[PATCH RFC v4 08/12] clk: zte: Introduce a driver for zx297520v3 matrix clocks

["Stefan Dösinger" <stefandoesinger@gmail.com>]

This clock controller controls high speed devices: CPU, DMA, RAM, SDIO,
Ethernet. The only non-clock, non-reset registers I have spotted here
are hardware spinlocks.

I put the entire set of PLL generated frequencies as consumed clocks in
the binding. Due to lack of a data sheet I can't rule out that the any
of the PLL subdivions are used.

Signed-off-by: Stefan Dösinger <stefandoesinger@gmail.com>
---
 drivers/clk/zte/clk-zx297520v3.c | 172 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 172 insertions(+)

diff --git a/drivers/clk/zte/clk-zx297520v3.c b/drivers/clk/zte/clk-zx297520v3.c
index 50263bca6e08..d90aadf18026 100644
--- a/drivers/clk/zte/clk-zx297520v3.c
+++ b/drivers/clk/zte/clk-zx297520v3.c
@@ -410,8 +410,180 @@ static const struct zx_clk_data zx297520v3_topclk_data = {
 	.reset_auxdev_name = "zx297520v3_toprst"
 };
 
+static const char * const cpu_sel[] = {
+	"osc26m",
+	"mpll",		/* 624 MHz */
+	"mpll_d2",	/* 312 MHz */
+	"mpll_d4",	/* 156 MHz */
+};
+
+static const char * const sd0_sel[] = {
+	"osc26m",
+	"mpll_d4",	/* 156 MHz */
+	"gpll_d2",	/* 100 MHz */
+	"mpll_d8",	/* 78 MHz */
+	"gpll_d4",	/* 50 MHz */
+	"gpll_d8",	/* 25 MHz */
+};
+
+static const char * const sd1_sel[] = {
+	"osc26m",
+	"gpll_d2",	/* 100 MHz */
+	"mpll_d8",	/* 78 MHz */
+	"gpll_d4",	/* 50 MHz */
+	"mpll_d16",	/* 39 MHz */
+	"gpll_d8",	/* 25 MHz */
+};
+
+static const char * const nand_sel[] = {
+	"mpll_d4",	/* 156 MHz */
+	"osc26m",
+};
+
+static const char * const edcp_sel[] = {
+	"osc26m",
+	"mpll_d4",	/* 156 MHz */
+	"mpll_d5",	/* 124.8 MHz */
+	"mpll_d6",	/* 104 MHz */
+};
+
+static const char * const tdm_sel[] = {
+	"osc26m",
+	"dpll_d4",	/* 122.88 MHz */
+	"mpll_d6",	/* 104 MHz */
+};
+
+static const struct zx_mux_desc zx297520v3_matrix_muxes[] = {
+	MUX(0,                             "cpu_mux",        cpu_sel,          0x20,  0, 2),
+	MUX(0,                             "sd0_mux",        sd0_sel,          0x50,  4, 3),
+	MUX(0,                             "sd1_mux",        sd1_sel,          0x50,  8, 3),
+	MUX(0,                             "nand_mux",       nand_sel,         0x50, 12, 2),
+	MUX(0,                             "edcp_mux",       edcp_sel,         0x50, 16, 2),
+	MUX(0,                             "tdm_mux",        tdm_sel,          0x50, 24, 2),
+};
+
+static const struct zx_gate_desc zx297520v3_matrix_gates[] = {
+	/* Both 0x24 and 0x28 bits 1 and 2 stop the CPU. There is also a bit in topclk+0x138, which
+	 * ZTE's uboot calls "A53 reset", which also stops the CPU. I can't really tell the
+	 * difference between matrix+28 and top+138. The clock (maxtrix+0x24) can be disabled and
+	 * enabled from the Cortex M0 and it will nicely stop and restart the A53, retaining all
+	 * state.
+	 *
+	 * 0x50, bits 0-3 have the DDR clock. A lot of DDR gates and resets are in 0x100.
+	 */
+	GATE(ZX297520V3_CPU_WCLK,          "cpu_wclk",       "cpu_mux",        0x24,  1,
+		CLK_IS_CRITICAL),
+	GATE(ZX297520V3_CPU_PCLK,          "cpu_pclk",       clk_main[0],      0x24,  2,
+		CLK_IS_CRITICAL),
+
+	/* ZSP aka LTE DSP clock. I think there is a mux at matrix+0x30, but I have no idea
+	 * about the frequencies it selects.
+	 */
+	GATE(ZX297520V3_ZSP_WCLK,          "zsp_wclk",       clk_unknown[0],   0x3c,  0, 0),
+
+	GATE(ZX297520V3_SD0_WCLK,          "sd0_wclk",       "sd0_mux",        0x54, 12, 0),
+	GATE(ZX297520V3_SD0_PCLK,          "sd0_pclk",       clk_main[0],      0x54, 13, 0),
+	GATE(ZX297520V3_SD0_CDET,          "sd0_cdet",       "osc32k",         0x54, 14, 0),
+	GATE(ZX297520V3_SD1_WCLK,          "sd1_wclk",       "sd1_mux",        0x54,  4, 0),
+	GATE(ZX297520V3_SD1_PCLK,          "sd1_pclk",       clk_main[0],      0x54,  5, 0),
+	/* I don't know how the cdet clock works. Card detection in the way the dwc,mmc driver uses
+	 * it appears broken no matter this clock's setting.
+	 */
+	GATE(ZX297520V3_SD1_CDET,          "sd1_cdet",       "osc32k",         0x54,  6, 0),
+
+	/* This is some "denali" NAND, not the qspi connected one */
+	GATE(ZX297520V3_NAND_WCLK,         "nand_wclk",      "nand_mux",       0x54, 20, 0),
+	GATE(ZX297520V3_NAND_PCLK,         "nand_pclk",      clk_main[0],      0x54, 21, 0),
+	GATE(ZX297520V3_SSC_WCLK,          "ssc_wclk",       clk_unknown[0],   0x84,  1, 0),
+	GATE(ZX297520V3_SSC_PCLK,          "ssc_pclk",       clk_main[0],      0x84,  2, 0),
+
+	/* Yes, WCLK bit > PCLK bit for EDCP */
+	GATE(ZX297520V3_EDCP_WCLK,         "edcp_wclk",      "edcp_mux",       0x64,  2, 0),
+	GATE(ZX297520V3_EDCP_PCLK,         "edcp_pclk",      clk_main[0],      0x64,  1, 0),
+
+	/* There are a lot more VOU related controls in these registers, but turning off the main
+	 * clock seems to shut off the entire VOU MMIO range.
+	 */
+	GATE(ZX297520V3_VOU_WCLK,          "vou_wclk",       clk_unknown[0],  0x168,  0, 0),
+	GATE(ZX297520V3_VOU_PCLK,          "vou_pclk",       clk_main[0],     0x168,  1, 0),
+
+	/* PDCFG. Like PMM, either clock bit will allow the device to function. */
+	GATE(ZX297520V3_PDCFG_WCLK,        "pdcfg_wclk",     clk_unknown[0],   0x88,  0,
+		CLK_IS_CRITICAL),
+	GATE(ZX297520V3_PDCFG_PCLK,        "pdcfg_pclk",     clk_main[0],      0x88,  1,
+		CLK_IS_CRITICAL),
+
+	/* ZTE's driver has a statemt to the effect of *(top->base+0x11c) = 5, with a comment
+	 * suggesting that this sets a 50 mhz clock. The clock code itself lists gmac clocks in
+	 * matrix+110 and lists the parents of these clock as 50mhz gpll output, but the GMAC
+	 * driver never enables the clocks. It turns out ZTE's code is highly misleading.
+	 *
+	 * The GMAC's work clock is definitly not any gpll output because it keeps working fine with
+	 * gpll disabled. The MDIO speed is mostly unaffected by mpll speed changes, so it is most
+	 * likely not fed by mpll either. All other PLLs can be disabled without breaking GMAC, so
+	 * osc26m is the only possible remaining parent.
+	 *
+	 * The GMAC Gates are left enabled by the boot loader and are required for the GMAC to work.
+	 *
+	 * As for the 50 MHz comment: See rmiiphy_wclk.
+	 */
+	GATE(ZX297520V3_GMAC_WCLK,         "gmac_wclk",      clk_main[0],     0x110,  0, 0),
+	GATE(ZX297520V3_GMAC_PCLK,         "gmac_pclk",      clk_main[0],     0x110,  1, 0),
+	GATE(ZX297520V3_GMAC_AHB,          "gmac_ahb",       "AHB_wclk",      0x110,  2, 0),
+
+	GATE(ZX297520V3_MBOX_PCLK,         "mbox_pclk",      clk_main[0],      0x88,  2, 0),
+	GATE(ZX297520V3_DMA_PCLK,          "dma_pclk",       clk_main[0],      0x94,  3, 0),
+
+	/* LSP uplink clocks. The PCLK is fairly obvious (disabling it shuts off the entire LSP
+	 * register area). The WCLK speeds were deduced by setting timers and qspi muxes to a
+	 * specific speed and seeing which bit in matrix+0x7c needs to be enabled for the device
+	 * to work.
+	 *
+	 * Due to the timers I am certain about the 26mhz and 32khz clocks. I cannot directly
+	 * observe the qspi mux frequency, so the clock rates depend on ZTE's qspi mux selection
+	 * being correct.
+	 *
+	 * Two additional bits are specific to sound components - the mux for the LSP's TDM IP is
+	 * in matrixclk and gets passed down. I2S has a mux in LSP, which can select the dpll_d4
+	 * clock.
+	 */
+	GATE(ZX297520V3_LSP_MPLL_D5_WCLK,  "lsp_mpll_d5",    "mpll_d5",        0x7c,  0, 0),
+	GATE(ZX297520V3_LSP_MPLL_D4_WCLK,  "lsp_mpll_d4",    "mpll_d4",        0x7c,  1, 0),
+	GATE(ZX297520V3_LSP_MPLL_D6_WCLK,  "lsp_mpll_d6",    "mpll_d6",        0x7c,  2, 0),
+	GATE(ZX297520V3_LSP_MPLL_D8_WCLK,  "lsp_mpll_d8",    "mpll_d8",        0x7c,  3, 0),
+	GATE(ZX297520V3_LSP_MPLL_D12_WCLK, "lsp_mpll_d12",   "mpll_d12",       0x7c,  4, 0),
+	GATE(ZX297520V3_LSP_OSC26M_WCLK,   "lsp_osc26m",     clk_main[0],      0x7c,  5, 0),
+	GATE(ZX297520V3_LSP_OSC32K_WCLK,   "lsp_osc32k",     "osc32k",         0x7c,  6, 0),
+	GATE(ZX297520V3_LSP_PCLK,          "lsp_pclk",       clk_main[0],      0x7c,  7, 0),
+	GATE(ZX297520V3_LSP_TDM_WCLK,      "lsp_tdm_wclk",   "tdm_mux",        0x7c,  8, 0),
+	GATE(ZX297520V3_LSP_DPLL_D4_WCLK,  "lsp_dpll_d4",    "dpll_d4",        0x7c,  9, 0),
+};
+
+static const char * const zx297529v3_matrix_inputs[] = {
+	"osc26m", "osc32k",
+	"mpll", "mpll_d2", "mpll_d3", "mpll_d4", "mpll_d5", "mpll_d6", "mpll_d8", "mpll_d12",
+	"mpll_d16", "mpll_d26",
+	"upll", "upll_d2", "upll_d3", "upll_d4", "upll_d5", "upll_d6", "upll_d8", "upll_d12",
+	"upll_d16",
+	"dpll", "dpll_d2", "dpll_d3", "dpll_d4", "dpll_d5", "dpll_d6", "dpll_d8", "dpll_d12",
+	"dpll_d16",
+	"gpll", "gpll_d2", "gpll_d3", "gpll_d4", "gpll_d5", "gpll_d6", "gpll_d8", "gpll_d12",
+	"gpll_d16",
+};
+
+static const struct zx_clk_data zx297520v3_matrixclk_data = {
+	.inputs = zx297529v3_matrix_inputs,
+	.num_inputs = ARRAY_SIZE(zx297529v3_matrix_inputs),
+	.muxes = zx297520v3_matrix_muxes,
+	.num_muxes = ARRAY_SIZE(zx297520v3_matrix_muxes),
+	.gates = zx297520v3_matrix_gates,
+	.num_gates = ARRAY_SIZE(zx297520v3_matrix_gates),
+	.reset_auxdev_name = "zx297520v3_matrixrst"
+};
+
 static const struct of_device_id of_match_zx297520v3[] = {
 	{ .compatible = "zte,zx297520v3-topclk", .data = &zx297520v3_topclk_data },
+	{ .compatible = "zte,zx297520v3-matrixclk", .data = &zx297520v3_matrixclk_data },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, of_match_zx297520v3);

-- 
2.53.0