Some peripherals may need a second clock source that may be different
from the system clock. This second clock is the generated clock (GCK)
and is managed by the PMC via PMC_PCR.
For simplicity, the clock source of the GCK is fixed to PLLA_CLK.
Signed-off-by: Wenyou Yang <wenyou.y...@atmel.com>
---
Hi Andreas, Bo Shen,
Thank you for your so many advices.
Bo Shen, sorry for forgetting version 2 to send for your comments.
Please help review, thank you in advance.
Best Regards,
Wenyou Yang
Changes in v2:
1./ add timeout to wait for GCK ready.
2./ add warning for timeout to wait for GCK ready.
3./ add printout when the improper GCK clock source is selected.
4./ rework AT91_PMC_PCR_GCKDIV_(x) macro to make sure x is right.
arch/arm/mach-at91/armv7/clock.c | 65 ++++++++++++++++++++++++++++
arch/arm/mach-at91/include/mach/at91_pmc.h | 13 ++++++
arch/arm/mach-at91/include/mach/clk.h | 3 ++
3 files changed, 81 insertions(+)
diff --git a/arch/arm/mach-at91/armv7/clock.c b/arch/arm/mach-at91/armv7/clock.c
index 0bf453e..de95d6b 100644
--- a/arch/arm/mach-at91/armv7/clock.c
+++ b/arch/arm/mach-at91/armv7/clock.c
@@ -5,6 +5,7 @@
* Copyright (C) 2005 Ivan Kokshaysky
* Copyright (C) 2009 Jean-Christophe PLAGNIOL-VILLARD <plagn...@jcrosoft.com>
* Copyright (C) 2013 Bo Shen <voice.s...@atmel.com>
+ * Copyright (C) 2015 Wenyou Yang <wenyou.y...@atmel.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
@@ -173,3 +174,67 @@ void at91_periph_clk_disable(int id)
writel(regval, &pmc->pcr);
}
+
+void at91_enable_periph_generated_clk(u32 id)
+{
+ struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
+ u32 regval, status;
+ u32 timeout = 1000;
+
+ if (id > AT91_PMC_PCR_PID_MASK)
+ return;
+
+ writel(id, &pmc->pcr);
+ regval = readl(&pmc->pcr);
+ regval &= ~AT91_PMC_PCR_GCKCSS;
+ regval &= ~AT91_PMC_PCR_GCKDIV;
+ regval |= AT91_PMC_PCR_GCKCSS_PLLA_CLK |
+ AT91_PMC_PCR_CMD_WRITE |
+ AT91_PMC_PCR_GCKDIV_(1) |
+ AT91_PMC_PCR_GCKEN;
+
+ writel(regval, &pmc->pcr);
+
+ do {
+ udelay(1);
+ status = readl(&pmc->sr);
+ } while ((!!(--timeout)) && (!(status & AT91_PMC_GCKRDY)));
+
+ if (!timeout)
+ printf("Timeout waiting for GCK ready!\n");
+}
+
+u32 at91_get_periph_generated_clk(u32 id)
+{
+ struct at91_pmc *pmc = (struct at91_pmc *)ATMEL_BASE_PMC;
+ u32 regval, clk_source, div;
+ u32 freq;
+
+ if (id > AT91_PMC_PCR_PID_MASK)
+ return 0;
+
+ writel(id, &pmc->pcr);
+ regval = readl(&pmc->pcr);
+
+ clk_source = regval & AT91_PMC_PCR_GCKCSS;
+ switch (clk_source) {
+ case AT91_PMC_PCR_GCKCSS_SLOW_CLK:
+ freq = CONFIG_SYS_AT91_SLOW_CLOCK;
+ break;
+ case AT91_PMC_PCR_GCKCSS_MAIN_CLK:
+ freq = gd->arch.main_clk_rate_hz;
+ break;
+ case AT91_PMC_PCR_GCKCSS_PLLA_CLK:
+ freq = gd->arch.plla_rate_hz;
+ break;
+ default:
+ printf("Improper GCK clock source selection!\n");
+ freq = 0;
+ break;
+ }
+
+ div = ((regval & AT91_PMC_PCR_GCKDIV) >> AT91_PMC_PCR_GCKDIV_OFFSET);
+ div += 1;
+
+ return freq / div;
+}
diff --git a/arch/arm/mach-at91/include/mach/at91_pmc.h
b/arch/arm/mach-at91/include/mach/at91_pmc.h
index 8a3fb94..5a51be6 100644
--- a/arch/arm/mach-at91/include/mach/at91_pmc.h
+++ b/arch/arm/mach-at91/include/mach/at91_pmc.h
@@ -153,8 +153,20 @@ typedef struct at91_pmc {
#define AT91_PMC_IXR_MOSCSELS 0x00010000
#define AT91_PMC_PCR_PID_MASK (0x3f)
+#define AT91_PMC_PCR_GCKCSS (0x7 << 8)
+#define AT91_PMC_PCR_GCKCSS_SLOW_CLK (0x0 << 8)
+#define AT91_PMC_PCR_GCKCSS_MAIN_CLK (0x1 << 8)
+#define AT91_PMC_PCR_GCKCSS_PLLA_CLK (0x2 << 8)
+#define AT91_PMC_PCR_GCKCSS_UPLL_CLK (0x3 << 8)
+#define AT91_PMC_PCR_GCKCSS_MCK_CLK (0x4 << 8)
+#define AT91_PMC_PCR_GCKCSS_AUDIO_CLK (0x5 << 8)
#define AT91_PMC_PCR_CMD_WRITE (0x1 << 12)
+#define AT91_PMC_PCR_DIV (0x3 << 16)
+#define AT91_PMC_PCR_GCKDIV (0xff << 20)
+#define AT91_PMC_PCR_GCKDIV_(x) ((x & 0xff) << 20)
+#define AT91_PMC_PCR_GCKDIV_OFFSET 20
#define AT91_PMC_PCR_EN (0x1 << 28)
+#define AT91_PMC_PCR_GCKEN (0x1 << 29)
#define AT91_PMC_PCK (1 << 0) /*
Processor Clock */
#define AT91RM9200_PMC_UDP (1 << 1) /* USB
Devcice Port Clock [AT91RM9200 only] */
@@ -236,6 +248,7 @@ typedef struct at91_pmc {
#define AT91_PMC_PCK1RDY (1 << 9) /*
Programmable Clock 1 */
#define AT91_PMC_PCK2RDY (1 << 10) /*
Programmable Clock 2 */
#define AT91_PMC_PCK3RDY (1 << 11) /*
Programmable Clock 3 */
+#define AT91_PMC_GCKRDY (1 << 24)
#define AT91_PMC_PROTKEY 0x504d4301 /* Activation
Code */
#endif
diff --git a/arch/arm/mach-at91/include/mach/clk.h
b/arch/arm/mach-at91/include/mach/clk.h
index 1d45e2d..dd1ed96 100644
--- a/arch/arm/mach-at91/include/mach/clk.h
+++ b/arch/arm/mach-at91/include/mach/clk.h
@@ -119,4 +119,7 @@ static inline unsigned long get_pit_clk_rate(void)
int at91_clock_init(unsigned long main_clock);
void at91_periph_clk_enable(int id);
void at91_periph_clk_disable(int id);
+void at91_enable_periph_generated_clk(u32 id);
+u32 at91_get_periph_generated_clk(u32 id);
+
#endif /* __ASM_ARM_ARCH_CLK_H__ */
--
1.7.9.5
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