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Subject[v2 7/8] iio: adc: aspeed: Fix the calculate error of clock.
Date
The adc clcok formula is
ast2400/2500:
ADC clock period = PCLK * 2 * (ADC0C[31:17] + 1) * (ADC0C[9:0] + 1)
ast2600:
ADC clock period = PCLK * 2 * (ADC0C[15:0] + 1)
They all have one fixed divided 2 and the legacy driver didn't handle it.
This patch register the fixed factory clock device as the parent of adc
clock scaler to fix this issue.

Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
---
drivers/iio/adc/aspeed_adc.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c
index 0153b28b83b7..7e674b607e36 100644
--- a/drivers/iio/adc/aspeed_adc.c
+++ b/drivers/iio/adc/aspeed_adc.c
@@ -80,6 +80,7 @@ struct aspeed_adc_data {
struct device *dev;
void __iomem *base;
spinlock_t clk_lock;
+ struct clk_hw *fixed_div_clk;
struct clk_hw *clk_prescaler;
struct clk_hw *clk_scaler;
struct reset_control *rst;
@@ -310,6 +311,7 @@ static int aspeed_adc_probe(struct platform_device *pdev)
int ret;
u32 adc_engine_control_reg_val;
char scaler_clk_name[32];
+ char fixed_div_clk_name[32];

model_data = of_device_get_match_data(&pdev->dev);
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*data));
@@ -328,10 +330,15 @@ static int aspeed_adc_probe(struct platform_device *pdev)
spin_lock_init(&data->clk_lock);
clk_parent_name = of_clk_get_parent_name(pdev->dev.of_node, 0);
if (model_data->version <= aspeed_adc_ast2500) {
+ /* ADC clock period = PCLK * 2 * (ADC0C[31:17] + 1) * (ADC0C[9:0] + 1) */
+ data->fixed_div_clk = clk_hw_register_fixed_factor(
+ &pdev->dev, "fixed-div", clk_parent_name, 0, 1, 2);
+ if (IS_ERR(data->fixed_div_clk))
+ return PTR_ERR(data->fixed_div_clk);
data->clk_prescaler = clk_hw_register_divider(
- &pdev->dev, "prescaler", clk_parent_name, 0,
- data->base + ASPEED_REG_CLOCK_CONTROL,
- 17, 15, 0, &data->clk_lock);
+ &pdev->dev, "prescaler", "fixed-div", 0,
+ data->base + ASPEED_REG_CLOCK_CONTROL, 17, 15, 0,
+ &data->clk_lock);
if (IS_ERR(data->clk_prescaler))
return PTR_ERR(data->clk_prescaler);

@@ -349,14 +356,23 @@ static int aspeed_adc_probe(struct platform_device *pdev)
goto scaler_error;
}
} else {
+ /* ADC clock period = period of PCLK * 2 * (ADC0C[15:0] + 1) */
+ snprintf(fixed_div_clk_name, sizeof(fixed_div_clk_name), "fixed-div-%s",
+ pdev->name);
+ data->fixed_div_clk = clk_hw_register_fixed_factor(
+ &pdev->dev, fixed_div_clk_name, clk_parent_name, 0, 1, 2);
+ if (IS_ERR(data->fixed_div_clk))
+ return PTR_ERR(data->fixed_div_clk);
snprintf(scaler_clk_name, sizeof(scaler_clk_name), "scaler-%s",
pdev->name);
data->clk_scaler = clk_hw_register_divider(
&pdev->dev, scaler_clk_name, clk_parent_name, 0,
data->base + ASPEED_REG_CLOCK_CONTROL, 0, 16, 0,
&data->clk_lock);
- if (IS_ERR(data->clk_scaler))
- return PTR_ERR(data->clk_scaler);
+ if (IS_ERR(data->clk_scaler)) {
+ ret = PTR_ERR(data->clk_scaler);
+ goto scaler_error;
+ }
}

data->rst = devm_reset_control_get_shared(&pdev->dev, NULL);
@@ -430,6 +446,7 @@ static int aspeed_adc_probe(struct platform_device *pdev)
scaler_error:
if (model_data->version <= aspeed_adc_ast2500)
clk_hw_unregister_divider(data->clk_prescaler);
+ clk_hw_unregister_fixed_factor(data->fixed_div_clk);
return ret;
}

@@ -448,6 +465,7 @@ static int aspeed_adc_remove(struct platform_device *pdev)
clk_hw_unregister_divider(data->clk_scaler);
if (model_data->version <= aspeed_adc_ast2500)
clk_hw_unregister_divider(data->clk_prescaler);
+ clk_hw_unregister_fixed_factor(data->fixed_div_clk);

return 0;
}
--
2.25.1
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