diff options
Diffstat (limited to 'arch/arm/mach-omap2/vc.c')
| -rw-r--r-- | arch/arm/mach-omap2/vc.c | 149 |
1 files changed, 141 insertions, 8 deletions
diff --git a/arch/arm/mach-omap2/vc.c b/arch/arm/mach-omap2/vc.c index d72b787a0d8..687aa86c0d5 100644 --- a/arch/arm/mach-omap2/vc.c +++ b/arch/arm/mach-omap2/vc.c @@ -24,6 +24,7 @@ #include "prm44xx.h" #include "pm.h" #include "scrm44xx.h" +#include "control.h" /** * struct omap_vc_channel_cfg - describe the cfg_channel bitfield @@ -69,6 +70,9 @@ static struct omap_vc_channel_cfg vc_mutant_channel_cfg = { }; static struct omap_vc_channel_cfg *vc_cfg_bits; + +/* Default I2C trace length on pcb, 6.3cm. Used for capacitance calculations. */ +static u32 sr_i2c_pcb_length = 63; #define CFG_CHANNEL_MASK 0x1f /** @@ -464,22 +468,135 @@ static void omap4_set_timings(struct voltagedomain *voltdm, bool off_mode) /* OMAP4 specific voltage init functions */ static void __init omap4_vc_init_channel(struct voltagedomain *voltdm) { - static bool is_initialized; - u32 vc_val; - omap4_set_timings(voltdm, true); omap4_set_timings(voltdm, false); +} + +struct i2c_init_data { + u8 loadbits; + u8 load; + u8 hsscll_38_4; + u8 hsscll_26; + u8 hsscll_19_2; + u8 hsscll_16_8; + u8 hsscll_12; +}; - if (is_initialized) +static const __initdata struct i2c_init_data omap4_i2c_timing_data[] = { + { + .load = 50, + .loadbits = 0x3, + .hsscll_38_4 = 13, + .hsscll_26 = 11, + .hsscll_19_2 = 9, + .hsscll_16_8 = 9, + .hsscll_12 = 8, + }, + { + .load = 25, + .loadbits = 0x2, + .hsscll_38_4 = 13, + .hsscll_26 = 11, + .hsscll_19_2 = 9, + .hsscll_16_8 = 9, + .hsscll_12 = 8, + }, + { + .load = 12, + .loadbits = 0x1, + .hsscll_38_4 = 11, + .hsscll_26 = 10, + .hsscll_19_2 = 9, + .hsscll_16_8 = 9, + .hsscll_12 = 8, + }, + { + .load = 0, + .loadbits = 0x0, + .hsscll_38_4 = 12, + .hsscll_26 = 10, + .hsscll_19_2 = 9, + .hsscll_16_8 = 8, + .hsscll_12 = 8, + }, +}; + +/** + * omap4_vc_i2c_timing_init - sets up board I2C timing parameters + * @voltdm: voltagedomain pointer to get data from + * + * Use PMIC + board supplied settings for calculating the total I2C + * channel capacitance and set the timing parameters based on this. + * Pre-calculated values are provided in data tables, as it is not + * too straightforward to calculate these runtime. + */ +static void __init omap4_vc_i2c_timing_init(struct voltagedomain *voltdm) +{ + u32 capacitance; + u32 val; + u16 hsscll; + const struct i2c_init_data *i2c_data; + + if (!voltdm->pmic->i2c_high_speed) { + pr_warn("%s: only high speed supported!\n", __func__); return; + } + + /* PCB trace capacitance, 0.125pF / mm => mm / 8 */ + capacitance = DIV_ROUND_UP(sr_i2c_pcb_length, 8); + + /* OMAP pad capacitance */ + capacitance += 4; + + /* PMIC pad capacitance */ + capacitance += voltdm->pmic->i2c_pad_load; - /* XXX These are magic numbers and do not belong! */ - vc_val = (0x60 << OMAP4430_SCLL_SHIFT | 0x26 << OMAP4430_SCLH_SHIFT); - voltdm->write(vc_val, OMAP4_PRM_VC_CFG_I2C_CLK_OFFSET); + /* Search for capacitance match in the table */ + i2c_data = omap4_i2c_timing_data; - is_initialized = true; + while (i2c_data->load > capacitance) + i2c_data++; + + /* Select proper values based on sysclk frequency */ + switch (voltdm->sys_clk.rate) { + case 38400000: + hsscll = i2c_data->hsscll_38_4; + break; + case 26000000: + hsscll = i2c_data->hsscll_26; + break; + case 19200000: + hsscll = i2c_data->hsscll_19_2; + break; + case 16800000: + hsscll = i2c_data->hsscll_16_8; + break; + case 12000000: + hsscll = i2c_data->hsscll_12; + break; + default: + pr_warn("%s: unsupported sysclk rate: %d!\n", __func__, + voltdm->sys_clk.rate); + return; + } + + /* Loadbits define pull setup for the I2C channels */ + val = i2c_data->loadbits << 25 | i2c_data->loadbits << 29; + + /* Write to SYSCTRL_PADCONF_WKUP_CTRL_I2C_2 to setup I2C pull */ + __raw_writel(val, OMAP2_L4_IO_ADDRESS(OMAP4_CTRL_MODULE_PAD_WKUP + + OMAP4_CTRL_MODULE_PAD_WKUP_CONTROL_I2C_2)); + + /* HSSCLH can always be zero */ + val = hsscll << OMAP4430_HSSCLL_SHIFT; + val |= (0x28 << OMAP4430_SCLL_SHIFT | 0x2c << OMAP4430_SCLH_SHIFT); + + /* Write setup times to I2C config register */ + voltdm->write(val, OMAP4_PRM_VC_CFG_I2C_CLK_OFFSET); } + + /** * omap_vc_i2c_init - initialize I2C interface to PMIC * @voltdm: voltage domain containing VC data @@ -519,6 +636,9 @@ static void __init omap_vc_i2c_init(struct voltagedomain *voltdm) mcode << __ffs(vc->common->i2c_mcode_mask), vc->common->i2c_cfg_reg); + if (cpu_is_omap44xx()) + omap4_vc_i2c_timing_init(voltdm); + initialized = true; } @@ -546,6 +666,19 @@ static u8 omap_vc_calc_vsel(struct voltagedomain *voltdm, u32 uvolt) return voltdm->pmic->uv_to_vsel(uvolt); } +/** + * omap_pm_setup_sr_i2c_pcb_length - set length of SR I2C traces on PCB + * @mm: length of the PCB trace in millimetres + * + * Sets the PCB trace length for the I2C channel. By default uses 63mm. + * This is needed for properly calculating the capacitance value for + * the PCB trace, and for setting the SR I2C channel timing parameters. + */ +void __init omap_pm_setup_sr_i2c_pcb_length(u32 mm) +{ + sr_i2c_pcb_length = mm; +} + void __init omap_vc_init_channel(struct voltagedomain *voltdm) { struct omap_vc_channel *vc = voltdm->vc; |