diff options
Diffstat (limited to 'drivers/iio/adc/vf610_adc.c')
| -rw-r--r-- | drivers/iio/adc/vf610_adc.c | 79 |
1 files changed, 75 insertions, 4 deletions
diff --git a/drivers/iio/adc/vf610_adc.c b/drivers/iio/adc/vf610_adc.c index 480f335a0f9f..23b8fb94ec09 100644 --- a/drivers/iio/adc/vf610_adc.c +++ b/drivers/iio/adc/vf610_adc.c @@ -68,6 +68,9 @@ #define VF610_ADC_CLK_DIV8 0x60 #define VF610_ADC_CLK_MASK 0x60 #define VF610_ADC_ADLSMP_LONG 0x10 +#define VF610_ADC_ADSTS_SHORT 0x100 +#define VF610_ADC_ADSTS_NORMAL 0x200 +#define VF610_ADC_ADSTS_LONG 0x300 #define VF610_ADC_ADSTS_MASK 0x300 #define VF610_ADC_ADLPC_EN 0x80 #define VF610_ADC_ADHSC_EN 0x400 @@ -98,6 +101,8 @@ #define VF610_ADC_CALF 0x2 #define VF610_ADC_TIMEOUT msecs_to_jiffies(100) +#define DEFAULT_SAMPLE_TIME 1000 + enum clk_sel { VF610_ADCIOC_BUSCLK_SET, VF610_ADCIOC_ALTCLK_SET, @@ -124,6 +129,17 @@ enum conversion_mode_sel { VF610_ADC_CONV_LOW_POWER, }; +enum lst_adder_sel { + VF610_ADCK_CYCLES_3, + VF610_ADCK_CYCLES_5, + VF610_ADCK_CYCLES_7, + VF610_ADCK_CYCLES_9, + VF610_ADCK_CYCLES_13, + VF610_ADCK_CYCLES_17, + VF610_ADCK_CYCLES_21, + VF610_ADCK_CYCLES_25, +}; + struct vf610_adc_feature { enum clk_sel clk_sel; enum vol_ref vol_ref; @@ -132,6 +148,8 @@ struct vf610_adc_feature { int clk_div; int sample_rate; int res_mode; + u32 lst_adder_index; + u32 default_sample_time; bool calibration; bool ovwren; @@ -155,11 +173,13 @@ struct vf610_adc { }; static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 }; +static const u32 vf610_lst_adder[] = { 3, 5, 7, 9, 13, 17, 21, 25 }; static inline void vf610_adc_calculate_rates(struct vf610_adc *info) { struct vf610_adc_feature *adc_feature = &info->adc_feature; unsigned long adck_rate, ipg_rate = clk_get_rate(info->clk); + u32 adck_period, lst_addr_min; int divisor, i; adck_rate = info->max_adck_rate[adc_feature->conv_mode]; @@ -174,6 +194,19 @@ static inline void vf610_adc_calculate_rates(struct vf610_adc *info) } /* + * Determine the long sample time adder value to be used based + * on the default minimum sample time provided. + */ + adck_period = NSEC_PER_SEC / adck_rate; + lst_addr_min = adc_feature->default_sample_time / adck_period; + for (i = 0; i < ARRAY_SIZE(vf610_lst_adder); i++) { + if (vf610_lst_adder[i] > lst_addr_min) { + adc_feature->lst_adder_index = i; + break; + } + } + + /* * Calculate ADC sample frequencies * Sample time unit is ADCK cycles. ADCK clk source is ipg clock, * which is the same as bus clock. @@ -182,12 +215,13 @@ static inline void vf610_adc_calculate_rates(struct vf610_adc *info) * SFCAdder: fixed to 6 ADCK cycles * AverageNum: 1, 4, 8, 16, 32 samples for hardware average. * BCT (Base Conversion Time): fixed to 25 ADCK cycles for 12 bit mode - * LSTAdder(Long Sample Time): fixed to 3 ADCK cycles + * LSTAdder(Long Sample Time): 3, 5, 7, 9, 13, 17, 21, 25 ADCK cycles */ adck_rate = ipg_rate / info->adc_feature.clk_div; for (i = 0; i < ARRAY_SIZE(vf610_hw_avgs); i++) info->sample_freq_avail[i] = - adck_rate / (6 + vf610_hw_avgs[i] * (25 + 3)); + adck_rate / (6 + vf610_hw_avgs[i] * + (25 + vf610_lst_adder[adc_feature->lst_adder_index])); } static inline void vf610_adc_cfg_init(struct vf610_adc *info) @@ -347,8 +381,40 @@ static void vf610_adc_sample_set(struct vf610_adc *info) break; } - /* Use the short sample mode */ - cfg_data &= ~(VF610_ADC_ADLSMP_LONG | VF610_ADC_ADSTS_MASK); + /* + * Set ADLSMP and ADSTS based on the Long Sample Time Adder value + * determined. + */ + switch (adc_feature->lst_adder_index) { + case VF610_ADCK_CYCLES_3: + break; + case VF610_ADCK_CYCLES_5: + cfg_data |= VF610_ADC_ADSTS_SHORT; + break; + case VF610_ADCK_CYCLES_7: + cfg_data |= VF610_ADC_ADSTS_NORMAL; + break; + case VF610_ADCK_CYCLES_9: + cfg_data |= VF610_ADC_ADSTS_LONG; + break; + case VF610_ADCK_CYCLES_13: + cfg_data |= VF610_ADC_ADLSMP_LONG; + break; + case VF610_ADCK_CYCLES_17: + cfg_data |= VF610_ADC_ADLSMP_LONG; + cfg_data |= VF610_ADC_ADSTS_SHORT; + break; + case VF610_ADCK_CYCLES_21: + cfg_data |= VF610_ADC_ADLSMP_LONG; + cfg_data |= VF610_ADC_ADSTS_NORMAL; + break; + case VF610_ADCK_CYCLES_25: + cfg_data |= VF610_ADC_ADLSMP_LONG; + cfg_data |= VF610_ADC_ADSTS_NORMAL; + break; + default: + dev_err(info->dev, "error in sample time select\n"); + } /* update hardware average selection */ cfg_data &= ~VF610_ADC_AVGS_MASK; @@ -713,6 +779,11 @@ static int vf610_adc_probe(struct platform_device *pdev) of_property_read_u32_array(pdev->dev.of_node, "fsl,adck-max-frequency", info->max_adck_rate, 3); + ret = of_property_read_u32(pdev->dev.of_node, "min-sample-time", + &info->adc_feature.default_sample_time); + if (ret) + info->adc_feature.default_sample_time = DEFAULT_SAMPLE_TIME; + platform_set_drvdata(pdev, indio_dev); init_completion(&info->completion); |