[PATCH RFC v4 09/12] clk: zte: Introduce a driver for zx297520v3 LSP clocks

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

"LSP" is ZTE's term for this part of the SoC, I suspect it stands for
"low speed peripherals". The main UART is here, together with the flash
controller and more surplus proprietary timers.

It also has two more I2C controllers that supposedly connect to a
battery charger, SPI for displays and I2S for analog telephones. The
boards I have don't have any of these components though.

Signed-off-by: Stefan Dösinger <stefandoesinger@gmail.com>
---
 drivers/clk/zte/clk-zx297520v3.c | 192 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 192 insertions(+)

diff --git a/drivers/clk/zte/clk-zx297520v3.c b/drivers/clk/zte/clk-zx297520v3.c
index d90aadf18026..26b05f2bf97a 100644
--- a/drivers/clk/zte/clk-zx297520v3.c
+++ b/drivers/clk/zte/clk-zx297520v3.c
@@ -581,9 +581,201 @@ static const struct zx_clk_data zx297520v3_matrixclk_data = {
 	.reset_auxdev_name = "zx297520v3_matrixrst"
 };
 
+/* LSP clock entries have a common pattern: Bit 0 for WCLK, Bit 1 for PCLK. Bit 4 (and sometimes
+ * more) for WCLK mux.
+ *
+ * Bit 8 and 9 are reset bits. I don't know the difference between the two, but they both need to be
+ * set to deassert the reset.
+ *
+ * Bits 15:12 can be a divisor, but not all clocks have it. Some clocks have a divisor in 19:16.
+ *
+ * The ID given in this table is the first register in the device's MMIO space. ZTE's drivers
+ * usually call this a version register, but it looks more like a device identifier.
+ *
+ * It looks like the registers map to devices like this:
+ *
+ * Timer reg	function	div	dev offset(lsp + xxxx)	ID
+ * 0x0: Read-only, probably device identifier			0x00752100
+ * 0x4:		timer_l1	Y	0x1000			0x02020000
+ * 0x8:		watchdog_l2	Y	0x2000			0x02020000
+ * 0xc:		watchdog_l3	Y	0x3000			0x02020000
+ * 0x10:	pwm		N	0x4000			0x01020000
+ * 0x14:	i2s0		Yh	0x5000			0x01030000
+ * 0x18:	always 0	-	-			-
+ * 0x1c:	i2s1		Yh	0x6000			0x01030000
+ * 0x20:	always 0	-	-			-
+ * 0x24:	qspi		N	0x7000			0x01040000
+ * 0x28:	uart1		N	0x8000			0x01060000
+ * 0x2c:	i2c1		N	0x9000			0x01020000
+ * 0x30:	spi0		Y	0xa000			0x01040000
+ * 0x34:	timer_lb	Y	0xb000			0x02020000
+ * 0x38:	timer_lc	Y	0xc000			0x02020000
+ * 0x3c:	uart2		N	0xd000			0x01060000
+ * 0x40:	watchdog_le	Y	0xe000			0x02020000
+ * 0x44:	timer_lf	Y	0xf000			0x02020000
+ * 0x48:	spi1		Y	0x10000			0x01040000
+ * 0x4c:	timer_l11	Y	0x11000			0x02020000
+ * 0x50:	tdm		Yh	0x12000			0x01040000
+ *
+ * Registers 0x58, 0x5c, 0x60, 0x64, 0x68 seem to contain more controls for i2s and tdm.
+ *
+ * I am not sure about the device at offset 0x4000 (clk reg 0x10). The ID matches that of i2c, but
+ * it has a larger register set. I suspect it is a PWM device, but I have not seen any ZTE kernel
+ * operate it - even devices with displays only use a GPIO to control the backlight.
+ */
+
+static const char * const timer_lsp_sel[] = {
+	"lsp_osc32k",
+	"lsp_osc26m",
+};
+
+static const char * const uart_lsp_sel[] = {
+	"lsp_osc26m",
+	"lsp_mpll_d6",
+};
+
+static const char * const i2s_lsp_sel[] = {
+	"lsp_osc26m",
+	"lsp_dpll_d4",
+	"lsp_mpll_d6",
+	/* Unknown */
+};
+
+static const char * const tdm_lsp_sel[] = {
+	"lsp_tdm_wclk",
+};
+
+static const char * const spi_lsp_sel[] = {
+	"lsp_osc26m",
+	"lsp_mpll_d4",
+	"lsp_mpll_d6",
+	/* Unknown */
+};
+
+static const char * const qspi_lsp_sel[] = {
+	"lsp_osc26m",
+	"lsp_mpll_d4",
+	"lsp_mpll_d5",
+	"lsp_mpll_d6",
+	"lsp_mpll_d8",
+	"lsp_mpll_d12",
+	"lsp_osc26m",
+	"lsp_osc26m",
+};
+
+static const struct zx_mux_desc zx297520v3_lsp_muxes[] = {
+	MUX(0,                             "timer_l1_mux",   timer_lsp_sel,    0x04,  4, 1),
+	MUX(0,                             "wdt_l2_mux",     timer_lsp_sel,    0x08,  4, 1),
+	MUX(0,                             "wdt_l3_mux",     timer_lsp_sel,    0x0c,  4, 1),
+	/* PWM: No mux bit can be set */
+	MUX(0,                             "i2s0_mux",       i2s_lsp_sel,      0x14,  4, 2),
+	/* 0x18: Always 0 */
+	MUX(0,                             "i2s1_mux",       i2s_lsp_sel,      0x1c,  4, 2),
+	/* 0x20: Always 0 */
+	MUX(0,                             "qspi_mux",       qspi_lsp_sel,     0x24,  4, 3),
+	MUX(0,                             "uart1_mux",      uart_lsp_sel,     0x28,  4, 1),
+	MUX(0,                             "i2c1_mux",       uart_lsp_sel,     0x2c,  4, 1),
+	MUX(0,                             "spi0_mux",       spi_lsp_sel,      0x30,  4, 2),
+	MUX(0,                             "timer_lb_mux",   timer_lsp_sel,    0x34,  4, 1),
+	MUX(0,                             "timer_lc_mux",   timer_lsp_sel,    0x38,  4, 1),
+	MUX(0,                             "uart2_mux",      uart_lsp_sel,     0x3c,  4, 1),
+	MUX(0,                             "wdt_le_mux",     timer_lsp_sel,    0x40,  4, 1),
+	MUX(0,                             "timer_lf_mux",   timer_lsp_sel,    0x44,  4, 1),
+	MUX(0,                             "spi1_mux",       spi_lsp_sel,      0x48,  4, 2),
+	MUX(0,                             "timer_l11_mux",  timer_lsp_sel,    0x4c,  4, 1),
+	/* TDM: No mux in LSP. Instead, it is in matrix with a separate clk line to LSP */
+};
+
+static const struct zx_div_desc zx297520v3_lsp_dividers[] = {
+	DIV(0,                             "timer_l1_div",   "timer_l1_mux",   0x04, 12, 4),
+	DIV(0,                             "wdt_l2_div",     "wdt_l2_mux",     0x08, 12, 4),
+	DIV(0,                             "wdt_l3_div",     "wdt_l3_mux",     0x0c, 12, 4),
+	/* PWM: No div */
+	DIV(0,                             "i2s0_div",       "i2s0_mux",       0x14, 16, 4),
+	/* 0x18: Always 0 */
+	DIV(0,                             "i2s1_div",       "i2s1_mux",       0x1c, 16, 4),
+	/* 0x20: Always 0 */
+	/* qspi, uart1, i2c1: No div */
+	DIV(0,                             "spi0_div",       "spi0_mux",       0x30, 12, 4),
+	DIV(0,                             "timer_lb_div",   "timer_lb_mux",   0x34, 12, 4),
+	DIV(0,                             "timer_lc_div",   "timer_lc_mux",   0x38, 12, 4),
+	/* uart2: No div */
+	DIV(0,                             "wdt_le_div",     "wdt_le_mux",     0x40, 12, 4),
+	DIV(0,                             "timer_lf_div",   "timer_lf_mux",   0x44, 12, 4),
+	DIV(0,                             "spi1_div",       "spi1_mux",       0x48, 12, 4),
+	DIV(0,                             "timer_l11_div",  "timer_l11_mux",  0x4c, 12, 4),
+	DIV(0,                             "tdm_div",        "lsp_tdm_wclk",   0x50, 16, 4),
+};
+
+static const struct zx_gate_desc zx297520v3_lsp_gates[] = {
+	GATE(ZX297520V3_TIMER_L1_WCLK,     "timer_l1_wclk",  "timer_l1_div",   0x04,  0, 0),
+	GATE(ZX297520V3_TIMER_L1_PCLK,     "timer_l1_pclk",  "lsp_pclk",       0x04,  1, 0),
+	GATE(ZX297520V3_WDT_L2_WCLK,       "wdt_l2_wclk",    "wdt_l2_div",     0x08,  0, 0),
+	GATE(ZX297520V3_WDT_L2_PCLK,       "wdt_l2_pclk",    "lsp_pclk",       0x08,  1, 0),
+	GATE(ZX297520V3_WDT_L3_WCLK,       "wdt_l3_wclk",    "wdt_l3_div",     0x0c,  0, 0),
+	GATE(ZX297520V3_WDT_L3_PCLK,       "wdt_l3_pclk",    "lsp_pclk",       0x0c,  1, 0),
+	/* I don't know the LSP parent. It must be one of the LSP inputs though. */
+	GATE(ZX297520V3_PWM_WCLK,          "pwm_wclk",       "lsp_osc26m",     0x10,  0, 0),
+	GATE(ZX297520V3_PWM_PCLK,          "pwm_pclk",       "lsp_pclk",       0x10,  1, 0),
+	GATE(ZX297520V3_I2S0_WCLK,         "i2s0_wclk",      "i2s0_div",       0x14,  0, 0),
+	GATE(ZX297520V3_I2S0_PCLK,         "i2s0_pclk",      "lsp_pclk",       0x14,  1, 0),
+	/* 0x1c: Always 0 */
+	GATE(ZX297520V3_I2S1_WCLK,         "i2s1_wclk",      "i2s1_div",       0x1c,  0, 0),
+	GATE(ZX297520V3_I2S1_PCLK,         "i2s1_pclk",      "lsp_pclk",       0x1c,  1, 0),
+	/* 0x20: Always 0 */
+	GATE(ZX297520V3_QSPI_WCLK,         "qspi_wclk",      "qspi_mux",       0x24,  0, 0),
+	GATE(ZX297520V3_QSPI_PCLK,         "qspi_pclk",      "lsp_pclk",       0x24,  1, 0),
+	GATE(ZX297520V3_UART1_WCLK,        "uart1_wclk",     "uart1_mux",      0x28,  0, 0),
+	GATE(ZX297520V3_UART1_PCLK,        "uart1_pclk",     "lsp_pclk",       0x28,  1, 0),
+	GATE(ZX297520V3_I2C1_WCLK,         "i2c1_wclk",      "i2c1_mux",       0x2c,  0, 0),
+	GATE(ZX297520V3_I2C1_PCLK,         "i2c1_pclk",      "lsp_pclk",       0x2c,  1, 0),
+	GATE(ZX297520V3_SPI0_WCLK,         "spi0_wclk",      "spi0_div",       0x30,  0, 0),
+	GATE(ZX297520V3_SPI0_PCLK,         "spi0_pclk",      "lsp_pclk",       0x30,  1, 0),
+	GATE(ZX297520V3_TIMER_LB_WCLK,     "timer_lb_wclk",  "timer_lb_div",   0x34,  0, 0),
+	GATE(ZX297520V3_TIMER_LB_PCLK,     "timer_lb_pclk",  "lsp_pclk",       0x34,  1, 0),
+	GATE(ZX297520V3_TIMER_LC_WCLK,     "timer_lc_wclk",  "timer_lc_div",   0x38,  0, 0),
+	GATE(ZX297520V3_TIMER_LC_PCLK,     "timer_lc_pclk",  "lsp_pclk",       0x38,  1, 0),
+	GATE(ZX297520V3_UART2_WCLK,        "uart2_wclk",     "uart2_mux",      0x3c,  0, 0),
+	GATE(ZX297520V3_UART2_PCLK,        "uart2_pclk",     "lsp_pclk",       0x3c,  1, 0),
+	GATE(ZX297520V3_WDT_LE_WCLK,       "wdt_le_wclk",    "wdt_le_div",     0x40,  0, 0),
+	GATE(ZX297520V3_WDT_LE_PCLK,       "wdt_le_pclk",    "lsp_pclk",       0x40,  1, 0),
+	GATE(ZX297520V3_TIMER_LF_WCLK,     "timer_lf_wclk",  "timer_lf_div",   0x44,  0, 0),
+	GATE(ZX297520V3_TIMER_LF_PCLK,     "timer_lf_pclk",  "lsp_pclk",       0x44,  1, 0),
+	GATE(ZX297520V3_SPI1_WCLK,         "spi1_wclk",      "spi1_div",       0x48,  0, 0),
+	GATE(ZX297520V3_SPI1_PCLK,         "spi1_pclk",      "lsp_pclk",       0x48,  1, 0),
+	GATE(ZX297520V3_TIMER_L11_WCLK,    "timer_l11_wclk", "timer_l11_div",  0x4c,  0, 0),
+	GATE(ZX297520V3_TIMER_L11_PCLK,    "timer_l11_pclk", "lsp_pclk",       0x4c,  1, 0),
+	GATE(ZX297520V3_TDM_WCLK,          "tdm_wclk",       "tdm_div",        0x50,  0, 0),
+	GATE(ZX297520V3_TDM_PCLK,          "tdm_pclk",       "lsp_pclk",       0x50,  1, 0),
+};
+
+static const char * const zx297529v3_lsp_inputs[] = {
+	"mpll_d5", "mpll_d4", "mpll_d6", "mpll_d8", "mpll_d12",
+	"osc26m", "osc32k", "tdm_wclk", "dpll_d4"
+};
+
+static const char * const zx297529v3_lsp_inputs_enable[] = {
+	"pclk"
+};
+
+static const struct zx_clk_data zx297520v3_lspclk_data = {
+	.inputs_enable = zx297529v3_lsp_inputs_enable,
+	.num_inputs_enable = ARRAY_SIZE(zx297529v3_lsp_inputs_enable),
+	.inputs = zx297529v3_lsp_inputs,
+	.num_inputs = ARRAY_SIZE(zx297529v3_lsp_inputs),
+	.muxes = zx297520v3_lsp_muxes,
+	.num_muxes = ARRAY_SIZE(zx297520v3_lsp_muxes),
+	.divs = zx297520v3_lsp_dividers,
+	.num_divs = ARRAY_SIZE(zx297520v3_lsp_dividers),
+	.gates = zx297520v3_lsp_gates,
+	.num_gates = ARRAY_SIZE(zx297520v3_lsp_gates),
+	.reset_auxdev_name = "zx297520v3_lsprst"
+};
+
 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 },
+	{ .compatible = "zte,zx297520v3-lspclk", .data = &zx297520v3_lspclk_data },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, of_match_zx297520v3);

-- 
2.53.0