[PATCH v3.1 4/4] clk: meson: gxbb-aoclk: Add CEC 32k clock

From: Neil Armstrong
Date: Tue Aug 01 2017 - 07:57:17 EST

The CEC 32K AO Clock is a dual divider with dual counter to provide a more
precise 32768Hz clock for the CEC subsystem from the external xtal.

Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
drivers/clk/meson/Makefile | 2 +-
drivers/clk/meson/gxbb-aoclk-32k.c | 194 +++++++++++++++++++++++++++++++++++++
drivers/clk/meson/gxbb-aoclk.c | 21 +++-
drivers/clk/meson/gxbb-aoclk.h | 16 +++
4 files changed, 231 insertions(+), 2 deletions(-)
create mode 100644 drivers/clk/meson/gxbb-aoclk-32k.c

diff --git a/drivers/clk/meson/Makefile b/drivers/clk/meson/Makefile
index de65427..b139d41 100644
--- a/drivers/clk/meson/Makefile
+++ b/drivers/clk/meson/Makefile
@@ -4,4 +4,4 @@

obj-$(CONFIG_COMMON_CLK_AMLOGIC) += clk-pll.o clk-cpu.o clk-mpll.o clk-audio-divider.o
obj-$(CONFIG_COMMON_CLK_MESON8B) += meson8b.o
-obj-$(CONFIG_COMMON_CLK_GXBB) += gxbb.o gxbb-aoclk.o gxbb-aoclk-regmap.o
+obj-$(CONFIG_COMMON_CLK_GXBB) += gxbb.o gxbb-aoclk.o gxbb-aoclk-regmap.o gxbb-aoclk-32k.o
diff --git a/drivers/clk/meson/gxbb-aoclk-32k.c b/drivers/clk/meson/gxbb-aoclk-32k.c
new file mode 100644
index 0000000..491634d
--- /dev/null
+++ b/drivers/clk/meson/gxbb-aoclk-32k.c
@@ -0,0 +1,194 @@
+/*
+ * Copyright (c) 2017 BayLibre, SAS.
+ * Author: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/bitfield.h>
+#include <linux/regmap.h>
+#include "gxbb-aoclk.h"
+
+/*
+ * The AO Domain embeds a dual/divider to generate a more precise
+ * 32,768KHz clock for low-power suspend mode and CEC.
+ * ______ ______
+ * | | | |
+ * ______ | Div1 |-| Cnt1 | ______
+ * | | /|______| |______|\ | |
+ * Xtal-->| Gate |---| ______ ______ X-X--| Gate |-->
+ * |______| | \| | | |/ | |______|
+ * | | Div2 |-| Cnt2 | |
+ * | |______| |______| |
+ * |_______________________|
+ *
+ * The dividing can be switched to single or dual, with a counter
+ * for each divider to set when the switching is done.
+ * The entire dividing mechanism can be also bypassed.
+ */
+
+#define CLK_CNTL0_N1_MASK GENMASK(11, 0)
+#define CLK_CNTL0_N2_MASK GENMASK(23, 12)
+#define CLK_CNTL0_DUALDIV_EN BIT(28)
+#define CLK_CNTL0_OUT_GATE_EN BIT(30)
+#define CLK_CNTL0_IN_GATE_EN BIT(31)
+
+#define CLK_CNTL1_M1_MASK GENMASK(11, 0)
+#define CLK_CNTL1_M2_MASK GENMASK(23, 12)
+#define CLK_CNTL1_BYPASS_EN BIT(24)
+#define CLK_CNTL1_SELECT_OSC BIT(27)
+
+#define PWR_CNTL_ALT_32K_SEL GENMASK(13, 10)
+
+struct cec_32k_freq_table {
+ unsigned long parent_rate;
+ unsigned long target_rate;
+ bool dualdiv;
+ unsigned int n1;
+ unsigned int n2;
+ unsigned int m1;
+ unsigned int m2;
+};
+
+static const struct cec_32k_freq_table aoclk_cec_32k_table[] = {
+ [0] = {
+ .parent_rate = 24000000,
+ .target_rate = 32768,
+ .dualdiv = true,
+ .n1 = 733,
+ .n2 = 732,
+ .m1 = 8,
+ .m2 = 11,
+ },
+};
+
+/*
+ * If CLK_CNTL0_DUALDIV_EN == 0
+ * - will use N1 divider only
+ * If CLK_CNTL0_DUALDIV_EN == 1
+ * - hold M1 cycles of N1 divider then changes to N2
+ * - hold M2 cycles of N2 divider then changes to N1
+ * Then we can get more accurate division.
+ */
+static unsigned long aoclk_cec_32k_recalc_rate(struct clk_hw *hw,
+ unsigned long parent_rate)
+{
+ struct aoclk_cec_32k *cec_32k = to_aoclk_cec_32k(hw);
+ unsigned long n1;
+ u32 reg0, reg1;
+
+ regmap_read(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, &reg0);
+ regmap_read(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL1, &reg1);
+
+ if (reg1 & CLK_CNTL1_BYPASS_EN)
+ return parent_rate;
+
+ if (reg0 & CLK_CNTL0_DUALDIV_EN) {
+ unsigned long n2, m1, m2, f1, f2, p1, p2;
+
+ n1 = FIELD_GET(CLK_CNTL0_N1_MASK, reg0) + 1;
+ n2 = FIELD_GET(CLK_CNTL0_N2_MASK, reg0) + 1;
+
+ m1 = FIELD_GET(CLK_CNTL1_M1_MASK, reg1) + 1;
+ m2 = FIELD_GET(CLK_CNTL1_M2_MASK, reg1) + 1;
+
+ f1 = DIV_ROUND_CLOSEST(parent_rate, n1);
+ f2 = DIV_ROUND_CLOSEST(parent_rate, n2);
+
+ p1 = DIV_ROUND_CLOSEST(100000000 * m1, f1 * (m1 + m2));
+ p2 = DIV_ROUND_CLOSEST(100000000 * m2, f2 * (m1 + m2));
+
+ return DIV_ROUND_UP(100000000, p1 + p2);
+ }
+
+ n1 = FIELD_GET(CLK_CNTL0_N1_MASK, reg0) + 1;
+
+ return DIV_ROUND_CLOSEST(parent_rate, n1);
+}
+
+static const struct cec_32k_freq_table *find_cec_32k_freq(unsigned long rate,
+ unsigned long prate)
+{
+ int i;
+
+ for (i = 0 ; i < ARRAY_SIZE(aoclk_cec_32k_table) ; ++i)
+ if (aoclk_cec_32k_table[i].parent_rate == prate &&
+ aoclk_cec_32k_table[i].target_rate == rate)
+ return &aoclk_cec_32k_table[i];
+
+ return NULL;
+}
+
+static long aoclk_cec_32k_round_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long *prate)
+{
+ const struct cec_32k_freq_table *freq = find_cec_32k_freq(rate,
+ *prate);
+
+ /* If invalid return first one */
+ if (!freq)
+ return aoclk_cec_32k_table[0].target_rate;
+
+ return freq->target_rate;
+}
+
+/*
+ * From the Amlogic init procedure, the IN and OUT gates needs to be handled
+ * in the init procedure to avoid any glitches.
+ */
+
+static int aoclk_cec_32k_set_rate(struct clk_hw *hw, unsigned long rate,
+ unsigned long parent_rate)
+{
+ const struct cec_32k_freq_table *freq = find_cec_32k_freq(rate,
+ parent_rate);
+ struct aoclk_cec_32k *cec_32k = to_aoclk_cec_32k(hw);
+ u32 reg = 0;
+
+ if (!freq)
+ return -EINVAL;
+
+ /* Disable clock */
+ regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0,
+ CLK_CNTL0_IN_GATE_EN | CLK_CNTL0_OUT_GATE_EN, 0);
+
+ reg = FIELD_PREP(CLK_CNTL0_N1_MASK, freq->n1 - 1);
+ if (freq->dualdiv)
+ reg |= CLK_CNTL0_DUALDIV_EN |
+ FIELD_PREP(CLK_CNTL0_N2_MASK, freq->n2 - 1);
+
+ regmap_write(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0, reg);
+
+ reg = FIELD_PREP(CLK_CNTL1_M1_MASK, freq->m1 - 1);
+ if (freq->dualdiv)
+ reg |= FIELD_PREP(CLK_CNTL1_M2_MASK, freq->m2 - 1);
+
+ regmap_write(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL1, reg);
+
+ /* Enable clock */
+ regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0,
+ CLK_CNTL0_IN_GATE_EN, CLK_CNTL0_IN_GATE_EN);
+
+ udelay(200);
+
+ regmap_update_bits(cec_32k->regmap, AO_RTC_ALT_CLK_CNTL0,
+ CLK_CNTL0_OUT_GATE_EN, CLK_CNTL0_OUT_GATE_EN);
+
+ regmap_update_bits(cec_32k->regmap, AO_CRT_CLK_CNTL1,
+ CLK_CNTL1_SELECT_OSC, CLK_CNTL1_SELECT_OSC);
+
+ /* Select 32k from XTAL */
+ regmap_update_bits(cec_32k->regmap,
+ AO_RTI_PWR_CNTL_REG0,
+ PWR_CNTL_ALT_32K_SEL,
+ FIELD_PREP(PWR_CNTL_ALT_32K_SEL, 4));
+
+ return 0;
+}
+
+const struct clk_ops meson_aoclk_cec_32k_ops = {
+ .recalc_rate = aoclk_cec_32k_recalc_rate,
+ .round_rate = aoclk_cec_32k_round_rate,
+ .set_rate = aoclk_cec_32k_set_rate,
+};
diff --git a/drivers/clk/meson/gxbb-aoclk.c b/drivers/clk/meson/gxbb-aoclk.c
index f61506c..6c161e0 100644
--- a/drivers/clk/meson/gxbb-aoclk.c
+++ b/drivers/clk/meson/gxbb-aoclk.c
@@ -59,6 +59,7 @@
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/init.h>
+#include <linux/delay.h>
#include <dt-bindings/clock/gxbb-aoclkc.h>
#include <dt-bindings/reset/gxbb-aoclkc.h>
#include "gxbb-aoclk.h"
@@ -105,6 +106,17 @@ static int gxbb_aoclk_do_reset(struct reset_controller_dev *rcdev,
GXBB_AO_GATE(uart2, 5);
GXBB_AO_GATE(ir_blaster, 6);

+static struct aoclk_cec_32k cec_32k_ao = {
+ .lock = &gxbb_aoclk_lock,
+ .hw.init = &(struct clk_init_data) {
+ .name = "cec_32k_ao",
+ .ops = &meson_aoclk_cec_32k_ops,
+ .parent_names = (const char *[]){ "xtal" },
+ .num_parents = 1,
+ .flags = CLK_IGNORE_UNUSED,
+ },
+};
+
static unsigned int gxbb_aoclk_reset[] = {
[RESET_AO_REMOTE] = 16,
[RESET_AO_I2C_MASTER] = 18,
@@ -131,8 +143,9 @@ static int gxbb_aoclk_do_reset(struct reset_controller_dev *rcdev,
[CLKID_AO_UART1] = &uart1_ao.hw,
[CLKID_AO_UART2] = &uart2_ao.hw,
[CLKID_AO_IR_BLASTER] = &ir_blaster_ao.hw,
+ [CLKID_AO_CEC_32K] = &cec_32k_ao.hw,
},
- .num = ARRAY_SIZE(gxbb_aoclk_gate),
+ .num = 7,
};

static int gxbb_aoclkc_probe(struct platform_device *pdev)
@@ -172,6 +185,12 @@ static int gxbb_aoclkc_probe(struct platform_device *pdev)
return ret;
}

+ /* Specific clocks */
+ cec_32k_ao.regmap = regmap;
+ ret = devm_clk_hw_register(dev, &cec_32k_ao.hw);
+ if (ret)
+ return ret;
+
return of_clk_add_hw_provider(dev->of_node, of_clk_hw_onecell_get,
&gxbb_aoclk_onecell_data);
}
diff --git a/drivers/clk/meson/gxbb-aoclk.h b/drivers/clk/meson/gxbb-aoclk.h
index 2e26108..e8604c8 100644
--- a/drivers/clk/meson/gxbb-aoclk.h
+++ b/drivers/clk/meson/gxbb-aoclk.h
@@ -9,7 +9,13 @@
#define __GXBB_AOCLKC_H

/* AO Configuration Clock registers offsets */
+#define AO_RTI_PWR_CNTL_REG1 0x0c
+#define AO_RTI_PWR_CNTL_REG0 0x10
#define AO_RTI_GEN_CNTL_REG0 0x40
+#define AO_OSCIN_CNTL 0x58
+#define AO_CRT_CLK_CNTL1 0x68
+#define AO_RTC_ALT_CLK_CNTL0 0x94
+#define AO_RTC_ALT_CLK_CNTL1 0x98

struct aoclk_gate_regmap {
struct clk_hw hw;
@@ -23,4 +29,14 @@ struct aoclk_gate_regmap {

extern const struct clk_ops meson_aoclk_gate_regmap_ops;

+struct aoclk_cec_32k {
+ struct clk_hw hw;
+ struct regmap *regmap;
+ spinlock_t *lock;
+};
+
+#define to_aoclk_cec_32k(_hw) container_of(_hw, struct aoclk_cec_32k, hw)
+
+extern const struct clk_ops meson_aoclk_cec_32k_ops;
+
#endif /* __GXBB_AOCLKC_H */
--
1.9.1