Messages in this thread | | | Date | Wed, 16 Apr 2014 12:41:05 +0200 | From | Tomasz Figa <> | Subject | Re: [PATCHv3 1/2] iio: adc: exynos_adc: Control special clock of ADC to support Exynos3250 ADC |
| |
Hi Chanwoo,
On 16.04.2014 12:11, 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_tsadc' clock as following: > - 'sclk_tsadc' clock: special clock for ADC which provide clock to internal ADC > > Exynos 4210/4212/4412 and Exynos5250/5420 has not included 'sclk_tsadc' clock > in FSYS_BLK. But, Exynos3250 based on Cortex-A7 has only included 'sclk_tsadc' > clock in FSYS_BLK. > > Cc: Jonathan Cameron <jic23@kernel.org> > Cc: Kukjin Kim <kgene.kim@samsung.com> > Cc: Naveen Krishna Chatradhi > Cc: linux-iio@vger.kernel.org > Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com> > Acked-by: Kyungmin Park <kyungmin.park@samsung.com> > --- > drivers/iio/adc/exynos_adc.c | 86 +++++++++++++++++++++++++++++++++++++------- > 1 file changed, 73 insertions(+), 13 deletions(-) > > diff --git a/drivers/iio/adc/exynos_adc.c b/drivers/iio/adc/exynos_adc.c > index d25b262..486771e 100644 > --- a/drivers/iio/adc/exynos_adc.c > +++ b/drivers/iio/adc/exynos_adc.c > @@ -40,8 +40,9 @@ > #include <linux/iio/driver.h> > > enum adc_version { > - ADC_V1, > - ADC_V2 > + ADC_V1 = 0x1, > + ADC_V2 = 0x2, > + ADC_V3 = (ADC_V1 | ADC_V2),
I don't think Exynos3250 has really a V3 of the ADC block. It looks like a V2, just with different integration details. This approach is confusing and will create problems if real V3 shows up.
In general, using a version enum and a lot of ifs for particular versions in the code is rather a bad practice, especially when multiple versions happen to require the same quirks.
Instead, a variant struct should be introduced with bitfields for particular quirks and/or register offsets and/or function pointers. Let me show example solutions inline with your changes below.
> }; > > /* EXYNOS4412/5250 ADC_V1 registers definitions */ > @@ -85,9 +86,11 @@ enum adc_version { > #define EXYNOS_ADC_TIMEOUT (msecs_to_jiffies(1000)) > > 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; > > @@ -100,6 +103,7 @@ struct exynos_adc { > 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-v3", .data = (void *)ADC_V3 }, > {}, > }; > MODULE_DEVICE_TABLE(of, exynos_adc_match); > @@ -128,7 +132,7 @@ static int exynos_read_raw(struct iio_dev *indio_dev, > mutex_lock(&indio_dev->mlock); > > /* Select the channel to be used and Trigger conversion */ > - if (info->version == ADC_V2) { > + if (info->version >= ADC_V2) { > con2 = readl(ADC_V2_CON2(info->regs)); > con2 &= ~ADC_V2_CON2_ACH_MASK; > con2 |= ADC_V2_CON2_ACH_SEL(chan->address);
This function should be split into exynos_adc_v1_read_raw() and exynos_adc_v2_read_raw(). Then a function pointer for int (*read_raw)(...) should be added to the variant struct I mentioned above. Then the generic part of existing exynos_read_raw() would just call variant->read_raw().
> @@ -165,7 +169,7 @@ static irqreturn_t exynos_adc_isr(int irq, void *dev_id) > info->value = readl(ADC_V1_DATX(info->regs)) & > ADC_DATX_MASK; > /* clear irq */ > - if (info->version == ADC_V2) > + if (info->version >= ADC_V2) > writel(1, ADC_V2_INT_ST(info->regs)); > else > writel(1, ADC_V1_INTCLR(info->regs));
void (*clear_irq)().
> @@ -226,11 +230,43 @@ static int exynos_adc_remove_devices(struct device *dev, void *c) > return 0; > } > > +static int exynos_adc_enable_clock(struct exynos_adc *info, bool enable) > +{ > + int ret; > + > + if (enable) { > + ret = clk_prepare_enable(info->clk); > + if (ret) { > + dev_err(info->dev, "failed to enable adc clock\n"); > + return ret; > + } > + if (info->version == ADC_V3) {
Here, a bitfield bool needs_sclk:1; in the variant struct would be sufficient.
> + ret = clk_prepare_enable(info->sclk); > + if (ret) { > + dev_err(info->dev, > + "failed to enable sclk_tsadc clock\n"); > + goto err; > + } > + } > + > + } else { > + if (info->version == ADC_V3) > + clk_disable_unprepare(info->sclk); > + clk_disable_unprepare(info->clk); > + } > + > + return 0; > +err: > + clk_disable_unprepare(info->clk); > + > + return ret; > +}
Ugh. Please split this into exynos_adc_enable_clock() and exynos_adc_disable_clock().
> + > static void exynos_adc_hw_init(struct exynos_adc *info) > { > u32 con1, con2; > > - if (info->version == ADC_V2) { > + if (info->version >= ADC_V2) { > con1 = ADC_V2_CON1_SOFT_RESET; > writel(con1, ADC_V2_CON1(info->regs)); >
This function should be completely split into v1_hw_init() and v2_hw_init() and the code calling currently exynos_adc_hw_init() could call variant->hw_init() directly.
> @@ -287,6 +323,7 @@ static int exynos_adc_probe(struct platform_device *pdev) > } > > info->irq = irq; > + info->dev = &pdev->dev; > > init_completion(&info->completion); > > @@ -300,6 +337,8 @@ static int exynos_adc_probe(struct platform_device *pdev) > > writel(1, info->enable_reg); > > + info->version = exynos_adc_get_version(pdev); > +
Instead of getting version, here a pointer to variant struct could be retrieved.
> info->clk = devm_clk_get(&pdev->dev, "adc"); > if (IS_ERR(info->clk)) { > dev_err(&pdev->dev, "failed getting clock, err = %ld\n", > @@ -308,6 +347,16 @@ static int exynos_adc_probe(struct platform_device *pdev) > goto err_irq; > } > > + if (info->version == ADC_V3) {
if (info->variant->needs_sclk) {
> + info->sclk = devm_clk_get(&pdev->dev, "sclk_tsadc"); > + if (IS_ERR(info->sclk)) { > + ret = PTR_ERR(info->sclk); > + dev_warn(&pdev->dev, > + "failed getting sclk clock, err = %d\n", ret); > + goto err_irq; > + } > + } > +
etc., etc.
Best regards, Tomasz
| |