[PATCH v6 13/27] clk: mediatek: pll: Add ops for PLLs using set/clr regs

[Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>]

MT8189 SoC uses a new combination of status and set/clr registers to
control its PLL enable state and perform BAR reset, that are different
than the current default clock prepare/unprepare operations are using.

Add new set of PLL clock operations to support this logic that relies
on the following registers for prepare/unprepare operations:
  - en/en_set/en_clr, rather than en register, for PLL enable
    control
  - rst_bar/rst_bar_set/rst_bar_clr, rather than default rst_bar
    register for BAR reset control

Also, handle rst_bar register setting/clearing with a timeout, to
verify the operation was correctly performed.

Reviewed-by: Brian Masney <bmasney@redhat.com>
Signed-off-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
---
 drivers/clk/mediatek/clk-pll.c | 67 ++++++++++++++++++++++++++++++++++++++++++
 drivers/clk/mediatek/clk-pll.h |  5 ++++
 2 files changed, 72 insertions(+)

diff --git a/drivers/clk/mediatek/clk-pll.c b/drivers/clk/mediatek/clk-pll.c
index 9a197a657dce..f32b9145f256 100644
--- a/drivers/clk/mediatek/clk-pll.c
+++ b/drivers/clk/mediatek/clk-pll.c
@@ -9,6 +9,7 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/platform_device.h>
@@ -32,6 +33,7 @@
 #define INTEGER_BITS		7
 
 #define PLL_STABILIZATION_DELAY	20 /* in us */
+#define RST_BAR_TIMEOUT		20 /* in us */
 
 int mtk_pll_is_prepared(struct clk_hw *hw)
 {
@@ -301,6 +303,61 @@ void mtk_pll_unprepare(struct clk_hw *hw)
 	mtk_pll_power_off(pll);
 }
 
+int mtk_pll_prepare_setclr(struct clk_hw *hw)
+{
+	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
+	u32 val = 0;
+	int ret;
+
+	mtk_pll_power_on(pll);
+
+	writel(BIT(pll->data->pll_en_bit), pll->en_set_addr);
+
+	__mtk_pll_tuner_enable(pll);
+
+	udelay(PLL_STABILIZATION_DELAY);
+
+	if (pll->data->flags & HAVE_RST_BAR) {
+		writel(pll->data->rst_bar_mask, pll->rst_bar_set_addr);
+
+		ret = readl_poll_timeout(pll->rst_bar_addr, val,
+					(val & pll->data->rst_bar_mask), 1,
+					RST_BAR_TIMEOUT);
+		if (ret) {
+			mtk_pll_unprepare_setclr(hw);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mtk_pll_prepare_setclr);
+
+void mtk_pll_unprepare_setclr(struct clk_hw *hw)
+{
+	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
+	u32 val = 0;
+
+	if (pll->data->flags & HAVE_RST_BAR) {
+		writel(pll->data->rst_bar_mask, pll->rst_bar_clr_addr);
+
+		/*
+		 * Ignore return code to continue unpreparing the PLL if
+		 * an error occurs on register read poll.
+		 */
+		readl_poll_timeout(pll->rst_bar_addr, val,
+				   !(val & pll->data->rst_bar_mask), 1,
+				   RST_BAR_TIMEOUT);
+	}
+
+	__mtk_pll_tuner_disable(pll);
+
+	writel(BIT(pll->data->pll_en_bit), pll->en_clr_addr);
+
+	mtk_pll_power_off(pll);
+}
+EXPORT_SYMBOL_GPL(mtk_pll_unprepare_setclr);
+
 static int mtk_pll_prepare_fenc_setclr(struct clk_hw *hw)
 {
 	struct mtk_clk_pll *pll = to_mtk_clk_pll(hw);
@@ -329,6 +386,16 @@ const struct clk_ops mtk_pll_ops = {
 	.set_rate	= mtk_pll_set_rate,
 };
 
+const struct clk_ops mtk_pll_setclr_ops = {
+	.is_prepared	= mtk_pll_is_prepared,
+	.prepare	= mtk_pll_prepare_setclr,
+	.unprepare	= mtk_pll_unprepare_setclr,
+	.recalc_rate	= mtk_pll_recalc_rate,
+	.determine_rate = mtk_pll_determine_rate,
+	.set_rate	= mtk_pll_set_rate,
+};
+EXPORT_SYMBOL_GPL(mtk_pll_setclr_ops);
+
 const struct clk_ops mtk_pll_fenc_setclr_ops = {
 	.is_prepared	= mtk_pll_is_prepared_fenc_setclr,
 	.prepare	= mtk_pll_prepare_fenc_setclr,
diff --git a/drivers/clk/mediatek/clk-pll.h b/drivers/clk/mediatek/clk-pll.h
index 3aaf3a7654b5..296bed073290 100644
--- a/drivers/clk/mediatek/clk-pll.h
+++ b/drivers/clk/mediatek/clk-pll.h
@@ -92,6 +92,7 @@ void mtk_clk_unregister_plls(const struct mtk_pll_data *plls, int num_plls,
 
 extern const struct clk_ops mtk_pll_ops;
 extern const struct clk_ops mtk_pll_fenc_setclr_ops;
+extern const struct clk_ops mtk_pll_setclr_ops;
 
 static inline struct mtk_clk_pll *to_mtk_clk_pll(struct clk_hw *hw)
 {
@@ -104,6 +105,10 @@ int mtk_pll_prepare(struct clk_hw *hw);
 
 void mtk_pll_unprepare(struct clk_hw *hw);
 
+int mtk_pll_prepare_setclr(struct clk_hw *hw);
+
+void mtk_pll_unprepare_setclr(struct clk_hw *hw);
+
 unsigned long mtk_pll_recalc_rate(struct clk_hw *hw, unsigned long parent_rate);
 
 void mtk_pll_calc_values(struct mtk_clk_pll *pll, u32 *pcw, u32 *postdiv,

-- 
2.55.0