[PATCH 1/2] misc: atmel-ssc: support to read ssc version

Bo Shen
2014-06-06T07:41:34Z

Read SSC IP version to check whether it supports frame sync
length extension feature.

Signed-off-by: Bo Shen <voice.shen@atmel.com>
---

drivers/misc/atmel-ssc.c | 7 +++++++
include/linux/atmel-ssc.h | 3 +++
2 files changed, 10 insertions(+)

diff --git a/drivers/misc/atmel-ssc.c b/drivers/misc/atmel-ssc.c
index 22de137..9f49bcb 100644
--- a/drivers/misc/atmel-ssc.c
+++ b/drivers/misc/atmel-ssc.c
@@ -136,6 +136,7 @@ static int ssc_probe(struct platform_device *pdev)
struct resource *regs;
struct ssc_device *ssc;
const struct atmel_ssc_platform_data *plat_dat;
+ u32 version;

ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL);
if (!ssc) {
@@ -173,8 +174,14 @@ static int ssc_probe(struct platform_device *pdev)
clk_prepare_enable(ssc->clk);
ssc_writel(ssc->regs, IDR, -1);
ssc_readl(ssc->regs, SR);
+ version = ssc_readl(ssc->regs, VERSION);
clk_disable_unprepare(ssc->clk);

+ if (version >= 0x300)
+ ssc->has_fslen_ext = 1;
+ else
+ ssc->has_fslen_ext = 0;
+
ssc->irq = platform_get_irq(pdev, 0);
if (!ssc->irq) {
dev_dbg(&pdev->dev, "could not get irq\n");
diff --git a/include/linux/atmel-ssc.h b/include/linux/atmel-ssc.h
index 571a12e..9ee1b68 100644
--- a/include/linux/atmel-ssc.h
+++ b/include/linux/atmel-ssc.h
@@ -19,6 +19,7 @@ struct ssc_device {
int user;
int irq;
bool clk_from_rk_pin;
+ int has_fslen_ext;
};

struct ssc_device * __must_check ssc_request(unsigned int ssc_num);
@@ -258,6 +259,8 @@ void ssc_free(struct ssc_device *ssc);
#define SSC_IMR_TXSYN_SIZE 1
#define SSC_IMR_TXSYN_OFFSET 10

+#define SSC_VERSION 0x000000fc
+
/* SSC PDC Receive Pointer Register */
#define SSC_PDC_RPR 0x00000100

--
1.8.5.2