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clk: aspeed: Register core clocks
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This registers the core clocks; those which are required to calculate
the rate of the timer peripheral so the system can load a clocksource
driver.

Reviewed-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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Joel Stanley authored and Stephen Boyd committed Jan 27, 2018
1 parent 5eda5d7 commit 99d01e0
Showing 1 changed file with 177 additions and 0 deletions.
177 changes: 177 additions & 0 deletions drivers/clk/clk-aspeed.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,23 @@

#define ASPEED_NUM_CLKS 35

#define ASPEED_RESET_CTRL 0x04
#define ASPEED_CLK_SELECTION 0x08
#define ASPEED_CLK_STOP_CTRL 0x0c
#define ASPEED_MPLL_PARAM 0x20
#define ASPEED_HPLL_PARAM 0x24
#define AST2500_HPLL_BYPASS_EN BIT(20)
#define AST2400_HPLL_STRAPPED BIT(18)
#define AST2400_HPLL_BYPASS_EN BIT(17)
#define ASPEED_MISC_CTRL 0x2c
#define UART_DIV13_EN BIT(12)
#define ASPEED_STRAP 0x70
#define CLKIN_25MHZ_EN BIT(23)
#define AST2400_CLK_SOURCE_SEL BIT(18)
#define ASPEED_CLK_SELECTION_2 0xd8

/* Globally visible clocks */
static DEFINE_SPINLOCK(aspeed_clk_lock);

/* Keeps track of all clocks */
static struct clk_hw_onecell_data *aspeed_clk_data;
Expand Down Expand Up @@ -91,6 +107,160 @@ static const struct aspeed_gate_data aspeed_gates[] = {
[ASPEED_CLK_GATE_LHCCLK] = { 28, -1, "lhclk-gate", "lhclk", 0 }, /* LPC master/LPC+ */
};

static const struct clk_div_table ast2400_div_table[] = {
{ 0x0, 2 },
{ 0x1, 4 },
{ 0x2, 6 },
{ 0x3, 8 },
{ 0x4, 10 },
{ 0x5, 12 },
{ 0x6, 14 },
{ 0x7, 16 },
{ 0 }
};

static const struct clk_div_table ast2500_div_table[] = {
{ 0x0, 4 },
{ 0x1, 8 },
{ 0x2, 12 },
{ 0x3, 16 },
{ 0x4, 20 },
{ 0x5, 24 },
{ 0x6, 28 },
{ 0x7, 32 },
{ 0 }
};

static struct clk_hw *aspeed_ast2400_calc_pll(const char *name, u32 val)
{
unsigned int mult, div;

if (val & AST2400_HPLL_BYPASS_EN) {
/* Pass through mode */
mult = div = 1;
} else {
/* F = 24Mhz * (2-OD) * [(N + 2) / (D + 1)] */
u32 n = (val >> 5) & 0x3f;
u32 od = (val >> 4) & 0x1;
u32 d = val & 0xf;

mult = (2 - od) * (n + 2);
div = d + 1;
}
return clk_hw_register_fixed_factor(NULL, name, "clkin", 0,
mult, div);
};

static struct clk_hw *aspeed_ast2500_calc_pll(const char *name, u32 val)
{
unsigned int mult, div;

if (val & AST2500_HPLL_BYPASS_EN) {
/* Pass through mode */
mult = div = 1;
} else {
/* F = clkin * [(M+1) / (N+1)] / (P + 1) */
u32 p = (val >> 13) & 0x3f;
u32 m = (val >> 5) & 0xff;
u32 n = val & 0x1f;

mult = (m + 1) / (n + 1);
div = p + 1;
}

return clk_hw_register_fixed_factor(NULL, name, "clkin", 0,
mult, div);
}

static void __init aspeed_ast2400_cc(struct regmap *map)
{
struct clk_hw *hw;
u32 val, freq, div;

/*
* CLKIN is the crystal oscillator, 24, 48 or 25MHz selected by
* strapping
*/
regmap_read(map, ASPEED_STRAP, &val);
if (val & CLKIN_25MHZ_EN)
freq = 25000000;
else if (val & AST2400_CLK_SOURCE_SEL)
freq = 48000000;
else
freq = 24000000;
hw = clk_hw_register_fixed_rate(NULL, "clkin", NULL, 0, freq);
pr_debug("clkin @%u MHz\n", freq / 1000000);

/*
* High-speed PLL clock derived from the crystal. This the CPU clock,
* and we assume that it is enabled
*/
regmap_read(map, ASPEED_HPLL_PARAM, &val);
WARN(val & AST2400_HPLL_STRAPPED, "hpll is strapped not configured");
aspeed_clk_data->hws[ASPEED_CLK_HPLL] = aspeed_ast2400_calc_pll("hpll", val);

/*
* Strap bits 11:10 define the CPU/AHB clock frequency ratio (aka HCLK)
* 00: Select CPU:AHB = 1:1
* 01: Select CPU:AHB = 2:1
* 10: Select CPU:AHB = 4:1
* 11: Select CPU:AHB = 3:1
*/
regmap_read(map, ASPEED_STRAP, &val);
val = (val >> 10) & 0x3;
div = val + 1;
if (div == 3)
div = 4;
else if (div == 4)
div = 3;
hw = clk_hw_register_fixed_factor(NULL, "ahb", "hpll", 0, 1, div);
aspeed_clk_data->hws[ASPEED_CLK_AHB] = hw;

/* APB clock clock selection register SCU08 (aka PCLK) */
hw = clk_hw_register_divider_table(NULL, "apb", "hpll", 0,
scu_base + ASPEED_CLK_SELECTION, 23, 3, 0,
ast2400_div_table,
&aspeed_clk_lock);
aspeed_clk_data->hws[ASPEED_CLK_APB] = hw;
}

static void __init aspeed_ast2500_cc(struct regmap *map)
{
struct clk_hw *hw;
u32 val, freq, div;

/* CLKIN is the crystal oscillator, 24 or 25MHz selected by strapping */
regmap_read(map, ASPEED_STRAP, &val);
if (val & CLKIN_25MHZ_EN)
freq = 25000000;
else
freq = 24000000;
hw = clk_hw_register_fixed_rate(NULL, "clkin", NULL, 0, freq);
pr_debug("clkin @%u MHz\n", freq / 1000000);

/*
* High-speed PLL clock derived from the crystal. This the CPU clock,
* and we assume that it is enabled
*/
regmap_read(map, ASPEED_HPLL_PARAM, &val);
aspeed_clk_data->hws[ASPEED_CLK_HPLL] = aspeed_ast2500_calc_pll("hpll", val);

/* Strap bits 11:9 define the AXI/AHB clock frequency ratio (aka HCLK)*/
regmap_read(map, ASPEED_STRAP, &val);
val = (val >> 9) & 0x7;
WARN(val == 0, "strapping is zero: cannot determine ahb clock");
div = 2 * (val + 1);
hw = clk_hw_register_fixed_factor(NULL, "ahb", "hpll", 0, 1, div);
aspeed_clk_data->hws[ASPEED_CLK_AHB] = hw;

/* APB clock clock selection register SCU08 (aka PCLK) */
regmap_read(map, ASPEED_CLK_SELECTION, &val);
val = (val >> 23) & 0x7;
div = 4 * (val + 1);
hw = clk_hw_register_fixed_factor(NULL, "apb", "hpll", 0, 1, div);
aspeed_clk_data->hws[ASPEED_CLK_APB] = hw;
};

static void __init aspeed_cc_init(struct device_node *np)
{
struct regmap *map;
Expand Down Expand Up @@ -132,6 +302,13 @@ static void __init aspeed_cc_init(struct device_node *np)
return;
}

if (of_device_is_compatible(np, "aspeed,ast2400-scu"))
aspeed_ast2400_cc(map);
else if (of_device_is_compatible(np, "aspeed,ast2500-scu"))
aspeed_ast2500_cc(map);
else
pr_err("unknown platform, failed to add clocks\n");

aspeed_clk_data->num = ASPEED_NUM_CLKS;
ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, aspeed_clk_data);
if (ret)
Expand Down

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