Potin Lai 於 6/10/2022 1:47 PM 寫道: > Introduce i2c-clk-high-min-percent property for setting a minimum clock > high percentage. > > This driver calculate clk_high and clk_low with giving duty cycle. If it > could not find a suit clk_high and clk_low, it apply default duty cycle > 50%. > > Signed-off-by: Potin Lai <potin.lai.pt@xxxxxxxxx> > --- > drivers/i2c/busses/i2c-aspeed.c | 56 ++++++++++++++++++++++++++------- > 1 file changed, 45 insertions(+), 11 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c > index 67e8b97c0c95..9715dc4f933f 100644 > --- a/drivers/i2c/busses/i2c-aspeed.c > +++ b/drivers/i2c/busses/i2c-aspeed.c > @@ -19,6 +19,7 @@ > #include <linux/irqchip/chained_irq.h> > #include <linux/irqdomain.h> > #include <linux/kernel.h> > +#include <linux/math.h> > #include <linux/module.h> > #include <linux/of_address.h> > #include <linux/of_irq.h> > @@ -27,6 +28,8 @@ > #include <linux/reset.h> > #include <linux/slab.h> > > +#define DEFAULT_I2C_CLK_DUTY_CYCLE 50 > + > /* I2C Register */ > #define ASPEED_I2C_FUN_CTRL_REG 0x00 > #define ASPEED_I2C_AC_TIMING_REG1 0x04 > @@ -149,9 +152,11 @@ struct aspeed_i2c_bus { > spinlock_t lock; > struct completion cmd_complete; > u32 (*get_clk_reg_val)(struct device *dev, > - u32 divisor); > + u32 divisor, > + u32 duty_cycle); > unsigned long parent_clk_frequency; > u32 bus_frequency; > + u32 duty_cycle; > /* Transaction state. */ > enum aspeed_i2c_master_state master_state; > struct i2c_msg *msgs; > @@ -798,9 +803,11 @@ static const struct i2c_algorithm aspeed_i2c_algo = { > > static u32 aspeed_i2c_get_clk_reg_val(struct device *dev, > u32 clk_high_low_mask, > - u32 divisor) > + u32 divisor, > + u32 duty_cycle) > { > u32 base_clk_divisor, clk_high_low_max, clk_high, clk_low, tmp; > + u32 tmp_base_clk_divisor; > > /* > * SCL_high and SCL_low represent a value 1 greater than what is stored > @@ -842,10 +849,32 @@ static u32 aspeed_i2c_get_clk_reg_val(struct device *dev, > "clamping clock divider: divider requested, %u, is greater than largest possible divider, %u.\n", > divisor, (1 << base_clk_divisor) * clk_high_low_max); > } else { > - tmp = (divisor + (1 << base_clk_divisor) - 1) > + for (tmp_base_clk_divisor = base_clk_divisor; > + tmp_base_clk_divisor <= ASPEED_I2CD_TIME_BASE_DIVISOR_MASK; > + tmp_base_clk_divisor++) { > + /* calculate clk_high and clk_low with duty cycle */ > + tmp = (divisor + (1 << tmp_base_clk_divisor) - 1) > + >> tmp_base_clk_divisor; > + > + clk_high = DIV_ROUND_UP(tmp * duty_cycle, 100); > + clk_low = tmp - clk_high; > + > + if (max(clk_high, clk_low) <= (clk_high_low_mask + 1)) > + break; > + } > + > + if (tmp_base_clk_divisor <= ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) > + base_clk_divisor = tmp_base_clk_divisor; > + else { > + dev_err(dev, > + "could not find clk_high and clk_low with duty cycle %u%%\n, recalculate with base_clk_divisor %u and duty_cycle 50%%", > + duty_cycle, base_clk_divisor); > + duty_cycle = 50; > + tmp = (divisor + (1 << base_clk_divisor) - 1) > >> base_clk_divisor; > - clk_low = tmp / 2; > - clk_high = tmp - clk_low; > + clk_high = DIV_ROUND_UP(tmp * duty_cycle, 100); > + clk_low = tmp - clk_high; > + } > > if (clk_high) > clk_high--; > @@ -863,22 +892,22 @@ static u32 aspeed_i2c_get_clk_reg_val(struct device *dev, > & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK); > } > > -static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor) > +static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor, u32 duty_cycle) > { > /* > * clk_high and clk_low are each 3 bits wide, so each can hold a max > * value of 8 giving a clk_high_low_max of 16. > */ > - return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor); > + return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor, duty_cycle); > } > > -static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor) > +static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor, u32 duty_cycle) > { > /* > * clk_high and clk_low are each 4 bits wide, so each can hold a max > * value of 16 giving a clk_high_low_max of 32. > */ > - return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor); > + return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor, duty_cycle); > } > > /* precondition: bus.lock has been acquired. */ > @@ -891,7 +920,7 @@ static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus) > clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK | > ASPEED_I2CD_TIME_THDSTA_MASK | > ASPEED_I2CD_TIME_TACST_MASK); > - clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor); > + clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor, bus->duty_cycle); > writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1); > writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2); > > @@ -1009,11 +1038,16 @@ static int aspeed_i2c_probe_bus(struct platform_device *pdev) > bus->bus_frequency = I2C_MAX_STANDARD_MODE_FREQ; > } > > + ret = of_property_read_u32(pdev->dev.of_node, > + "i2c-clk-high-min-percent", &bus->duty_cycle); > + if (ret < 0 || !bus->duty_cycle || bus->duty_cycle > 100) > + bus->duty_cycle = DEFAULT_I2C_CLK_DUTY_CYCLE; > + > match = of_match_node(aspeed_i2c_bus_of_table, pdev->dev.of_node); > if (!match) > bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val; > else > - bus->get_clk_reg_val = (u32 (*)(struct device *, u32)) > + bus->get_clk_reg_val = (u32 (*)(struct device *, u32, u32)) > match->data; > > /* Initialize the I2C adapter */ Hi Maintainers, Could someone please help me review this patch and give me some advice? Thanks! Potin