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SubjectRe: [PATCH v4 2/5] clk: aspeed: Register core clocks
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On Tue, 2017-10-03 at 17:25 +1030, Joel Stanley wrote:
> 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.

> Signed-off-by: Joel Stanley <joel@jms.id.au>

> ---
> v4:
>   - Add defines to document the BIT() macros
> v3:
>   - Fix ast2400 ahb calculation
>   - Remove incorrect 'this is wrong' comment
>   - Separate out clkin calc to be per platform
>   - Support 48MHz clkin on ast2400
> ---
>  drivers/clk/clk-aspeed.c | 177 +++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 177 insertions(+)

> diff --git a/drivers/clk/clk-aspeed.c b/drivers/clk/clk-aspeed.c
> index a45eb351bb05..d39cf51a5114 100644
> --- a/drivers/clk/clk-aspeed.c
> +++ b/drivers/clk/clk-aspeed.c
> @@ -20,7 +20,23 @@
>  
>  #include <dt-bindings/clock/aspeed-clock.h>
>  
> +#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;
> @@ -98,6 +114,160 @@ static const struct aspeed_gate_data aspeed_gates[] __initconst = {
>   [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;
> @@ -139,6 +309,13 @@ 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");
> +

I'm still unsure about this approach with the scu compatible, but otherwise:

Reviewed-by: Andrew Jeffery <andrew@aj.id.au>

>   aspeed_clk_data->num = ASPEED_NUM_CLKS;
>   ret = of_clk_add_hw_provider(np, of_clk_hw_onecell_get, aspeed_clk_data);
>   if (ret)[unhandled content-type:application/pgp-signature]
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