[PATCH v5 19/20] clk: imx: pll14xx: support spread spectrum clock generation
Dario Binacchi
dario.binacchi at amarulasolutions.com
Thu Dec 5 03:17:54 PST 2024
Add support for spread spectrum clock (SSC) generation to the pll14xxx
driver.
Signed-off-by: Dario Binacchi <dario.binacchi at amarulasolutions.com>
---
(no changes since v1)
drivers/clk/imx/clk-pll14xx.c | 126 ++++++++++++++++++++++++++++++++++
drivers/clk/imx/clk.h | 16 +++++
2 files changed, 142 insertions(+)
diff --git a/drivers/clk/imx/clk-pll14xx.c b/drivers/clk/imx/clk-pll14xx.c
index d63564dbb12c..1e66c3bb230d 100644
--- a/drivers/clk/imx/clk-pll14xx.c
+++ b/drivers/clk/imx/clk-pll14xx.c
@@ -20,6 +20,8 @@
#define GNRL_CTL 0x0
#define DIV_CTL0 0x4
#define DIV_CTL1 0x8
+#define SSCG_CTRL 0xc
+
#define LOCK_STATUS BIT(31)
#define LOCK_SEL_MASK BIT(29)
#define CLKE_MASK BIT(11)
@@ -31,6 +33,10 @@
#define KDIV_MASK GENMASK(15, 0)
#define KDIV_MIN SHRT_MIN
#define KDIV_MAX SHRT_MAX
+#define SSCG_ENABLE BIT(31)
+#define MFREQ_CTL_MASK GENMASK(19, 12)
+#define MRAT_CTL_MASK GENMASK(9, 4)
+#define SEL_PF_MASK GENMASK(1, 0)
#define LOCK_TIMEOUT_US 10000
@@ -40,6 +46,8 @@ struct clk_pll14xx {
enum imx_pll14xx_type type;
const struct imx_pll14xx_rate_table *rate_table;
int rate_count;
+ bool ssc_enable;
+ struct imx_pll14xx_ssc ssc_conf;
};
#define to_clk_pll14xx(_hw) container_of(_hw, struct clk_pll14xx, hw)
@@ -347,6 +355,27 @@ static int clk_pll1416x_set_rate(struct clk_hw *hw, unsigned long drate,
return 0;
}
+static void clk_pll1443x_enable_ssc(struct clk_hw *hw, unsigned long parent_rate,
+ unsigned int pdiv, unsigned int mdiv)
+{
+ struct clk_pll14xx *pll = to_clk_pll14xx(hw);
+ struct imx_pll14xx_ssc *conf = &pll->ssc_conf;
+ u32 sscg_ctrl, mfr, mrr;
+
+ sscg_ctrl = readl_relaxed(pll->base + SSCG_CTRL);
+ sscg_ctrl &=
+ ~(SSCG_ENABLE | MFREQ_CTL_MASK | MRAT_CTL_MASK | SEL_PF_MASK);
+
+ mfr = parent_rate / (conf->mod_freq * pdiv * (1 << 5));
+ mrr = (conf->mod_rate * mdiv * (1 << 6)) / (100 * mfr);
+
+ sscg_ctrl |= SSCG_ENABLE | FIELD_PREP(MFREQ_CTL_MASK, mfr) |
+ FIELD_PREP(MRAT_CTL_MASK, mrr) |
+ FIELD_PREP(SEL_PF_MASK, conf->mod_type);
+
+ writel_relaxed(sscg_ctrl, pll->base + SSCG_CTRL);
+}
+
static int clk_pll1443x_set_rate(struct clk_hw *hw, unsigned long drate,
unsigned long prate)
{
@@ -368,6 +397,9 @@ static int clk_pll1443x_set_rate(struct clk_hw *hw, unsigned long drate,
writel_relaxed(FIELD_PREP(KDIV_MASK, rate.kdiv),
pll->base + DIV_CTL1);
+ if (pll->ssc_enable)
+ clk_pll1443x_enable_ssc(hw, prate, rate.pdiv, rate.mdiv);
+
return 0;
}
@@ -408,6 +440,9 @@ static int clk_pll1443x_set_rate(struct clk_hw *hw, unsigned long drate,
gnrl_ctl &= ~BYPASS_MASK;
writel_relaxed(gnrl_ctl, pll->base + GNRL_CTL);
+ if (pll->ssc_enable)
+ clk_pll1443x_enable_ssc(hw, prate, rate.pdiv, rate.mdiv);
+
return 0;
}
@@ -542,3 +577,94 @@ struct clk_hw *imx_dev_clk_hw_pll14xx(struct device *dev, const char *name,
return hw;
}
EXPORT_SYMBOL_GPL(imx_dev_clk_hw_pll14xx);
+
+void imx_clk_pll14xx_enable_ssc(struct clk_hw *hw, struct imx_pll14xx_ssc *conf)
+{
+ struct clk_pll14xx *pll = to_clk_pll14xx(hw);
+
+ pll->ssc_enable = true;
+ memcpy(&pll->ssc_conf, conf, sizeof(pll->ssc_conf));
+}
+EXPORT_SYMBOL_GPL(imx_clk_pll14xx_enable_ssc);
+
+static int clk_pll14xx_ssc_mod_type(const char *name,
+ enum imx_pll14xx_ssc_mod_type *mod_type)
+{
+ int i;
+ struct {
+ const char *name;
+ enum imx_pll14xx_ssc_mod_type id;
+ } mod_types[] = {
+ { .name = "down-spread", .id = IMX_PLL14XX_SSC_DOWN_SPREAD },
+ { .name = "up-spread", .id = IMX_PLL14XX_SSC_UP_SPREAD },
+ { .name = "center-spread", .id = IMX_PLL14XX_SSC_CENTER_SPREAD }
+ };
+
+ pr_info("%s, name: %s\n", __func__, name);
+ for (i = 0; i < ARRAY_SIZE(mod_types); i++) {
+ if (!strcmp(name, mod_types[i].name)) {
+ *mod_type = mod_types[i].id;
+ return 0;
+ }
+ }
+
+ return -EINVAL;
+}
+
+int imx_clk_pll14xx_ssc_parse_dt(struct device_node *np, const char *pll_name,
+ struct imx_pll14xx_ssc *conf)
+{
+ int i, ret, num_clks;
+ const char *s;
+
+ if (!conf)
+ return -EINVAL;
+
+ ret = of_property_count_strings(np, "clock-names");
+ if (ret < 0)
+ return ret;
+
+ num_clks = ret;
+ for (i = 0; i < num_clks; i++) {
+ ret = of_property_read_string_index(np, "clock-names", i, &s);
+ if (strcmp(pll_name, s))
+ continue;
+
+ ret = of_property_read_u32_index(np, "fsl,ssc-modfreq-hz", i,
+ &conf->mod_freq);
+ if (ret)
+ return ret;
+
+ ret = of_property_read_u32_index(np, "fsl,ssc-modrate-percent", i,
+ &conf->mod_rate);
+ if (ret) {
+ pr_err("missing fsl,ssc-modrate-percent property for %pOFn\n",
+ np);
+ return ret;
+ }
+
+ ret = of_property_read_string_index(np, "fsl,ssc-modmethod", i, &s);
+ if (ret) {
+ pr_err("failed to get fsl,ssc-modmethod property for %pOFn\n",
+ np);
+ return ret;
+ }
+
+ if (strlen(s) == 0)
+ return -ENODEV;
+
+ ret = clk_pll14xx_ssc_mod_type(s, &conf->mod_type);
+ if (ret) {
+ pr_err("wrong fsl,ssc-modmethod property for %pOFn\n", np);
+ return ret;
+ }
+
+ pr_debug("%s: mod_freq: %d, mod_rate: %d: mod_method: %s [%d]\n",
+ __func__, conf->mod_freq, conf->mod_rate, s, conf->mod_type);
+
+ return 0;
+ }
+
+ return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(imx_clk_pll14xx_ssc_parse_dt);
diff --git a/drivers/clk/imx/clk.h b/drivers/clk/imx/clk.h
index 52055fda3058..edd28b78b115 100644
--- a/drivers/clk/imx/clk.h
+++ b/drivers/clk/imx/clk.h
@@ -69,6 +69,18 @@ struct imx_pll14xx_clk {
int flags;
};
+enum imx_pll14xx_ssc_mod_type {
+ IMX_PLL14XX_SSC_DOWN_SPREAD,
+ IMX_PLL14XX_SSC_UP_SPREAD,
+ IMX_PLL14XX_SSC_CENTER_SPREAD,
+};
+
+struct imx_pll14xx_ssc {
+ unsigned int mod_freq;
+ unsigned int mod_rate;
+ enum imx_pll14xx_ssc_mod_type mod_type;
+};
+
extern struct imx_pll14xx_clk imx_1416x_pll;
extern struct imx_pll14xx_clk imx_1443x_pll;
extern struct imx_pll14xx_clk imx_1443x_dram_pll;
@@ -494,4 +506,8 @@ struct clk_hw *imx_clk_gpr_mux(const char *name, const char *compatible,
struct clk_hw *imx8m_anatop_get_clk_hw(int id);
#endif
+void imx_clk_pll14xx_enable_ssc(struct clk_hw *hw, struct imx_pll14xx_ssc *conf);
+int imx_clk_pll14xx_ssc_parse_dt(struct device_node *np, const char *pll_name,
+ struct imx_pll14xx_ssc *conf);
+
#endif
--
2.43.0
More information about the linux-arm-kernel
mailing list