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clk: renesas: r8a7795: add R clk 

R can select between two parents. We deal with it like this: During
initialization, check if EXTALR is populated. If so, use it for R. If
not, use R_Internal. clk_mux doesn't help here because we don't want to
switch parents depending on the clock rate. The clock rate (and source)
should stay constant for the watchdog, so I think a setup like this
during initialization makes sense.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
This commit is contained in:
Wolfram Sang 2016-03-30 16:58:20 +02:00 committed by Geert Uytterhoeven
parent 5524a67f3a
commit 1e6237e32e
1 changed files with 16 additions and 0 deletions
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16
drivers/clk/renesas/r8a7795-cpg-mssr.c
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@ -13,6 +13,7 @@
*/
#include <linux/bug.h>
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/device.h>
#include <linux/err.h>
@ -65,6 +66,7 @@ enum r8a7795_clk_types {
CLK_TYPE_GEN3_PLL3,
CLK_TYPE_GEN3_PLL4,
CLK_TYPE_GEN3_SD,
CLK_TYPE_GEN3_R,
};
#define DEF_GEN3_SD(_name, _id, _parent, _offset) \
@ -121,6 +123,8 @@ static const struct cpg_core_clk r8a7795_core_clks[] __initconst = {
DEF_DIV6_RO("osc", R8A7795_CLK_OSC, CLK_EXTAL, CPG_RCKCR, 8),
DEF_DIV6_RO("r_int", CLK_RINT, CLK_EXTAL, CPG_RCKCR, 32),
DEF_BASE("r", R8A7795_CLK_R, CLK_TYPE_GEN3_R, CLK_RINT),
};
static const struct mssr_mod_clk r8a7795_mod_clks[] __initconst = {
@ -587,6 +591,18 @@ struct clk * __init r8a7795_cpg_clk_register(struct device *dev,
case CLK_TYPE_GEN3_SD:
return cpg_sd_clk_register(core, base, __clk_get_name(parent));
case CLK_TYPE_GEN3_R:
/* RINT is default. Only if EXTALR is populated, we switch to it */
value = readl(base + CPG_RCKCR) & 0x3f;
if (clk_get_rate(clks[CLK_EXTALR])) {
parent = clks[CLK_EXTALR];
value |= BIT(15);
}
writel(value, base + CPG_RCKCR);
break;
default:
return ERR_PTR(-EINVAL);
}