0;
hw = clk_hw_register_composite(dev, name, parent_names, num_parents,
&mux->hw, &cclk_mux_ops,
NULL, NULL,
&gate->hw, &cclk_gate_ops,
flags);
if (IS_ERR(hw)) {
kfree(gate);
kfree(mux);
}
fail:
return hw;
}
static const char *sys_parents[] __initdata = { "hsi", NULL, "pll" };
static const struct clk_div_table ahb_div_table[] = {
@ -407,6 +521,10 @@ static const struct clk_div_table apb_div_table[] = {
{ 0 },
};
static const char *rtc_parents[4] = {
"no-clock", "lse", "lsi", "hse-rtc"
};
static void __init stm32f4_rcc_init(struct device_node *np)
{
const char *hse_clk;
@ -492,6 +610,23 @@ static void __init stm32f4_rcc_init(struct device_node *np)
goto fail;
}
clks[CLK_HSE_RTC] = clk_hw_register_divider(NULL, "hse-rtc", "clk-hse",
0, base + STM32F4_RCC_CFGR, 16, 5, 0,
&stm32f4_clk_lock);
if (IS_ERR(clks[CLK_HSE_RTC])) {
pr_err("Unable to register hse-rtc clock\n");
goto fail;
}
clks[CLK_RTC] = stm32_register_cclk(NULL, "rtc", rtc_parents, 4,
base + STM32F4_RCC_BDCR, 15, 8, 0, &stm32f4_clk_lock);
if (IS_ERR(clks[CLK_RTC])) {
pr_err("Unable to register rtc clock\n");
goto fail;
}
of_clk_add_hw_provider(np, stm32f4_rcc_lookup_clk, NULL);
return;
fail: