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SubjectRe: [PATCHv4 2/4] iio: adc: exynos_adc: Control special clock of ADC to support Exynos3250 ADC
Hi Tomasz,

On 06/18/2014 04:58 PM, Tomasz Figa wrote:
> Hi Chanwoo,
>
> On 18.06.2014 04:20, Chanwoo Choi wrote:
>> This patch control special clock for ADC in Exynos series's FSYS block.
>> If special clock of ADC is registerd on clock list of common clk framework,
>> Exynos ADC drvier have to control this clock.
>>
>> Exynos3250/Exynos4/Exynos5 has 'adc' clock as following:
>> - 'adc' clock: bus clock for ADC
>>
>> Exynos3250 has additional 'sclk_adc' clock as following:
>> - 'sclk_adc' clock: special clock for ADC which provide clock to internal ADC
>>
>> Exynos 4210/4212/4412 and Exynos5250/5420 has not included 'sclk_adc' clock
>> in FSYS_BLK. But, Exynos3250 based on Cortex-A7 has only included 'sclk_adc'
>> clock in FSYS_BLK.
>>
>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
>> Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
>> ---
>> drivers/iio/adc/exynos_adc.c | 93 ++++++++++++++++++++++++++++++++++++++------
>> 1 file changed, 81 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c
>> index c30def6..6b026ac 100644
>> --- a/drivers/iio/adc/exynos_adc.c
>> +++ b/drivers/iio/adc/exynos_adc.c
>> @@ -41,7 +41,8 @@
>>
>> enum adc_version {
>> ADC_V1,
>> - ADC_V2
>> + ADC_V2,
>> + ADC_V2_EXYNOS3250,
>> };
>>
>> /* EXYNOS4412/5250 ADC_V1 registers definitions */
>> @@ -85,9 +86,11 @@ enum adc_version {
>> #define EXYNOS_ADC_TIMEOUT (msecs_to_jiffies(100))
>>
>> struct exynos_adc {
>> + struct device *dev;
>> void __iomem *regs;
>> void __iomem *enable_reg;
>> struct clk *clk;
>> + struct clk *sclk;
>> unsigned int irq;
>> struct regulator *vdd;
>> struct exynos_adc_ops *ops;
>> @@ -96,6 +99,7 @@ struct exynos_adc {
>>
>> u32 value;
>> unsigned int version;
>> + bool needs_sclk;
>
> This should be rather a part of the variant struct. See my comments to
> patch 1/4.

OK, I'll include 'needs_sclk' in "variant" structure.

>
>> };
>>
>> struct exynos_adc_ops {
>> @@ -103,11 +107,21 @@ struct exynos_adc_ops {
>> void (*clear_irq)(struct exynos_adc *info);
>> void (*start_conv)(struct exynos_adc *info, unsigned long addr);
>> void (*stop_conv)(struct exynos_adc *info);
>> + void (*disable_clk)(struct exynos_adc *info);
>> + int (*enable_clk)(struct exynos_adc *info);
>> };
>>
>> static const struct of_device_id exynos_adc_match[] = {
>> - { .compatible = "samsung,exynos-adc-v1", .data = (void *)ADC_V1 },
>> - { .compatible = "samsung,exynos-adc-v2", .data = (void *)ADC_V2 },
>> + {
>> + .compatible = "samsung,exynos-adc-v1",
>> + .data = (void *)ADC_V1,
>> + }, {
>> + .compatible = "samsung,exynos-adc-v2",
>> + .data = (void *)ADC_V2,
>> + }, {
>> + .compatible = "samsung,exynos3250-adc-v2",
>> + .data = (void *)ADC_V2_EXYNOS3250,
>> + },
>> {},
>> };
>> MODULE_DEVICE_TABLE(of, exynos_adc_match);
>> @@ -156,11 +170,42 @@ static void exynos_adc_v1_stop_conv(struct exynos_adc *info)
>> writel(con, ADC_V1_CON(info->regs));
>> }
>>
>> +static void exynos_adc_disable_clk(struct exynos_adc *info)
>> +{
>> + if (info->needs_sclk)
>> + clk_disable_unprepare(info->sclk);
>> + clk_disable_unprepare(info->clk);
>> +}
>> +
>> +static int exynos_adc_enable_clk(struct exynos_adc *info)
>> +{
>> + int ret;
>> +
>> + ret = clk_prepare_enable(info->clk);
>> + if (ret) {
>> + dev_err(info->dev, "failed enabling adc clock: %d\n", ret);
>> + return ret;
>> + }
>> +
>> + if (info->needs_sclk) {
>> + ret = clk_prepare_enable(info->sclk);
>> + if (ret) {
>> + clk_disable_unprepare(info->clk);
>> + dev_err(info->dev,
>> + "failed enabling sclk_tsadc clock: %d\n", ret);
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> static struct exynos_adc_ops exynos_adc_v1_ops = {
>> .init_hw = exynos_adc_v1_init_hw,
>> .clear_irq = exynos_adc_v1_clear_irq,
>> .start_conv = exynos_adc_v1_start_conv,
>> .stop_conv = exynos_adc_v1_stop_conv,
>> + .disable_clk = exynos_adc_disable_clk,
>> + .enable_clk = exynos_adc_enable_clk,
>> };
>>
>> static void exynos_adc_v2_init_hw(struct exynos_adc *info)
>> @@ -210,6 +255,8 @@ static struct exynos_adc_ops exynos_adc_v2_ops = {
>> .start_conv = exynos_adc_v2_start_conv,
>> .clear_irq = exynos_adc_v2_clear_irq,
>> .stop_conv = exynos_adc_v2_stop_conv,
>> + .disable_clk = exynos_adc_disable_clk,
>> + .enable_clk = exynos_adc_enable_clk,
>
> Based on the fact that all variants use the same function, I don't think
> there is a reason to add .{disable,enable}_clk in the ops struct. If
> they diverge in future, they could be added later, but right now it
> doesn't have any value.

OK, I'll not add .{disable,enable}_clk and then just use following functions for clock control:
- exynos_adc_prepare_clk() : once execute this function in _probe()
- exynos_adc_unprepare_clk() : once execute this function in _remove()
- exynos_adc_enable_clk()
- exynos_adc_disable_clk()

Best Regards,
Chanwoo Choi



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