clk: add si5351 i2c common clock driver

This patch adds a common clock driver for Silicon Labs Si5351a/b/c
i2c programmable clock generators. Currently, the driver does not
support VXCO feature of si5351b. Passing platform_data or DT bindings
selectively allows to overwrite stored Si5351 configuration which is
very helpful for clock generators with empty eeprom configuration.
Corresponding device tree binding documentation is also added.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Tested-by: Daniel Mack <zonque@gmail.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Michal Bachraty <michal.bachraty@streamunlimited.com>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

1 files changed, 114 insertions, 0 deletions

diff --git a/include/linux/platform_data/si5351.h b/include/linux/platform_data/si5351.h
new file mode 100644
index 00000000000..92dabcaf649
--- /dev/null
+++ b/include/linux/platform_data/si5351.h
@@ -0,0 +1,114 @@
+/*
+ * Si5351A/B/C programmable clock generator platform_data.
+ */
+
+#ifndef __LINUX_PLATFORM_DATA_SI5351_H__
+#define __LINUX_PLATFORM_DATA_SI5351_H__
+
+struct clk;
+
+/**
+ * enum si5351_variant - SiLabs Si5351 chip variant
+ * @SI5351_VARIANT_A: Si5351A (8 output clocks, XTAL input)
+ * @SI5351_VARIANT_A3: Si5351A MSOP10 (3 output clocks, XTAL input)
+ * @SI5351_VARIANT_B: Si5351B (8 output clocks, XTAL/VXCO input)
+ * @SI5351_VARIANT_C: Si5351C (8 output clocks, XTAL/CLKIN input)
+ */
+enum si5351_variant {
+	SI5351_VARIANT_A = 1,
+	SI5351_VARIANT_A3 = 2,
+	SI5351_VARIANT_B = 3,
+	SI5351_VARIANT_C = 4,
+};
+
+/**
+ * enum si5351_pll_src - Si5351 pll clock source
+ * @SI5351_PLL_SRC_DEFAULT: default, do not change eeprom config
+ * @SI5351_PLL_SRC_XTAL: pll source clock is XTAL input
+ * @SI5351_PLL_SRC_CLKIN: pll source clock is CLKIN input (Si5351C only)
+ */
+enum si5351_pll_src {
+	SI5351_PLL_SRC_DEFAULT = 0,
+	SI5351_PLL_SRC_XTAL = 1,
+	SI5351_PLL_SRC_CLKIN = 2,
+};
+
+/**
+ * enum si5351_multisynth_src - Si5351 multisynth clock source
+ * @SI5351_MULTISYNTH_SRC_DEFAULT: default, do not change eeprom config
+ * @SI5351_MULTISYNTH_SRC_VCO0: multisynth source clock is VCO0
+ * @SI5351_MULTISYNTH_SRC_VCO1: multisynth source clock is VCO1/VXCO
+ */
+enum si5351_multisynth_src {
+	SI5351_MULTISYNTH_SRC_DEFAULT = 0,
+	SI5351_MULTISYNTH_SRC_VCO0 = 1,
+	SI5351_MULTISYNTH_SRC_VCO1 = 2,
+};
+
+/**
+ * enum si5351_clkout_src - Si5351 clock output clock source
+ * @SI5351_CLKOUT_SRC_DEFAULT: default, do not change eeprom config
+ * @SI5351_CLKOUT_SRC_MSYNTH_N: clkout N source clock is multisynth N
+ * @SI5351_CLKOUT_SRC_MSYNTH_0_4: clkout N source clock is multisynth 0 (N<4)
+ *                                or 4 (N>=4)
+ * @SI5351_CLKOUT_SRC_XTAL: clkout N source clock is XTAL
+ * @SI5351_CLKOUT_SRC_CLKIN: clkout N source clock is CLKIN (Si5351C only)
+ */
+enum si5351_clkout_src {
+	SI5351_CLKOUT_SRC_DEFAULT = 0,
+	SI5351_CLKOUT_SRC_MSYNTH_N = 1,
+	SI5351_CLKOUT_SRC_MSYNTH_0_4 = 2,
+	SI5351_CLKOUT_SRC_XTAL = 3,
+	SI5351_CLKOUT_SRC_CLKIN = 4,
+};
+
+/**
+ * enum si5351_drive_strength - Si5351 clock output drive strength
+ * @SI5351_DRIVE_DEFAULT: default, do not change eeprom config
+ * @SI5351_DRIVE_2MA: 2mA clock output drive strength
+ * @SI5351_DRIVE_4MA: 4mA clock output drive strength
+ * @SI5351_DRIVE_6MA: 6mA clock output drive strength
+ * @SI5351_DRIVE_8MA: 8mA clock output drive strength
+ */
+enum si5351_drive_strength {
+	SI5351_DRIVE_DEFAULT = 0,
+	SI5351_DRIVE_2MA = 2,
+	SI5351_DRIVE_4MA = 4,
+	SI5351_DRIVE_6MA = 6,
+	SI5351_DRIVE_8MA = 8,
+};
+
+/**
+ * struct si5351_clkout_config - Si5351 clock output configuration
+ * @clkout: clkout number
+ * @multisynth_src: multisynth source clock
+ * @clkout_src: clkout source clock
+ * @pll_master: if true, clkout can also change pll rate
+ * @drive: output drive strength
+ * @rate: initial clkout rate, or default if 0
+ */
+struct si5351_clkout_config {
+	enum si5351_multisynth_src multisynth_src;
+	enum si5351_clkout_src clkout_src;
+	enum si5351_drive_strength drive;
+	bool pll_master;
+	unsigned long rate;
+};
+
+/**
+ * struct si5351_platform_data - Platform data for the Si5351 clock driver
+ * @variant: Si5351 chip variant
+ * @clk_xtal: xtal input clock
+ * @clk_clkin: clkin input clock
+ * @pll_src: array of pll source clock setting
+ * @clkout: array of clkout configuration
+ */
+struct si5351_platform_data {
+	enum si5351_variant variant;
+	struct clk *clk_xtal;
+	struct clk *clk_clkin;
+	enum si5351_pll_src pll_src[2];
+	struct si5351_clkout_config clkout[8];
+};
+
+#endif