| Message ID | 20210824091243.9393-12-billy_tsai@aspeedtech.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add support for ast2600 ADC | expand |
On Tue, 24 Aug 2021 17:12:39 +0800 Billy Tsai <billy_tsai@aspeedtech.com> wrote: > The adc clcok formula is clock > 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. What are the impacts of this being wrong before? Is this something we should look to backport? Comment inline. > > Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com> > --- > drivers/iio/adc/aspeed_adc.c | 26 ++++++++++++++++++++++++++ > 1 file changed, 26 insertions(+) > > diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c > index ea3e9a52fcc9..8fe7da1a651f 100644 > --- a/drivers/iio/adc/aspeed_adc.c > +++ b/drivers/iio/adc/aspeed_adc.c > @@ -4,6 +4,12 @@ > * > * Copyright (C) 2017 Google, Inc. > * Copyright (C) 2021 Aspeed Technology Inc. > + * > + * ADC clock formula: > + * Ast2400/Ast2500: > + * clock period = period of PCLK * 2 * (ADC0C[31:17] + 1) * (ADC0C[9:0] + 1) > + * Ast2600: > + * clock period = period of PCLK * 2 * (ADC0C[15:0] + 1) > */ > > #include <linux/clk.h> > @@ -77,6 +83,7 @@ struct aspeed_adc_data { > struct regulator *regulator; > 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; > @@ -196,6 +203,13 @@ static void aspeed_adc_unregister_divider(void *data) > clk_hw_unregister_divider(clk); > } > > +static void aspeed_adc_unregister_fixed_divider(void *data) > +{ > + struct clk_hw *clk = data; > + > + clk_hw_unregister_fixed_factor(clk); > +} > + > static void aspeed_adc_reset_assert(void *data) > { > struct reset_control *rst = data; > @@ -312,6 +326,18 @@ static int aspeed_adc_probe(struct platform_device *pdev) > /* Register ADC clock prescaler with source specified by device tree. */ > spin_lock_init(&data->clk_lock); > snprintf(clk_parent_name, 32, of_clk_get_parent_name(pdev->dev.of_node, 0)); > + snprintf(clk_name, 32, "%s-fixed-div", data->model_data->model_name); ARRAY_SIZE > + data->fixed_div_clk = clk_hw_register_fixed_factor( > + &pdev->dev, clk_name, clk_parent_name, 0, 1, 2); > + if (IS_ERR(data->fixed_div_clk)) > + return PTR_ERR(data->fixed_div_clk); > + > + ret = devm_add_action_or_reset(data->dev, > + aspeed_adc_unregister_fixed_divider, > + data->clk_prescaler); > + if (ret) > + return ret; > + snprintf(clk_parent_name, 32, clk_name); > if (data->model_data->need_prescaler) { > snprintf(clk_name, 32, "%s-prescaler", > data->model_data->model_name);
diff --git a/drivers/iio/adc/aspeed_adc.c b/drivers/iio/adc/aspeed_adc.c index ea3e9a52fcc9..8fe7da1a651f 100644 --- a/drivers/iio/adc/aspeed_adc.c +++ b/drivers/iio/adc/aspeed_adc.c @@ -4,6 +4,12 @@ * * Copyright (C) 2017 Google, Inc. * Copyright (C) 2021 Aspeed Technology Inc. + * + * ADC clock formula: + * Ast2400/Ast2500: + * clock period = period of PCLK * 2 * (ADC0C[31:17] + 1) * (ADC0C[9:0] + 1) + * Ast2600: + * clock period = period of PCLK * 2 * (ADC0C[15:0] + 1) */ #include <linux/clk.h> @@ -77,6 +83,7 @@ struct aspeed_adc_data { struct regulator *regulator; 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; @@ -196,6 +203,13 @@ static void aspeed_adc_unregister_divider(void *data) clk_hw_unregister_divider(clk); } +static void aspeed_adc_unregister_fixed_divider(void *data) +{ + struct clk_hw *clk = data; + + clk_hw_unregister_fixed_factor(clk); +} + static void aspeed_adc_reset_assert(void *data) { struct reset_control *rst = data; @@ -312,6 +326,18 @@ static int aspeed_adc_probe(struct platform_device *pdev) /* Register ADC clock prescaler with source specified by device tree. */ spin_lock_init(&data->clk_lock); snprintf(clk_parent_name, 32, of_clk_get_parent_name(pdev->dev.of_node, 0)); + snprintf(clk_name, 32, "%s-fixed-div", data->model_data->model_name); + data->fixed_div_clk = clk_hw_register_fixed_factor( + &pdev->dev, clk_name, clk_parent_name, 0, 1, 2); + if (IS_ERR(data->fixed_div_clk)) + return PTR_ERR(data->fixed_div_clk); + + ret = devm_add_action_or_reset(data->dev, + aspeed_adc_unregister_fixed_divider, + data->clk_prescaler); + if (ret) + return ret; + snprintf(clk_parent_name, 32, clk_name); if (data->model_data->need_prescaler) { snprintf(clk_name, 32, "%s-prescaler", data->model_data->model_name);
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 | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)