diff options
Diffstat (limited to 'drivers/clk')
-rw-r--r-- | drivers/clk/sunxi/clk-mod0.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/clk/sunxi/clk-mod0.c b/drivers/clk/sunxi/clk-mod0.c index 8a7f7036aea..4a563850ee6 100644 --- a/drivers/clk/sunxi/clk-mod0.c +++ b/drivers/clk/sunxi/clk-mod0.c @@ -16,6 +16,7 @@ #include <linux/clk-provider.h> #include <linux/clkdev.h> +#include <linux/of_address.h> #include "clk-factors.h" @@ -92,3 +93,191 @@ static void __init sun5i_a13_mbus_setup(struct device_node *node) clk_prepare_enable(mbus); } CLK_OF_DECLARE(sun5i_a13_mbus, "allwinner,sun5i-a13-mbus-clk", sun5i_a13_mbus_setup); + +struct mmc_phase_data { + u8 offset; +}; + +struct mmc_phase { + struct clk_hw hw; + void __iomem *reg; + struct mmc_phase_data *data; + spinlock_t *lock; +}; + +#define to_mmc_phase(_hw) container_of(_hw, struct mmc_phase, hw) + +static int mmc_get_phase(struct clk_hw *hw) +{ + struct clk *mmc, *mmc_parent, *clk = hw->clk; + struct mmc_phase *phase = to_mmc_phase(hw); + unsigned int mmc_rate, mmc_parent_rate; + u16 step, mmc_div; + u32 value; + u8 delay; + + value = readl(phase->reg); + delay = (value >> phase->data->offset) & 0x3; + + if (!delay) + return 180; + + /* Get the main MMC clock */ + mmc = clk_get_parent(clk); + if (!mmc) + return -EINVAL; + + /* And its rate */ + mmc_rate = clk_get_rate(mmc); + if (!mmc_rate) + return -EINVAL; + + /* Now, get the MMC parent (most likely some PLL) */ + mmc_parent = clk_get_parent(mmc); + if (!mmc_parent) + return -EINVAL; + + /* And its rate */ + mmc_parent_rate = clk_get_rate(mmc_parent); + if (!mmc_parent_rate) + return -EINVAL; + + /* Get MMC clock divider */ + mmc_div = mmc_parent_rate / mmc_rate; + + step = DIV_ROUND_CLOSEST(360, mmc_div); + return delay * step; +} + +static int mmc_set_phase(struct clk_hw *hw, int degrees) +{ + struct clk *mmc, *mmc_parent, *clk = hw->clk; + struct mmc_phase *phase = to_mmc_phase(hw); + unsigned int mmc_rate, mmc_parent_rate; + unsigned long flags; + u32 value; + u8 delay; + + /* Get the main MMC clock */ + mmc = clk_get_parent(clk); + if (!mmc) + return -EINVAL; + + /* And its rate */ + mmc_rate = clk_get_rate(mmc); + if (!mmc_rate) + return -EINVAL; + + /* Now, get the MMC parent (most likely some PLL) */ + mmc_parent = clk_get_parent(mmc); + if (!mmc_parent) + return -EINVAL; + + /* And its rate */ + mmc_parent_rate = clk_get_rate(mmc_parent); + if (!mmc_parent_rate) + return -EINVAL; + + if (degrees != 180) { + u16 step, mmc_div; + + /* Get MMC clock divider */ + mmc_div = mmc_parent_rate / mmc_rate; + + /* + * We can only outphase the clocks by multiple of the + * PLL's period. + * + * Since the MMC clock in only a divider, and the + * formula to get the outphasing in degrees is deg = + * 360 * delta / period + * + * If we simplify this formula, we can see that the + * only thing that we're concerned about is the number + * of period we want to outphase our clock from, and + * the divider set by the MMC clock. + */ + step = DIV_ROUND_CLOSEST(360, mmc_div); + delay = DIV_ROUND_CLOSEST(degrees, step); + } else { + delay = 0; + } + + spin_lock_irqsave(phase->lock, flags); + value = readl(phase->reg); + value &= ~GENMASK(phase->data->offset + 3, phase->data->offset); + value |= delay << phase->data->offset; + writel(value, phase->reg); + spin_unlock_irqrestore(phase->lock, flags); + + return 0; +} + +static const struct clk_ops mmc_clk_ops = { + .get_phase = mmc_get_phase, + .set_phase = mmc_set_phase, +}; + +static void __init sun4i_a10_mmc_phase_setup(struct device_node *node, + struct mmc_phase_data *data) +{ + const char *parent_names[1] = { of_clk_get_parent_name(node, 0) }; + struct clk_init_data init = { + .num_parents = 1, + .parent_names = parent_names, + .ops = &mmc_clk_ops, + }; + + struct mmc_phase *phase; + struct clk *clk; + + phase = kmalloc(sizeof(*phase), GFP_KERNEL); + if (!phase) + return; + + phase->hw.init = &init; + + phase->reg = of_iomap(node, 0); + if (!phase->reg) + goto err_free; + + phase->data = data; + phase->lock = &sun4i_a10_mod0_lock; + + if (of_property_read_string(node, "clock-output-names", &init.name)) + init.name = node->name; + + clk = clk_register(NULL, &phase->hw); + if (IS_ERR(clk)) + goto err_unmap; + + of_clk_add_provider(node, of_clk_src_simple_get, clk); + + return; + +err_unmap: + iounmap(phase->reg); +err_free: + kfree(phase); +} + + +static struct mmc_phase_data mmc_output_clk = { + .offset = 8, +}; + +static struct mmc_phase_data mmc_sample_clk = { + .offset = 20, +}; + +static void __init sun4i_a10_mmc_output_setup(struct device_node *node) +{ + sun4i_a10_mmc_phase_setup(node, &mmc_output_clk); +} +CLK_OF_DECLARE(sun4i_a10_mmc_output, "allwinner,sun4i-a10-mmc-output-clk", sun4i_a10_mmc_output_setup); + +static void __init sun4i_a10_mmc_sample_setup(struct device_node *node) +{ + sun4i_a10_mmc_phase_setup(node, &mmc_sample_clk); +} +CLK_OF_DECLARE(sun4i_a10_mmc_sample, "allwinner,sun4i-a10-mmc-sample-clk", sun4i_a10_mmc_sample_setup); |