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From: Tudor Ambarus <tudor.ambarus@linaro.org>
To: peter.griffin@linaro.org,
	krzysztof.kozlowski@linaro.org
Cc: alim.akhtar@samsung.com,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	andre.draszik@linaro.org,
	willmcvicker@google.com,
	kernel-team@android.com,
	s.nawrocki@samsung.com,
	cw00.choi@samsung.com,
	mturquette@baylibre.com,
	sboyd@kernel.org,
	semen.protsenko@linaro.org,
	linux-clk@vger.kernel.org,
	jaewon02.kim@samsung.com,
	Tudor Ambarus <tudor.ambarus@linaro.org>
Subject: [PATCH v2 2/3] clk: samsung: gs101: propagate PERIC1 USI SPI clock rate
Date: Tue, 26 Mar 2024 17:28:12 +0000
Message-ID: <20240326172813.801470-3-tudor.ambarus@linaro.org>
In-Reply-To: <20240326172813.801470-1-tudor.ambarus@linaro.org>
References: <20240326172813.801470-1-tudor.ambarus@linaro.org>
Precedence: bulk
MIME-Version: 1.0
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When SPI transfer is being prepared, the spi-s3c64xx driver will call
clk_set_rate() to change the rate of SPI source clock (IPCLK). But IPCLK
is a gate (leaf) clock, so it must propagate the rate change up the
clock tree, so that corresponding MUX/DIV clocks can actually change
their values. Add CLK_SET_RATE_PARENT flag to corresponding clocks for
all USI instances in GS101 PERIC1: USI{0, 9, 10, 11, 12, 13}. This change
involves the following clocks:

PERIC1 USI*:

    Clock                              Div range    MUX Selection
    -------------------------------------------------------------------
    gout_peric1_peric1_top0_ipclk_*    -            -
    dout_peric1_usi*_usi               /1..16       -
    mout_peric1_usi*_usi_user          -            {24.5 MHz, 400 MHz}

With input clock of 400 MHz this scheme provides the following IPCLK
rate range, for each USI block:

    PERIC1 USI*:       1.5 MHz ... 400 MHz

Accounting for internal /4 divider in SPI blocks, and because the max
SPI frequency is limited at 50 MHz, it gives us next SPI SCK rates:

    PERIC1 USI_SPI*:   384 KHz ... 49.9 MHz

Which shall be fine for the applications of the SPI bus.

Note that with this we allow the reparenting of the MUX_USIx clocks to
OSCCLK. Each instance of the USI IP has its own MUX_USI clock, thus the
reparenting of a MUX_USI clock corresponds to a single instance of the
USI IP. The datasheet mentions OSCCLK just in the low-power mode
context, but the downstream driver reparents too the MUX_USI clocks to
OSCCLK. Follow the downstream driver and do the same.

Fixes: 63b4bd1259d9 ("clk: samsung: gs101: add support for cmu_peric1")
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
---
 drivers/clk/samsung/clk-gs101.c | 90 ++++++++++++++++++---------------
 1 file changed, 48 insertions(+), 42 deletions(-)

diff --git a/drivers/clk/samsung/clk-gs101.c b/drivers/clk/samsung/clk-gs101.c
index d065e343a85d..ddf2d57eed68 100644
--- a/drivers/clk/samsung/clk-gs101.c
+++ b/drivers/clk/samsung/clk-gs101.c
@@ -3230,47 +3230,53 @@ static const struct samsung_mux_clock peric1_mux_clks[] __initconst = {
 	MUX(CLK_MOUT_PERIC1_I3C_USER,
 	    "mout_peric1_i3c_user", mout_peric1_nonbususer_p,
 	    PLL_CON0_MUX_CLKCMU_PERIC1_I3C_USER, 4, 1),
-	MUX(CLK_MOUT_PERIC1_USI0_USI_USER,
-	    "mout_peric1_usi0_usi_user", mout_peric1_nonbususer_p,
-	    PLL_CON0_MUX_CLKCMU_PERIC1_USI0_USI_USER, 4, 1),
-	MUX(CLK_MOUT_PERIC1_USI10_USI_USER,
-	    "mout_peric1_usi10_usi_user", mout_peric1_nonbususer_p,
-	    PLL_CON0_MUX_CLKCMU_PERIC1_USI10_USI_USER, 4, 1),
-	MUX(CLK_MOUT_PERIC1_USI11_USI_USER,
-	    "mout_peric1_usi11_usi_user", mout_peric1_nonbususer_p,
-	    PLL_CON0_MUX_CLKCMU_PERIC1_USI11_USI_USER, 4, 1),
-	MUX(CLK_MOUT_PERIC1_USI12_USI_USER,
-	    "mout_peric1_usi12_usi_user", mout_peric1_nonbususer_p,
-	    PLL_CON0_MUX_CLKCMU_PERIC1_USI12_USI_USER, 4, 1),
-	MUX(CLK_MOUT_PERIC1_USI13_USI_USER,
-	    "mout_peric1_usi13_usi_user", mout_peric1_nonbususer_p,
-	    PLL_CON0_MUX_CLKCMU_PERIC1_USI13_USI_USER, 4, 1),
-	MUX(CLK_MOUT_PERIC1_USI9_USI_USER,
-	    "mout_peric1_usi9_usi_user", mout_peric1_nonbususer_p,
-	    PLL_CON0_MUX_CLKCMU_PERIC1_USI9_USI_USER, 4, 1),
+	nMUX(CLK_MOUT_PERIC1_USI0_USI_USER,
+	     "mout_peric1_usi0_usi_user", mout_peric1_nonbususer_p,
+	     PLL_CON0_MUX_CLKCMU_PERIC1_USI0_USI_USER, 4, 1),
+	nMUX(CLK_MOUT_PERIC1_USI10_USI_USER,
+	     "mout_peric1_usi10_usi_user", mout_peric1_nonbususer_p,
+	     PLL_CON0_MUX_CLKCMU_PERIC1_USI10_USI_USER, 4, 1),
+	nMUX(CLK_MOUT_PERIC1_USI11_USI_USER,
+	     "mout_peric1_usi11_usi_user", mout_peric1_nonbususer_p,
+	     PLL_CON0_MUX_CLKCMU_PERIC1_USI11_USI_USER, 4, 1),
+	nMUX(CLK_MOUT_PERIC1_USI12_USI_USER,
+	     "mout_peric1_usi12_usi_user", mout_peric1_nonbususer_p,
+	     PLL_CON0_MUX_CLKCMU_PERIC1_USI12_USI_USER, 4, 1),
+	nMUX(CLK_MOUT_PERIC1_USI13_USI_USER,
+	     "mout_peric1_usi13_usi_user", mout_peric1_nonbususer_p,
+	     PLL_CON0_MUX_CLKCMU_PERIC1_USI13_USI_USER, 4, 1),
+	nMUX(CLK_MOUT_PERIC1_USI9_USI_USER,
+	     "mout_peric1_usi9_usi_user", mout_peric1_nonbususer_p,
+	     PLL_CON0_MUX_CLKCMU_PERIC1_USI9_USI_USER, 4, 1),
 };
 
 static const struct samsung_div_clock peric1_div_clks[] __initconst = {
 	DIV(CLK_DOUT_PERIC1_I3C, "dout_peric1_i3c", "mout_peric1_i3c_user",
 	    CLK_CON_DIV_DIV_CLK_PERIC1_I3C, 0, 4),
-	DIV(CLK_DOUT_PERIC1_USI0_USI,
-	    "dout_peric1_usi0_usi", "mout_peric1_usi0_usi_user",
-	    CLK_CON_DIV_DIV_CLK_PERIC1_USI0_USI, 0, 4),
-	DIV(CLK_DOUT_PERIC1_USI10_USI,
-	    "dout_peric1_usi10_usi", "mout_peric1_usi10_usi_user",
-	    CLK_CON_DIV_DIV_CLK_PERIC1_USI10_USI, 0, 4),
-	DIV(CLK_DOUT_PERIC1_USI11_USI,
-	    "dout_peric1_usi11_usi", "mout_peric1_usi11_usi_user",
-	    CLK_CON_DIV_DIV_CLK_PERIC1_USI11_USI, 0, 4),
-	DIV(CLK_DOUT_PERIC1_USI12_USI,
-	    "dout_peric1_usi12_usi", "mout_peric1_usi12_usi_user",
-	    CLK_CON_DIV_DIV_CLK_PERIC1_USI12_USI, 0, 4),
-	DIV(CLK_DOUT_PERIC1_USI13_USI,
-	    "dout_peric1_usi13_usi", "mout_peric1_usi13_usi_user",
-	    CLK_CON_DIV_DIV_CLK_PERIC1_USI13_USI, 0, 4),
-	DIV(CLK_DOUT_PERIC1_USI9_USI,
-	    "dout_peric1_usi9_usi", "mout_peric1_usi9_usi_user",
-	    CLK_CON_DIV_DIV_CLK_PERIC1_USI9_USI, 0, 4),
+	DIV_F(CLK_DOUT_PERIC1_USI0_USI,
+	      "dout_peric1_usi0_usi", "mout_peric1_usi0_usi_user",
+	      CLK_CON_DIV_DIV_CLK_PERIC1_USI0_USI, 0, 4,
+	      CLK_SET_RATE_PARENT, 0),
+	DIV_F(CLK_DOUT_PERIC1_USI10_USI,
+	      "dout_peric1_usi10_usi", "mout_peric1_usi10_usi_user",
+	      CLK_CON_DIV_DIV_CLK_PERIC1_USI10_USI, 0, 4,
+	      CLK_SET_RATE_PARENT, 0),
+	DIV_F(CLK_DOUT_PERIC1_USI11_USI,
+	      "dout_peric1_usi11_usi", "mout_peric1_usi11_usi_user",
+	      CLK_CON_DIV_DIV_CLK_PERIC1_USI11_USI, 0, 4,
+	      CLK_SET_RATE_PARENT, 0),
+	DIV_F(CLK_DOUT_PERIC1_USI12_USI,
+	      "dout_peric1_usi12_usi", "mout_peric1_usi12_usi_user",
+	      CLK_CON_DIV_DIV_CLK_PERIC1_USI12_USI, 0, 4,
+	      CLK_SET_RATE_PARENT, 0),
+	DIV_F(CLK_DOUT_PERIC1_USI13_USI,
+	      "dout_peric1_usi13_usi", "mout_peric1_usi13_usi_user",
+	      CLK_CON_DIV_DIV_CLK_PERIC1_USI13_USI, 0, 4,
+	      CLK_SET_RATE_PARENT, 0),
+	DIV_F(CLK_DOUT_PERIC1_USI9_USI,
+	      "dout_peric1_usi9_usi", "mout_peric1_usi9_usi_user",
+	      CLK_CON_DIV_DIV_CLK_PERIC1_USI9_USI, 0, 4,
+	      CLK_SET_RATE_PARENT, 0),
 };
 
 static const struct samsung_gate_clock peric1_gate_clks[] __initconst = {
@@ -3305,27 +3311,27 @@ static const struct samsung_gate_clock peric1_gate_clks[] __initconst = {
 	GATE(CLK_GOUT_PERIC1_PERIC1_TOP0_IPCLK_1,
 	     "gout_peric1_peric1_top0_ipclk_1", "dout_peric1_usi0_usi",
 	     CLK_CON_GAT_GOUT_BLK_PERIC1_UID_PERIC1_TOP0_IPCLKPORT_IPCLK_1,
-	     21, 0, 0),
+	     21, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_GOUT_PERIC1_PERIC1_TOP0_IPCLK_2,
 	     "gout_peric1_peric1_top0_ipclk_2", "dout_peric1_usi9_usi",
 	     CLK_CON_GAT_GOUT_BLK_PERIC1_UID_PERIC1_TOP0_IPCLKPORT_IPCLK_2,
-	     21, 0, 0),
+	     21, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_GOUT_PERIC1_PERIC1_TOP0_IPCLK_3,
 	     "gout_peric1_peric1_top0_ipclk_3", "dout_peric1_usi10_usi",
 	     CLK_CON_GAT_GOUT_BLK_PERIC1_UID_PERIC1_TOP0_IPCLKPORT_IPCLK_3,
-	     21, 0, 0),
+	     21, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_GOUT_PERIC1_PERIC1_TOP0_IPCLK_4,
 	     "gout_peric1_peric1_top0_ipclk_4", "dout_peric1_usi11_usi",
 	     CLK_CON_GAT_GOUT_BLK_PERIC1_UID_PERIC1_TOP0_IPCLKPORT_IPCLK_4,
-	     21, 0, 0),
+	     21, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_GOUT_PERIC1_PERIC1_TOP0_IPCLK_5,
 	     "gout_peric1_peric1_top0_ipclk_5", "dout_peric1_usi12_usi",
 	     CLK_CON_GAT_GOUT_BLK_PERIC1_UID_PERIC1_TOP0_IPCLKPORT_IPCLK_5,
-	     21, 0, 0),
+	     21, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_GOUT_PERIC1_PERIC1_TOP0_IPCLK_6,
 	     "gout_peric1_peric1_top0_ipclk_6", "dout_peric1_usi13_usi",
 	     CLK_CON_GAT_GOUT_BLK_PERIC1_UID_PERIC1_TOP0_IPCLKPORT_IPCLK_6,
-	     21, 0, 0),
+	     21, CLK_SET_RATE_PARENT, 0),
 	GATE(CLK_GOUT_PERIC1_PERIC1_TOP0_IPCLK_8,
 	     "gout_peric1_peric1_top0_ipclk_8", "dout_peric1_i3c",
 	     CLK_CON_GAT_GOUT_BLK_PERIC1_UID_PERIC1_TOP0_IPCLKPORT_IPCLK_8,
-- 
2.44.0.396.g6e790dbe36-goog