[U-Boot] [PATCH V3 5/9] EXYNOS5: DWMMC: API to set mmc clock divisor

Amar
2012-12-31T10:58:16Z

This API computes the divisor value based on MPLL clock and
writes it into the FSYS1 register.

Changes from V1:
1)Updated the function exynos5_mmc_set_clk_div() to receive
'device_i'd as input parameter instead of 'index'.

Changes from V2:
1)Updation of commit message and resubmition of proper patch set.

Signed-off-by: Amar <amarendra.xt@samsung.com>
---
arch/arm/cpu/armv7/exynos/clock.c | 38 ++++++++++++++++++++++++++++++++--
arch/arm/include/asm/arch-exynos/clk.h | 4 ++++
2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/arch/arm/cpu/armv7/exynos/clock.c b/arch/arm/cpu/armv7/exynos/clock.c
index 973b84e..cd42689 100644
--- a/arch/arm/cpu/armv7/exynos/clock.c
+++ b/arch/arm/cpu/armv7/exynos/clock.c
@@ -490,7 +490,7 @@ static unsigned long exynos4_get_mmc_clk(int dev_index)
(struct exynos4_clock *)samsung_get_base_clock();
unsigned long uclk, sclk;
unsigned int sel, ratio, pre_ratio;
- int shift;
+ int shift = 0;

sel = readl(&clk->src_fsys);
sel = (sel >> (dev_index << 2)) & 0xf;
@@ -539,7 +539,7 @@ static unsigned long exynos5_get_mmc_clk(int dev_index)
(struct exynos5_clock *)samsung_get_base_clock();
unsigned long uclk, sclk;
unsigned int sel, ratio, pre_ratio;
- int shift;
+ int shift = 0;

sel = readl(&clk->src_fsys);
sel = (sel >> (dev_index << 2)) & 0xf;
@@ -659,6 +659,40 @@ static void exynos5_set_mmc_clk(int dev_index, unsigned int div)
writel(val, addr);
}

+/* exynos5: set the mmc clock div ratio in fsys1 */
+int exynos5_mmc_set_clk_div(int dev_id)
+{
+ struct exynos5_clock *clk =
+ (struct exynos5_clock *)samsung_get_base_clock();
+ unsigned int addr;
+ unsigned int clock;
+ unsigned int tmp;
+ unsigned int i;
+
+ /* get mpll clock */
+ clock = get_pll_clk(MPLL) / 1000000;
+
+ /*
+ * CLK_DIV_FSYS1
+ * MMC0_PRE_RATIO [15:8], MMC0_RATIO [3:0]
+ * CLK_DIV_FSYS2
+ * MMC2_PRE_RATIO [15:8], MMC2_RATIO [3:0]
+ */
+ if (dev_id <= PERIPH_ID_SDMMC1)
+ addr = (unsigned int)&clk->div_fsys1;
+ else
+ addr = (unsigned int)&clk->div_fsys2;
+
+ tmp = readl(addr) & ~FSYS1_MMC0_DIV_MASK;
+ for (i = 0; i <= 0xf; i++) {
+ if ((clock / (i + 1)) <= 400) {
+ writel(tmp | i << 0, addr);
+ break;
+ }
+ }
+ return 0;
+}
+
/* get_lcd_clk: return lcd clock frequency */
static unsigned long exynos4_get_lcd_clk(void)
{
diff --git a/arch/arm/include/asm/arch-exynos/clk.h b/arch/arm/include/asm/arch-exynos/clk.h
index 1935b0b..2fd7c3e 100644
--- a/arch/arm/include/asm/arch-exynos/clk.h
+++ b/arch/arm/include/asm/arch-exynos/clk.h
@@ -29,6 +29,9 @@
#define VPLL 4
#define BPLL 5

+#define FSYS1_MMC0_DIV_MASK 0xff0f
+#define FSYS1_MMC0_DIV_VAL 0x0701
+
unsigned long get_pll_clk(int pllreg);
unsigned long get_arm_clk(void);
unsigned long get_i2c_clk(void);
@@ -36,6 +39,7 @@ unsigned long get_pwm_clk(void);
unsigned long get_uart_clk(int dev_index);
unsigned long get_mmc_clk(int dev_index);
void set_mmc_clk(int dev_index, unsigned int div);
+int exynos5_mmc_set_clk_div(int dev_index);
unsigned long get_lcd_clk(void);
void set_lcd_clk(void);
void set_mipi_clk(void);
--
1.8.0