Re: [PATCHv3 1/2] iio: adc: exynos_adc: Control special clock of ADC to support Exynos3250 ADC
From: Tomasz Figa
Date: Wed Apr 16 2014 - 06:41:26 EST
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@xxxxxxxxxx>
Cc: Kukjin Kim <kgene.kim@xxxxxxxxxxx>
Cc: Naveen Krishna Chatradhi
Cc: linux-iio@xxxxxxxxxxxxxxx
Signed-off-by: Chanwoo Choi <cw00.choi@xxxxxxxxxxx>
Acked-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
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
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